River Flood Warning 55, NWS Tallahassee, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
905 PM EST WED DEC 10 2008

...HEAVY RAIN THREAT CONTINUES WITH SEVERE WEATHER THREAT TO FOLLOW
AFTER MIDNIGHT...

.DISCUSSION...00 UTC SURFACE ANALYSIS SHOWS A 1007 MB SURFACE LOW
CENTERED ABOUT 75 MILES SOUTH OF MOBILE ALABAMA. A COLD FRONT WAS
ANALYZED FROM THIS LOW ACROSS THE CENTRAL GULF DOWN TO THE WESTERN
COAST OF THE YUCATAN. A WARM FRONTAL BOUNDARY WAS NOTED FROM THIS
SURFACE LOW UP I-65/I-85 CORRIDOR AND INTO THE MID ATLANTIC STATES.
A SURGE OF DEWPOINTS IN THE LOW TO MID 70S IS NOTED ACROSS THE
NORTHERN GULF HEADING TOWARD OUR COASTAL COUNTIES. BEHIND THE
SURFACE LOW...DEWPOINTS OVER THE GULF ARE AS LOW AS THE MID 30S NEAR
THE TEXAS COAST. A SECONDARY WARM FRONT CAN BE ANALYZED IN THE
PRESSURE PATTERN AS WELL AS BY THE BACKING WINDS ACROSS SOUTHERN
GEORGIA/ALABAMA IN OUR CWA. THIS BOUNDARY APPEARS TO BE FROM NEAR
CRESTVIEW TO MOULTRIE. THIS BOUNDARY WILL CREATE INCREASED HELICITY
VALUES AND LEAD TO AN INCREASED TORNADO RISK.

UPPER AIR DATA AT 500 MB AT 00 UTC SHOWS THE TROF AND CLOSED LOW
LOSING MUCH OF ITS POSITIVE TILT. THIS IS LIKELY THE INDICATION THAT
THE UPPER LOW WILL BEGIN TO PUSH MORE EASTWARD NOW WITH TIME. WHAT
IS REMARKABLE IS THAT THE MODELS AND THE UPPER AIR DATA SHOW THAT
THIS LOW WILL BE DEEPENING...AND NOT FILLING (AS YOU WOULD EXPECT
THIS FAR SOUTH)...THUS WE WILL LIKELY SEE THE SURFACE LOW INTENSIFY
AND THIS WILL LEAD TO INCREASING COVERAGE AND INTENSITY OF SHOWERS
AND THUNDERSTORMS THROUGHOUT THE NIGHT.

925-850 MB THETA-E ANALYSIS SHOWS THE NORTH-SOUTH THETA-E RIDGE AXIS
LOCATED ACROSS THE FLORIDA PANHANDLE AND INTO THE FAR WESTERN BIG
BEND. THIS MOIST TONGUE WILL BE THE FOCUS FOR CONTINUED MODERATE TO
HEAVY RAIN THROUGHOUT THE EVENING AND THEN SHIFTING EASTWARD WITH
TIME AS THE SURFACE LOW MOVES NORTHEAST. IT IS THIS VERY MOISTURE
RICH AIRMASS THAT IS OF IMMEDIATE CONCERN TO US FOR LOCALLY HEAVY
RAINFALL.

GIVEN HEIGHT FALLS /ON THE ORDER OF 220 METERS IN 12 HOURS/ THE
ASSOCIATED QUASI-GEOSTROPHIC FORCING FOR ASCENT WILL BE EXTREME.
DEEP LAYER (700-300 MB) Q-VECTOR CONVERGENCE IS IMPRESSIVE TO SAY
THE LEAST BETWEEN 06Z AND 12Z. COUPLE THIS WITH A 110 KT 250MB JET
MOVING OVERHEAD AND YOU ARRIVE AT THE POTENTIAL FOR A VERY INTENSE
BAND OF RAINFALL ACROSS THE REGION...PARTICULARLY BETWEEN DE FUNIAK
SPRINGS AND MONTICELLO.

THE SEVERE POTENTIAL REMAINS...AS OUR REGION IS WITHIN A SLIGHT
RISK. OF IMMEDIATE CONCERN IS THE EXTREMELY FAVORABLE DYNAMIC AND
KINEMATIC ENVIRONMENT. MANY OF THE MODELS SHOW A STRENGTHENING LOW
LEVEL JET UP TO 70 KTS. THE ONLY ISSUE THAT REMAINS IS INSTABILITY.
OUR LOCAL SOUNDING WAS NOT OVERLY IMPRESSIVE IN THE LOW
LEVELS...WITH ISOTHERMAL AND WEAK LAPSE RATES UP TO 850MB. THUS...IF
THE FORCING AND DYNAMICS CAN OVERCOME THE WEAK THERMO
ENVIRONMENT...THE SEVERE POTENTIAL WILL INCREASE.

