Monday, August 27, 2012
Isaac soon to become a hurricane
Isaac will become a hurricane later today as he turns towards the central Gulf Coast. Right now the official forecast takes Isaac into southeastern Louisiana early Wednesday morning as a strong category 1 or minimal category 2 storm. From here Isaac will continue northwest into northern Louisiana near Monroe by Thursday night. The slow movement of Isaac will cause flooding problems along his path as up to 6 to 8 inches of rain could fall. Right now the official track keeps Isaac well enough off to our east where we would see very little in the way of rainfall. It does appear our winds would increase however beginning Wednesday as the difference of pressure between Isaac and a high pressure to our north will cause gusty north northeasterly winds, as high as 30MPH. There would also be a slight chance of a few wrap around showers and thunderstorms, especially Thursday based on the current track. There are still a couple of forecast models that want to bring Isaac right over East Texas. If this were to happen the track of heavy rain would move right across our area with wide spread amounts over 4 inches likely. This scenario appears unlikely at this time but bears watching due to the fact we could use the rain. It appears there will be one way Isaac will affect East Texas even if the path is well off to our east, in the wallet. Anytime a tropical system moves across this area of the Gulf oil prices seem to rise. So if you have the means, be sure to top off the gas tank today as prices will probably begin to rise latter today and tomorrow morning. Hurricane Katrina and Rita took a similar path and caused a huge spike in gas prices. Of course Isaac does not appear to be become near the strength of those storms but it will still be strong enough to cause pressure on the Gulf Coast oil industry.
Thursday, May 17, 2012
East Texas Earthquake History
Update. May 17th Earthquake was revised to a 4.8!
At 3:12AM this morning the Earth shook to the magnitude of 4.3 on the Richter Scale as the second earthquake to hit East Texas this month gave a rude awaking to many this morning. Although not unheard of, earthquakes across East Texas are very rare. It has been over 30 years since the last earthquake over 3.0 on the Richter scale hit east Texas which occurred in Jacksonville in November of 1981. When we think of earthquakes we normally associate California or any other western state where much of the country’s strongest earthquakes have occurred. But earthquakes occur all over the United States and even here in East Texas. Since 1850 there have now been 11 earthquakes reported in East Texas with a magnitude of 3.0 or greater on the Richter Scale. So let’s take a look at when, where, and why these quakes occurred. The first major earthquake to affect East Texas was probably the great Madrid Fault quake of 1811 in the Boot Heel of Missouri and measured 8.1 on the Richter Scale. This quake caused damage as far away as Boston, MA so I have a hard time believing East Texas did not feel the effects from this quake. However, this first recorded earthquake greater than 3.0 to hit East Texas occurred on January 9th 1891 in Rusk. This quake measured 4.0 on the Richter Scale and reportedly caused significant damage in a few areas. However, there was also a strong tornado that moved across the area that evening and much of the damage reported was probably from weather and not the Earthquake. The next earthquake to affect East Texas was also the strongest recorded in the area, a 4.7 magnitude quake on March 19th 1957 northeast of Diana. A few windows were broken and much of northeast Texas felt this quake. For the next seven years the seismic activity across East Texas was quite until April of 1964 when the most active seismic activity hit East Texas. On April 23rd the first quake struck in the southeastern part of Texas near Hemphill and would be the first of eight earthquakes to hit the area over the next few months. In April there were quakes on the 23rd, 24th, 27th, and 28th, with the one on the 28th measuring 4.4 on the Richter Scale. The quakes between the 23rd and 27th all measured between 3.4 and 3.7 on the Richter Scale. There were two smaller quakes on April 30th and May 7th followed by a 4.2 magnitude quake on June 2nd. The last earthquake in East Texas that year occurred on August 16th and was minor. The next series of earthquakes did not hit East Texas until 1981 when on June 9th a 3.2 magnitude quake hit Center, fairly close to where today’s quake hit. The next quake that year hit on November 6th I Jacksonville registering 3.3 on the Richter Scale. The last two known earthquakes in East Texas to be a magnitude of 3.0 or higher of course have occurred this month, a 3.9 on the 10th and a 4.3 today. Today’s quake has caused some damage in the Timpson area and even one injury but thankfully nothing too extreme. When you look at the fault lines across the country you will notice there are literally hundreds that run northwest to southeast across East Texas. That fault lines are classified here as “Class B” faults meaning there is very little seismic activity. It is also interesting to note that studies have suggested that much of the seismic activity along these faults could have been artificially created due to the extraction of oil. I by no means am an expert on this subject but have taking a few geology and geography classes while studying meteorology and find the subject interesting. All the information above in this article came from doing some research this morning on the USGS website. Based on the information I have learned today I would not be surprised to see one or two more quakes before the fault settles down again. Thankfully major damage rarely occurs from earthquakes under 6.0 here in the United States with our stronger building codes and the type of faults across East Texas have yet to produce that strong of an earthquake.
