Thursday, October 23, 2008

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 230536
SWODY1
SPC AC 230533

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1233 AM CDT THU OCT 23 2008

VALID 231200Z - 241200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
THE CYCLONE OVER THE EAST CENTRAL PLAINS HAS BECOME CUT-OFF FROM THE
MAIN BELT OF THE POLAR WESTERLIES...NOW GENERALLY NEAR/NORTH OF THE
CANADIAN/U.S. BORDER AREA. AND...EASTWARD MOTION THROUGH MUCH OF
THIS PERIOD LIKELY WILL BE SLOW...MOSTLY IN RESPONSE TO THE
PROGRESSION OF A SIGNIFICANT IMPULSE AROUND ITS
SOUTHERN/SOUTHEASTERN PERIPHERY. IT APPEARS THAT THE COUPLING OF
THIS FEATURE WITH THE SUBTROPICAL STREAM COULD LEAD TO WEAK WAVE
DEVELOPMENT ALONG A LOW-LEVEL BAROCLINIC ZONE FORMING ACROSS THE
NORTHEASTERN GULF OF MEXICO LATE TONIGHT INTO EARLY FRIDAY...WHEN A
SLOW EASTWARD ACCELERATION OF THE MID/UPPER LOW MAY COMMENCE...AS
THE EXIT REGION OF A STRONG POLAR JET STREAK NOSES EAST OF THE
CANADIAN ROCKIES.

WHILE THE OCCLUDING SURFACE FRONT ASSOCIATED WITH THE PLAINS SURFACE
LOW MAY STALL/WEAKEN ACROSS THE LOWER MISSISSIPPI VALLEY...THE
EXPANSIVE EASTERN U.S. SURFACE RIDGE IS PROGGED TO BE SLOW TO
WEAKEN/RETREAT EASTWARD. AS A RESULT...A SHRINKING WARM SECTOR
WEDGE OF MOIST...POTENTIALLY POSITIVELY BUOYANT BOUNDARY LAYER AIR
IS EXPECTED TO BECOME CONFINED TO PARTS OF SOUTHEASTERN
LOUISIANA/SOUTHERN MISSISSIPPI AND SOUTHWESTERN ALABAMA. COUPLED
WITH WEAK MID-LEVEL LAPSE RATES ACROSS MUCH OF THIS REGION...DUE TO
A RELATIVELY WARM MID/UPPER LEVEL ENVIRONMENT...AND THE LIKELIHOOD
OF CONSIDERABLE CLOUD COVER...PROBABILITIES FOR THUNDERSTORMS
TODAY/TONIGHT INLAND OF THE CENTRAL/EASTERN GULF COAST APPEAR LOW.

...CENTRAL GULF COAST REGION...
CYCLONIC MID/HIGH LEVEL FLOW ACROSS THE WARM SECTOR WILL BE STRONG
ENOUGH TO CREATE SUFFICIENT DEEP LAYER SHEAR FOR SUPERCELLS.
BUT...WEAK LOW-LEVEL SHEAR/SMALL LOW-LEVEL HODOGRAPHS SHOULD LIMIT
THE DAMAGING WIND/TORNADO POTENTIAL...EVEN IF BOUNDARY LAYER
DESTABILIZATION BECOMES SUPPORTIVE OF SCATTERED STORM DEVELOPMENT
DURING THE DAYTIME HOURS.

..KERR/BOTHWELL.. 10/23/2008

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