SWODY2
SPC AC 311727
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1227 PM CDT SAT MAR 31 2012
VALID 011200Z - 021200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE OH
VALLEY...
...OH VALLEY...
NORTHWEST FLOW WILL BE IN PLACE ACROSS THE NERN STATES SUNDAY WITH A
SHORTWAVE TROUGH MOVING SEWD ACROSS THE ERN GREAT LAKES DURING THE
DAY. AT THE SFC...A COLD FRONT SHOULD MOVE SWD INTO THE OH VALLEY
DURING THE AFTERNOON WITH AN AXIS OF MODERATE INSTABILITY DEVELOPING
FROM WRN KY NEWD ACROSS IND INTO WRN OH. SOME CONVECTION MAY BE
ONGOING ACROSS THE LOWER OH VALLEY SUNDAY MORNING WITH NEW
CONVECTION DEVELOPING ALONG AND AHEAD OF THE FRONT FROM CNTRL IND
SEWD ACROSS SRN OH. MODEL FORECASTS MOVE THIS CONVECTION SWD ACROSS
KY AND WV DURING THE LATE AFTERNOON AND EVENING.
A 75 TO 85 KT MID-LEVEL JET ASSOCIATED WITH THE SHORTWAVE TROUGH
OVER ERN GREAT LAKES WILL MOVE SEWD INTO THE CNTRL APPALACHIAN MTNS
SUNDAY WITH THE SERN EDGE OF THE JET AFFECTING THE OH VALLEY. THIS
WILL CREATE MODERATE TO STRONG DEEP LAYER SHEAR PROFILES ACROSS THE
SLIGHT RISK AREA. IN ADDITION...FORECAST SOUNDINGS BY MID-AFTERNOON
SHOW A MODERATELY UNSTABLE AIRMASS IN PLACE ACROSS SRN IND...SW OH
AND MOST OF KY WITH MUCAPE IN THE 1000 TO 1500 J/KG RANGE. THIS
COMBINED WITH STEEP MID-LEVEL LAPSE RATES MAY BE SUFFICIENT FOR
SUPERCELLS WITH LARGE HAIL IF CELLS CAN REMAIN DISCRETE. IF
SUPERCELLS CAN ORGANIZE...THEN AN ISOLATED TORNADO THREAT MAY EXIST
AS WELL. HOWEVER...THE DOMINANT CONVECTIVE MODE FOR SUNDAY REMAINS
UNCERTAIN AT THIS TIME AND FRONTAL FORCING COULD ENCOURAGE THE
DEVELOPMENT OF A LINE POSING A WIND DAMAGE THREAT.
...CNTRL GULF COAST STATES...
A LARGE AREA OF MODERATE TO STRONG INSTABILITY WILL AGAIN DEVELOP
ACROSS THE CNTRL GULF COAST STATES BY MIDDAY SUNDAY. ALTHOUGH NO
CLEAR FOCUS WILL EXIST...THE GFS DOES DEVELOP SCATTERED
THUNDERSTORMS SUNDAY AFTERNOON FROM WRN TN SEWD ACROSS NRN MS INTO
AL. FORECAST SOUNDINGS ALONG THIS CORRIDOR AT 21Z SHOW MLCAPE VALUES
OF 2000 TO 2500 J/KG...O-6 KM SHEAR IN THE 20 TO 25 KT RANGE...SFC
DEWPOINTS APPROACHING 70 F AND STEEP LOW-LEVEL LAPSE RATES. THIS
ENVIRONMENT SHOULD BE FAVORABLE FOR MARGINALLY SEVERE PULSE STORMS
WITH AN ISOLATED WIND DAMAGE THREAT MAINLY NEAR PEAK HEATING.
...UPPER MS VALLEY...
AN UPPER-LEVEL RIDGE WILL MOVE EWD ACROSS THE GREAT PLAINS INTO THE
MS VALLEY ON SUNDAY. AT THE SFC...A MOIST AXIS SHOULD BE LOCATED
FROM THE MID MO VALLEY NWD INTO SRN MN WHERE MODERATE INSTABILITY
SHOULD EXIST BY EARLY SUNDAY EVENING. LATER ON SUNDAY
EVENING...MODEL FORECASTS INITIATE THUNDERSTORMS ALONG THE NRN EDGE
OF THE INSTABILITY AXIS AS A COLD FRONT ADVANCES SEWD INTO THE UPPER
MS VALLEY. FORECAST SOUNDINGS JUST AHEAD OF THE FRONT LATE SUNDAY
EVENING SHOW ELEVATED INSTABILITY WITH MUCAPE IN THE 1000 TO 1500
J/KG RANGE AND CLOUD LAYER SHEAR OF 40 TO 45 KT. THIS COULD SUPPORT
A MARGINAL HAIL THREAT WITH THE STRONGER CORES WITH THREAT
PERSISTING INTO THE OVERNIGHT PERIOD.
..BROYLES.. 03/31/2012
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