693
FXUS62 KJAX 181825
AFDJAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
125 PM EST WED DEC 18 2024
..NEW AVIATION
AVIATION
(18Z TAFS)
ISSUED AT 126 PM EST WED DEC 18 2024
MVFR CEILINGS OF 2,000 - 3,000 FEET WILL PREVAIL AT THE DUVAL
COUNTY TERMINALS AND GNV THROUGH AT LEAST 20Z AS SHOWERS DEVELOP
ALONG AND WEST OF INTERSTATE 95. VFR CONDITIONS SHOULD OTHERWISE
PREVAIL THROUGH AT LEAST SUNSET AT THE SGJ AND SSI TERMINALS.
SHOWERS WILL AT LEAST BRIEFLY IMPACT THE DUVAL COUNTY TERMINALS
AND GNV THROUGH AROUND 21Z, WITH A BRIEF THUNDERSTORM POSSIBLE AT
THESE TERMINALS THROUGH AROUND SUNSET. HOWEVER, CONFIDENCE WAS
TOO LOW TO INDICATE THUNDERSTORMS IN THE AFTERNOON TAFS AT THIS
TIME, SO PLEASE CHECK FOR AMENDMENTS AS THE AFTERNOON PROGRESSES.
SHOWERS THAT DEVELOP ALONG AND WEST OF INTERSTATE 95 THIS
AFTERNOON SHOULD SHIFT EASTWARD TOWARDS THE COASTAL TERMINALS
AFTER SUNSET, BUT CONFIDENCE FOR IMPACTS TO THE SGJ AND SSI
TERMINALS WAS TOO LOW TO INDICATE ANYTHING OTHER THAN VICINITY
COVERAGE AT THIS TIME. THE BIGGER IMPACT TO THE TERMINALS WILL
OCCUR OVERNIGHT, AS LOW STRATUS CEILINGS AND POTENTIALLY DENSE FOG
IMPACT THE REGIONAL TERMINALS AFTER 02Z. IFR TO LIFR CONDITIONS IN
DENSE FOG AND LOW STRATUS CEILINGS SHOULD PREVAIL THROUGH AT LEAST
14Z THURSDAY BEFORE GRADUAL IMPROVEMENT OCCURS DURING THE LATE
MORNING AND EARLY AFTERNOON HOURS. EAST SOUTHEASTERLY SURFACE
SUSTAINED AROUND 10 KNOTS THIS AFTERNOON WILL DIMINISH TOWARDS
SUNSET AND WILL THEN SHIFT TO NORTHWESTERLY TOWARDS SUNRISE ON
THURSDAY, WITH SPEEDS REMAINING SUSTAINED AT 5 KNOTS OR LESS
THROUGH THE MORNING HOURS.
UPDATE
ISSUED AT 1220 PM EST WED DEC 18 2024
EARLY AFTERNOON SURFACE ANALYSIS DEPICTS HIGH PRESSURE (1025
MILLIBARS) POSITIONED ALONG THE SOUTHEASTERN SEABOARD, WHILE A
WAVY FRONTAL BOUNDARY EXTENDS FROM THE CAROLINAS WESTWARD ACROSS
THE TENNESSEE VALLEY AND THEN SOUTHWESTWARD ACROSS THE OZARKS AND
THE LOWER MISSISSIPPI VALLEY. MEANWHILE, PERSISTENT COASTAL
TROUGHING POSITIONED OVER OUR ATLANTIC WATERS HAS NUDGED EASTWARD
TOWARDS THE GULF STREAM WATERS SINCE EARLIER THIS MORNING.
