340
FXUS62 KTAE 271949
AFDTAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
349 PM EDT WED OCT 27 2021
NEAR TERM [THROUGH THURSDAY]
THE MUCH ANTICIPATED SQUALL LINE DEVELOPED OVER TX EARLIER THIS
MORNING AND IS MARCHING ACROSS LA AS OF 19Z. THIS QUASI-LINEAR
CONVECTIVE SYSTEM (QLCS) HAS A HISTORY OF PRODUCING SEVERE WEATHER
PRIMARILY IN THE FORM OF DAMAGING WIND GUSTS WITH A FEW EMBEDDED
TORNADIC SIGNATURES AT THOSE LOCATIONS. THE QLCS IS LOCATED AHEAD OF
A STRONG COLD FRONT AND HAS WARM FRONT EXTENDING EASTWARD ALONG THE
NORTH-CENTRAL GULF. THE LATTER BOUNDARY IS EXPECTED TO PUSH RICH
MARITIME AIR INLAND, PROMPTING DEWPOINTS TO CLIMB (UPPER 60S INTO
THE 70S) WHILE CLOUDS CONTINUE TO INCREASE. A NARROW CORRIDOR OF
RELATIVELY HIGHER INSTABILITY/BUOYANCY IN AN OTHERWISE LOW CAPE
ENVIRONMENT SHOULD DEVELOP AS WELL, ESPECIALLY ALONG AND SOUTH OF
THE COAST. THIS WARM-AIR ADVECTION YIELDS TEMPERATURES FOLLOWING A
NON-DIURNAL UPWARD TREND IN THE PRE-DAWN HOURS (LOWS MAINLY IN THE
60S). HIGH TEMPERATURES TAP OUT IN THE UPPER 70S/LOW 80S.
SOUTHERLY WINDS INCREASE AS THE SQUALL LINE NEARS OUR WESTERNMOST
COUNTIES LATE TONIGHT, IN ADDITION TO STRENGTHENING LOW AND MID-
LEVEL JETS (30-40 KTS & 50+ KTS RESPECTIVELY). GUSTY WINDS ARE
EXPLICITLY MENTIONED IN THE THURSDAY FORECAST TO ACCOUNT. AS A
RESULT, THE ATMOSPHERE WILL BE HIGHLY SHEARED, WHICH FAVORS A
SEVERE THREAT IN THE FORM OF DAMAGING WIND GUSTS (PRIMARY) WITH A
FEW TORNADOES POSSIBLE (SECONDARY). THESE EXPECTATIONS ARE
CAPTURED IN THE DAY 1 AND 2 SPC OUTLOOKS WHERE A SLIGHT RISK
(LEVEL 2/5) EXISTS FOR OUR FL COUNTIES AND JUST NORTH OF THE FL/GA
BORDER. A MARGINAL RISK (LEVEL 1/5) IS IN PLACE EVERYWHERE ELSE
DURING THE 2-DAY PERIOD. POCKETS OF HEAVY RAINFALL ARE ALSO
POSSIBLE, WHICH COULD PRODUCE SOME LOCALIZED FLOODING (ESPECIALLY
THE PANHANDLE), BUT THE PROGRESSIVE NATURE OF THE QLCS SHOULD
PRECLUDE A WIDESPREAD FLOOD THREAT (SEE HYDROLOGY SECTION).
HI-RESOLUTION MODEL GUIDANCE SUGGESTS THAT THE SQUALL LINE ETA AT
THE WESTERN FL PANHANDLE AND SOUTHEAST AL IS AROUND 6Z, WHEN DIURNAL
INSTABILITY IS MINIMAL. THIS FACT MAY CAUSE THE LINE TO
WEAKEN/FRAGMENT, THUS LEADING TO POSSIBLY TWO WAVES OF STORMS.
