[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 050538
SWODY1
SPC AC 050536

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1236 AM CDT THU OCT 05 2006

VALID 051200Z - 061200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
SIGNIFICANT AMPLIFICATION OF LARGE SCALE MID/UPPER LEVEL FLOW WILL
OCCUR ACROSS THE CONUS THIS PERIOD AS CURRENT SPLIT-FLOW REGIME
UNDERGOES A TRANSITION TO MORE OF AN OMEGA-BLOCK CONFIGURATION
CENTERED ON THE CNTRL U.S. BY FRIDAY MORNING. DEEP CLOSED LOW OFF
THE WEST COAST WILL EDGE SLOWLY INLAND AND EWD TOWARD THE GREAT
BASIN TODAY WHILE DOWNSTREAM SUB-TROPICAL RIDGE MAINTAINS ITS
DOMINANCE ACROSS THE SOUTH...AND EXPANDS OVER THE CNTRL AND NRN
PLAINS. A LEAD SHORT WAVE TROUGH AND ASSOCIATED FRONT WILL MOVE OFF
THE NEW ENGLAND COAST TODAY AS THE NEXT UPSTREAM TROUGH DEVELOPS
SEWD AND AMPLIFIES ACROSS THE GREAT LAKES THROUGH TONIGHT. STRONGEST
HEIGHT FALLS WITH THIS TROUGH WILL MOVE TOWARD THE MID ATLANTIC
REGION THROUGH EARLY FRIDAY...EVENTUALLY INDUCING SECONDARY
CYCLOGENESIS ALONG THE COLD FRONT TRAILING FROM LEAD SYSTEM.

...CNTRL APPALACHIANS ACROSS VA/NC...
LOW LEVEL WIND SHIFT/BACK DOOR FRONT ASSOCIATED WITH UPPER TROUGH
CROSSING NEW ENGLAND IS EXPECTED TO SETTLE SWD/SWWD ACROSS ERN AND
SRN VA/NRN NC THROUGH THE AFTERNOON. NEUTRAL LARGE SCALE UPPER
FORCING FOR ASCENT WILL EXIST ACROSS THE REGION BETWEEN DEPARTING
SHORT WAVE TROUGH AND AMPLIFYING UPSTREAM SYSTEM OVER THE GREAT
LAKES. NONETHELESS...OROGRAPHIC LIFT AND MESOSCALE FORCING NEAR THE
BOUNDARY...ALONG WITH WEAK TO LOCALLY MODEST DIURNAL
DESTABILIZATION...SHOULD PROVE SUFFICIENT FOR TSTM DEVELOPMENT OVER
PARTS OF VA/NC...AND ERN KY/TN...THROUGH AFTERNOON. WITH INSTABILITY
AND SHEAR ACROSS THE AREA EXPECTED TO REMAIN GENERALLY WEAK DURING
THIS TIME FRAME...SEVERE HAIL/WIND POTENTIAL SHOULD BE LIMITED.

LARGE SCALE FORCING FOR ASCENT AND DEEP LAYER SHEAR SHOULD INCREASE
STEADILY ACROSS THE MID ATLANTIC REGION THROUGH LATE EVENING AS THE
MID/UPPER LEVEL TROUGH DIGS SEWD FROM THE GREAT LAKES. IT IS
POSSIBLE THAT STORM ORGANIZATION AND COVERAGE COULD INCREASE DURING
THIS TIME IF INSTABILITY CAN PERSIST INTO THE EVENING HOURS. GIVEN
UNCERTAINTY IN AVAILABLE INSTABILITY AFTER DARK...HIGHER SEVERE
WEATHER PROBABILITIES WILL NOT BE ISSUED AT THIS TIME.

...SOUTHWEST TO GREAT BASIN...
AN EXTENSIVE SWATH OF STRONG DEEP LAYER MERIDIONAL FLOW WILL PERSIST
AHEAD OF THE PACIFIC COAST TROUGH AND CONTRIBUTE TO CONTINUED NWD
TRANSPORT OF EAST PACIFIC MOISTURE ACROSS THE SRN PLATEAU AND GREAT
BASIN REGIONS. CLOUD COVER...PRECIPITATION...AND MEAGER LOW LEVEL
MOISTURE ARE EXPECTED TO LIMIT MORE WIDESPREAD STRONG
DESTABILIZATION. HOWEVER...POCKETS OF STRONGER INSOLATION...
OROGRAPHIC FORCING...AND IMPULSES ROTATING THROUGH THE LARGE SCALE
TROUGH...WILL ALL SUPPORT EPISODIC DEVELOPMENT OF BANDS/LINES OF
DEEP CONVECTION SPREADING OVER A LARGE REGION. THIS ACTIVITY WILL
EXIST WITHIN STRONG UNIDIRECTIONAL SHEAR AND IT IS POSSIBLE THAT
LINE SEGMENTS AND CELLS COULD BECOME BETTER ORGANIZED AND PERSISTENT
AS LOCALLY STRONGER INSTABILITY IS ENCOUNTERED AND/OR STRONGER
FORCING IS REALIZED DURING THE FORECAST PERIOD. WHILE SMALL SCALE
LEWPS AND BOWS WITH ENHANCED DOWNBURST WIND AND HAIL THREAT APPEAR
POSSIBLE...AN ACCURATE DEPICTION OF AN AREA OF GREATER SEVERE
WEATHER POTENTIAL IS NOT POSSIBLE AT THIS TIME. PARTS OF THE REGION
MAY BE UPGRADED IN LATER OUTLOOKS AS MESOSCALE DETAILS BECOME BETTER
DEFINED.

..CARBIN.. 10/05/2006