OTHERWISE, ARCTIC HIGH PRESSURE (1038 MILLIBARS) WAS SPILLING
SOUTHEASTWARD FROM THE CANADIAN PRAIRIES THOUGH THE UPPER MIDWEST
AND THE PLAINS STATES. ALOFT...RIDGING POSITIONED ACROSS THE
NORTHWESTERN CARIBBEAN SEA CONTINUES TO FLATTEN IN RESPONSE TO A
SHARPENING TROUGH THAT WAS DIVING SOUTHEASTWARD ACROSS THE OHIO,
TENNESSEE, AND LOWER MISSISSIPPI VALLEYS. DENSE FOG THAT PLAGUED
LOCATIONS ALONG AND WEST OF THE I-95 CORRIDORS EARLIER THIS
MORNING HAS DISSIPATED, BUT A LEFTOVER LOW STRATUS CLOUD LAYER HAS
BEEN SLOW TO LIFT OVER INLAND PORTIONS OF SOUTHEAST GA AND ALSO
FOR LOCATIONS WEST OF U.S. HIGHWAY 301 IN NORTHEAST AND NORTH
CENTRAL FL. SUNSHINE THIS MORNING AND A MOIST LOW LEVEL AIR MASS
ALONG THE I-95 CORRIDOR HAS DEVELOPED A HEALTHY CUMULUS DECK THAT
WAS PROGRESSING INLAND, WITH TEMPERATURES IN THESE AREAS ALREADY
CLIMBING THROUGH THE MID AND UPPER 70S AS OF NOON, WHILE VALUE
REMAIN IN THE UPPER 60S TO AROUND 70 FOR LOCATIONS THAT ARE STUCK
WITH LOWER STRATUS CLOUDINESS. DEWPOINTS AT NOON WERE MOSTLY IN
THE MID TO UPPER 60S.
THE AFOREMENTIONED TROUGH WILL CONTINUE TO DIG SOUTHEASTWARD THIS
AFTERNOON, WITH INCREASINGLY UNSTABLE CONDITIONS ALOFT LIKELY
DEVELOPING SCATTERED SHOWERS AND ISOLATED, LOW-TOPPED CONVECTION
ALONG MESOSCALE AND DIFFERENTIAL HEATING BOUNDARIES, ESPECIALLY
TOWARDS SUNSET THIS EVENING. SHORT-TERM, HIGH RESOLUTION GUIDANCE
HAS BEEN LESS AGGRESSIVE WITH CONVECTIVE DEVELOPMENT LATER TODAY
AND THIS EVENING, LIKELY DUE TO A LACK OF DEEPER MOISTURE OVER OUR
AREA, WHICH WILL REMAIN DOWNSTREAM OF AN APPROACHING COLD FRONT
THAT WILL LIKELY NOT ARRIVE UNTIL AFTER MIDNIGHT ACROSS INLAND
SOUTHEAST GA AND THE SUWANNEE VALLEY AND TOWARDS SUNRISE OR THE
EARLY MORNING HOURS ON THURSDAY ELSEWHERE. WE'LL KEEP THE MENTION
OF A FEW STRONGER STORMS IN THE FORECAST LATER TODAY FOR NOW, BUT
THE EXPECTED INSTABILITY (500-1,000 J/KG OF ML CAPE) MAY NOT HAVE
MUCH OF A TRIGGER TO WORK WITH GIVEN THE LACK OF DEEPER MOISTURE
LATER TODAY. THE LOSS OF DAYTIME HEATING THIS EVENING SHOULD
RESULT IN A DECREASING COVERAGE OF SHOWERS TOWARDS MIDNIGHT, AND
DENSE FOG IS THEN LIKELY TO DEVELOP IN THE WARM AND HUMID AIR MASS
DOWNSTREAM OF THE APPROACHING FRONT ACROSS NORTHEAST AND NORTH
CENTRAL FL THIS EVENING, WITH THE FRONTAL PASSAGE LIKELY CLEARING
FOG AND LOW STRATUS OUT OF THE PICTURE BEFORE SUNRISE FOR INLAND
SOUTHEAST GA AND THE SUWANNEE VALLEY.
HIGHS THIS AFTERNOON SHOULD CLIMB TO THE UPPER 70S TO AROUND 80 AT
MOST INLAND LOCATIONS, EXCEPT LOWER 80S FOR NORTH CENTRAL FL. AN
ONSHORE BREEZE WILL KEEP COASTAL HIGHS IN THE MID TO UPPER 70S.
COOL AIR ADVECTION ARRIVING IN THE WAKE OF THE OVERNIGHT FRONTAL
PASSAGE WILL DROP LOWS INTO THE 50S FOR INLAND SOUTHEAST GA
TOWARDS SUNRISE, WHILE 60S PREVAIL ELSEWHERE.