EITHER WAY, CONVECTION IS LIKELY TO BE ELEVATED DURING THIS TIME
PERIOD, WHICH IS SUPPORTED BY MODEL SOUNDINGS, BUT COULD BECOME
SURFACE BASED IF THE NOCTURNAL INVERSION BREAKS. THE LATTER WOULD
FAVOR AN INCREASED TORNADO THREAT. THE LINE THEN REACHES THE MIDDLE
TWO-THIRDS OF THE SERVICE AREA IN THE EARLY MORNING HOURS AND IS
FORECAST TO EXIT THE AREA BY THE AFTERNOON. ALTHOUGH THE SEVERE
THREAT ENDS WITH THE QLCS DEPARTURE, MULTIPLE HAZARDS REMAIN IN
PLACE THANKS TO A STRONG TRAILING COLD FRONT PRODUCING WESTERLY
WINDS STRONG ENOUGH TO PROMPT A GALE WARNING OFFSHORE (SEE MARINE
SECTION), HIGH SURF ADVISORY AT THE PANHANDLE BEACHES, WIND ADVISORY
ALONG OUR ENTIRE COASTLINE, AND COASTAL FLOOD ADVISORY FROM WAKULLA
TO DIXIE COUNTY! LASTLY, LINGERING CONVECTION CANNOT BE RULED OUT IN
THE WAKE OF THE MAIN LINE(S) OF STORMS FROM IMPULSES ROTATING
THROUGH THE BASE OF THE MEAN UPPER TROUGH OVER THE SOUTHEAST US.
SHORT TERM [THURSDAY NIGHT THROUGH FRIDAY NIGHT]
BY THURSDAY NIGHT, THE SQUALL LINE SHOULD BE WELL OUT OF THE
REGION; HOWEVER, A FEW LINGERING SHOWERS BEHIND THE SQUALL LINE
AND COLD FRONT COULD BE POSSIBLE GIVEN THE STRONG UPPER LEVEL
SUPPORT. DURING THE OVERNIGHT HOURS ON THURSDAY, THE AXIS OF THE UPPER
LEVEL TROUGH THAT IS FORCING THE SEVERE STORMS ACROSS THE REGION
TONIGHT AND INTO THURSDAY MORNING IS EXPECTED TO MOVE OVER THE
REGION, WHICH WILL ONLY INCREASE WINDY CONDITIONS OVER THE AREA.
THIS IS DUE TO THE DECREASING HEIGHTS AS WELL AS WELL AS A TIGHT
PRESSURE GRADIENT EXPECTED OVER THE REGION. WITH GEOPOTENTIAL
HEIGHTS DECREASING ACROSS THE REGION, A WELL MIXED BOUNDARY LAYER
CAN BE EXPECTED, WHICH WILL AID IN THE SUPPORT FOR STRONG WINDS.
GIVEN THESE STRONG WINDS, ESPECIALLY OVER COASTAL REGIONS, A WIND
ADVISORY HAS BEEN ISSUED FOR ALL COASTAL ZONES IN THE AREA FROM
WALTON COUNTY TO DIXIE COUNTY. THESE STRONG WINDS HAVE ALSO LEAD
TO THE POTENTIAL FOR COASTAL FLOODING ALONG APALACHEE BAY AS
STRONG WESTERLY WINDS ARE EXPECTED TO PILE WATER INTO THE BAY
THROUGH FRIDAY. STRONG COLD AIR ADVECTION CAA WILL DRIVE
TEMPERATURES TO BE THE COLDEST OF THE FALL THUS FAR WITH HIGHS
ONLY REACHING THE MID TO UPPER 60S ON FRIDAY. THURSDAY NIGHT LOWS
WILL DROP INTO THE LOW TO MID 50S ACROSS MUCH OF THE AREA.
LONG TERM [SATURDAY THROUGH WEDNESDAY]
THE LONG TERM WILL PREDOMINANTLY REMAIN COOL AND DRY AS THE UPPER
LEVEL TROUGH LIFTS NORTH OF THE REGION BY SATURDAY NIGHT, WHICH IS
EXPECTED TO USHER IN SURFACE HIGH PRESSURE AND ZONAL FLOW ALOFT
THROUGH THE MIDDLE TO END OF THE NEXT WORK WEEK. WITH THE UPPER
LEVEL TROUGH MAINTAINING INFLUENCE OVER THE REGION THROUGH MUCH OF
THE WEEKEND, CAA WILL MAINTAIN COOLER TEMPERATURES OVER THE
REGION. HIGH TEMPERATURES WILL SLOWLY REBOUND FROM THE UPPER 60S
TO THE MID 70S BY MONDAY; HOWEVER, LOW TEMPERATURES ARE EXPECTED
TO REMAIN IN THE LOW TO MID 50S FOR MUCH OF THE LONG TERM WITH
PORTIONS OF SE ALABAMA AND SW GEORGIA SEEING UPPER 40S A FEW
NIGHTS DUE TO A FEW EFFICIENT RADIATIONAL COOLING NIGHTS.
