975
FXUS62 KJAX 182210
AFDJAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
510 PM EST WED DEC 18 2024
..NEW UPDATE
UPDATE
ISSUED AT 508 PM EST WED DEC 18 2024
FOR THE LATEST NE FL AND SE GA DAILY KEY MESSAGES PLEASE VISIT:
HTTPS://WWW.WEATHER.GOV/MEDIA/JAX/BRIEFINGS/NWS-JAX-BRIEFING.PDF
SEAS HAVE TICKED BACK UPWARDS TO 5-7 FT ACROSS THE NE FL COASTAL
WATERS AS INDICATED BY THE MARINE BUOYS AT 41117 AND 41070, SO
HAVE RE-POSTED SCA FLAGS TONIGHT FOR THE ELEVATED SEAS THAT SHOULD
SUBSIDE TOWARDS MORNING.
SYNOPSIS
ISSUED AT 254 PM EST WED DEC 18 2024
AFTERNOON SURFACE ANALYSIS DEPICTS GRADUALLY HIGH PRESSURE (1024
MILLIBARS) MIGRATING EASTWARD OFF THE SOUTHEASTERN SEABOARD,
WHILE A WAVY FRONTAL BOUNDARY EXTENDS FROM THE SOUTHERN
APPALACHIANS SOUTHWESTWARD ACROSS THE TENNESSEE AND LOWER
MISSISSIPPI VALLEYS. MEANWHILE, ARCTIC HIGH PRESSURE (1036
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 TOWARDS
THE SOUTHEASTERN STATES. THE LAST PATCH OF LOWER STRATUS
CLOUDINESS THAT REMAINS FROM THIS MORNING'S WIDESPREAD DENSE FOG
EVENT WAS DISSIPATING OVER THE SUWANNEE VALLEY THIS AFTERNOON,
WITH HEALTHY CUMULUS AND STRATOCUMULUS FIELD NOW OVERHEAD
ELSEWHERE. A BROKEN LINE OF SHOWERS THAT DEVELOPED ALONG A
DIFFERENTIAL HEATING / SEA BREEZE BOUNDARY ALONG THE U.S. HIGHWAY
301 CORRIDOR IN NORTHEAST AND NORTH CENTRAL FL EARLIER THIS
AFTERNOON HAS MADE VERY SLOW INLAND PROGRESS TOWARDS THE I-75
CORRIDOR, WITH ACTIVITY OCCASIONALLY PULSING BUT NOT YET PRODUCING
LIGHTNING STRIKES. TEMPERATURES WERE IN THE 70S AREA-WIDE AS OF
20Z, WITH DEWPOINTS MOSTLY IN THE MID TO UPPER 60S.
NEAR TERM
(THROUGH TONIGHT)
ISSUED AT 254 PM EST WED DEC 18 2024
THE AFOREMENTIONED TROUGH WILL CONTINUE TO DIG SOUTHEASTWARD
TONIGHT, WITH INCREASINGLY UNSTABLE CONDITIONS ALOFT DEVELOPING
SCATTERED SHOWERS AND ISOLATED, LOW-TOPPED AND LIKELY BRIEF
CONVECTION POSSIBLE ALONG MESOSCALE AND DIFFERENTIAL HEATING
BOUNDARIES THROUGH AROUND SUNSET THIS EVENING. SHORT-TERM, HIGH
RESOLUTION GUIDANCE CONTINUES TO INDICATE THAT THIS ACTIVITY WILL
REMAIN LARGELY DIURNALLY DRIVEN BY THE WARM AND HUMID AIR MASS
THAT IS IN PLACE AHEAD OF THE APPROACHING COLD FRONT, WITH DEEPER
MOISTURE POOLING ALONG THE FRONT LIKELY NOT ARRIVING UNTIL THE
OVERNIGHT HOURS ACROSS INLAND SOUTHEAST GA AND THE SUWANNEE
VALLEY. THE LOSS OF DAYTIME HEATING THIS EVENING SHOULD RESULT IN
A DECREASING COVERAGE OF SHOWERS AS THE EVENING PROGRESSES, WITH
A FEW SHOWERS POSSIBLE ALONG THE SOUTHEASTWARD MOVING FRONTAL
BOUNDARY OVERNIGHT.