SHORT TERM
(THURSDAY THROUGH FRIDAY NIGHT)
ISSUED AT 329 AM EST WED DEC 18 2024
THU & THU NIGHT...DRIER AND COOLER WITH LINGERING LOW LEVEL CLOUDS
THURSDAY UNDER LOW LEVEL NNW WINDS. JUST ABOVE THE SURFACE, WSW
MID AND UPPER LEVEL FLOW WILL CONTINUE A RELATIVELY 'WARM' AIRMASS
WITH HIGHS IN THE 70S FOR MOST LOCATIONS AND A LOW CHANCE (10-20%)
OF A PASSING SHOWER OR T'STORM ACROSS NE FL WITH THE APPROACH &
PASSAGE OF A STRONG MID/UPPER LEVEL SHORT WAVE TROUGH. SURFACE
BASED INSTABILITY OF 800-1000 J/KG UNDER STRONG UPPER LEVEL
LIFT/SHEAR FAVOR T'STORM POTENTIAL ALONG AND SOUTH OF A ST.
AUGUSTINE TO OCALA LINE THROUGH EARLY AFTERNOON, BUT INVADING
MID/UPPER LEVEL DRY AIR WILL LIKELY TEMPER DEEPER CONVECTIVE
GROWTH BUT COULD ENHANCE AN ISOLATED STRONG STORM CAPABLE OF
SMALL HAIL. TEMPERATURES COOL THU NIGHT INTO THE UPPER 40S ACROSS
SE GA TO THE 50S ACROSS NE FL, BUT NOT A DRAMATIC COOL DOWN YET.
FRI & FRI NIGHT...DRY WEATHER AND COOLING TREND BEGINS FRIDAY
TRAILING THE THU EVENING SHORT WAVE TROUGH PASSAGE WITH HIGH
TEMPERATURES RANGING IN THE 60S FOR MOST AREAS TO NEAR 70 ACROSS
NORTH-CENTRAL FL. FRI AFTERNOON, A REINFORCING DRY COLD FRONT
MOVES SOUTH OF THE AREA, TRAILED BY COLDER AND DRIER DEEP-LAYER
WNW FLOW ACROSS THE REGION. THIS REGIME WILL USHER IN A MUCH
COLDER AIRMASS FOR THE WEEKEND, WITH LOWS FALLING INTO THE MID 30S
TO LOW 40S BY DAYBREAK SATURDAY MORNING AND JUST LIGHT ENOUGH OF A
PRESSURE GRADIENT FOR SOME PATCHY INLAND FROST TO FORM IN
SHELTERED AREAS WITH APPARENT TEMPERATURES (AKA WIND CHILLS) NEAR
30 DEGF FOR PARTS OF SE GA AND THE SUWANNEE RIVER VALLEY BY
DAYBREAK SAT MORNING.
LONG TERM
(SATURDAY THROUGH TUESDAY)
ISSUED AT 329 AM EST WED DEC 18 2024
SAT & SUN...DRY WITH WITH BELOW NORMAL TEMPERATURES WITH HIGHS IN
THE 50S TO LOW 60S WITH INLAND LIGHT FREEZES FOR SE GA AND
PORTIONS OF THE SUWANNEE RIVER VALLEY AND FROST FARTHER EAST
TOWARD THE ST. JOHNS RIVER BASIN AS SURFACE HIGH PRESSURE BUILDS
NORTH THEN NORTHEAST OF THE REGION.
MON & TUE...NNE FLOW BEGINS TO DEVELOP AS THE SURFACE RIDGE BUILDS
OFFSHORE OF THE NEW ENGLAND COAST WITH ANOTHER INVERTED COASTAL
TROUGH AXIS FORMING OVER THE LOCAL WATERS. THIS WILL MODERATE
TEMPERATURES ACROSS COASTAL SE GA AND MUCH OF NE FL, WHILE A RIDGE
AXIS WEDGING DOWN THE LEE SIDE OF THE APPALACHIANS HOLDS ONTO
ANOTHER NIGHT OF CHILLY TEMPERATURES AND FROST POTENTIAL MON
NIGHT/TUE MORNING FOR INLAND SE GA. THE INVERTED COASTAL TROUGH
WILL INCREASE LOCAL ONSHORE FLOW LATE MON INTO TUE WITH A CHANCE
OF COASTAL SHOWERS AND A RETURN OF SURF ZONE AND MARINE HAZARDS
INCLUDING ELEVATED RIP CURRENT RISK AND SMALL CRAFT CONDITIONS.
