[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 010550
SWODY1
SPC AC 010548

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1148 PM CST THU NOV 30 2006

VALID 011200Z - 021200Z

...THERE IS A MDT RISK OF SVR TSTMS FOR PORTIONS OF MD...PA AND
NY...

...THERE IS A SLGT RISK OF SVR TSTMS FROM NC THROUGH THE MID
ATLANTIC...NERN U.S. AND ERN PORTIONS OF THE OH VALLEY...

...SYNOPSIS...

SHORTWAVE TROUGH OVER THE LOWER MS VALLEY THIS EVENING WILL EJECT
NEWD INTO THE LOWER GREAT LAKES AND NERN U.S. BY FRIDAY AFTERNOON.
ATTENDANT SURFACE CYCLONE CURRENTLY OVER WRN KY WILL OCCLUDE AS IT
LIFTS NWD INTO THE GREAT LAKES BY LATE MORNING. HOWEVER...SECONDARY
CYCLOGENESIS IS EXPECTED FARTHER EAST ACROSS NY AS STRONG FORCING
FOR ASCENT WITHIN DIVERGENT EXIT REGION OF CYCLONIC UPPER JET LIFTS
NEWD INTO THIS REGION. ARCTIC FRONT CURRENTLY EXTENDS FROM THE UPPER
GREAT LAKES AREA SWWD TO A SURFACE LOW NEAR WRN KY THEN SWD INTO THE
CNTRL GULF AREA. NRN PORTION OF THIS BOUNDARY WILL MOVE LITTLE DUE
TO ACCELERATING SLY FLOW IN WARM SECTOR ACCOMPANYING CYCLOGENESIS.
HOWEVER...SRN PORTION OF THIS BOUNDARY WILL CONTINUE EAST THROUGH
THE SERN STATES...MID ATLANTIC AND NERN U.S. BEFORE MOVING OFFSHORE
FRIDAY NIGHT.


...MID ATLANTIC THROUGH NERN STATES AND ERN PORTION OF OH VALLEY...

LOW LEVEL JET WILL STRENGTHEN TO IN EXCESS OF 70 KT FROM NC INTO THE
NERN U.S. AS SECONDARY CYCLONE DEEPENS OVER NY. LOW TO MID 60S
BOUNDARY LAYER DEWPOINTS CURRENTLY RESIDE ACROSS VA AND THE
CAROLINAS. THE STRENGTHENING SLY LOW LEVEL JET WILL CONTRIBUTE TO
NWD ADVECTION OF THIS MOISTURE THROUGH FRIDAY. AS UPPER TROUGH
EJECTS NEGATIVELY TILTED INTO THE NERN STATES...A MID LEVEL THERMAL
TROUGH WILL SPREAD OVER A PORTION OF THE WARM SECTOR AND CONTRIBUTE
TO SLIGHTLY BETTER MID LEVEL LAPSE RATES THAN IN THURSDAYS WARM
SECTOR. PRE-FRONTAL MUCAPE AROUND 500 J/KG WILL BE
POSSIBLE...ESPECIALLY IF POCKETS OF HEATING CAN DEVELOP. INSTABILITY
COULD BE SLIGHTLY HIGHER WITHIN ZONE OF FORCED DEEP LAYER ASCENT
ALONG SURFACE FRONT. 

CONVECTION WILL LIKELY BE ONGOING ALONG THE FRONT OVER PORTIONS OF
THE OH VALLEY EARLY FRIDAY. STRENGTHENING LOW-MID LEVEL WIND FIELDS
AND INCREASING ISALLOBARIC AND FRONTOGENETIC FORCING SHOULD MAINTAIN
A FORCED LINE OF STORMS EWD THROUGH THE NERN STATES. THIS ACTIVITY
WILL LIKELY STRENGTHEN AS THE ATMOSPHERE UNDERGOES FURTHER
DESTABILIZATION DURING THE AFTERNOON. LOW LEVEL AND CLOUD LAYER
SHEAR PROFILES WITH LARGE HODOGRAPHS WILL SUPPORT ORGANIZED STORMS
INCLUDING LEWP/BOWS WITHIN THE LINE. A FEW SUPERCELL STRUCTURES WILL
ALSO BE POSSIBLE ALONG THE LINE OR IF STORMS MANAGE TO DEVELOP AHEAD
OF THE LINE. WITH THE LOW LEVEL JET STRENGTHENING TO 60+ KT JUST OFF
THE SURFACE...POTENTIAL WILL EXIST FOR THIS MOMENTUM TO BE
TRANSPORTED DOWN TO THE SURFACE AS FRONTAL CONVECTION SPREADS EWD.
PRIMARY THREAT WILL BE DAMAGING WIND...BUT AN ISOLATED TORNADO OR
TWO MAY ALSO BE POSSIBLE. GREATEST THREAT FOR SWATHS OF WIDESPREAD
DAMAGING WIND IS EXPECTED IN MODERATE RISK AREA WITH MORE ISOLATED
WIND POTENTIAL IN SLIGHT RISK REGION.

...NC...

STRONGEST FORCING WILL LIFT N OF THIS REGION. THIS ALONG WITH MODEST
LAPSE RATES AND INSTABILITY MAY SERVE TO LIMIT OVERALL SEVERE
THREAT. HOWEVER...GIVEN STRENGTH OF LOW LEVEL WIND FIELDS...WILL
MAINTAIN A THREAT FOR ISOLATED WIND DAMAGING WITH ANY CONVECTION
DEVELOPING ALONG OR JUST AHEAD OF
THE FRONT.

..DIAL.. 12/01/2006