At 3:12AM this morning the Earth shook to the magnitude of 4.3 on the Richter Scale as the second earthquake to hit East Texas this month gave a rude awaking to many this morning. Although not unheard of, earthquakes across East Texas are very rare. It has been over 30 years since the last earthquake over 3.0 on the Richter scale hit east Texas which occurred in Jacksonville in November of 1981. When we think of earthquakes we normally associate California or any other western state where much of the country’s strongest earthquakes have occurred. But earthquakes occur all over the United States and even here in East Texas. Since 1850 there have now been 11 earthquakes reported in East Texas with a magnitude of 3.0 or greater on the Richter Scale. So let’s take a look at when, where, and why these quakes occurred. The first major earthquake to affect East Texas was probably the great Madrid Fault quake of 1811 in the Boot Heel of Missouri and measured 8.1 on the Richter Scale. This quake caused damage as far away as Boston, MA so I have a hard time believing East Texas did not feel the effects from this quake. However, this first recorded earthquake greater than 3.0 to hit East Texas occurred on January 9th 1891 in Rusk. This quake measured 4.0 on the Richter Scale and reportedly caused significant damage in a few areas. However, there was also a strong tornado that moved across the area that evening and much of the damage reported was probably from weather and not the Earthquake. The next earthquake to affect East Texas was also the strongest recorded in the area, a 4.7 magnitude quake on March 19th 1957 northeast of Diana. A few windows were broken and much of northeast Texas felt this quake. For the next seven years the seismic activity across East Texas was quite until April of 1964 when the most active seismic activity hit East Texas. On April 23rd the first quake struck in the southeastern part of Texas near Hemphill and would be the first of eight earthquakes to hit the area over the next few months. In April there were quakes on the 23rd, 24th, 27th, and 28th, with the one on the 28th measuring 4.4 on the Richter Scale. The quakes between the 23rd and 27th all measured between 3.4 and 3.7 on the Richter Scale. There were two smaller quakes on April 30th and May 7th followed by a 4.2 magnitude quake on June 2nd. The last earthquake in East Texas that year occurred on August 16th and was minor. The next series of earthquakes did not hit East Texas until 1981 when on June 9th a 3.2 magnitude quake hit Center, fairly close to where today’s quake hit. The next quake that year hit on November 6th I Jacksonville registering 3.3 on the Richter Scale. The last two known earthquakes in East Texas to be a magnitude of 3.0 or higher of course have occurred this month, a 3.9 on the 10th and a 4.3 today. Today’s quake has caused some damage in the Timpson area and even one injury but thankfully nothing too extreme. When you look at the fault lines across the country you will notice there are literally hundreds that run northwest to southeast across East Texas. That fault lines are classified here as “Class B” faults meaning there is very little seismic activity. It is also interesting to note that studies have suggested that much of the seismic activity along these faults could have been artificially created due to the extraction of oil. I by no means am an expert on this subject but have taking a few geology and geography classes while studying meteorology and find the subject interesting. All the information above in this article came from doing some research this morning on the USGS website. Based on the information I have learned today I would not be surprised to see one or two more quakes before the fault settles down again. Thankfully major damage rarely occurs from earthquakes under 6.0 here in the United States with our stronger building codes and the type of faults across East Texas have yet to produce that strong of an earthquake.
Friday, April 6, 2012
4/3/2012 Sulphur Springs, TX Tornado
Tuesday was a very active weather day across North and East Texas with numerous severe thunderstorms and tornadoes. I went chasing and caught a storm developing over Rains County. By the time we reached Sulphur Springs a tornado warning was issued for strong rotation south of the city. What surprised us was on the back side of the supercell, to the northwest of the radar indicated tornado, we started to notice rapid rotation to our north moving towards Sulphur Springs. The video below shows what we saw.
Now the image below shows the approximate area where the tornado in this video was shot. I know I mentioned I did not see any power flashes in the video but after watching the video closely, it appears there were two power flashes. One around 10 seconds in behind the funnel and another at 16 seconds ahead of the funnel.
Now the image below is a photo showing the funnel the the east of Sulphur Springs. At this time we did not notice any power flashes and thanks to the tree line it is hard to tell if it is on the ground.
The next image shows the velocity data and where the approximate location of the funnel. It looks as though the radar is starting to show a new area of converging rotation forming where the photo was taken.
As we continued to follow the storm, rotation was easily seen with every once in a while a thin funnel appearing to touch down. The next image shows the biggest funnel that did touchdown just on the south side of I30 knocking down at least one tree.
The image below show much stronger converging rotation near the location of the image above.
It should be noted that this storm was around 95 miles away from the Ft. Worth Doppler Radar with the lowest tilt hitting the storm just above 11,000' in elevation. So there is no way of knowing what the lowest levels of the storm looked like on radar as the video and photos were shot. Based on what we saw it looks as though Sulphur Springs got pretty lucky as what could have been a tornado going through town either stayed just off the ground or dissipated right before hitting town.
Now the image below shows the approximate area where the tornado in this video was shot. I know I mentioned I did not see any power flashes in the video but after watching the video closely, it appears there were two power flashes. One around 10 seconds in behind the funnel and another at 16 seconds ahead of the funnel.
Now the image below is a photo showing the funnel the the east of Sulphur Springs. At this time we did not notice any power flashes and thanks to the tree line it is hard to tell if it is on the ground.
The next image shows the velocity data and where the approximate location of the funnel. It looks as though the radar is starting to show a new area of converging rotation forming where the photo was taken.
As we continued to follow the storm, rotation was easily seen with every once in a while a thin funnel appearing to touch down. The next image shows the biggest funnel that did touchdown just on the south side of I30 knocking down at least one tree.
The image below show much stronger converging rotation near the location of the image above.
It should be noted that this storm was around 95 miles away from the Ft. Worth Doppler Radar with the lowest tilt hitting the storm just above 11,000' in elevation. So there is no way of knowing what the lowest levels of the storm looked like on radar as the video and photos were shot. Based on what we saw it looks as though Sulphur Springs got pretty lucky as what could have been a tornado going through town either stayed just off the ground or dissipated right before hitting town.
Friday, March 30, 2012
Severe Storms Possible Northwest of Dallas
There is a conditional chance of severe storms across parts of North Texas and Southern Oklahoma this afternoon. Forecast sounding near Wichita Falls show showing an extreme amount of instability that could lead to explosive thunderstorm development later this afternoon. The one ingredient lacking to prevent this from being a major severe weather outbreak is forcing to give lift to surface parcels which would in turn cause the storms to develop.
A dryline will be advancing eastward across northwest Texas later this afternoon. This could provide enough forcing to allow one or two isolated storms to develop, especially near the intersection of the thermal axis and moisture axis.
We can also see that surface moisture is forecast to be converging along the dryline which give added belief in the threat of thunderstorms development.
Now all of the area is under extreme instability with LIs running between -11 and -14 across all of north Texas and southern Oklahoma.
Over the same area however, there is a small cap. The lid strength index is positive over most of the area, greater than 0°. Usually a lid strength index less than 2° shows there is a chance the cap will break and allow scattered storms to develop. However, with the extreme lack in forcing the cap could very well win out today. There is forecast to be a small upper level disturbance move across this region later this afternoon. This could be just enough lift to take advantage of the extreme instability available.
Many times a weakness in the cap develops near the nose of the low level lapse rate axis. If this occurs today isolated storms could develop very close to Wichita Falls later this afternoon.
If storms do develop they will do so in an environment that is not only conducive for very large hail, overall high instability, but they could also produce an isolated tornado. The amount of 0-3km CAPE is approaching 200 J/kg in a few areas which will provide plenty of stretching potential of Strom Relative Helicity which could lead to tornadogenesis.
There does appear to be just enough low level storm relative helicity to introduce a tornado threat as well. So the next few hours will determine what if any storm can develop and whether or not I will be making the four hour drive to see what Mother Nature has to offer.
