A Beautiful Sunday Afternoon.

With the fantastic weather this afternoon, my family and I took off and went to the Azalea District for a nice afternoon walk. Here are some pictures, I hope you enjoy.

Another round of severe storms possible today:

After a bumpy afternoon and evening yesterday, things could get a bit dicey this afternoon once again. The rain from last night cooled the lower levels of the atmosphere causing a boundary, or front to sag south across the Gulf coast. Out to our west we are watching a disturbance move through the upper levels of the atmosphere and this will help drag that front north as a warm front later this afternoon. There are two areas of concern for severe weather this afternoon. The first is across the southern counties of East Texas where this disturbance will move through this evening. This will cause the air to rise and form strong to severe thunderstorms, starting around 5:00PM in our extreme southwestern counties. The main threat with these storms will be strong gusty winds and isolated weak tornadoes.

The second area of concern is across the I-20 and I-30 corridors where the warm front is expected to move through this afternoon and evening. Some breaks in the clouds this afternoon should allow enough sunshine to warm temperatures into the mid to upper 70s. This along with cold mid level atmospheric temperatures will provide a large amount of energy and instability needed for thunderstorm growth. The only thing lacking is enough forcing to lift the air and get storms cranking. As the warm front moves through, and an increase in upper level winds move in, I think a few storms will develop. We will have to watch these very closely as there will be the potential for large hail, gusty winds, and tornadoes. In both areas storms should diminish around midnight. Another storm system will move towards East Texas tomorrow bringing another chance of severe weather.

Once this second storm system moves through the threat of severe weather is over for the weekend and temperatures will cool down. We will see lows in the 30s in most locations this weekend so get ready. Stay tuned to KLTV and KLTV.com for the latest on our severe weather threat.

Nacogdoches/Shelby County Storm

3D image of the storm on Nacogdoches/Shelby county line.



Inflow notch on the storm.

Severe Weather Possible This Week....

Severe weather is possible throughout the week as numerous storm systems move across the Southern Plains. The first threat of severe weather will move into East Texas tomorrow as a strong storm system to our north drags a cold front across our area. As this cold front moves in, a line of strong to severe thunderstorms will breakout, starting around midday in our northwestern counties and exiting our southeastern counties by early Wednesday morning. The main severe weather threat with this system is strong gusty winds and hail, although an isolated weak tornado can't be ruled out.

Our second chance of severe weather will enter the area late Wednesday as the cold front, now stalled across the Gulf coast, begins to move north as a warm front. Ahead of this warm front, warm air will be forced over cooler air at the surfaced causing thunderstorms to form above the planetary boundary layer, air near the surface of the Earth affected by friction. There will be a lot of what we called elevated energy available for these storms to grow, so large hail is a possibility when any of the stronger storms Wednesday night into Thursday morning. Along and south of the warm front, thunderstorms will have the best chance for rotation so we will have to watch for the possibility of tornadoes if any stronger storms can form.



By Thursday afternoon the warm front should have moved north of East Texas putting all of our area in the warm sector of our next developing storm system. With ample daytime heating, enough energy will be present for isolated to scattered thunderstorms Thursday afternoon. With the available directional wind shear, or winds turn with height, a few of these storm late Thursday could be very strong with large hail, gusty winds, and even a couple of tornadoes. The image below shows 0-1KM EHI or energy helicity index. This value takes into consideration both the amount of energy available for a storm and the amount of spin in the atmosphere. Any number greater than 2 means tornadoes are possible and a number over 4 means strong tornadoes are possible. Right now the EHI over East Texas is forecast to be as high as 3.75.(Some meteorologist will say strong tornadoes are possible with a reading greater than 2 but, the majority of strong tornadoes are associated with a higher number)



By Friday afternoon a strong cold front will move through East Texas again but this time, we should clear out and cool off for the weekend. With this front scattered to numerous strong thunderstorms will develop bringing a chance of gusty winds, hail, and even isolated tornadoes. All of East Texas should remain on guard for the threat of severe weather and stay tuned to KLTV and KLTV.com for the latest.

