DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 301715
SWODY2
SPC AC 301713

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1213 PM CDT FRI MAR 30 2012

VALID 311200Z - 011200Z

...NO SVR TSTM AREAS FORECAST...

...OZARKS/LOWER MS VALLEY/GULF COAST...
NORTHWEST FLOW IS FORECAST ACROSS THE LOWER MS VALLEY AND GULF COAST
STATES ON SATURDAY. AT THE SFC...SLY FLOW WILL EXIST ACROSS MUCH OF
THE REGION WITH A BROAD WARM SECTOR EXTENDING FROM THE SRN PLAINS
EWD INTO THE TN VALLEY AND CNTRL GULF COAST STATES. MODERATE TO
STRONG INSTABILITY IS FORECAST BY AFTERNOON WITH THE MODELS
DEVELOPING SCATTERED THUNDERSTORMS IN MANY AREAS. THE INSTABILITY
COMBINED WITH MODERATE DEEP LAYER SHEAR WILL BE SUFFICIENT FOR A
SEVERE THREAT WHERE STORMS DEVELOP. HOWEVER...LARGE-SCALE ASCENT
SHOULD REMAIN WEAK WHICH WILL KEEP CONVECTIVE DEVELOPMENT UNFOCUSED.
FOR THAT REASON...WILL NOT TRY TO PIN AN AREA DOWN FOR A GREATER
SEVERE THREAT. INSTEAD WILL BROADEN THE LOW-END PROBABILITIES IN
ORDER TO CONVEY A MARGINAL SEVERE THREAT ACROSS A WIDESPREAD AREA.

...MID MO VALLEY/MID MS VALLEY...
NORTHWEST FLOW WILL BE IN PLACE ACROSS THE MID TO UPPER MS VALLEY
SATURDAY AS SEVERAL MINOR DISTURBANCES MOVE SEWD ACROSS THE REGION.
A NARROW AXIS OF INSTABILITY IS FORECAST FROM WRN MO EXTENDING NWD
INTO IA WHERE SOME OF THE MODELS DEVELOP SCATTERED THUNDERSTORMS.
FORECAST SOUNDINGS SATURDAY AFTERNOON ALONG THE INSTABILITY AXIS
SHOW MLCAPE VALUES AROUND 1500 J/KG WITH 40 KT OF DEEP LAYER SHEAR
AND STEEP MID-LEVEL LAPSE RATES. THIS ENVIRONMENT SHOULD BE
SUPPORTIVE OF SUPERCELLS WITH ISOLATED LARGE HAIL ASSUMING THAT
STORMS CAN INITIATE WHEN THE CAP WEAKENS IN THE LATE AFTERNOON.
HOWEVER...MUCH UNCERTAINTY EXISTS FOR THIS SCENARIO BECAUSE MANY OF
THE MODELS DO NOT DEVELOP STORMS. FOR THIS REASON WILL LEAVE THE
AREA AS A SEE TEXT.

...SOUTH TX...
AN AXIS OF MODERATE TO STRONG INSTABILITY IS FORECAST SATURDAY
AFTERNOON ACROSS THE TX COASTAL PLAINS. THUNDERSTORMS SHOULD
INITIATE IN THE HIGHER TERRAIN OF NRN MEXICO AND MOVE SLOWLY EWD
INTO SOUTH TX LATE SATURDAY AFTERNOON. IN ADDITION TO THE
INSTABILITY...FORECAST SOUNDINGS IN SOUTH TX SATURDAY AFTERNOON SHOW
25 TO 30 KT OF DEEP LAYER SHEAR AND STEEP MID-LEVEL LAPSE RATES.
THIS ENVIRONMENT SHOULD SUPPORT A MARGINAL THREAT FOR WIND DAMAGE
AND HAIL.

..BROYLES.. 03/30/2012

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