Severe Weather Forecast

U.S. Convective Outlook

417 
acus01 kwns 210059 
swody1 
Storm Prediction Center ac 210057 


Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0757 PM CDT sun may 20 2012 


Valid 210100z - 211200z 


..no severe thunderstorm areas forecast... 


..Upper/Middle MS valley... 
a broad zone of thunderstorms continues this evening along an axis 
from Lake Michigan southward into the middle MS valley. Most of the 
storms have decreased in intensity compared to earlier this 
afternoon...but sufficient instability persists from Arkansas/Tennessee northward 
for a risk of isolated gusty winds and hail with the strongest 
cells. This threat should continue to diminish through the evening. 




... 
Isolated intense storms affected parts of west central Texas for a few 
hours this evening. However...recent radar/satellite trends suggest 
this threat is nearly over. 


... 
An isolated strong storm persists over northeast Colorado. This activity 
may remain intense for another hour or so before weakening with the 
onset of diurnal cooling. 


.Hart.. 05/21/2012 






Mesoscale Discussion

266 
acus11 kwns 210032 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 210032 
txz000-210200- 


Mesoscale discussion 0856 
National Weather Service Storm Prediction Center Norman OK 
0732 PM CDT sun may 20 2012 


Areas affected...parts of northwest Texas 


Concerning...Severe Thunderstorm Watch 286... 


Valid 210032z - 210200z 


The severe weather threat for Severe Thunderstorm Watch 286 
continues. 


Summary...ww 286 probably should be continued at least another hour 
or two...but it could be cancelled prior to scheduled 04z expiration 
if current trends continue. 


Discussion...initial storm...near intersection of convective outflow 
and surface frontal zone...has dissipated southwest of Wichita 
Falls...but isolated to widely scattered new convective development 
continues along the surface front extending west southwestward 
toward the Lubbock area. Although cape is still moderately large 
and inhibition appears weak...activity has remained somewhat 
suppressed...even in the presence of sufficient shear for 
supercells...beneath 30+ knots northwesterly 500 mb flow. Support for 
a substantial further increase in storm coverage and intensity prior 
to the onset of more rapid boundary layer cooling is not obvious. 
However...isolated new storm development still does not appear out 
of the question through 01-02z...particularly along and just north 
of the front...to the east southeast of Lubbock...where lingering 
boundary layer instability remains strongest. 


.Kerr.. 05/21/2012 


..please see www.Spc.NOAA.Gov for graphic product... 


Attention...WFO...oun...sjt...lub... 


Latitude...Lon 33240130 33630090 33689968 33719933 32999960 33060018 
33140053 33240130