Slight chance of Severe Weather for parts of East Texas:

After 80 degree temperatures the last five days across East Texas, an abrupt end to the warmth is coming. A strong cold front will move into East Texas late tonight bringing a chance of showers and thunderstorms to the area, a few of which could be strong. There is a slight chance on or two storms could form later this afternoon and any storm that does develop could produce strong gusty winds and small hail. Most of the energy needed for strong to severe thunderstorms will move to our north so I am not expecting a great deal of severe weather.

I am however expecting a large area of East Texas to experience heavy rain. They way it looks now, most of East Texas should see between 2 and 3 inches of rain with a few spots receiving more than 5 inches before Saturday. This would put a huge dent in the rainfall deficit across East Texas, which is over 5 inches for most of the area.



In addition to the heavy rainfall across East Texas, much colder weather will be moving into the area. Temperatures will fall for most of the day tomorrow, reaching the upper 40s by the evening and not getting out of the 40s until late Saturday. With a northeast wind around 10 to 15 MPH, wind chill temperatures will run in the 30s for most of Thursday and Friday.

Salem, AL EF-2 Tornado Analysis.

On Saturday February 28th of this year we saw another example of a strong tornado produced in a low instability high shear environment across East Central Alabama. Many times when we look at the threat of severe weather in the meteorological world we look for high levels of CAPE(Convective Available Potential Energy) and shear to outline an area where the greatest threat is. But there have many instances where we have seen low level of CAPE that produced strong tornadoes. The Salem, AL EF-2 tornado is just another example of why need to look at all severe weather parameters to determine the severity of impending storms.



So let’s take a look at the conditions that came together to form this severe weather event. Tornado watches were in effect throughout the early morning hours Saturday for the possibility of isolated tornadoes to form, especially along a northward moving boundary of increased moisture. In the image below you can see an area of dark green (or higher dew points) indicating a boundary between very moist are and slightly drier air to the north. This boundary was slowly moving to the north and along it, low level helicities, or atmospheric spin, would increase leading to the possibility of tornadoes.



With the added moisture to the south of this boundary, instability levels increase, as shown by the orange shading indicated LI’s of -2°C. Now this value of instability is not all that great but, when you combine it with other atmospheric conditions, severe weather can occur.



By looking at the previous two images you will notice the surface winds are out of the southwest around 15 knots. As you move up the atmosphere winds along this boundary winds were also out of the southwest and then eventually out of the west setting up what we call unidirectional shear. Usually we look to have directional shear, or winds form different direction and speed as we move up in the atmosphere. Something we must factor into the storms environment is the relative winds associated with that particular storm. In the image below, storm relive 1KM winds are indicated or, the inflow to the storm. You will notice that right along the edge of the boundary, the relative inflow backs, or turns counter-clockwise, to the southeast. This increases the storm’s relative helicity and gives the storm a better chance of producing a tornado.



As stated earlier, many times weather enthusiasts look for area of high CAPE to determine where the most severe weather will occur. CAPE basically shows the buoyancy of air. The larger the number, the faster the air will rise. We look for areas of rapid upward motion for the development of severe thunderstorms. In my opinion, many times we get caught up in just looking at areas of high CAPE and not focusing on all aspects of the storm’s environment. Prime example of this is looking at the amount of CAPE that was available for Saturday’s storms. The image below shows the surfaced based CAPE, or buoyancy available from a parcel of air lifted from the surface, was just over 500 J/kg in Lee County.



We normally look for CAPE values to be greater than 1500 J/kg for severe weather and tornadoes. But when we look at where the 500 J/kg of CAPE is located in the profile of the atmosphere and what is happening through that layer, we get a much better indication of what can happen. In the image below we can see the 0-3KM CAPE, or the amount of buoyancy from the surface to 3KM in the atmosphere, is greater than 160 J/kg. This is a fairly significant amount of CAPE for such a shallow layer of the atmosphere.



When we look at a volumetric scan of the storm as the updraft was located near Chewacla State Park, we can see the high reflectivity colors, or red, do not exceed very far beyond the 3KM mark in the atmosphere. In “text book” supercell producing thunderstorms we usually look for these areas of high reflectivity to exceed 30,000’, three times higher than the storms of this day.



So what was occurring in the 0-3KM layer of the atmosphere that lead to the development of a strong EF-2 tornado? As stated earlier, the storm relative winds were backing to the southeast in the 1st KM layer of the atmosphere. This lead to an increase in the storm relative helicity(SRH) values the storm would experience as it moved into Lee County. Notice in the image below that 0-3KM SRH were over 300 in Lee County at the time the storm was west of Auburn.



