[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 121615
SWODY1
SPC AC 121614

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1114 AM CDT WED JUL 12 2006

VALID 121630Z - 131200Z

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO EARLY
TONIGHT FROM THE OH VALLEY TO INTERIOR SRN NEW ENGLAND....

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO EARLY
TONIGHT FOR MT AND WRN ND....

...NY/PA TO NRN KY THROUGH THIS EVENING...
A SURFACE LOW AND ASSOCIATED MID LEVEL WAVE OVER SWRN ONTARIO WILL
MOVE EWD ACROSS CENTRAL NY THROUGH TONIGHT.  VERY MOIST PROFILES ARE
PRESENT IN ADVANCE OF THIS SYSTEM ACROSS PA/NY...WITH WIDESPREAD
CLOUDS/RAINFALL ACROSS CENTRAL PA AND MUCH OF NY EXPECTED TO LIMIT
SURFACE HEATING.  HOWEVER...A FEW BREAKS IN THE CLOUDS ARE PRESENT
OVER E/SE PA INVOF A WEAK LEE TROUGH...WITH LOWER 70 DEWPOINTS
SPREADING NWD ACROSS THIS AREA.  THIS RICH MOISTURE AND TEMPERATURES
IN THE 70S ACROSS SRN NY AND AT LEAST MID 80S ERN PA/NJ WILL
CONTRIBUTE TO AFTERNOON MLCAPE VALUES OF 500-1000 J/KG.

THOUGH INSTABILITY WILL BE MARGINAL IN THE TROPICAL TYPE
ENVIRONMENT...FORECAST WIND PROFILES SUGGEST THE POTENTIAL FOR
SUPERCELLS GIVEN EFFECTIVE BULK SHEAR OF 30-40 KT AND 0-1 KM SRH IN
EXCESS OF 200 M2/S2 ACROSS NE PA AND SE NY THIS AFTERNOON.  THE MORE
FOCUSED THREAT AREA SHOULD BE E OF THE LEE TROUGH AND ALONG THE SRN
FRINGE OF THE THICKER CLOUDS THAT ARE REINFORCING A WEAK BOUNDARY
ACROSS SRN NY/NE PA.  CLOUD BREAKS TO THE S SHOULD ALLOW A FEW
DISCRETE STORMS TO FORM IN THE LARGER AREA OF CONVECTION...AND A FEW
TORNADOES MAY OCCUR GIVEN THE RICH LOW-LEVEL MOISTURE AND PRONOUNCED
LOW-LEVEL SHEAR.

FARTHER SW...REGIONAL SOUNDINGS AND VWP/S REVEAL A BELT OF 30-40 KT
WSWLY FLOW IN THE 1-3 KM AGL LAYER FROM KY TO PA. 
MEANWHILE...SURFACE HEATING/DESTABILIZATION ALONG THE SERN FRINGE OF
THE THICKER CLOUDS WILL ALLOW THE DEVELOPMENT OF MODERATE
INSTABILITY THIS AFTERNOON.  THE STEEPER LOW-LEVEL LAPSE RATES AND
BELT OF STRONGER LOW-LEVEL FLOW SHOULD BE FAVORABLE FOR A FEW STORMS
WITH DAMAGING OUTFLOW WINDS THIS AFTERNOON.

...NRN HIGH PLAINS THIS AFTERNOON/TONIGHT...
A MID LEVEL SHORTWAVE TROUGH OVER ERN WA/ORE AND WRN ID THIS MORNING
WILL EJECT ENEWD TOWARD ERN MT AND THE SRN PRAIRIE PROVINCES BY
EARLY THURSDAY.  IN ADVANCE OF THIS TROUGH...A SURFACE LOW NOW IN E
CENTRAL MT SHOULD DEVELOP NEWD TOWARD SE SASKATCHEWAN...WHILE
BOUNDARY LAYER DEWPOINTS IN THE LOW-MID 60S SPREAD NWD ACROSS THE
DAKOTAS.  FARTHER W ACROSS MT...THE LOW-LEVELS ARE QUITE DRY
ACCORDING THE SURFACE OBSERVATIONS AND 12Z SOUNDINGS.  HIGH-BASED
CONVECTION MAY MOVE EWD/NEWD OFF THE HIGHER TERRAIN OF SW MT THIS
AFTERNOON AS THE MID LEVEL WAVE APPROACHES.  DESPITE WEAK
INSTABILITY...DEEP INVERTED-V PROFILES COULD SUPPORT A FEW DAMAGING
GUSTS ACROSS SW/CENTRAL MT FROM MID-LATE AFTERNOON.

OTHER THUNDERSTORMS MAY ALSO FORM THIS AFTERNOON ALONG THE LEE
TROUGH ACROSS THE WRN DAKOTAS. INSTABILITY WILL BE SOMEWHAT
STRONGER THIS AREA COMPARED TO MT GIVEN AFTERNOON BOUNDARY LAYER
DEWPOINTS IN THE 50S...AND VERTICAL SHEAR SHOULD BECOME AT LEAST
MARGINALLY FAVORABLE FOR ORGANIZED SEVERE STORMS AS LOW-MID LEVEL
FLOW INCREASES IN ADVANCE OF THE MID LEVEL WAVE APPROACHING MT.

...TX PANHANDLE/WRN OK THIS AFTERNOON/EVENING...
A WEAK MID LEVEL WAVE OVER THE NRN TX PANHANDLE WILL MOVE SLOWLY EWD
TOWARD WRN OK. STRONG SURFACE HEATING IS EXPECTED ACROSS THE TX
PANHANDLE IN THE WAKE OF SCATTERED EARLY MORNING CONVECTION...WITH
THE STRONGER SURFACE HEATING IN OK ALONG AND S OF I-40.  AFTERNOON
TEMPERATURES OF 95-100 F WILL RESULT IN STEEP LOW-LEVEL LAPSE RATES
AND MODERATE INSTABILITY...WHILE ROUGHLY 25 KT WLY/WNWLY MID LEVEL
FLOW WILL PERSIST AROUND THE SRN PERIPHERY OF THE TX PANHANDLE WAVE.
 SCATTERED THUNDERSTORMS WILL DEVELOP THIS AFTERNOON...WITH THE
POTENTIAL FOR SOME ORGANIZATION TO MULTICELL CLUSTERS. THE
STRONGEST STORMS MAY PRODUCE LOCALLY STRONG/DAMAGING DOWNBURSTS AND
MARGINALLY SEVERE HAIL.

..THOMPSON/GUYER.. 07/12/2006