U.S. Severe Weather Forecast (Convective Outlook)

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Day 2 convective outlook corr 1 
National Weather Service Storm Prediction Center Norman OK 
0123 am CDT Sat may 23 2015 


Valid 241200z - 251200z 


..there is a slight risk of severe thunderstorms across central and south 
Texas... 


..there is a marginal risk of severe thunderstorms from the lower MS valley to the 
Central Plains... 


Corrected probability graphic. 


... 
Scattered to numerous thunderstorms are expected across much of the 
southern and Central Plains Sunday. The strongest convection will 
likely develop across central and south Texas where large 
hail...damaging winds...and perhaps a few tornadoes can be expected. 
Elsewhere...isolated hail and wind may accompany strong convection 
from portions of the lower Mississippi Valley into the Central 
Plains. 


..southern/Central Plains... 


Broad but weak 12hr height falls will spread into the southern/Central 
Plains Sunday ahead of low-latitude short-wave trough. Latest model 
guidance is fairly consistent ejecting a short-wave trough into the 
main body of Texas by 24/18z...then northeastward into the middle MS valley during 
the overnight hours. Extremely high precipitable water values...ranging from 1.75-2 
inches...will surge northward ahead of this feature from the western Gulf 
basin...northward into eastern Kansas. Numerous showers/thunderstorms will develop ahead 
of the short wave within modestly sheared but weak lapse rate 
environment. Much of the convection will produce very heavy 
rainfall and extensive clouds will limit boundary layer heating. 
One exception will be near the dry line...but within Post short wave 
regime. Latest forecast soundings suggest the greatest 
shear/instability combination will be across central/southern Texas prior to 
large scale forcing ejecting north into the middle MS valley. Greatest 
severe risk will be across this region for thunderstorm activity that 
evolves along southern fringe of stronger flow aloft within base of 
ejecting trough. Isolated supercells could produce large 
hail...damaging winds and perhaps a few tornadoes. It/S not clear 
if organized deep convection will develop along the dry line during 
the late afternoon hours and for this reason 5 percent severe probs 
will be maintained. 


Farther north across Nebraska...thunderstorms should develop within 
southeasterly low-level flow beneath seasonally weak middle-level southerly 500mb 
flow. A few slow-moving supercells could evolve across this region 
that would pose a risk of large hail. 


.Darrow.. 05/23/2015