MARINE
ISSUED AT 1220 PM EST WED DEC 18 2024
ELEVATED SEAS WILL REMAIN IN PLACE TODAY, ESPECIALLY OFFSHORE,
WHERE SMALL CRAFT SHOULD EXERCISE CAUTION DUE TO WAVE HEIGHTS OF
5-6 FEET THROUGH TONIGHT. MEANWHILE, A PERSISTENT COASTAL TROUGH
WILL DEVELOP SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS LATER
THIS AFTERNOON, MAINLY ACROSS THE NORTHEAST FLORIDA WATERS. THIS
TROUGH WILL LIFT NORTHWARD THIS EVENING AHEAD OF AN APPROACHING
COLD FRONT. DENSE SEA FOG WILL LIKELY REDEVELOP BEFORE MIDNIGHT
ACROSS OUR LOCAL WATERS, AND MAY PERSIST THROUGH THE EARLY MORNING
HOURS ON THURSDAY BEFORE THE FRONT CROSSES OUR LOCAL WATERS. SEAS
WILL SUBSIDE SLIGHTLY TO 3-5 FEET BOTH NEAR SHORE AND OFFSHORE ON
THURSDAY AND THURSDAY NIGHT.
NORTHWESTERLY WINDS WILL DEVELOP ON THURSDAY IN THE WAKE OF THIS
FRONT, WITH WINDS THEN SHIFTING TO NORTHERLY BY LATE FRIDAY AS A
REINFORCING DRY COLD FRONT PUSHES SOUTHWARD THROUGH OUR AREA.
STRONG HIGH PRESSURE BUILDING OVER THE GREAT LAKES REGION IN THE
WAKE OF THIS REINFORCING FRONT WILL RESULT IN STRENGTHENING NORTH-
NORTHEASTERLY WINDS AND BUILDING SEAS FROM FRIDAY NIGHT THROUGH
THE WEEKEND, WITH SMALL CRAFT ADVISORY CONDITIONS EXPECTED
OFFSHORE AND POSSIBLY NEAR SHORE.
RIP CURRENTS: AN ONSHORE BREEZE WILL COMBINE WITH ELEVATED
BREAKERS OF 3-5 FEET AT ALL AREA BEACHES THIS AFTERNOON TO CREATE
A HIGHER END MODERATE RIP CURRENT RISK.
FIRE WEATHER
ISSUED AT 1220 PM EST WED DEC 18 2024
SOUTHEASTERLY SURFACE AND TRANSPORT WINDS WILL SHIFT TO SOUTHERLY
EARLY THIS AFTERNOON AT INLAND LOCATIONS AND THEN SOUTHWESTERLY
LATER THIS AFTERNOON ACROSS INLAND PORTIONS OF SOUTHEAST GA AND
THE SUWANNEE VALLEY. LIGHT SPEEDS AND LOW MIXING HEIGHTS WILL
RESULT IN LOW DAYTIME DISPERSION VALUES ACROSS SOUTHEAST GA AND
MOST OF NORTHEAST FL, WITH POOR VALUES EXPECTED FOR NORTH CENTRAL
FL. SURFACE AND TRANSPORT WINDS WILL SHIFT TO NORTHWESTERLY ON
THURSDAY MORNING, FOLLOWED BY SURFACE WINDS SHIFTING TO NORTH-
NORTHEASTERLY AT COASTAL LOCATIONS DURING THE AFTERNOON HOURS,
WHERE LOW DAYTIME DISPERSION VALUES ARE EXPECTED TO CONTINUE. POOR
VALUES ARE FORECAST TOMORROW ALONG THE I-95 CORRIDOR, WHILE FAIR
VALUES ARE EXPECTED INLAND. WEST-NORTHWESTERLY TRANSPORT WINDS
WILL THEN BECOME BREEZY ON FRIDAY AREA-WIDE, WITH A DRIER AIR MASS
FILTERING INTO OUR REGION AND GOOD DAYTIME DISPERSION VALUES
LIKELY.
PRELIMINARY POINT TEMPS/POPS
AMG 57 71 46 63 / 20 10 10 0
SSI 60 71 51 64 / 40 10 10 0
JAX 61 75 51 69 / 40 10 10 0
SGJ 63 73 56 70 / 30 10 10 0
GNV 62 77 52 69 / 30 10 10 0
OCF 62 78 54 70 / 20 20 0 0
JAX WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GA...NONE.
AM...NONE.
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