STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK
DAY 2 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWI47 KWNS.
VALID 111200Z - 121200Z
THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
35 S ILM 15 ESE RDU 25 SSW DCA 20 W PSF 30 WSW EEN 25 SSE PSM.
THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
10 ESE P28 40 E LAA 25 WSW LIC 25 SW CYS 10 W BFF 50 S EAR
10 NW TOP 35 S SZL 10 E UMN 10 ESE P28.
GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 45 WSW FHU
25 SSW GUP 15 ENE GUC RWL 55 SSW COD 50 SW BIL 45 N SHR 55 SSE 81V
50 NW MHN 25 SE BBW 25 SW LNK 35 NNE SZL 65 SSW CKV 20 S BWG
40 WSW BRL 50 S FAR 60 N DVL ...CONT... 20 E PSX 15 S NIR
20 WSW LRD.
...SYNOPSIS...
MID-LEVEL LOW INITIALLY OVER THE GREAT LAKES IS FORECAST TO OPEN
AND LIFT NEWD INTO QUEBEC IN RESPONSE TO MID AND UPPER-LEVEL JET
STREAKS TRANSLATING OUT OF THE MEAN TROUGH BASE AND INTO NEW
ENGLAND. ELSEWHERE...A BROAD AREA OF MODESTLY STRONG CYCLONIC MID-
LEVEL FLOW WILL PERSIST FROM THE NRN/CNTRL PLAINS SEWD THROUGH THE
OH/TN VALLEYS INTO THE MIDDLE ATLANTIC STATES. IN THE LOW LEVELS...
OCCLUDED SURFACE CYCLONE WILL EXIST OVER SERN ONTARIO BY LATE
AFTERNOON WITH ASSOCIATED FRONTAL SYSTEM EXTENDING FROM SRN NEW
ENGLAND SWD ALONG THE MIDDLE ATLANTIC COAST AND THEN WWD ACROSS THE
GULF COAST INTO CNTRL TX. IN ADDITION...A SECONDARY BAROCLINIC ZONE
IS FORECAST TO STRENGTHEN THROUGH THE LATTER HALF OF THE PERIOD
FROM THE CNTRL ROCKIES SEWD INTO MIDDLE MS VALLEY.
...MIDDLE ATLANTIC STATES NWD INTO SRN NEW ENGLAND...
SCATTERED TSTMS MAY BE ONGOING INITIALLY ALONG AND AHEAD OF SURFACE
FRONT FROM ERN PA/NJ NWD INTO NEW ENGLAND. FRONTAL CONVERGENCE AND
LOW-LEVEL WAA ACROSS THE WARM SECTOR SHOULD SUSTAIN THESE STORMS
THROUGH THE MORNING INTO AFTERNOON NEWD ACROSS MUCH OF NEW
ENGLAND...EFFECTIVELY LIMITING AIR MASS DESTABILIZATION. FARTHER
S...BREAKS IN THE CLOUDS/INCREASED DIABATIC HEATING COUPLED WITH
SURFACE DEWPOINTS IN THE UPPER 60S TO MID 70S WILL CONTRIBUTE TO A
MODERATELY UNSTABLE AIR MASS WITH MLCAPES OF 1500-2500 J/KG AHEAD
OF SURFACE COLD FRONT.
FORCING FOR ASCENT AHEAD OF MID-LEVEL TROUGH IN CONJUNCTION WITH
LOW-LEVEL FRONTAL CONVERGENCE SHOULD BE SUFFICIENT TO INITIATE
VIGOROUS DEEP...MOIST CONVECTION BY EARLY AFTERNOON ACROSS THE
SLIGHT RISK AREA. ETAKF FORECAST SOUNDINGS INDICATE UNIDIRECTIONAL
WIND PROFILES WITH SUFFICIENT SPEED SHEAR TO SUPPORT ORGANIZED
STORM CLUSTERS/LINES. GIVEN THE RELATIVELY HIGH WET-BULB ZERO
HEIGHTS/FREEZING LEVELS...IT APPEARS THAT DAMAGING WINDS WILL BE
THE PRIMARY SEVERE WEATHER THREAT WITH ANY EMBEDDED SMALL BOWING
SEGMENTS.
...CNTRL PLAINS...
DEEPENING LOW PRESSURE OVER SERN CO/SWRN KS SHOULD ENHANCE THE
ADVECTION OF POST-FRONTAL...BOUNDARY-LAYER MOISTURE NWD/NWWD ACROSS
KS INTO ERN CO/FAR SWRN NEB DURING THE DAY. THIS INCREASE IN
MOISTURE BENEATH STEEP MID-LEVEL LAPSE RATES /7.5-8.5 C/KM/ WILL
CONTRIBUTE TO MODERATE INSTABILITY WITH AFTERNOON MLCAPES OF 1000-
1500 J/KG.
DAYTIME HEATING AND LOW-LEVEL UPSLOPE WIND COMPONENT MAY ALLOW
ISOLATED TSTMS TO DEVELOP BY LATE AFTERNOON/EARLY EVENING ALONG THE
HIGHER TERRAIN OF NERN CO/SERN WY. THE PRESENCE OF 30-40KT NWLY
MID-LEVEL WINDS ABOVE LOW-LEVEL SELY FLOW WILL RESULT IN 40-50KTS
OF 0-6KM AGL SHEAR. THUS...IT APPEARS THAT A FEW SUPERCELLS WILL BE
POSSIBLE WITH LARGE HAIL BEING THE PRIMARY SEVERE WEATHER THREAT.
ADDITIONAL TSTMS ARE EXPECTED TO DEVELOP LATE FRIDAY EVENING INTO
FRIDAY NIGHT FARTHER SE ACROSS KS. HERE...A STRENGTHENING LLJ
SHOULD ENHANCE LOW-LEVEL WAA/ISENTROPIC ASCENT ALONG AND N OF A
SURFACE BOUNDARY WHICH SHOULD EXIST FROM E-CNTRL CO INTO SERN MO.
MODEST AMOUNTS OF ELEVATED INSTABILITY AND DEEP-LAYER SHEAR SUGGEST
THE POTENTIAL FOR LARGE HAIL/DAMAGING WINDS WITH THE STRONGEST
STORMS.
...SERN U.S. WWD ACROSS THE GULF COAST INTO TX...
A LARGE POOL OF SURFACE DEWPOINTS IN THE 70S IS EXPECTED TO PERSIST
TO THE S OF FRONTAL BOUNDARY WHICH WILL SLOWLY MOVE S/SEWD THROUGH
THE REGION. DAYTIME HEATING IN COMBINATION WITH THIS RICH LOW-LEVEL
AIR MASS WILL ONCE AGAIN CONTRIBUTE TO AFTERNOON MLCAPES
APPROACHING 2500-3500 J/KG. TSTMS ARE EXPECTED TO DEVELOP ALONG THE
FRONT FAIRLY EARLY IN THE PERIOD WITH ADDITIONAL DEVELOPMENT
EXPECTED ACROSS THE WARM SECTOR BY EARLY AFTERNOON. WEAK LOW-LEVEL
CONVERGENCE/MID-LEVEL FLOW SUGGEST THAT THE MAJORITY OF ACTIVITY
SHOULD REMAIN SUB-SEVERE. HOWEVER...ISOLATED DAMAGING WIND GUSTS
WILL BE POSSIBLE WITH TSTM CLUSTERS THAT CAN ORGANIZE COLD POOLS.
..MEAD.. 07/10/03
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED FOR 0800Z
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