Severe Thunderstorm Warning 40, NWS Tallahassee, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
225 PM EDT FRI APR 12

CURRENT WATER VAPOR IMAGERY CONTINUES TO SHOW A NEGATIVELY TILTED
UPPER TROUGH FROM THE N CENTRAL GULF TO THE WESTERN GREAT LAKES.
ANIMATION OVER THE PAST 4 HOURS SHOWS SLOW EASTWARD MOVEMENT OF THIS
TROF TOWARD OUR FORECAST AREA. AT THE SURFACE...MSAS ANALYSIS SHOWS
A WEAK CLOSED LOW OFF THE MOB/PNS COAST...GENERATING SHOWERS AND
SOME THUNDERSTORMS WHICH ARE MOVING ASHORE BETWEEN ST. GEORGE ISLAND
AND CHOCTAWHATCHEE BAY.

MODELS/ZONES: MODELS AGREE A TEAM EFFORT BETWEEN THE LOW OVER THE N
CENTRAL GULF AND THE RETURN FLOW ON THE BACK SIDE OF THE SURFACE
RIDGE WILL KEEP THE FORECAST AREA IN A VERY MOIST ENVIRONMENT OVER
THE NEXT COUPLE OF DAYS. THE SURFACE FRONT OVER THE MID MS VALLEY IS
FORECAST TO WEAKEN AND DISSIPATE WITHOUT MOVING INTO OUR CWA.
NONETHELESS...AREA POPS WILL REMAIN IN THE GOOD CHANCE TO LIKELY
CATEGORY THROUGH SATURDAY...BEFORE STARTING TO DIMINISH SATURDAY
EVENING. MODELS HAVE CONVERGED ON SHOWING A WEAK INVERTED TROF...NO
MORE CLOSED SURFACE LOW...UNDER A CLOSED UPPER LOW STUCK OVER THE
NORTH CENTRAL GULF THROUGH SUNDAY MORNING. THIS LOW WILL OPEN AND
MOVE E LATER SUNDAY...WITH A SHORTWAVE TROUGH PASSING TO THE N.

LOW LEVEL FLOW INDICATES MAIN AREA OF CONCERN FOR PRECIPITATION WILL
AGAIN BE SOUTHEAST AL AND FL PANHANDLE ZONES. MODEL POPS GUIDANCE IS
VERY CLOSE SO HAVE BLENDED. EXPECT SLIGHTLY HIGHER POPS SATURDAY DUE
TO CONTINUED PROXIMITY OF CLOSED UPPER LOW. AS UPPER SYSTEM WEAKENS
WILL LOWER POPS SUNDAY. MAJOR DIFFERENCE IN MODEL TEMPERATURE POPS
OCCURS WITH MAX TEMP SUNDAY...DUE TO MODEL DIFFERENCES IN CLOUD
FORECAST. FOR THIS PACKAGE HAVE BLENDED.

THE CHOCTAWHATCHEE RIVER BASIN IS STILL AN AREA OF CONCERN FOR FLOOD
POTENTIAL. CURRENT FORECAST REMAINS BELOW FLOOD STAGE...BUT THIS
WILL NEED TO BE MONITORED. HAVE NOT ISSUED A FLOOD WATCH OR
STATEMENTS...BUT SHOULD STILL ALLOW FOR THE POSSIBILITY OF NUISANCE
FLOODING OVER WRN ZONES WITH ADDITIONAL RAINFALL THIS AFTERNOON AND
EVENING.

FIRE WEATHER: NO HIGHLIGHTS. RH VALUES WILL REMAIN ABOVE CRITICAL
LEVELS.

MARINE: GRADIENT IS ALREADY TIGHTENING AHEAD OF SURFACE LOW. LOOKS
LIKE SCA CONDITIONS WILL EXIST FOR A SHORT PERIOD OVER BOTH WESTERN
AND EASTERN WATERS. AS THE UPPER LOW WEAKENS...THIS WILL TRANSLATE
TO A WEAKER SURFACE REFLECTION AS WELL...LOOSENING THE GRADIENT OVER
NIGHT.

EXTENDED (TUESDAY THROUGH FRIDAY): SURFACE RIDGE WILL HANG ON OVER
THE CWA...WITH SE TO S FLOW SUSTAINING A MOIST FLOW AND SMALL POPS.

PRELIMINARY NUMBERS...
TLH 64 77 62 80 6743
PFN 65 77 64 76 5644
DHN 63 74 62 78 5644
ABY 62 75 62 78 5744
VLD 63 77 62 80 5744
CTY 63 79 61 80 6633

.TLH...
.AL...NONE.
.GA...NONE.
.FL...NONE.

AFD