AVIATION
[THROUGH 18Z THURSDAY]
MID-TO-HIGH CLOUDS STREAMING IN FROM THE WEST WITH LGT WINDS ARE
MAKING FOR VFR CONDS THAT PREVAILS THROUGH THE AFTERNOON. A SQUALL
LINE APPROACHES DHN/ECP BY LATE TONIGHT. SOUTHERLY WINDS INCREASE
AHEAD OF THE LINE. SOME STORMS MAY BE STRONG TO SEVERE. THE LINE
THEN REACHES TLH/ABY EARLY MORNING, AND FINALLY VLD LATE MORNING.
STRONG WEST/SW WINDS FILTER IN BEHIND THE LINE, WHERE FREQUENT GUSTS
AT OR ABOVE 25 KTS ARE EXPECTED. THERE MAY ALSO BE SOUTHERLY LLWS OF
~40 KTS AT 2KFT NEAR DHN/ECP/ABY FROM 9-15Z.
MARINE
DETERIORATING BOATING CONDITIONS CAN BE EXPECTED OVER THE NEXT
SEVERAL HOURS, AND WILL PERSIST THROUGH SATURDAY MORNING. A STRONG
COLD FRONT WITH SOME STRONG TO SEVERE THUNDERSTORMS IS EXPECTED
TO PUSH THROUGH OUR FORECAST WATERS TONIGHT AND THROUGH THE
THURSDAY MORNING. GUSTY WESTERLY WINDS UP TO 40 KNOTS AT TIMES ARE
EXPECTED POST FRONTAL WITH SUSTAINED WINDS NEAR 30 KNOTS WILL
ELEVATE SEAS UP TO 15 FEET THROUGH FRIDAY NIGHT. GIVEN THESE
CONDITIONS, A GALE WARNING HAS BEEN ISSUED TODAY TO REPLACE THE
GALE WATCH. BEYOND FRIDAY NIGHT, SMALL CRAFT ADVISORY CONDITIONS
ARE EXPECTED TO EXTEND THROUGH SATURDAY AND SATURDAY NIGHT AS SEAS
WILL TAKE TIME TO SETTLE AS THE UPPER LEVEL SYSTEM FINALLY LIFTS
NORTH OF THE REGION DURING THE DAY SATURDAY. CONDITIONS SHOULD
CONTINUE TO IMPROVE THROUGH SUNDAY AND INTO THE FOLLOWING WORK
WEEK.
FIRE WEATHER
SOUTHERLY WINDS INCREASE TONIGHT AHEAD OF A SQUALL LINE APPROACHING
THE FROM THE WEST. THIS SYSTEM WILL BRING THE POTENTIAL FOR STRONG
TO SEVERE STORMS AND POCKETS OF HEAVY RAINFALL AS IT SWEEPS THROUGH
THE TRI-STATE AREA OVERNIGHT THROUGH TOMORROW AFTERNOON. THEREFORE,
HIGH DISPERSIONS ARE EXPECTED FROM WEST TO EAST ON THURSDAY AND
REMAIN IN PLACE AREAWIDE ON FRIDAY FROM STRONG WEST TO SOUTHWEST
TRANSPORT WINDS. TRAILING SHOWERS ARE POSSIBLE IN THE SQUALL LINE'S
WAKE GENERALLY ALONG AND SOUTH OF I-10, BEFORE CONDITIONS DRY OUT BY
HALLOWEEN.
HYDROLOGY
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO ROLL THROUGH THE REGION
MAINLY OVERNIGHT TONIGHT AND THROUGH THE EARLY MORNING HOURS ON
THURSDAY. WHILE HEAVY RAINFALL IS EXPECTED WITH SOME OF THESE
STORMS, THE PROGRESSION OF THE SQUALL LINE AND PROCEEDING SHOWERS
SHOULD BE FAST ENOUGH THAT WIDESPREAD FLASH FLOODING IS NOT
ANTICIPATED. AREA RIVERS ARE ALSO IN DECENT SHAPE, THEREFORE,
THERE ARE ALSO NO CONCERNS WITH RIVER FLOODING AT THIS TIME. THE
MAIN CONCERN HYDROLOGY WISE WILL BE THE COASTAL FLOODING IN
APALACHEE BAY DUE TO VERY STRONG ONSHORE FLOW ALONG TAYLOR AND
DIXIE COUNTIES. GIVEN THIS THREAT, A COASTAL FLOOD ADVISORY HAS
BEEN ISSUED FROM WAKULLA COUNTY TO DIXIE COUNTY. ALTHOUGH ONSHORE
FLOW IS NOT EXPECTED BEHIND THE FRONT ALONG WAKULLA AND JEFFERSON
COUNTIES, A COASTAL FLOOD ADVISORY WAS STILL ISSUED DUE TO THE
EXPECTED PILING UP OF WATER IN APALACHEE BAY GIVEN THE STRONG AND
CONSISTENT FLOW INTO THE BAY.
