The GFS has slowed down the frontal passage (Fig 1) by about 150 miles and is coming more in line with the NAM and WRF (Fig 2). We still do not see a dry line forming on the GFS solution so we would be looking mainly at a squall line event Thursday evening. The NAM still shows a dryline and develops a secondary surface low, much like the GFS was hinting Monday morning, causing backing winds over north central TX and south central OK (Fig 3). This will aid in low level mesocyclone development which could lead to a tornado or two developing during storm initiation. I still like the northern target better for the possibility of tornadoes but the 12Z NAM has a better potential for tornadoes in the Southern Plains. Looks as though there could be a significant tornado or two late Thursady into Friday in eastern OK and north west AR but the chase terrain here is not the greatest. As of now I will probably head out Thursday after Midday and wait to see what happens.