[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 140545
SWODY1
SPC AC 140544

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1144 PM CST MON MAR 13 2006

VALID 141200Z - 151200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
LARGE UPPER TROUGH WILL PROGRESS EWD ACROSS THE ERN U.S. TODAY. 
OCCLUDED SURFACE LOW AND VERTICALLY STACKED SYSTEM ARE EXPECTED OVER
SERN CANADA TODAY.  SECONDARY SURFACE LOW DEVELOPMENT IS PROGGED
ALONG THE ME COAST THIS MORNING...WITH THIS LOW BECOMING THE PRIMARY
LOW AS IT DEEPENS NEWD TOWARD THE CANADIAN MARITIMES.  TRAILING COLD
FRONT...INITIALLY EXTENDING FROM THE HUDSON VALLEY SWD TO NJ AND
THEN SWWD THROUGH CENTRAL NC/SC/GA TO THE GULF OF MEXICO...WILL
PROGRESS EWD OFF THE ERN SEABOARD THIS AFTERNOON AND THEN SWD
THROUGH FL AFTER 00Z.

IN THE WEST...A COLD UPPER TROUGH...CURRENTLY LOCATED OFF THE NRN
CA/PACIFIC NW COAST...WILL DE-AMPLIFY TODAY AS IT MOVES INLAND.

...NC/SC...
SURFACE COLD FRONT IS EXPECTED TO MOVE EWD ACROSS THE NC/SC COASTAL
PLAINS THIS MORNING...AND THEN OFFSHORE BY EARLY AFTERNOON.  CLOUD
COVER SPREADING EWD ACROSS THE MID ATLANTIC/SERN STATES BY 12Z TODAY
MAY LIMIT SURFACE HEATING.  COLDER MID-LEVEL TEMPERATURES EXPECTED
TO LAG THE COLD FRONT WILL RESULT IN MODEST LAPSE RATES ALONG THE
COAST. DESPITE THESE LIMITING FACTORS...SURFACE DEWPOINTS ALREADY
IN THE LOWER 60S ACROSS THE COASTAL PLAINS OF THE CAROLINAS AND SOME
SURFACE HEATING SHOULD YIELD AT LEAST WEAK INSTABILITY /MLCAPE 500
TO NEAR 1000 J/KG/ AHEAD OF THE COLD FRONT.

VEERING WINDS AHEAD OF THE COLD FRONT WILL TEND TO MINIMIZE
CONVERGENCE.  HOWEVER...GIVEN HEIGHT FALLS WITH THE UPPER TROUGH...
FORCING MAY BE SUFFICIENT TO SUPPORT A NARROW LINE OF CONVECTION
THIS MORNING BEFORE THE COLD FRONT MOVES OFFSHORE.  THIS COULD
ENHANCE DOWNWARD TRANSFER OF MOMENTUM ASSOCIATED WITH 40-50+ KT MEAN
FLOW REGIME...CONTRIBUTING TO AT LEAST SOME POTENTIAL FOR DAMAGING
SURFACE GUSTS.

...WRN STATES...
MID-LEVEL SPEED MAX ASSOCIATED WITH THE PACIFIC TROUGH WILL SHIFT
INLAND OVER CENTRAL CA/SRN NV DURING THE FIRST HALF OF THE FORECAST
PERIOD...REACHING THE CENTRAL ROCKIES BY 12Z WEDNESDAY.  NORTH OF
THE JET AXIS...COLD-MID LEVEL TEMPERATURES /SUB -30 C AT 500 MB/
WILL STEEPEN LAPSE RATES AIDING IN CONVECTIVE DEVELOPMENT ACROSS
PORTIONS OF NRN/CENTRAL CA... ESPECIALLY IF PARTIAL SUNSHINE
DEVELOPS.  COLD...STEEP LAPSE RATE ENVIRONMENT FAVORS HAIL WITH
STRONG UPDRAFTS...BUT OVERALL INSTABILITY DOES NOT APPEAR SUPPORTIVE
OF ANYTHING LARGER THAN MARGINAL SEVERE HAIL.

..PETERS/GRAMS.. 03/14/2006