Severe weather - March 18, 2012

It appears that a fairly potent severe weather outbreak will occur in the TX and OK panhandles and north into western KS and NE.  The SPC has issued a slight risk for their Day 2 convective outlook with hatched 30% probabilities in aforementioned areas.  

A strong, upper level trough is currently digging along the west coast of the US and moving eastward.  

 

The models are in pretty good agreement that the trough will traverse the 4 corners region and become slightly negative-tilted as it ejects into the plains.  The NAM and GFS are in slight disagreement in regards to the position of the dryline in the panhandles (NAM being farther west), but both models are showing decent destabilization east of the dryline (MLCAPE values 1000-1500) and a backing sfc wind profile.  Models show sfc dews will be in the upper 50's to low 60's east of the dryline in the eastern sections of the panhandles.  However, i believe the models are underforecasting the moisture and I believe we will see dews in the low to mid 60's as far north as WC OK, thus increasing instability.  The 850 winds are in the 30 kt range and are backing SSE.  If that holds true, then we should see some tornadoes tomorrow if storms can stay discrete.

   I expect that  storms will fire in the early afternoon hours along the dryline in the central Panhandles and stay semi-discrete for a couple hours.  Then, as the main jet streak approaches and lift increases, several clusters of storms will merge into a solid squall line with embedded supercells and trek east with a risk of strong damaging winds and isolated tornadoes.  I wouldn't be surprised if SPC puts a MOD risk for tomorrow in these areas (especially for high wind threat).  We will probably see a handful of tubes tomorrow too.

 

You can see the negative tilting to the trough!  Speed max present over northeast NM and into OK panhandle.  

 

Notice backing sfc wind profile east of dryline!

Here is a forecast sounding for 00Z for Childress, TX (KCDS):

 

 

Great directional and speed shear!  Cape values are meager because of low dewpoint values, but this may be due to convective feedback in the models.  

 

Some cons with this system are the strong meridional component of the upper level flow; storms could become linear quickly.   Also, the possible lack of stronger instability due to a cirrus shield and less moisture (assuming the models are accurate).  

I'd be chasing this event but I have work obligations until 3 and I recently had back surgery again and don't know if I can take the several hours of driving to get to the storms before dark. If I were chasing I would park myself near Pampa and await initiation.  Storms to the north will have stronger mid level flow and upper level support but less instability.  

 I will probably be chasing the next day nearer to home.  Will post more on that tomorrow.

We'll see how the day unfolds!