Wednesday, March 21, 2012
Cold Core Chase Today
All the ingredients are coming together for a cold core set up mini supercell event.The image above shows the surface features in conjunction with the 500mb low pressure. Looks to be a near classic cold core set up. Highlighted area shows where the best combination of parameters come together for supercell development.
Tuesday, March 20, 2012
Cold Core Set Up Tomorrow?
A cut off upper level low pressure could give parts of Texas a surprise severe weather event. High resolution models are trending towards a "Cold Core" set up where low topped mini super cells could develop tomorrow producing small hail, gusty winds, and possibly a tornado or two. Right now the Storm Prediction Center does not have this area under a risk of severe weather. These types of events usually don't materialize until all the mesoscale features come together so we really won't know what will happen until the set up begins to take shape tomorrow afternoon. Looking at the image above, the amount of surface based CAPE is nothing to get excited about. Nowhere do we find CAPE at or above 1000 J/kg.
However, the image above here shows 0-3km CAPE approaching 200 J/kg, which is large enough for rapid low level convection needed to generate storms.
When we look at a forecast sounding just south of Forth Worth we can see the majority of the CAPE is located in the lower levels of the atmosphere. In fact, the LIs are positive because all of the energy is located below the 500mb level. In addition, the wind shown on the hodograph turn drastically with height, in the levels where the CAPE is located. This is producing effective bulk shear on the order of 35 to 40 knots. So with enough forcing we could see a few storms develop and in this environment they would likely be low topped super cells. The sounding above shows the maximum parcel level to be around 28,000', not very impressive when you think of severe weather. Even though the CAPE is small, the majority is in areas below freezing thanks too the cold air aloft. So small hail would be likely.
The above image is a crude surface drawing showing you where surface features are forecast to be during peak heating in conjunction with the 500mb low. The forcing associated with this low should be enough for scattered storms to develop.
In the final image above, the high resolution WRF model is breaking out an arc of scattered cells around the forcing associated with the 500mb low. If this does occur in the environment the forecast sounding predicts, these will more than likely be low topped super cells. The tornado threat looks very low thanks to the fairly high cloud base the NAM is predicting. However, the LCL is as low as 915m on the sounding above which could lead to an isolated tornado if the surface environment sets up the way it is forecast by the NAM. Right now I look for the SPC to have a 5% chance of hail tomorrow across North Texas with no tornado threat during their first outlook. Once the surface features tomorrow afternoon are known, a 2% tornado risk may be introduced.
So What Happened With Yesterday’s Tornado Threat?
Yesterday much of East Texas was under a moderate risk of severe weather including a 10% chance of tornadoes, which is an elevated risk for tornadoes. We had strong southeasterly winds at the surface with strong westerly winds aloft giving East Texas a significant amount of shear and spin to the atmosphere. All that was missing was the energy to lift the air for convective initiation. If you remember from yesterday’s forecast sounding models were painting a pretty scary picture across East Texas. Temperatures were forecast to reach close to 80 degrees with dewpoints in the middle 60s. This provided a forecast Surface CAPE over 2500 J/kg.
With a little extra sunshine, drier air mixed down to the surface producing dewpoint about 5 degrees cooler than forecast. As you can see if we modify the forecast sounding with the actual dewpoints, the CAPE nearly disappears and the lower levels of the profile experience Convective Inhibition, or a cap.
So with the new cap in place any updraft that tried to originate was quickly forced down to the surface keeping thunderstorms from developing. Many times when everything points to a significant severe weather event, an unforeseen event puts the brakes on severe thunderstorm development.
With a little extra sunshine, drier air mixed down to the surface producing dewpoint about 5 degrees cooler than forecast. As you can see if we modify the forecast sounding with the actual dewpoints, the CAPE nearly disappears and the lower levels of the profile experience Convective Inhibition, or a cap.
So with the new cap in place any updraft that tried to originate was quickly forced down to the surface keeping thunderstorms from developing. Many times when everything points to a significant severe weather event, an unforeseen event puts the brakes on severe thunderstorm development.
Monday, March 19, 2012
A Moderate Risk for Severe Storms Including Tornadoes Today
There is a moderate risk of severe thunderstorms across East Texas today including the threat of tornadoes. A very warm and moist air mass has set up across East Texas thanks to 7 days of a southeasterly flow off the Gulf of Mexico. Dew point temperatures are forecast to peak in the lower 70s ahead of a developing line of thunderstorms. The image below shows most of East Texas covered in yellow meaning dewpoints will be at least 65 degrees providing plenty of energy for thunderstorm development.
The latest High Resolution Rapid Refresh model breaks out a broken line of thunderstorms later this afternoon heading towards East Texas. This will be the first round of at least three lines of storms that develop.
The 0-6KM shear available across East Texas is more than enough for the storms that develop to become supercellular. Shear values will be approaching 50 to 60 knots across the area allowing mid level rotation to form with any storm that develops.
As these rotating thunderstorms move into East Texas they will be encountering low level helicity levels that are conducive for low level rotation which could lead to tornadogenesis. The image below shows areas of light green and yellow out ahead of the storms show low level helicity between 200 and 300 m^2/s^2.
The environment also shows large hail to be very possible across East Texas this afternoon and evening. The forecast soundings for both Forth Worth and Shreveport show large amounts of CAPE in the hail growth region. With the high shear levels, ice particles we be in the hail growth region longer making golfball to baseball size hail possible with the strongest storms.
One thing you will notice is the winds are more favorable for tornadoes the farther east you go. The good news is the farther east the storms move, the less forcing they will encounter so they may begin to weaken just a bit.
It does appear after the first round of storms moves through, more storms will develop throughout the night and into tomorrow morning. Before the rain ends Wednesday much of East Texas will receive between 3 and 6 inches of rain with a few areas picking up over 8 inches of rain.
Thursday, March 8, 2012
Strong Storms and Heavy Rain Likely Today
A strong cold front was moving south across the Southern Plains this morning and will be moving into our northern counties later this afternoon pushing all the way through East Texas by Friday morning. Out ahead of this front showers and an occasional thundershower will develop this morning into the early afternoon hours.
By late afternoon as the front moves into the I-20 corridor during peak afternoon heating, there will be a chance of a severe storm or two. Right now the overall severe threat does not appear that great but the strongest storms will be capable of producing wind gusts to 60 mph and hail up to the size of quarters. The tornado threat appears to be fairly low today as most of the stronger storms will develop right along the cold front which will make the storms slightly elevated, thus not allowing them to ingest the surface air needed to produce tornadoes. However, if an isolated strong storm or two develops out ahead of the cold front, a tornado threat could develop briefly this afternoon.