This large amount of helicity was in the same layer of the atmosphere where the buoyancy, CAPE, was the greatest. So where the updraft of the storm was the strongest, there was enough spin in the atmosphere to produce a strong mesocyclone located in the radar image below which lead to the formation of a strong EF-2 tornado in Salem a few minutes later.



So the right combinations of ingredients came together to produce a tornado who’s estimated wind speed was around 130 mph. If we were to just have looked at the CAPE and wind flow throughout the atmosphere, we might have missed the threat for a strong tornado. But by looking at all aspects needed for tornado development, we can see it does not take much CAPE to produce a significant tornado under the right conditions.

Wild Weather Day in Alabama....

***UPDATE: RADAR LOOPS ADDED***

It was a wild 24 hours across parts of the Southeast Saturday into Sunday Morning. Severe weather and tornadoes followed by snow affected much of the southeast as a strong storm system moved from the Mid South to the Southeast Atlantic Coast. Three tornadoes touched down in East Central Alabama Saturday morning and ranged from an EF-0 to an EF-2 in intensity. I took a few snap shots from the FFC Doppler velocity data to show where the rotation was as it moved through Lee County. The first shot shows an area of rotation just east of Notasulga near the Macon-Lee County line. This area of rotation would eventually touch the ground near Salem, AL becoming the strongest tornado of the day. A second area of rotation is just north of Auburn. This rotation would lead to the EF-1 tornado near The Bottle at the intersection of highway 147 and US 280. Top winds in this tornado were estimated to be near 100mph. (source National Weather Service BMX) The next image shows a strong area of rotation near exit 51 on interstate 85 or near Chewacla State Park. I have not heard of any damage reports from this area so it appears the rotation was still in the air. The final image is the area of rotation as it passed through Salem. From the damage survey performed by the National Weather Service in Birmingham, an EF-2 tornado passed through at this time. Several buildings and homes were damaged and there were a few minor injuries. If you look closely at this image and compare to the last image, the rotation does not appear to be as tight. A large area of light blue color is becoming dominate in this image showing a strong outflow which eventually lead to the demise of this tornado. The Salem tornado was on the ground for 2.65 miles and had a maximum width of 500 yards. Top winds were estimated to be near 130 mph making this a strong EF-2 tornado. (source National Weather Service BMX) If you look closely again at the last image, the large area of light blue is showing the possibility of strong straight line winds over a large area. A few minutes later this area spread across Smiths Station causing wind damage to many building and trees. Normally having a day packed with severe weather is wild enough but Mother Nature was not done with East Central Alabama. A little more than 24 hours later this area received the heaviest snow it has seen in many years. Parts of Eastern Lee County received over 5 inches of snow. Below is a map from the National Weather Service in Birmingham showing the snowfall accumulations for Alabama on Sunday. A wild weather day indeed!

Fire Danger This Week.......

Dry conditions in Texas over the past few weeks have lead to a high fire danger across our state. Nearly 80% of Texas Counties are under outdoor burning bans and we can expect to see that number increase. Low relative humidity and strong gusty winds later this week will increase the threat for grass fires across the state. As of, today much of East Texas is 5 inches or more behind on yearly rainfall and we are only 2 months into the new year.


The relative humidity at times this week will dip below 20% across East Texas and with strong gusty winds, outdoor burning is not recommended, even in counties which are not under outdoor burning bans. So is there any relief in sight? Unfortunately it appears this dry pattern will continue for a while. We will see a strong ridge of high pressure in the upper levels of the atmosphere across the southern plains producing sinking air across our region for much of the week.





By the weekend there are some signs this ridge will begin to break down and allow a trough of low pressure to move into the southern plains giving us a chance of scattered showers and thunderstorms. That’s the good news. The bad news is we will not see a strong surge of Gulf moisture ahead of this trough which would allow widespread showers and storms giving most of the area some beneficial rains.

As we head towards the middle part of next week there is the potential of a large storm system forming which could produce heavy rain and severe weather for parts of East Texas followed by some much cooler weather by the end of next week. We could do without the severe weather but the possibility of heavy rain would be great news for East Texas. So until we receive the heavy rain we need, please refrain from outdoor burning.

