Potential Severe Weather Outbreak looks possible for Thursday for parts of the state from I-35 to east.





DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1258 AM CDT WED APR 13 2011

VALID 141200Z - 151200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF SE KS...ERN OK...FAR SW MO AND FAR NW AR...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CNTRL PLAINS...SRN PLAINS...MID-MO VALLEY...OZARKS AND ARKLATEX...

...REGIONAL OUTBREAK OF SEVERE STORMS AND POSSIBLY TORNADOES ACROSS PARTS OF THE SRN AND CNTRL PLAINS THURSDAY AFTERNOON AND EVENING...

...SRN PLAINS/CNTRL PLAINS/OZARKS/MID-MO VALLEY...
AN IMPRESSIVE NEGATIVELY-TILTED UPPER-LEVEL TROUGH IS FORECAST TO CLOSE OFF OVER THE CNTRL HIGH PLAINS THURSDAY. THE EXIT REGION OF A 70 TO 80 KT MID-LEVEL JET ROUNDING THE BASE OF THE TROUGH WILL CREATE STRONG DEEP LAYER SHEAR PROFILES ACROSS THE REGION CREATING AN ENVIRONMENT FAVORABLE FOR SEVERE STORM DEVELOPMENT. AT THE SFC...A WELL-DEVELOPED LOW IS FORECAST TO DEEPEN QUICKLY ACROSS CNTRL KS AT MIDDAY MOVING NWD INTO NEB. THUNDERSTORM INITIATION SHOULD FIRST OCCUR NEAR AND TO THE NORTH OF THE SFC LOW DURING THE AFTERNOON WHERE STRONG LOW-LEVEL CONVERGENCE AND COLD TEMPS ALOFT SHOULD RESULT IN A LARGE HAIL THREAT. THE MODELS ARE CONSISTENT DEVELOPING STRONG CONVECTION DURING THE LATE AFTERNOON SEWD INTO CNTRL TO ERN KS AND ECNTRL OK ALONG THE WRN EDGE OF AN AXIS OF MODERATE INSTABILITY. THE STORMS SHOULD INITIATE JUST TO THE EAST OF A DRYLINE ORIENTED NORTH TO SOUTH ALONG THE I-35 CORRIDOR.

FORECAST SOUNDINGS ALONG THE INSTABILITY AXIS AT 00Z FRIDAY SHOW MLCAPE VALUES FROM 1500 J/KG IN ECNTRL KS TO 2500 TO 3000 J/KG IN ECNTRL OK. THIS COMBINED WITH 0-6 KM SHEAR VALUES OF 50 TO 65 KT WILL CREATE A THERMODYNAMIC AND SHEAR ENVIRONMENT FAVORABLE FOR SUPERCELLS AND LARGE HAIL ESPECIALLY ACROSS THE MODERATE RISK AREA IN SE KS...ERN OK...FAR NW AR AND FAR SW MO. THE GREATEST SEVERE THREAT COVERAGE SHOULD OCCUR ON THE NOSE OF A PLUME OF STEEP MID-LEVEL LAPSE RATES WHICH COMBINED WITH THE MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR WILL BE FAVORABLE FOR VERY LARGE HAIL WITH THE MORE DOMINANT SUPERCELLS. TORNADOES WILL ALSO BE POSSIBLE ESPECIALLY AS THE LOW-LEVEL JET STRENGTHENS DURING THE EARLY EVENING. FORECAST SOUNDINGS IN ERN OK FROM 00Z TO 03Z SHOW 0-3 KM STORM RELATIVELY HELICITIES OF 350 TO 450 M2/S2 WHICH WILL MAKE AN ISOLATED THREAT FOR STRONG TORNADOES POSSIBLE. HOWEVER...THIS THREAT SHOULD BE CONDITIONAL UPON MOISTURE RETURN AND STORM MODE. SQUALL-LINE DEVELOPMENT INSTEAD OF THE TENDENCY FOR DISCRETE CONVECTION WOULD RESULT IN MORE OF A WIND DAMAGE THREAT.

FURTHER SOUTH ACROSS NE TX...FORECAST SOUNDINGS AT 21Z TO 00Z SHOW A STOUT CAPPING INVERSION WHICH IS EXPECTED TO HOLD FOR MUCH OF THE AFTERNOON AND EVENING. FOR THIS REASON...THE SEVERE THREAT SHOULD DROP OFF QUICKLY WITH SWD EXTENT IN NE TX. DURING THE EVENING AND OVERNIGHT PERIOD...THE MODELS ARE CONSISTENT WITH DEVELOPING AN MCS IN THE OZARKS AND DRIVING THIS FEATURE EWD INTO THE LOWER TO MID MS VALLEY. ALTHOUGH SEVERE THREAT COVERAGE SHOULD DECREASE DURING THE LATE EVENING AND OVERNIGHT PERIOD...A THREAT FOR HAIL AND ISOLATED WIND DAMAGE MAY CONTINUE AS FAR EAST AS SCNTRL MO AND ECNTRL AR WHERE SFC DEWPOINTS SHOULD BE IN THE LOWER 60S F AND 40 TO 50 KTS OF LOW-LEVEL FLOW IS FORECAST.

..BROYLES.. 04/13/2011