SWODY2
SPC AC 011730
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT MON JUN 01 2009
VALID 021200Z - 031200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN AND CNTRL PLAINS
INTO THE MID MS AND OH VALLEYS...
...SYNOPSIS...
BLOCKING PATTERN WILL CONTINUE THROUGH TUESDAY WITH A LARGE SCALE
TROUGH AMPLIFYING ACROSS THE GREAT LAKES AND A CLOSED UPPER LOW
PERSISTING OFF THE CA COAST. A RIDGE AXIS WILL EXTEND FROM THE
PACIFIC NW SEWD INTO THE CNTRL ROCKIES. VORTICITY MAXIMUM CURRENTLY
NEAR THE FOUR CORNERS AREA WILL DRIFT SLOWLY EWD INTO KS AND OK
SATURDAY AFTERNOON.
AT THE SURFACE CP HIGH PRESSURE WILL SURGE SWD THROUGH THE PLAINS
AND UPPER MS VALLEY IN ASSOCIATION WITH NRN STREAM IMPULSE MOVING
SEWD THROUGH BROADER UPPER TROUGH. THIS WILL RESULT IN ENHANCEMENT
AND SWD PROGRESSION OF BAROCLINIC ZONE NOW EXTENDING FROM THE CNTRL
PLAINS EWD INTO THE GREAT LAKES REGION. BY LATE AFTERNOON THE FRONT
SHOULD EXTEND FROM THE OH-MID MS VALLEYS SWWD INTO THE TX PANHANDLE
WHERE IT WILL INTERSECT THE DRYLINE THAT WILL EXTEND SWD THROUGH WRN
TX.
...CNTRL AND SRN PLAINS AREA...
AS UPPER LOW CURRENTLY NEAR THE FOUR CORNERS AREA DRIFTS EWD INTO KS
AND OK...A BELT OF 25-30 KT MID LEVEL FLOW WILL DEVELOP THROUGH NRN
PORTIONS OF WRN TX INTO WRN OK. THIS BELT OF STRONGER FLOW WILL
ADVECT STEEPER MID-LEVEL LAPSE RATES EWD ABOVE LOW-MID 60S DEWPOINTS
WITH 2000-2500 J/KG MLCAPE EXPECTED OVER A PORTION OF THE SRN HIGH
PLAINS AND 1500-2000 J/KG POSSIBLE FARTHER NWD INTO KS. STORMS WILL
LIKELY BE IN PROGRESS WITHIN ZONE OF LIFT ALONG AND NORTH OF FRONTAL
BOUNDARY FROM NEB AND POSSIBLY INTO NRN KS. POTENTIAL FOR ONGOING
CONVECTION FARTHER SOUTH IN WARM SECTOR REMAINS UNCERTAIN AT THIS
TIME. STORMS ARE EXPECTED TO INTENSIFY ALONG THE FRONT AS BOUNDARY
LAYER DESTABILIZES. WITH STRONGER MID LEVEL FLOW REMAINING POST
FRONTAL...STORMS DEVELOPING ALONG FRONT SHOULD BE MULTICELLULAR IN
CHARACTER WITH A THREAT FOR ISOLATED STRONG WIND GUSTS AND HAIL.
ACTIVITY WILL DEVELOP SEWD DURING THE EVENING.
FARTHER SOUTH FROM NRN PARTS OF WRN TX INTO SWRN OK...OTHER STORMS
SHOULD DEVELOP ALONG NRN END OF DRYLINE OR ON DRYLINE/COLD FRONT
INTERSECTION WHERE VERTICAL SHEAR WILL BE AUGMENTED BY THE BELT OF
25-30 KT MID LEVEL FLOW. VERTICAL SHEAR OF 30-40 KT AND MODERATE
INSTABILITY WILL BE SUPPORTIVE OF SOME SUPERCELL STRUCTURES...BUT
LOW LEVEL HODOGRAPHS WILL REMAIN SMALL DUE TO WEAK LOW LEVEL WINDS.
PRIMARY THREATS WILL BE ISOLATED LARGE HAIL AND DAMAGING WIND
GUSTS...BUT A BRIEF TORNADO OR TWO MAY ALSO BE POSSIBLE DURING THE
EARLY EVENING.
...MID MS THROUGH OH VALLEYS...
LOWER 60S BOUNDARY LAYER DEWPOINTS OVER THE MID MS VALLEY WILL
ADVECT EWD THROUGH THE OH VALLEY UNDER THE INFLUENCE OF MODEST SWLY
LOW LEVEL FLOW. AS THE BOUNDARY LAYER WARMS THE PRE-FRONTAL WARM
SECTOR IS EXPECTED TO BECOME MODERATELY UNSTABLE...BUT MODEST
MID-LEVEL LAPSE RATES WILL LIMIT MLCAPE TO GENERALLY BELOW 2000
J/KG. STORMS WILL LIKELY REDEVELOP ALONG AND SOUTH OF THE FRONT AS
THE BOUNDARY LAYER DESTABILIZES DURING THE DAY. STRONGER MID-UPPER
FLOW ASSOCIATED WITH THE AMPLIFYING UPPER TROUGH WILL REMAIN ALONG
AND NORTH OF THE FRONT...WITH MODEST UNIDIRECTIONAL DEEP LAYER FLOW
AND VERTICAL SHEAR LIKELY IN WARM SECTOR. STORMS DEVELOPING ALONG
THE FRONT COULD DEVELOP SOME SUPERCELL CHARACTERISTICS...BUT THE
PRIMARY MODE WILL LIKELY TRANSITION TO MULTICELL LINES OR LINE
SEGMENTS WITH ISOLATED DAMAGING WIND AND HAIL POSSIBLE THROUGH EARLY
EVENING.
..DIAL.. 06/01/2009
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