INHERITED POPS ARE NEAR 100 PERCENT...BUT NOT QUITE THERE. SO WILL
GO AHEAD AND RAISE POPS CWA WIDE...EXCEPT MAYBE THE FAR SOUTHEASTERN
BIG BEND TO 100 PERCENT AS WE ARE EXCEEDINGLY CONFIDENT IT WILL
RAIN. REMAINDER OF FORECAST VARIABLES LOOK GOOD AT THIS TIME AND
THINK THE SEVERE WORDING HANDLES THE ONGOING THREAT JUST FINE.

&&

.MARINE...WINDS OVER THE COASTAL WATERS REMAIN JUST BELOW SCA
CRITERIA BUT THE SEAS ARE THERE. EXPECT THAT AS THE FRONT MOVES
THROUGH LATE TONIGHT AND INTO THURSDAY...WINDS WILL INCREASE OUT OF
THE WEST. THERE REMAINS SOME UNCERTAINTY IF THE WINDS WILL BECOME
STRONG ENOUGH TO REACH GALE FORCE. THE RAW GFS MODEL OUTPUT WOULD
SUPPORT IT...BUT WITH THE SURFACE GRADIENT NOT OVERLY IMPRESSIVE
WITH THE 1026MB HIGH COMING IN BEHIND THE SYSTEM...WE MAY ONLY SEE
OCCASIONAL/FREQUENT GUSTS TO GALE FORCE. GIVEN THE INHERENT
UNCERTAINTIES...WONT DISCONTINUE GALE WATCH AT THIS TIME.

&&

.AVIATION...MVFR TO OCNL IFR CIGS WILL PREVAIL THROUGH TONIGHT.  A
SURFACE LOW WILL DEVELOP ALONG THE NRN GULF COAST OVERNIGHT AND LIFT
NEWD ACROSS GA ON THURSDAY...DRAGGING A COLD FRONT THROUGH THE AREA
FROM WEST TO EAST DURING THE DAY THURSDAY.  ALONG AND AHEAD OF THIS
FRONT...THE POTENTIAL FOR STRONG TO SEVERE TSRA EXISTS OVERNIGHT AND
INTO THURSDAY...ENDING FROM WEST TO EAST DURING THE DAY THURSDAY.
IFR VSBYS WITH TORRENTIAL DOWNPOURS AND CONVECTIVE GUSTS ABOVE 40 KT
WILL OCCUR WITH THE STRONGER TSRA.  SOUTHERLY WINDS TONIGHT WILL
VEER AROUND TO WESTERLY ON THURSDAY WITH GUSTS BETWEEN 20-25 KTS
POSSIBLE.

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
AL...FLOOD WATCH THROUGH LATE TONIGHT FOR THE FOLLOWING ZONES:
     COFFEE...DALE...GENEVA...HENRY...HOUSTON.

GA...FLOOD WATCH THROUGH THURSDAY MORNING FOR THE FOLLOWING ZONES:
     BAKER...CALHOUN...CLAY...DECATUR...DOUGHERTY...EARLY...
     LEE...MILLER...MITCHELL...QUITMAN...RANDOLPH...SEMINOLE...
     TERRELL...TURNER...WORTH.

FL...FLOOD WATCH THROUGH LATE TONIGHT FOR THE FOLLOWING ZONES: BAY...
     CALHOUN...COASTAL WALTON...HOLMES...INLAND WALTON...
     JACKSON...WASHINGTON.

     HIGH SURF ADVISORY UNTIL 9 AM CST FRIDAY FOR THE FOLLOWING
     ZONES: BAY...COASTAL WALTON...GULF.

GM...SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY ALL ZONES.

     GALE WATCH FROM 4 AM EST THU TO 4 AM EST FRI COASTAL WATERS
     FROM OCHLOCKONEE RIVER TO DESTIN FL OUT 60 NM.

     SMALL CRAFT ADVISORY FROM 4 AM TO 10 PM EST FRIDAY COASTAL
     WATERS FROM OCHLOCKONEE RIVER TO DESTIN FL 20 TO 60 NM.

     SMALL CRAFT ADVISORY FROM 4 AM TO 10 AM EST FRIDAY FOR THE
     FOLLOWING ZONES: COASTAL WATERS FROM OCHLOCKONEE RIVER TO
     APALACHICOLA FL OUT TO 20 NM...COASTAL WATERS FROM
     APALACHICOLA TO DESTIN FL OUT 20 NM.

