Day 2 Severe Weather Outlook

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE FLORIDA PANHANDLE...SOUTHEAST ALABAMA...SOUTHWEST GEORGIA...

...SUMMARY...
SEVERE THUNDERSTORMS PRODUCING DAMAGING WINDS AND A COUPLE OF TORNADOES ARE FORECAST FROM LATE SUNDAY MORNING INTO SUNDAY EVENING ACROSS THE CENTRAL GULF COAST REGION.

...DISCUSSION...
BROAD SCALE POSITIVE UPPER TROUGHING WILL CONTINUE ACROSS THE EASTERN CONUS SUNDAY. A WELL-DEFINED CUTOFF LOW CURRENTLY OVER CENTRAL BAJA CALIFORNIA IS EMBEDDED WITHIN A SUBTROPICAL JET. THIS UPPER LOW WILL MOVE INTO NORTHERN MEXICO TONIGHT, BECOMING NEGATIVELY TILTED AS IT BEGINS TO PHASE WITH THE PARENT TROUGH. THE SHORTWAVE WILL THEN EJECT INTO THE LOWER APPALACHIANS BY SUNDAY EVENING, RESULTING IN SURFACE CYCLOGENESIS TAKING PLACE OVER THE NORTHWESTERN GULF, WITH THE LOW PRESSURE CENTER GRADUALLY MOVING EAST NORTHEASTWARD ACROSS SOUTHERN LOUISIANA INTO CENTRAL MISSISSIPPI/ALABAMA AND NORTHERN GEORGIA. THE LOW WILL BRING A POWERFUL ARCTIC COLD FRONT NORTHEASTWARD INTO THE GULF COAST AND SOUTHEAST STATES BY SUNDAY NIGHT.

A SMALL, PINCHED OFF WARM SECTOR IS FORECAST TO DEVELOP SUNDAY MORNING ACROSS THE CENTRAL GULF COAST, WITH MID 60S DEWPOINTS REACHING INTO CENTRAL ALABAMA AND GEORGIA. THE NORTHEASTWARD EXTENT OF THE WARMER/MOISTER AIRMASS WILL STRONGLY DEPEND ON HOW FAR SOUTH ONGOING COLD AIR DAMMING CAN INFLUENCE, THOUGH SOME RECOVERY IS EXPECTED IN SOUTHERN GEORGIA. MODERATE HEIGHT FALLS BY EARLY SUNDAY AFTERNOON AND A PLUME OF MODEST (6.5-7.0 C/KM) LAPSE RATES ACROSS THE CENTRAL GULF COAST REGION WILL SUPPORT AT LEAST WEAK INSTABILITY WITHIN THE WARM SECTOR, THOUGH THE NORTHEASTERN EXTENT MAY REMAIN CAPPED. CLOSER TO THE GULF, DEWPOINTS POSSIBLY REACHING THE UPPER 60S WITH UNSEASONABLY WARM DAYTIME HEATING INTO THE MID-70S COULD SUPPORT AN AREA OF MODERATE INSTABILITY WITH MLCAPE AROUND 1000 J/KG, MAINLY OVER THE FLORIDA PANHANDLE, SOUTHEAST ALABAMA, AND SOUTHWEST GEORGIA. VERY STRONG KINEMATIC PROFILES AS A RESULT OF A SOUTHERLY 45-55KT LOW-LEVEL JET AND 60-75KT SOUTHWESTERLY MID-LEVEL FLOW OVERHEAD WILL CONTRIBUTE TO FAIRLY ENLARGED, CURVED HODOGRAPHS, AT LEAST THROUGH LATE AFTERNOON, FAVORING LOW-LEVEL HELICITY VALUES IN EXCESS OF 200-250 M2/S2. SHEAR MAY BECOME UNIDIRECTIONAL WITH TIME IN THE EVENING, THOUGH EFFECTIVE SHEAR VALUES SHOULD REMAIN ABOVE 50-60KT.

LITTLE CONVECTION IS CURRENTLY MODELED BY 12Z SUNDAY OVER THE WARM SECTOR. AS INCREASING HEIGHT FALLS AND SURFACE CYCLOGENESIS QUICKLY INCREASES THE FORCING FOR ASCENT, ESPECIALLY ALONG THE COLD FRONT, QUICK DEVELOPMENT OF A HIGHLY FORCED SQUALL LINE IS EXPECTED BY MID TO LATE MORNING. A COMBINATION OF STRONG WIND PROFILES AND A RATHER EXTREME TEMPERATURE GRADIENT ALONG THE COLD FRONT (POSSIBLY UPWARDS OF 20F) SHOULD SUPPORT RAPID PROPAGATION EAST NORTHEASTWARD. DAMAGING WIND GUSTS OF 60-70MPH WILL BE COMMON, WITH A FEW QLCS EMBEDDED TORNADIC CIRCULATIONS ALSO POSSIBLE DUE TO THE STRONG HELICITY. A FEW LOW-TOPPED SUPERCELLS MAY ALSO DEVELOP, MAINLY EARLY TO MID AFTERNOON OVER THE CENTRAL FLORIDA PANHANDLE INTO SOUTHEAST ALABAMA WHERE THE GREATEST INSTABILITY SHOULD EXIST. ANY ISOLATED SUPERCELL THAT DEVELOPS COULD POSE A TORNADO AND PERHAPS MARGINAL HAIL THREAT. A VERY CONDITIONAL STRONG TORNADO THREAT COULD EVOLVE WITH ANY SUPERCELL THAT CAN FAVORABLY INTERACT WITH THE RATHER STRONG HELICITY, THOUGH CONFIDENCE IS VERY LOW IN THIS SCENARIO.

BY MID TO LATE EVENING, BETTER DYNAMICS BEGIN TO LIFT NORTHEAST, LEAVING A WEAKENING SQUALL LINE PROGRESSING EASTWARD ACROSS SOUTHEAST GEORGIA INTO THE FLORIDA BIG BEND. WIND DAMAGE POTENTIAL MAY PERSIST INTO THE OVERNIGHT HOURS, THOUGH THIS WILL BECOME INCREASINGLY ISOLATED/MARGINAL WITH TIME.