Once the front moves through the threat of rain and thunderstorms will not end any time soon. An area of low pressure in the mid and upper levels of the atmosphere will keep southerly winds just off the surface forcing warm moist air to move over much cooler air at the surface as highs will struggle to reach the middle 50s. This will provide the perfect situation for an over running precipitation event starting tonight and lasting through most of Friday. Forecasts show an average of 1 to 3 inches of rain occurring with this event before ending late Friday.
Another disturbance will move to our north on Saturday providing the same type of over running precipitation event once again. This event will last through Saturday evening before a warm front is pushed north across the area Sunday morning. This will not shut of the rain either. An area of low pressure at the surface will surge north from the Gulf Coast into the Ozarks on Sunday. This will give East Texas another chance of showers and storms. Before all is said and done early Monday morning, much of East Texas could see at least 5 inches of rain with some local areas receiving up to 8 inches.
Tuesday, February 28, 2012
Severe Threat Very Small Today
Yesterday I showed you the conditions coming together for a conditional threat of severe weather across East Texas. Today after looking at the latest data it appears the EML (elevated mixed layer) or cap will be to strong across East Texas for thunderstorm development. All the other conditions I mentioned in yesterday’s write up are still coming together so if A storm were able to develop, it would likely become severe rapidly producing large hail, gusty winds, and tornadoes. But that just doesn’t appear likely.
When we take a look at the forecast sounding for this afternoon we notice a very large area of CIN (convective inhibition). This is a large amount of negative energy (blue shaded region), or sinking air, that would not allow upward motion of air parcels allowing for thunderstorm growth.
Now yesterday I mentioned this as well and was concerned what would happen if we saw a few more breaks in the clouds allowing for warmer afternoon temperatures, like we saw yesterday. Well when the forecast sounding is modified for a surface temperature around 76°F it looks a lot more conducive for thunderstorm development. Notice the area of CIN (blue shaded area) is much smaller than the actual forecast. Also the amount of CAPE, or buoyant energy (yellow shaded area), is much greater. This could allow for explosive thunderstorm development if we see surface temperatures warm into the upper 70s this afternoon.
Again in theory severe weather is possible this afternoon based on forecast soundings. That is why looking at the actual sounding is so important. So this morning I wanted to see what was happening downstream from East Texas because this air mass will be over us later today. By looking at the actual sounding from Del Rio area we can see the EML is very strong with a temperature of 15°C at 800mb. We you modify the forecast sounding for that 800mb temperatures the convective temperature, or the temperatures at where air rises freely allowing thunderstorms to develop, is well into the 80s which we will not see today. So based on all the information I see right now East Texas appears to be safe from severe weather this afternoon. We will see a line of showers and storms move in overnight but by that time the dynamics for severe weather and tornadoes will be off to our north and east. But if the temperatures are able to reach the upper 70s to near 80, there could be an isolated severe storm late today but right now that does not seem very likely at all.
When we take a look at the forecast sounding for this afternoon we notice a very large area of CIN (convective inhibition). This is a large amount of negative energy (blue shaded region), or sinking air, that would not allow upward motion of air parcels allowing for thunderstorm growth. 
Now yesterday I mentioned this as well and was concerned what would happen if we saw a few more breaks in the clouds allowing for warmer afternoon temperatures, like we saw yesterday. Well when the forecast sounding is modified for a surface temperature around 76°F it looks a lot more conducive for thunderstorm development. Notice the area of CIN (blue shaded area) is much smaller than the actual forecast. Also the amount of CAPE, or buoyant energy (yellow shaded area), is much greater. This could allow for explosive thunderstorm development if we see surface temperatures warm into the upper 70s this afternoon.
Again in theory severe weather is possible this afternoon based on forecast soundings. That is why looking at the actual sounding is so important. So this morning I wanted to see what was happening downstream from East Texas because this air mass will be over us later today. By looking at the actual sounding from Del Rio area we can see the EML is very strong with a temperature of 15°C at 800mb. We you modify the forecast sounding for that 800mb temperatures the convective temperature, or the temperatures at where air rises freely allowing thunderstorms to develop, is well into the 80s which we will not see today. So based on all the information I see right now East Texas appears to be safe from severe weather this afternoon. We will see a line of showers and storms move in overnight but by that time the dynamics for severe weather and tornadoes will be off to our north and east. But if the temperatures are able to reach the upper 70s to near 80, there could be an isolated severe storm late today but right now that does not seem very likely at all.
Monday, February 27, 2012
Conditional Severe Weather Threat Tuesday
A strong area of low pressure at the surface will develop in western Kansas tomorrow afternoon and race off to the northeast into south central Nebraska during the evening hours. As this system develops strong southerly winds will bring warm moist air into East Texas which could set the stage for strong to severe thunderstorms late Tuesday into Wednesday morning. Instability is forecast to be marginal for severe storms but with a little more sunshine than predicted, things could get much worse.
Right now forecast models are indicating Mean Layer CAPE values to be at or slightly above 1000 J/kg. This is basically the beginning threshold for the possibility of severe thunderstorms. This will provide enough energy to accelerate surface air upward causing clouds, and eventually thunderstorms to develop.
Now that we see there is just enough energy to produce severe convection we need to see what is happening to the air as it rises to predict what kind of storm will develop. For supercell thunderstorms to develop we usually like to see effective shear, or the amount of shear the entire updraft will encounter, to be greater than 40 knots. Tomorrow afternoon much of East Texas is seeing effective shear greater than 70 knots. Now usually this would set off an alarm in my head but with the MLCAPE only being around 1000 J/kg, many of the updrafts will actually be sheared apart before a storm can develop. More on this later. So if a storm develops it would become a supercell.
The amount of storm relative helicity or the amount of spin available for the lower levels of the storm to ingest, are also showing high enough levels to produce low level storm rotation. We usually look for values at or higher than 200 and much of East Texas tomorrow afternoon is above 300. So if a storm can develops it would easily be able to produce low level rotation which could lead to tornadogenesis.
Now that we now the storms that develop tomorrow should be supercellular, what type of supercell is likely to develop? For this we need to take a look at the storm relative anvil winds to give us an idea of the titling available to the main updraft. High precipitation supercells develop in areas with numerous storms, which won’t happen tomorrow, or storm relative anvil winds less than 40 knots. Classic super cells tend to form when the storm relative anvil winds are between 40 and 60 knots with anything higher than 60 knots leading to low precipitation supercells. The storm relative anvil winds tomorrow are between 50 and 70 knots, so classic and low precipitation supercells would more than likely be the storm mode. This means the rain cooled down draft will be well displaced from the updraft helping to keep the storm strong and making it live longer.
