[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 201246
SWODY1
SPC AC 201244

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0744 AM CDT FRI OCT 20 2006

VALID 201300Z - 211200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM NJ INTO SRN/ERN NEW
ENGLAND...

...SYNOPSIS...
BROAD CYCLONIC FLOW WILL PREVAIL OVER THE LWR 48 THIS PERIOD...
DOWNSTREAM FROM E PACIFIC RIDGE.  FAST-MOVING SHORTWAVE TROUGH NOW
OVER THE UPR OH VLY EXPECTED TO AMPLIFY INTO A POTENT NEGATIVE-TILT
IMPULSE OVER SRN NEW ENGLAND LATER TODAY AS SYSTEM CONTINUES TO
MERGE WITH SHORTWAVE THAT CROSSED THE MID MS VLY YESTERDAY.  FARTHER
W...STRONG SPEED MAX NOW ENTERING ID SHOULD ALSO FURTHER AMPLIFY AS
IT CONTINUES SE ACROSS THE CNTRL RCKYS LATER TODAY/EARLY SATURDAY.

AT THE SFC...LOW NOW CONSOLIDATING IN S CNTRL PA EXPECTED TO
STRENGTHEN SUBSTANTIALLY LATER TODAY/TONIGHT AS IT CROSSES SRN NEW
ENGLAND AND THEN TURNS MORE NEWD ACROSS DOWNEAST ME.  IN THE
PLAINS...MT COLD FRONT SHOULD ACCELERATE SE AND OVERTAKE LEE TROUGH
OVER S CNTRL NEB/NRN AND WRN KS.

...NJ INTO SRN/ERN NEW ENGLAND...
OVERNIGHT SHOWERS IN THE MID ATLANTIC REGION APPEAR TO HAVE BEEN
ASSOCIATED WITH LEAD IMPULSE BEING ABSORBED INTO STRONGER SHORTWAVE
APPROACHING FROM THE OH VLY.  THIS CONVECTION HAS SERVED TO MOISTEN
THE BOUNDARY LAYER...AND SHOULD CONTINUE NE ACROSS SRN NEW ENGLAND
AND OFF THE MID ATLANTIC CST LATER TODAY.  IN WAKE OF THE
SHOWERS...MODEST SURFACE HEATING SHOULD OCCUR AHEAD OF COLD FRONT
ASSOCIATED WITH STRENGTHENING PA SFC LOW.

WHILE MID LEVEL LAPSE RATES LIKELY WILL REMAIN WEAK AND SURFACE
HEATING WILL BE LIMITED...COMBINATION OF EVEN MODERATE DIURNAL
HEATING WITH STRONG DPVA...FRONTAL ASCENT AND MOIST LOW LEVEL
ENVIRONMENT SHOULD SUPPORT DEVELOPMENT OF LOW-TOPPED CONVECTION/
POSSIBLE TSTMS ALONG AND JUST AHEAD OF COLD FRONT.  WHILE THE STORMS
MAY FORM AS FAR W AS ERN PA OR NJ...MORE SUBSTANTIAL ACTIVITY MAY
NOT OCCUR UNTIL FRONT PASSES THE NYC AREA EARLY IN THE AFTN.

RAPIDLY STRENGTHENING LOW TO MID LEVEL WIND FIELD /WITH 500 MB
SPEEDS INCREASING TO AOA 60 KTS/ AND LINEAR FORCING MAY SUPPORT
DEVELOPMENT OF A NARROW SQLN...WITH EMBEDDED SMALL SCALE BOWS/
ROTATING STORMS PRODUCING HIGH WIND AND POSSIBLY ONE OR TWO
TORNADOES.  THIS THREAT MAY REACH INTO THE CSTL ME AREA BY EVENING
AS UPR SYSTEM ASSUMES A NEGATIVE TILT AND SFC LOW DEEPENS NEWD.

...CNTRL PLNS...
SURFACE HEATING...CONVERGENCE ALONG LEE TROUGH/COLD FRONT AND ASCENT
ASSOCIATED WITH APPROACHING/AMPLIFYING UPR TROUGH MAY SUPPORT THE
DEVELOPMENT OF SCATTERED HIGH-BASED STORMS FROM SRN/CNTRL NEB INTO
WRN/NRN KS.  DEEPLY MIXED ENVIRONMENT WITH MODERATE UNIDIRECTIONAL
WNWLY FLOW MAY SUPPORT MARGINALLY SEVERE HAIL AND GUSTY WINDS FOR A
BRIEF PERIOD EARLY THIS EVENING.

..CORFIDI/CROSBIE.. 10/20/2006