Friday, October 28, 2011

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 280541
SWODY1
SPC AC 280539

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1239 AM CDT FRI OCT 28 2011

VALID 281200Z - 291200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
A FRONTAL ZONE ACROSS THE SOUTH ATLANTIC AND GULF COAST STATES
APPEARS LIKELY TO LINGER THROUGH MUCH OF THE DAY AND BECOME A FOCUS
FOR INCREASINGLY SIGNIFICANT SURFACE WAVE DEVELOPMENT BY LATE
TONIGHT/EARLY SATURDAY. MODELS SUGGEST THAT AN INITIAL WAVE MAY
MIGRATE ACROSS THE EASTERN GULF STATES...IN ASSOCIATION WITH A
WEAKENING/INCREASINGLY SHEARED SHORT WAVE IMPULSE NOW LIFTING OUT OF
THE SOUTHERN PLAINS. HOWEVER...A MORE SUBSTANTIAL WAVE... LIKELY
THE INITIATION OF MUCH STRONGER SURFACE CYCLOGENESIS THAT PROBABLY
WILL TAKE PLACE SATURDAY/SATURDAY NIGHT...IS PROGGED TO FORM NEAR
SOUTHERN MID ATLANTIC COASTAL AREAS DURING THE LATTER PART OF THIS
FORECAST PERIOD. THIS IS EXPECTED TO OCCUR AS A SERIES OF DIGGING
SHORT WAVE IMPULSES CONTRIBUTE TO AN AMPLIFYING LARGER SCALE UPPER
TROUGH NEAR THE APPALACHIANS BY 12Z SATURDAY.

CONVECTIVE POTENTIAL ACROSS MUCH OF THE NATION IS EXPECTED TO REMAIN
LOW TO NEGLIGIBLE...AS THE LARGE SCALE PATTERN MAINTAINS GENERALLY
STABLE CONDITIONS. THE FLORIDA PENINSULA SHOULD BE ONE
EXCEPTION...AS VERY MOIST AIR CONTINUES TO ADVECT NORTHWARD FROM THE
LOWER LATITUDES. LAPSE RATES MAY REMAIN POOR...BUT WEAKENING
MID-LEVEL INHIBITION SHOULD ALLOW FOR PERIODS OF SHOWERS AND
THUNDERSTORMS...SOME OF WHICH COULD BE SOMEWHAT VIGOROUS GIVEN THE
PRESENCE OF WEAK TO MODERATE CAPE...AND PERHAPS THE DEVELOPMENT OF
MARGINALLY FAVORABLE SHEAR FOR ORGANIZED CONVECTION. HOWEVER...WARM
MID-LEVELS AND WEAK LOW-LEVEL FLOW FIELDS/SHEAR STILL SEEM LIKELY TO
MINIMIZE THE RISK FOR SEVERE WEATHER.

FARTHER NORTH...MODELS ALSO INDICATE WEAK DESTABILIZATION WILL OCCUR
TO THE LEE OF THE SOUTHERN APPALACHIANS LATE THIS EVENING AND
OVERNIGHT...ABOVE A COLD SURFACE BASED LAYER...NORTH OF THE SURFACE
FRONT. THIS IS EXPECTED TO OCCUR COINCIDENT WITH STRENGTHENING
LOWER/MID TROPOSPHERIC WARM ADVECTION AND MID/UPPER FORCING FOR
UPWARD VERTICAL MOTION...WHICH SEEMS LIKELY TO BE SUFFICIENT TO
SUPPORT CONSIDERABLE CONVECTIVE DEVELOPMENT... INCLUDING WEAK
THUNDERSTORM ACTIVITY.

..KERR.. 10/28/2011

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