So now that we know what our storm mode should be, it is time to see if the parameters are there to allow the low level rotation that should occur with any storm that develops could turn into a tornado. One area we look at is the storm’s inflow. Inflow of 20 knots or greater is usually a good indicator that tornadoes could develop. Tomorrow most of East Texas will see storm relative inflow greater than 25 knots. We also need to see the directional shear meaning winds changing direction as you move up through the atmosphere. Now in tomorrow’s set up the wind are fairly unidirectional, or blowing from the same direction, as you move up through the atmosphere. Normally this would limit the tornado threat. However when you factor in the storms motion, the low level storm relative winds become southeasterly setting the stage for directional shear.
Another factor we look for in tornado development is the CAPE in the lowest level of the atmosphere. This is the amount of energy to force air to rise. The stronger the lowest level CAPE is the better chance there is any surface vorticity can be stretched into the storm’s low level rotation which in turn can lead to the development of a tornado. Tomorrow we are seeing 0-3KM CAPE values approaching 80J/kg over much of East Texas leading to a VGP, vorticity generating potential of greater than 0.40. VGP values greater than 0.30 can lead to tornado development.
Finally we like to see what the lowest level shear values will be to determine tornado development. Usually 0-1km shear levels above 20 knots are favorable for tornado development. Tomorrow much of East Texas is seeing that level between 25 and 35 knots.
So all the factors are coming together for what seems to be a fairly active severe weather day. So why is there not a higher risk of severe weather tomorrow and the threat right now is only figured to be conditional? Remember earlier I mentioned many times when the bulk shear is as high as it will be tomorrow the storm’s updraft can be sheared apart. With the lack of forcing and no surface convergence, storms will develop from rising air caused by differential heating across the area. The image below is a Skew-T forecast for tomorrow evening at Tyler, TX. I have pointed out a very strong cap located around 700mb, or about 9,000’ in the atmosphere. This will put a lid on all thunderstorm development which is why there is not a greater risk of severe weather. If the storm system would move a little farther south then the forcing, or lift across East Texas would be greater allowing for a few thunderstorms to develop. What we really need to watch out for tomorrow is any additional clearing which could happen tomorrow afternoon. With the surface winds being out of the south southwest tomorrow, slightly drier low level winds could remove the lower cloud deck. This would allow temperatures to approach the convective temperature, which is around 77°F tomorrow afternoon. If this does happen then isolated thunderstorms will develop, like we see in the summer. But these storms will develop in an atmosphere that is very likely to develop not only severe storms, but tornadoes as well.
So we will have to monitor what happens throughout the afternoon tomorrow. A little more sunshine and it could get very active. If the clouds hang around then the likelihood for severe weather will diminish and very little rain will occur until the cold front moves into East Texas early Wednesday morning.
Tuesday, February 21, 2012
Severe weather awareness week: LIGHTNING
One of the most deadly of all weather phenomena is lightning. Lighting is basically a large spark of static electricity within the clouds or between the cloud and the Earth. Over the past 30 years lightning has killed an average of 55 people per year but that number continues to drop thanks to educating the public on lightning safety. In fact, last year had the lowest amount of lightning deaths on record with 26.
As a thunderstorm develops, air inside the storm moves up and down in the form of updrafts and downdrafts. Inside the currents of air are ice particles, whether small ice crystals or large hailstones. These ice crystals will collide with each other causing a buildup of static electricity, much like what happen when you rub your feet across the floor only to get shocked by the door knob as you reach for it. The thunderstorm is doing the same thing. As the ice particles continue to collide in the storm, some become positively charged and some become negatively charged. The positive charged ice crystals will move towards the top of the thunderstorm while the negative charged ice crystals will settle across the bottom or mid level of the storm. As the storm moves over the ground the surface charge becomes positive. Once the difference becomes great enough a discharge of static electricity will occur just like the shock that comes off your finger as you reach for the door knob. Only in this case the shock is a bolt of lightning that can reach a temperature of 50,000°F. As the air heats around the lightning bolt it will expend very rapidly causing a loud boom or thunder.
In some cases the positive charge at the top of the storm can become so great that a large lightning bolt will race from the top of the cloud towards the ground well out ahead of the storm. This is called positive lightning and occurs because the ground well ahead of the storm has not yet become positively charged. In some cases this lightning bolt can hit up to ten miles away from the storm. This is the most dangerous type of lightning as many times it will strike when you don’t know a storm is near you due to the lack of clouds and it usually has the strongest amount of electric current.
So next time you hear thunder it is time to move indoors. For every five seconds you can count between lightning and its thunder is a distance of 5 miles. So even the faintest sound of thunder means it is close enough to strike. Also, it is a great idea to wait 30 minutes after the last sound of thunder to make sure the storm has passed to a safe distance.
Monday, February 20, 2012
What's going on???
Not sure why I see Photobucket all over the blog this morning. Might need to update the template. Sorry for the inconvenience.
Severe weather awareness week: HAIL
Today starts severe weather awareness week in the state of Texas. Each day we will write a brief story on one type of severe weather to educate you on how this severe weather phenomenon occurs so you can take precautions to protect life and property. Today’s discussion will cover hail.
Hail can be a very dangerous and damaging form of severe weather. Here in East Texas we are hit every year with many hailstorms, some of which have produced a substantial amount of damage. Yours truly has replaced the roof on my home twice in 4 years and had a car totaled by hail. In fact, nearly 40 percent of all home insurance claims in the state of Texas are from hail damage.
So how does hail form and why are some stones much bigger than other stones? Hail forms when small ice particles are held above the freezing level by strong thunderstorm updrafts allowing for super cooled water droplets to freeze on these ice particles causing the hail stone to grow. As long as the updraft is strong enough, the hail stone will continue to grow. At times the hail stone will fall out of the main draft falling towards the ground only to be picked back up by the updraft before hitting the ground. This will cause the stone to take a roller coaster ride up and down inside the storm collecting more water droplets that will refreeze causing the stone to become even large. So the stronger the updraft, the larger the hail stone. Hail the size of peas will be supported by updraft speeds of 24 mph where as softball size hail need an updraft speed of 104 mph! The largest hailstone to hit the United State fell in Vivian, SD July 23 2010. This hailstone measured 8” in diameter and weighed nearly 2 pounds. A stone this size can reach downward speeds of over 120 mph! So it is easy to see how hail can be very deadly and damaging during severe thunderstorms.