SPOTTER INFORMATION STATEMENT
SPOTTER ACTIVATION IS REQUESTED. SPOTTERS ARE ALWAYS ENCOURAGED
TO SAFELY REPORT SIGNIFICANT WEATHER CONDITIONS WHEN THEY OCCUR
(WHILE FOLLOWING ALL LOCAL, STATE, AND CDC GUIDELINES) BY CALLING
THE OFFICE OR TWEETING US @NWSTALLAHASSEE.
PRELIMINARY POINT TEMPS/POPS
TALLAHASSEE 63 77 57 69 51 / 90 90 30 30 10
PANAMA CITY 68 77 59 69 54 / 90 60 40 40 20
DOTHAN 61 74 53 64 50 / 80 60 10 20 0
ALBANY 59 74 55 65 51 / 90 90 10 20 0
VALDOSTA 59 75 57 69 50 / 70 90 30 20 0
CROSS CITY 62 77 63 72 54 / 60 90 40 50 20
APALACHICOLA 69 78 60 69 54 / 90 80 50 60 30
TAE WATCHES/WARNINGS/ADVISORIES
FL...COASTAL FLOOD ADVISORY FROM 4 PM THURSDAY TO 11 AM EDT FRIDAY
FOR COASTAL DIXIE-COASTAL JEFFERSON-COASTAL TAYLOR-COASTAL
WAKULLA.
HIGH RIP CURRENT RISK FROM 8 PM EDT /7 PM CDT/ THIS EVENING
THROUGH SATURDAY MORNING FOR COASTAL BAY-COASTAL FRANKLIN-
COASTAL GULF-SOUTH WALTON.
HIGH SURF ADVISORY FROM 2 AM EDT /1 AM CDT/ THURSDAY TO 8 AM EDT
/7 AM CDT/ SATURDAY FOR COASTAL BAY-COASTAL GULF-SOUTH
WALTON.
WIND ADVISORY FROM 2 AM EDT /1 AM CDT/ THURSDAY TO 8 PM EDT /7
PM CDT/ FRIDAY FOR COASTAL BAY-COASTAL FRANKLIN-COASTAL
GULF-SOUTH WALTON.
GA...NONE.
AL...NONE.
GM...GALE WATCH FROM 11 PM EDT /10 PM CDT/ THIS EVENING THROUGH LATE
FRIDAY NIGHT FOR APALACHEE BAY OR COASTAL WATERS FROM
KEATON BEACH TO OCHLOCKONEE RIVER FL OUT TO 20 NM-COASTAL
WATERS FROM OCHLOCKONEE RIVER TO APALACHICOLA FL OUT TO 20
NM-COASTAL WATERS FROM SUWANNEE RIVER TO KEATON BEACH FL
OUT 20 NM-COASTAL WATERS FROM MEXICO BEACH TO APALACHICOLA
FL OUT 20 NM-COASTAL WATERS FROM MEXICO BEACH TO OKALOOSA
WALTON COUNTY LINE FL OUT 20 NM-WATERS FROM SUWANNEE RIVER
TO APALACHICOLA FL FROM 20 TO 60 NM-WATERS FROM
APALACHICOLA TO MEXICO BEACH FL FROM 20 TO 60 NM-WATERS
FROM MEXICO BEACH TO OKALOOSA WALTON COUNTY LINE FL FROM 20
TO 60 NM.
NEAR TERM...IG3
SHORT TERM...BUNKER
LONG TERM...BUNKER
AVIATION...IG3
MARINE...BUNKER
FIRE WEATHER...IG3
HYDROLOGY...BUNKER
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