[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 040450
SWODY1
SPC AC 040448

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1148 PM CDT TUE OCT 03 2006

VALID 041200Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM NY/PA WSWWD ACROSS THE OH
VALLEY...

...SYNOPSIS...
MID-LEVEL SHORT-WAVE TROUGH WILL MOVE ACROSS THE OH VALLEY/GREAT
LAKES REGION THIS PERIOD...ON NRN PERIPHERY OF S CENTRAL U.S. UPPER
RIDGE. AS THE TROUGH REACHES THE ERN CONUS...THE OVERALL UPPER FLOW
FIELD WILL AMPLIFY...AS RIDGE EXPANDS NWD ACROSS THE CENTRAL CONUS
UPSTREAM OF ERN TROUGH AND DOWNSTREAM OF LARGE UPPER LOW/TROUGH OVER
THE W COAST.

AT THE SURFACE...A N-S BAROCLINIC ZONE IS FORECAST TO REMAIN ROUGHLY
STATIONARY ACROSS THE GREAT BASIN AND SRN CA AHEAD OF UPPER LOW. 
MEANWHILE...THE COLD FRONT ASSOCIATED WITH THE ERN U.S. SHORT-WAVE
TROUGH IS INITIALLY FORECAST TO EXTEND FROM LOWER MI WSWWD INTO OK
AND THE SRN TX PANHANDLE.  BY LATE AFTERNOON/EARLY EVENING...THE
FRONT IS FORECAST TO EXTEND FROM NEW ENGLAND WSWWD ALONG THE OH
RIVER AND THEN INTO CENTRAL OK...AND THEN WILL CONTINUE SHIFTING
SEWD THROUGH THE END OF THE PERIOD.

...NY/PA WSWWD ACROSS THE OH VALLEY...
CONVECTION WILL BE ONGOING INVOF FRONT AT THE START OF THE
PERIOD...AND WILL CONTINUE/SHIFT SEWD WITH TIME IN CONJUNCTION WITH
THE FRONT.  THIS WILL HINDER THE POTENTIAL FOR SIGNIFICANT
HEATING/DESTABILIZATION ACROSS PARTS OF THE REGION -- PARTICULARLY
ACROSS OH/PA/NY -- DURING THE DAY.  NONETHELESS...WITH 35 TO 45 KT
MID-LEVEL FLOW SPREADING SEWD ACROSS THE MID AND UPPER OH
VALLEY...EXPECT LOCALLY-DAMAGING WINDS AND SOME HAIL WITH STORMS
ORGANIZED LINEARLY ALONG/AHEAD OF FRONT.

SOMEWHAT GREATER DESTABILIZATION WILL BE POSSIBLE FROM SWRN OH SWWD
ALONG FRONT...BUT WITH DEEP-LAYER WIND FIELD EXPECTED TO BE WEAKER
WITH SWWD EXTENT ALONG THE FRONT...THREAT FOR HAIL/DAMAGING WINDS
SHOULD STILL REMAIN RELATIVELY LOW.  THEREFORE...WILL MAINTAIN 15%
SEVERE PROBABILITY ALONG THE FRONT ACROSS THIS REGION...WITH THREAT
LIKELY DIMINISHING DURING THE EVENING AS BOUNDARY LAYER STABILIZES
AND FRONT SHIFTS SEWD AWAY FROM THE STRONGER FLOW ALOFT.

...ID AND VICINITY...
MARGINAL INSTABILITY IS FORECAST ACROSS PARTS OF THE GREAT BASIN AND
NWRN CONUS...THOUGH ONGOING STORMS AT THE BEGINNING OF THE PERIOD
SHOULD LIMIT OVERALL DEGREE OF DESTABILIZATION.  GREATEST
INSTABILITY IS FORECAST BY THE MODELS ACROSS ERN OREGON AND INTO
ID...BENEATH DIFFLUENT UPPER FLOW ON NERN PERIPHERY OF UPPER LOW. 
EXPECT STORMS TO REDEVELOP/INCREASE DURING THE AFTERNOON...WITH A
FEW STRONGER/ORGANIZED UPDRAFTS POSSIBLE GIVEN ENHANCED /AROUND 40
KT/ SLY MID-LEVEL FLOW ACROSS THIS REGION.  THOUGH MARGINAL
INSTABILITY WILL TEMPER OVERALL SEVERE THREAT...MARGINAL HAIL OR A
LOCALLY STRONGER GUST OR TWO MAY OCCUR WITH MORE INTENSE CONVECTIVE
CELLS THROUGH EARLY EVENING.

..GOSS/TAYLOR.. 10/04/2006