Hail can be a very dangerous and damaging form of severe weather. Here in East Texas we are hit every year with many hailstorms, some of which have produced a substantial amount of damage. Yours truly has replaced the roof on my home twice in 4 years and had a car totaled by hail. In fact, nearly 40 percent of all home insurance claims in the state of Texas are from hail damage.
So how does hail form and why are some stones much bigger than other stones? Hail forms when small ice particles are held above the freezing level by strong thunderstorm updrafts allowing for super cooled water droplets to freeze on these ice particles causing the hail stone to grow. As long as the updraft is strong enough, the hail stone will continue to grow. At times the hail stone will fall out of the main draft falling towards the ground only to be picked back up by the updraft before hitting the ground. This will cause the stone to take a roller coaster ride up and down inside the storm collecting more water droplets that will refreeze causing the stone to become even large. So the stronger the updraft, the larger the hail stone. Hail the size of peas will be supported by updraft speeds of 24 mph where as softball size hail need an updraft speed of 104 mph! The largest hailstone to hit the United State fell in Vivian, SD July 23 2010. This hailstone measured 8” in diameter and weighed nearly 2 pounds. A stone this size can reach downward speeds of over 120 mph! So it is easy to see how hail can be very deadly and damaging during severe thunderstorms.
Severe weather awareness week: HAIL
Today starts severe weather awareness week in the state of Texas. Each day we will write a brief story on one type of severe weather to educate you on how this severe weather phenomenon occurs so you can take precautions to protect life and property. Today’s discussion will cover hail.
Hail can be a very dangerous and damaging form of severe weather. Here in East Texas we are hit every year with many hailstorms, some of which have produced a substantial amount of damage. Yours truly has replaced the roof on my home twice in 4 years and had a car totaled by hail. In fact, nearly 40 percent of all home insurance claims in the state of Texas are from hail damage.
So how does hail form and why are some stones much bigger than other stones? Hail forms when small ice particles are held above the freezing level by strong thunderstorm updrafts allowing for super cooled water droplets to freeze on these ice particles causing the hail stone to grow. As long as the updraft is strong enough, the hail stone will continue to grow. At times the hail stone will fall out of the main draft falling towards the ground only to be picked back up by the updraft before hitting the ground. This will cause the stone to take a roller coaster ride up and down inside the storm collecting more water droplets that will refreeze causing the stone to become even large. So the stronger the updraft, the larger the hail stone. Hail the size of peas will be supported by updraft speeds of 24 mph where as softball size hail need an updraft speed of 104 mph! The largest hailstone to hit the United State fell in Vivian, SD July 23 2010. This hailstone measured 8” in diameter and weighed nearly 2 pounds. A stone this size can reach downward speeds of over 120 mph! So it is easy to see how hail can be very deadly and damaging during severe thunderstorms.
Hail can be a very dangerous and damaging form of severe weather. Here in East Texas we are hit every year with many hailstorms, some of which have produced a substantial amount of damage. Yours truly has replaced the roof on my home twice in 4 years and had a car totaled by hail. In fact, nearly 40 percent of all home insurance claims in the state of Texas are from hail damage.
So how does hail form and why are some stones much bigger than other stones? Hail forms when small ice particles are held above the freezing level by strong thunderstorm updrafts allowing for super cooled water droplets to freeze on these ice particles causing the hail stone to grow. As long as the updraft is strong enough, the hail stone will continue to grow. At times the hail stone will fall out of the main draft falling towards the ground only to be picked back up by the updraft before hitting the ground. This will cause the stone to take a roller coaster ride up and down inside the storm collecting more water droplets that will refreeze causing the stone to become even large. So the stronger the updraft, the larger the hail stone. Hail the size of peas will be supported by updraft speeds of 24 mph where as softball size hail need an updraft speed of 104 mph! The largest hailstone to hit the United State fell in Vivian, SD July 23 2010. This hailstone measured 8” in diameter and weighed nearly 2 pounds. A stone this size can reach downward speeds of over 120 mph! So it is easy to see how hail can be very deadly and damaging during severe thunderstorms.
Friday, February 3, 2012
Severe storms possible today
A strong storm system across the High Plains today will drag a cold front into East Texas providing a chance of rain and thunderstorms today and tonight, some of which could be strong to severe. The severe storms we saw across East Texas last night have moved out of the area and this morning we are left with low clouds fog and drizzle. With a few breaks in the low clouds later this morning, peaks of sunshine will help warm us into the lower to middle 70s. This will provide the energy needed for thunderstorms to develop across the area this afternoon into the evening hours. All of East Texas is under a slight risk of severe storms this afternoon with the main threat being gusty winds. If we can see enough sun to raise temperatures in to the middle 70s area wide, then there would be enough energy in the atmosphere for a few hail storms as well.
As for the tornado threat, right now it looks pretty small across East Texas. It looks as though a broken line of storms could develop to our west this afternoon. These storms will move into the area during the late afternoon and evening hours. The overall low level shear across East Texas at this time is not that impressive but if any storm is able to remain isolated, it could tap into what shear is available and produce an isolated tornado. The greatest tornado threat today looks to remain to our northwest near the Wichita Falls area where low level shear will be much greater this afternoon.
A second line of thunderstorms looks to develop this evening along the cold front that will be moving into the area. These storms could also produce strong gusty winds and small hail as they move through late tonight into the early morning hours on Saturday. By Noon Saturday the front and its line of storms should be east of the area allowing for drier and slightly cooler air to move in. By the end of this event much of East Texas could receive another inch of much needed rainfall.
As for the tornado threat, right now it looks pretty small across East Texas. It looks as though a broken line of storms could develop to our west this afternoon. These storms will move into the area during the late afternoon and evening hours. The overall low level shear across East Texas at this time is not that impressive but if any storm is able to remain isolated, it could tap into what shear is available and produce an isolated tornado. The greatest tornado threat today looks to remain to our northwest near the Wichita Falls area where low level shear will be much greater this afternoon.
A second line of thunderstorms looks to develop this evening along the cold front that will be moving into the area. These storms could also produce strong gusty winds and small hail as they move through late tonight into the early morning hours on Saturday. By Noon Saturday the front and its line of storms should be east of the area allowing for drier and slightly cooler air to move in. By the end of this event much of East Texas could receive another inch of much needed rainfall.