Nice End to Monday!

What a beautiful way to end a Monday. In case you missed it, the high clouds yesterday across East Texas caused a beautiful golden sunset across our area. We will see a few high clouds again today so be on the lookout for another beautiful sunset this evening. However, it appears some drier air is moving into the upper levels of the atmosphere so we probably will not see such a dramatic sight.

Tornado Development

With severe weather awareness week coming to an end, here is a short video on how wind shear can generate a spin in the atmosphere which can lead to supercells and tornadoes.

Giant Hail..............

As we continue with severe weather awareness week today I will discuss large hail and the severe storms that have produced some of the largest hail on record. Hail is a type of precipitation which grows inside the thunderstorm due to strong updrafts suspending ice crystals in the storm cloud until they grow to a point where the updraft can no longer support them and they fall to the Earth. The largest know hail stone to strike the United States is in the photo below from a storm in Aurora, NE.



This hailstone is just over 7” in diameter and 18.75” in circumference. It was the largest stone in one piece from this storm however, there were reports of larger stones that broke apart on impact with the ground. In some places up 12” diameter creators were left on the ground. Below is a short movie of the volumetric radar return from the storm that produced this giant hail. What is amazing about this storm is not only the height, topping out over 61,000’, but the strong reflectivity near the top of the storm, 60dbz at nearly 46,000’.



Another powerful storm that produced very large hail was right here in East Texas last year when softball size hail was reported near Bullard on February 5th. Below is a short movie of the volumetric radar return from the storm that produced this giant hail. Notice the storm was nowhere near the height that produced the giant hail in Nebraska. This storm formed during the cool season so you do not need to have storms as high to produce very large hail because the mid levels of the atmosphere are much colder.



You can imagine that chunks of ice the size of softballs or larger can be very dangerous if caught outside. The last known death in the United States occurred in March of 2000 when a man in Lake Worth, TX was hit in the head by softball size hail. Now the Great Plains are known for very large hail at times but parts of south Asia and China are known for devastating hail storms. In July of 2002, 25 people lost their lives during a hail storm in the Henan Province of China. Bangladesh is also notorious for very large hail. In fact the heaviest hailstone on record fell there in April of 1986 and weighed just over 2.2 pounds. I have not seen the actual dimensions on this stone but I would have to imagine it would have been slightly larger than volleyball size.



So how can a storm suspend ice particles this size? It all has to do with the strength of the updraft. Once we start to see hailstones the size of softballs or larger, the storm’s updraft speed will exceed 100mph! This was the case back in October 2007 when a massive hail storm hit Santo Cristo, Brazil. In the photos you see stones over 10cm in diameter, or about the size of softballs.





So unlike with tornadoes, the United States is not the hail capital of the world. While we get our fair share, even here in East Texas, other parts of the world see this severe weather phenomenon as well. Large hail is commonly found along the front range of mountain chains with the storms along the Himalayas producing the most and largest hail on Earth.

Lightning The Underrated Killer!

Every second on Earth around 45 bolts of lightning occur. That amounts to a staggering 1.4 billion flashes of lightning per year. Of these total bolts about 20%actually hit the Earth’s surface meaning there are nearly 280 million cloud to ground or ground to cloud lightning sbolt from the blue,trikes each year. With a tremendous amount of electricity, an average of one terawatt or one trillion watts per bolt, and an extremely high temperature, around 50,000°F, it is no wonder lightning is such a great threat to life and property. The greatest know loss of life from one lightning strike was in Brescia, Italy in 1769 when 3000 people lost their lives because lightning struck a church containing 100 tons of gunpowder that resulted in a huge explosion destroying a sixth of the city.(source Wikipedia) To see how lightning strikes are distributed around the world, take a look at the image below. Notice there is a great concentration of lightning near the equatorial regions of the world where thunderstorms are very common. The lightning capital of the US would be the peninsula of Florida where 6 to 9 months of the year sea breeze fronts collide across the center of the State causing thunderstorms to develop most afternoons.



On average lightning kills 66 Americans each year. This number is greater than that caused from hurricanes and tornadoes. Here are some interesting statistics of lightning victims in 2007.