&&

AVIATION...GOULD/VAN DYKE
RADAR/MESOSCALE...MROCZKA
REST OF DISCUSSION...GODSEY

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TALLAHASSEE FL
457 AM EST WED DEC 10 2008

ALZ065>069-FLZ007>019-026>029-034-GAZ120>131-142>148-155>161-
GMZ730-750-755-765-770-775-111100-
COFFEE-DALE-HENRY-GENEVA-HOUSTON-INLAND WALTON-COASTAL WALTON-
HOLMES-WASHINGTON-JACKSON-BAY-CALHOUN-GULF-FRANKLIN-GADSDEN-LEON-
JEFFERSON-MADISON-LIBERTY-WAKULLA-TAYLOR-LAFAYETTE-DIXIE-QUITMAN-
CLAY-RANDOLPH-TERRELL-DOUGHERTY-LEE-WORTH-TURNER-TIFT-BEN HILL-
IRWIN-EARLY-MILLER-BAKER-MITCHELL-COLQUITT-COOK-BERRIEN-SEMINOLE-
DECATUR-GRADY-THOMAS-BROOKS-LOWNDES-LANIER-
APALACHEE BAY OR COASTAL WATERS FROM KEATON BEACH TO OCHLOCKONEE
RIVER FL OUT TO 20 NM-
COASTAL WATERS FROM APALACHICOLA TO DESTIN FL OUT 20 NM-
COASTAL WATERS FROM  OCHLOCKONEE RIVER TO APALACHICOLA FL OUT TO
20 NM-
COASTAL WATERS FROM  SUWANNEE RIVER TO KEATON BEACH OUT 20 NM-
WATERS FROM APALACHICOLA TO DESTIN FL FROM 20 TO 60 NM-
WATERS FROM  SUWANNEE RIVER TO APALACHICOLA FL FROM 20 TO 60 NM-
457 AM EST WED DEC 10 2008 /357 AM CST WED DEC 10 2008/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST ALABAMA...
SOUTHWEST AND SOUTH CENTRAL GEORGIA...AND THE FLORIDA BIG BEND
AND PANHANDLE...AND ADJACENT COASTAL WATERS.

.DAY ONE...TODAY AND TONIGHT...

...STRONG TO POSSIBLY SEVERE STORMS EXPECTED TODAY AND TONIGHT...
...HIGH SURF ADVISORY FOR THE EASTERN PANHANDLE THROUGH
THURSDAY...

A STRONG STORM SYSTEM DEVELOPING ALONG THE NORTHERN GULF COAST
WILL IMPACT THE REGION THROUGH THURSDAY. AS A COLD FRONT
APPROACHES FROM THE NORTHWEST...LOW PRESSURE WILL DEVELOP JUST
SOUTH OF MOBILE AND LIFT NORTHEAST THROUGH TONIGHT. WIDESPREAD
SHOWERS AND THUNDERSTORMS WILL DEVELOP WITH THIS SYSTEM BEGINNING
ACROSS THE FLORIDA PANHANDLE AND SOUTHEAST ALABAMA THIS MORNING
AND SPREADING EAST THROUGH TODAY AND INTO TONIGHT.

STRONG STORMS WITH ISOLATED SEVERE STORMS ARE EXPECTED AS THE
SYSTEM MOVES THROUGH. DAMAGING STRAIGHT LINE WINDS APPEAR TO BE
THE MAIN THREAT AT THIS TIME. HOWEVER...ISOLATED TORNADOES WILL BE
POSSIBLE AS WELL. THE SEVERE THREAT WILL END FROM WEST TO EAST AS
THE COLD FRONT MOVES THROUGH LATE TONIGHT AND THURSDAY MORNING.

HEAVY RAINFALL IS EXPECTED FROM THIS SYSTEM...ESPECIALLY ACROSS
THE FLORIDA PANHANDLE AND SOUTHEAST ALABAMA. RAINFALL TOTALS OF 2
TO 4 INCHES ARE POSSIBLE ACROSS THIS AREA.

STRONG ONSHORE FLOW TODAY AND TONIGHT WILL GENERATE LARGE SURF
ALONG THE BEACHES OF THE FLORIDA PANHANDLE. REFER TO THE LATEST
COASTAL FLOOD STATEMENT FOR THE LATEST ON THE HIGH SURF ADVISORY.

AN EXTENDED PERIOD OF SMALL CRAFT ADVISORY CONDITIONS WITH GUSTS
TO GALE FORCE IS EXPECTED OVER THE MARINE WATERS THROUGH TONIGHT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY...

THE STRONG COLD FRONT WILL EXIT THE REGION TO THE EAST THURSDAY
MORNING. STRONG WEST AND THEN NORTHWEST WINDS WILL FOLLOW THE
FRONT...USHERING IN A MUCH COLDER AIR MASS. TEMPERATURES WILL
LIKELY DROP TO NEAR FREEZING BY FRIDAY MORNING.

THE STRONG WINDS BEHIND THE FRONT WILL CONTINUE TO GENERATE LARGE
SURF ALONG AREA BEACHES AND SMALL CRAFT ADVISORY CONDITIONS OVER
THE MARINE WATERS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATER TODAY.

FOR ADDITIONAL INFORMATION...VISIT THE NATIONAL WEATHER SERVICE
WEBSITE ON THE INTERNET AT WEATHER.GOV...THEN CLICK ON YOUR AREA
OF INTEREST ON THE NATIONAL MAP.

CAMP