Wednesday, February 1, 2012
A Severe Storm or Two is Possible Today
There is a conditional threat of severe across parts of East Texas this afternoon, mainly north of interstate 20. A few breaks in the low level clouds late this morning is already allowing surface temperatures to approach 70 degrees. At the same time colder air in the mid levels of the atmosphere are spreading across the northern counties of East Texas. This imbalance will cause air to rise in a few areas leading to an isolated thunderstorm or two. Any storm that develops this afternoon will have the potential to produce hail, possibly up to 2 inches in diameter. The upper air disturbance that is moving through the area will exit East Texas later this evening and our thunderstorm chances will diminish. Again this is a conditional threat meaning there is a good chance no storms will develop at all. But if they do, we will probably see a few large hail reports this afternoon.
Tuesday, January 31, 2012
Severe Weather Possible Friday
The next few days will see a few disturbances rapidly moving across the area as the mild winter weather continues. The first fast moving disturbance will move through the area tomorrow near the Red River Valley providing enough lift for an isolated thunderstorm or two. With the surface temperatures being as warm as they are, there will be enough surface instability for a marginally severe storm with the main threat being small hail and gusty winds. With the surface winds remaining rather weak and a uniform shear profile tomorrow, the tornado threat at this time appears very low. Most areas look to remain dry as it only appears isolated convection but the next system heading our why for Friday looks much stronger.
Forecast models differ on the timing and position of the next system but all agree much of the area will receive rain. What is becoming interesting with this next system is the NAM forecast model, a higher resolution short range model, is starting to slow the system down while at the same time strengthening it. If what the NAM is predicting right now does come true, we could see a significant round of severe weather across parts of the area including tornadoes.
At the time of this writing the latest forecast time available for the NAM was 18Z Friday, or noon CST. At this time a strong, negatively tilted trough is forecast to be moving through West Texas. As this happens warm moist air from the Gulf will be forced north across the state of Texas adding to the amount of surface instability available for thunderstorm development. Winds at the surface will be out of the southeast around 15 to 20 miles an hour.
At the same time the winds at 850mb, or about 5000 feet in the air, will be out of the south around 50 to 60 miles per hour. This will produce a large turning of wind with height in the lowest level of the atmosphere allowing for large storm relative helicity to be ingested by any thunderstorm that develops. This will help any storm that develops to be capable of producing a tornado.
The main limiting factor in severe weather development is the level of instability available for storms. Right now it is forecast to be fairly low. However, usually in strong negatively tilted troughs the amount of surface instability can be underestimated 84 hours out by the forecast model. The 700mb chart is showing very high relative humidity levels across the area indicating cloud cover.
There is an area of very dry 700mb air that will wrap around the storm system allowing for breaks in the clouds which will in turn heat the air mass adding to the low level instability.
Severe weather outbreaks are always a blend of perfect timing between all severe weather parameters. This system bears watching the next few days. The upper air pattern is fairly similar to the April 9th event in 2009 nine which produced numerous long lived tornadoes across the area. The upper air jet streak is forecast to punch just south of the area putting the Red River Valley and much of East Texas in the left exit region which gives added lift to air parcels. The entire area will also be in the area of diffluent wind flow which also adds to air parcel lifting.
So if the current trend continues, this meteorologist will be out roaming the plains looking for tornadoes Friday afternoon and evening.
Forecast models differ on the timing and position of the next system but all agree much of the area will receive rain. What is becoming interesting with this next system is the NAM forecast model, a higher resolution short range model, is starting to slow the system down while at the same time strengthening it. If what the NAM is predicting right now does come true, we could see a significant round of severe weather across parts of the area including tornadoes.
At the time of this writing the latest forecast time available for the NAM was 18Z Friday, or noon CST. At this time a strong, negatively tilted trough is forecast to be moving through West Texas. As this happens warm moist air from the Gulf will be forced north across the state of Texas adding to the amount of surface instability available for thunderstorm development. Winds at the surface will be out of the southeast around 15 to 20 miles an hour.
At the same time the winds at 850mb, or about 5000 feet in the air, will be out of the south around 50 to 60 miles per hour. This will produce a large turning of wind with height in the lowest level of the atmosphere allowing for large storm relative helicity to be ingested by any thunderstorm that develops. This will help any storm that develops to be capable of producing a tornado. 
The main limiting factor in severe weather development is the level of instability available for storms. Right now it is forecast to be fairly low. However, usually in strong negatively tilted troughs the amount of surface instability can be underestimated 84 hours out by the forecast model. The 700mb chart is showing very high relative humidity levels across the area indicating cloud cover.
There is an area of very dry 700mb air that will wrap around the storm system allowing for breaks in the clouds which will in turn heat the air mass adding to the low level instability. 
Severe weather outbreaks are always a blend of perfect timing between all severe weather parameters. This system bears watching the next few days. The upper air pattern is fairly similar to the April 9th event in 2009 nine which produced numerous long lived tornadoes across the area. The upper air jet streak is forecast to punch just south of the area putting the Red River Valley and much of East Texas in the left exit region which gives added lift to air parcels. The entire area will also be in the area of diffluent wind flow which also adds to air parcel lifting.
So if the current trend continues, this meteorologist will be out roaming the plains looking for tornadoes Friday afternoon and evening.
Tuesday, January 24, 2012
Severe weather possible tomorrow
The unusual wet patter for a La Nina year looks to continue as a strong storm system promises to bring heavy rain and thunderstorms to the area starting tonight. Rainfall could add up to more than 2 inches for many areas before this storm system finally exits the area late Thursday. In addition to heavy rain, there is a slight chance for severe thunderstorms tomorrow across parts of East Texas, mainly south of Interstate 20.
The way it looks right now an area of low pressure will develop tonight across extreme south Texas and begin to move northeast towards Shreveport by Thursday morning. This low pressure will pull in warm moist air from the Gulf, allowing for showers and thunderstorms to develop. Areas along and south of the low pressures track will be in what we call the “warm sector” of the storm system. It is in this area where we could see a few severe storms, especially from noon to 6PM tomorrow afternoon. Now we normally don’t expect to see severe weather during January but it is not unheard of. January 20th, 2010 was the last major severe weather event during the month of January in East Texas. Now the atmosphere will not be as volatile as we saw for that event but, the amount of energy and shear in the atmosphere is very similar to watch just occurred in the Southeast Sunday night. So for areas along and south of a Marshall to Longview to Tyler To Palestine line there is a threat of gusty winds and maybe an isolated tornado or two if an isolated thunderstorm can develop. The good news for East Texas is that as storms develop tomorrow they should quickly form into a squall line, limiting the tornado threat.