98% were outside

89% were male

30% were males between the ages of 20-25

25% were standing under a tree

25% occurred on or near the water

So what can we do to keep our selves safe during a thunderstorm? Some easy rules to follow would include finding indoor sturdy shelter during a thunderstorm. Stay away from windows. If you are on the golf course and hear thunder, return to the club house immediately. Standing in an open field holding a metal club makes you a lightning rod. If you are caught outdoors and cannot make it to a shelter the best advice is to crouch down, tuck your head, cover your ears, and only have your toes touching the ground. If you lay flat on the surface then you have a much better chance of being struck indirectly form lightning from an underground current. For more on lightning safety click here. When is it no longer safe to be outside? If you can hear thunder, your best bet is to move inside. To determine how far away lightning is from your location, count the seconds in between the lightning bolt and thunder. For every five seconds you count, a distance of one mile passes. So if you see a lightning bolt and 30 seconds later you hear the thunder, the lightning was approximately 6 miles away. Lightning has been known to strike and cause injury or death up to 10 miles away from the parent storm. This type of strike is known as a “Bolt From The Blue.” So staying inside 30 minutes after you hear the last clap of thunder is the best way to keep you and you family safe.



While lightning can be a beautiful sight, it is best to take precautions to insure your safety during natures underrated killer.

The Video That Started It All......................

Today starts Severe Weather Awareness Week here in Texas so I thought we would review the best practices for keeping you and your family safe during severe weather. Today we will discuss where to seek shelter from a tornado if caught outside or in your car. For years the meteorological community has been telling people if you are caught outside or in your car during a tornado the best place to seek shelter in and a ditch or ravine and to cover your head. This is still the best choice for protecting yourself during a tornado if caught outside without sturdy shelter nearby but during April of 1991, a large tornado outbreak hit Kansas and from this event, video of a news team first trying to outrun a tornado and then seeking shelter under an overpass changed the public’s outlook on where to seek shelter.




Unfortunately this misleading information caused three people to lose their lives as they sought shelter under an overpass during the Moore, OK F5 tornado on May 3rd, 1999. So why not an overpass? Well, the main reason is with most over passes, you are in an open area where debris from the storm can harm you as wind speeds increase, not only from increasing elevation but from the air flow being squeezed between the narrow opening of the overpass. Without going into the subject of fluid dynamics, the best way to explain what happens as winds hit an overpass is to relate the winds to water flowing out of a garden hose. If you put your thumb over the flow of water, what happens? The velocity of the water increases due to the same amount of volume being squeezed through a smaller opening. So the winds in a relatively weak tornado can increase dramatically causing more bodily harm to those who seek shelter under an overpass. Below is a graphic created by the National Weather Service on why Overpasses do not provide adequate shelter from tornadoes.

Taylor County, GA Supercell........

Southeast Severe Weather

Valentine's Night Storm........

For all those lovers of exciting weather Cupid shot his arrow into the atmosphere and whipped up some elevated thunderstorms Valentine’s Night bringing a vivid lightning show and small hail to parts of East Texas. The lightning shots you see here were taken from my front porch as a strong storm moved out of Eastern Henderson County into Smith County.




This storm produced a large amount of small hail, covering the ground and causing hazardous travel along 346 from Flint to Whitehouse. The largest hailstone I found was penny size which technically is severe near the intersection of 346 and Oakbrook. These storms fired with a combination of many atmospheric conditions which came together over East Texas.



First, in the mid levels of the atmosphere a weak disturbance was entering West Texas causing the winds to diverge over East Texas. This causes the air to rise which could lead to clouds and precipitation. Second, a strong jet stream in the upper level of the atmosphere was moving just to our south. This put East Texas in what we call the left exit region of the jet stream which also adds in lifting the air.


Third, strong wind shear was noted in the atmosphere from 6,000’ to 30,000’. This will help aid in thunderstorm development by pushing the rain cooled air downstream, away from the storms updraft allowing the storm to become stronger.





The only thing missing for thunderstorm development, moisture. The low levels of the atmosphere where we normally find the moisture needed for thunderstorm development were too dry for surface based storm development. However, in the lower mid levels of the atmosphere a thin layer of moisture was moving into East Texas. This was all that was needed to help fire what we call elevated thunderstorms. Since the low levels of the atmosphere were dry, we were giving a vivid lightning storm with great visibility, giving many photo opportunities.