SWODY2
SPC AC 020537
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1237 AM CDT SUN MAY 02 2010
VALID 031200Z - 041200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL GULF COAST INTO
THE ERN CAROLINAS...
...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF IL...IND AND
LOWER MI...
...SYNOPSIS...
NRN BRANCH SHORT WAVE TROUGH INITIALLY FROM A VORTEX OVER WRN
ONTARIO INTO THE MID MO VALLEY WILL ACCELERATE EWD THROUGH THE GREAT
LAKES REGION IN RESPONSE TO APPROACH OF AN INTENSE UPPER-LEVEL JET
STREAK THROUGH THE PACIFIC NW INTO NRN HIGH PLAINS. MEANWHILE...A
SRN STREAM VORTICITY MAXIMA INITIALLY NEAR THE TX/NM BORDER WILL
MOVE MORE SLOWLY EWD...EVENTUALLY REACHING THE LOWER MS VALLEY BY
TUESDAY MORNING.
IN THE LOW-LEVELS...A SURFACE FRONT INITIALLY SITUATED ALONG THE
APPALACHIANS SWWD TO THE CNTRL GULF COAST WILL SHIFT EWD TOWARD THE
MID AND SERN ATLANTIC COAST. ELSEWHERE...COLD FRONT WILL INTENSIFY
MONDAY WHILE PROGRESSING EWD THROUGH THE UPPER GREAT LAKES. THE
SWRN EXTENSION OF THIS BOUNDARY WILL REMAIN ANCHORED BY A WEAK
SURFACE LOW OVER TX.
...CAROLINAS SWWD TO THE CNTRL/ERN GULF COAST...
CLUSTERS OF STRONG TO POTENTIALLY SEVERE TSTMS ARE EXPECTED TO BE
ONGOING AT THE ONSET OF THE PERIOD OVER THE CNTRL GULF STATES WITHIN
A MOIST AND AT LEAST MARGINALLY UNSTABLE AIR MASS. PERSISTENT
SLY/SWLY FLOW WITHIN PRE-FRONTAL WARM SECTOR WILL SERVE TO MAINTAIN
A MOIST BOUNDARY LAYER WITH DEW POINTS IN THE 60S TO LOWER 70S.
HOWEVER...CONSIDERABLE UNCERTAINTY EXISTS WITH REGARD AIR MASS
DESTABILIZATION OWING TO THE POTENTIAL FOR WIDESPREAD CLOUDS AND
CONVECTIVE PRECIPITATION.
CURRENT THINKING IS THAT STORMS SHOULD INCREASE IN COVERAGE AND
INTENSITY THROUGH THE DAY IN ADVANCE OF SURFACE FRONT PROGRESSING
EWD THROUGH THE APPALACHIANS. LOW-LEVEL SHEAR IS NOT EXPECTED TO BE
PARTICULARLY STRONG...BUT THE PRESENCE OF 40-50 KT DEEP...SWLY SHEAR
WILL BE SUPPORTIVE OF EMBEDDED BOWING AND SUPERCELL STRUCTURES WITH
THE THREAT FOR DAMAGING WINDS AND PERHAPS A COUPLE TORNADOES INTO
MONDAY EVENING.
...UPPER GREAT LAKES INTO MID MS VALLEY...
DAYTIME HEATING...BOUNDARY LAYER DEW POINTS IN THE 50S AND THE EWD
PROGRESSION OF COLD POOL /I.E. -22 TO -24 C AT 500 MB/ ATTENDANT TO
MIDLEVEL TROUGH WILL CONTRIBUTE TO THE DEVELOPMENT OF STEEP LAPSE
RATES AND MLCAPE OF 500-1000 J/KG ALONG COLD FRONT BY AFTERNOON.
ISOLATED TO SCATTERED DIURNAL STORMS ARE EXPECTED TO DEVELOP ALONG
THE FRONT...AIDED BY INCREASING DEEP ASCENT AHEAD OF SHORT WAVE
TROUGH.
VERTICAL SHEAR WILL STEADILY STRENGTHEN THROUGH THE DAY OWING TO THE
EWD PROGRESSION OF A 50-60 KT MIDLEVEL JET STREAK ACROSS THE
LOW-LEVEL BAROCLINIC ZONE...AND THE DEVELOPMENT OF A 30+ KT SWLY
LLJ. AS SUCH...THE SETUP WILL FAVOR A FEW ORGANIZED/ROTATING STORMS
WITH THE THREAT FOR HAIL AND DAMAGING WIND GUSTS.
THE DIMINISHING INFLUENCE OF THE GREAT LAKES SHORT WAVE TROUGH WITH
SWD EXTENT ALONG THE FRONTAL ZONE MAKES CONVECTIVE INITIATION MORE
UNCERTAIN. THEREFORE...WHILE SIMILAR DISTRIBUTIONS IN INSTABILITY
AND VERTICAL SHEAR ARE FORECAST TO EXIST AS FAR S AS THE OZARK
PLATEAU...ONLY LOW SEVERE WEATHER PROBABILITIES WILL BE INCLUDED DUE
TO A LOWER CONFIDENCE IN STORM DEVELOPMENT.
..MEAD.. 05/02/2010
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