On the positive side, this system should bring heavy rain to the area. Now we cannot rule out a few local areas of flash flooding, but with 2 plus inches of rain falling over the area in a short period of time, lake levels should rise. The past few heavy rain events have occurred a little slower than what is expected with this system and over a drier ground. Soil moisture has increased with the rains of November and December so rapid run off should occur with heavier downpours causing our lake levels to rise. Stay with KLTV and KLTV.com for the latest. Any change in the track of this low pressure will cause a change in the threat area for severe weather.
Now earlier I stated there were similarities to the Sunday/Monday event with tomorrow’s storm system. But events were fairly what we usually reference to as a low instability high shear event. CAPE values in central Alabama early Monday morning were between 500 and 1000 J/kg and the forecast CAPE values here for tomorrow are around 500 J/kg, usually not what we would look for in a severe weather situation.
However the 0-3KM CAPE, or the amount of energy available closest to the surface, is forecast to be between 100 and 200 J/kg tomorrow afternoon. This is more than enough to produce healthy low level rising of air parcels, some we look for in tornado formation.
I this this low level energy that creates the stretching possibilities of any low level spin to help generate strong gusty winds along with tornadoes.
Another factor we look for in the development of tornadoes would be the low level helicity, or the amount of spin available for the thunderstorm to ingest. Values at or above 150 are usually enough to help with the development of tornadoes. Tomorrow’s forecast values are between 200 and 300.
Finally we look for the 0-1KM shear values. Anything over 20 knots is favorable for tornado development in severe weather situations. Tomorrow’s values are forecast to be between 30 and 40 knots, more than enough to help in tornadogenesis.
The two major differences in tomorrow’s setup I see from Alabama’s tornado outbreak is the amount of forcing and the orientation of the shear vectors to the front. In Alabama the forcing was displaced farther to the north along with shear vectors which were more perpendicular to the front. This allows storms to separate and ingest all the available energy and spin. This lead to a couple of very strong supercells which produced at least two ling track tornadoes.
As seen in the first image, a very strong vorticity maximum will be moving into the area to provide a large amount of forcing. In addition the shear vectors will be parallel. Combining these two factors will allow for any storms that form to quickly form into a squall line. This should limit the overall tornado threat but increase the gusty wind threat.
So what we will be watching for is any isolated thunderstorm to develop ahead of the main line of storms. Any isolated storm could produce tornadoes but should be quickly ingested by the main line.The overall severe weather threat will depend on the eventual track of the developing low pressure. If this system moves farther north, all of East Texas will be under a threat of severe weather. A bit farther south and the severe weather threat will be pushed along the Gulf coast.
The way it looks right now an area of low pressure will develop tonight across extreme south Texas and begin to move northeast towards Shreveport by Thursday morning. This low pressure will pull in warm moist air from the Gulf, allowing for showers and thunderstorms to develop. Areas along and south of the low pressures track will be in what we call the “warm sector” of the storm system. It is in this area where we could see a few severe storms, especially from noon to 6PM tomorrow afternoon. Now we normally don’t expect to see severe weather during January but it is not unheard of. January 20th, 2010 was the last major severe weather event during the month of January in East Texas. Now the atmosphere will not be as volatile as we saw for that event but, the amount of energy and shear in the atmosphere is very similar to watch just occurred in the Southeast Sunday night. So for areas along and south of a Marshall to Longview to Tyler To Palestine line there is a threat of gusty winds and maybe an isolated tornado or two if an isolated thunderstorm can develop. The good news for East Texas is that as storms develop tomorrow they should quickly form into a squall line, limiting the tornado threat.
On the positive side, this system should bring heavy rain to the area. Now we cannot rule out a few local areas of flash flooding, but with 2 plus inches of rain falling over the area in a short period of time, lake levels should rise. The past few heavy rain events have occurred a little slower than what is expected with this system and over a drier ground. Soil moisture has increased with the rains of November and December so rapid run off should occur with heavier downpours causing our lake levels to rise. Stay with KLTV and KLTV.com for the latest. Any change in the track of this low pressure will cause a change in the threat area for severe weather.
Now earlier I stated there were similarities to the Sunday/Monday event with tomorrow’s storm system. But events were fairly what we usually reference to as a low instability high shear event. CAPE values in central Alabama early Monday morning were between 500 and 1000 J/kg and the forecast CAPE values here for tomorrow are around 500 J/kg, usually not what we would look for in a severe weather situation.
However the 0-3KM CAPE, or the amount of energy available closest to the surface, is forecast to be between 100 and 200 J/kg tomorrow afternoon. This is more than enough to produce healthy low level rising of air parcels, some we look for in tornado formation.
I this this low level energy that creates the stretching possibilities of any low level spin to help generate strong gusty winds along with tornadoes.
Another factor we look for in the development of tornadoes would be the low level helicity, or the amount of spin available for the thunderstorm to ingest. Values at or above 150 are usually enough to help with the development of tornadoes. Tomorrow’s forecast values are between 200 and 300.
Finally we look for the 0-1KM shear values. Anything over 20 knots is favorable for tornado development in severe weather situations. Tomorrow’s values are forecast to be between 30 and 40 knots, more than enough to help in tornadogenesis.
The two major differences in tomorrow’s setup I see from Alabama’s tornado outbreak is the amount of forcing and the orientation of the shear vectors to the front. In Alabama the forcing was displaced farther to the north along with shear vectors which were more perpendicular to the front. This allows storms to separate and ingest all the available energy and spin. This lead to a couple of very strong supercells which produced at least two ling track tornadoes. As seen in the first image, a very strong vorticity maximum will be moving into the area to provide a large amount of forcing. In addition the shear vectors will be parallel. Combining these two factors will allow for any storms that form to quickly form into a squall line. This should limit the overall tornado threat but increase the gusty wind threat.
So what we will be watching for is any isolated thunderstorm to develop ahead of the main line of storms. Any isolated storm could produce tornadoes but should be quickly ingested by the main line.The overall severe weather threat will depend on the eventual track of the developing low pressure. If this system moves farther north, all of East Texas will be under a threat of severe weather. A bit farther south and the severe weather threat will be pushed along the Gulf coast.
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