THE BIGGER WEATHER IMPACT OVERNIGHT WILL BE THE DEVELOPMENT OF
DENSE FOG AND LOW STRATUS CLOUD COVER DOWNSTREAM OF THE
APPROACHING FRONT ACROSS NORTHEAST AND NORTH CENTRAL FL
OVERNIGHT, WITH THE FRONTAL PASSAGE LIKELY CLEARING FOG AND LOW
STRATUS OUT OF THE PICTURE TOWARDS SUNRISE FOR INLAND SOUTHEAST GA
AND THE SUWANNEE VALLEY. 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 254 PM EST WED DEC 18 2024
A COLD FRONT WILL CONTINUE MOVING THROUGH THE AREA ON THURSDAY. AS
WITH THE PAST COUPLE OF MORNINGS, FOG WILL LINGER FOR A FEW HOURS
AFTER FIRST LIGHT ON THURSDAY. WITH THE COLD FRONT STILL MAKING
ITS WAY THROUGH OUR SOUTHERN LOCATIONS, THERE WILL BE A LOW CHANCE
(10-20%) FOR MORNING COASTAL SHOWERS FOR LOCATIONS SOUTH OF THE
JAX METRO. WITH A COOLER AND DRIER AIRMASS BEGINNING TO SETTLE
INTO THE AREA, DAYTIME TEMPERATURES WILL BEGIN TO TREND DOWNWARD
INTO THE END OF THE WEEK. DAYTIME HIGHS TO SPAN IN THE 70S WITH
WARMER TEMPERATURES ALONG THE SOUTHERN COUNTIES OF THE LOCAL AREA.
OVERNIGHT LOWS MAKE A RETURN TO 40S FOR SE GA, WITH LOWS IN THE
50S FOR NE FL.
BY FRIDAY, THE COOLING TREND CONTINUES AS ANOTHER COLD FRONT WILL
BRING MUCH COLDER TEMPERATURES AND DRY WEATHER FOR THE AREA AS WE
HEAD INTO THE WEEKEND. DAYTIME HIGHS DIPPING INTO THE 60S FOR
LOCATIONS ALONG AND NORTH OF THE I-10 CORRIDOR, WITH 70S ALONG
NORTH CENTRAL FLORIDA. BY FRIDAY NIGHT, LOWS WILL GET INTO THE LOW
30S FOR INLAND LOCATIONS OF SE GA AND SOUTHWARD INTO THE SUWANNEE
VALLEY REGION IN NE FL. UPPER 30S AND LOW 40S FOR LOCATIONS IN
NORTH CENTRAL FLORIDA AND ALONG THE COAST. LIGHT WINDS DURING THE
EARLY HOURS HEADING SATURDAY, WITH THE COLDER TEMPERATURES WILL
ALLOW FOR PATCHY FROST TO FORM ALONG INLAND LOCATIONS IN SE GA AND
TOWARDS THE SUWANNEE VALLEY REGION.
LONG TERM
(SATURDAY THROUGH NEXT WEDNESDAY)
ISSUED AT 254 PM EST WED DEC 18 2024
A COLD AIR MASS SETTLING INTO THE AREA WILL ALLOW FOR BELOW
NORMAL TEMPERATURES TO DEVELOP THROUGH THE WEEKEND AND ON MONDAY.
DAYTIME HIGHS IN THE 50S AREAWIDE ON SATURDAY AND SUNDAY WILL DIP
TO THE 30S FOR MOST LOCATIONS WEST OF THE ST. JOHNS RIVER.
SATURDAY NIGHT IS ON TRACK TO BE THE COLDEST NIGHT OF THE WEEKEND.
WE WILL LIKELY SEE LOCATIONS OF INLAND SE GA TOWARDS THE SUWANNEE
VALLEY REGION DEVELOP A LIGHT FREEZE WITH LOCATIONS WEST OF THE
I-95 CORRIDOR DEVELOP FROST ON SATURDAY NIGHT. A SIMILAR PATTERN
WILL DEVELOP ON SUNDAY, BUT WITH SLIGHTLY WARMER TEMPERATURES THAN
SATURDAY, WITH ANOTHER NIGHT OF FROST ALONG INLAND SE GA AND THE
SUWANNEE VALLEY REGION OF NE FL.
TEMPERATURES WILL BEGIN TO WARM UP DURING THE FIRST HALF OF THE
UPCOMING WEEK WITH A COASTAL TROUGH BEGINNING TO DEVELOP ALONG THE
ATLANTIC COAST. COASTAL SHOWERS CHANCES INCREASE ON MONDAY EVENING
AS ONSHORE FLOW RETURNS. THIS WILL ALSO LIKELY SET UP A RETURN OF
SURF ZONE AND MARINE HAZARDS INCLUDING ELEVATED RIP CURRENT RISK
AND SMALL CRAFT CONDITIONS.
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.
MARINE
ISSUED AT 254 PM EST WED DEC 18 2024
SMALL CRAFT SHOULD CONTINUE TO EXERCISE CAUTION THROUGH TONIGHT,
AS SEAS BOTH NEAR SHORE AND OFFSHORE WILL REMAIN IN THE 4-6 FOOT
RANGE. OTHERWISE, SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
THIS EVENING WILL DECREASE IN COVERAGE OVERNIGHT 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.
NORTH 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.
SEAS WILL BRIEFLY SUBSIDE TO THE 3-5 FOOT RANGE BOTH NEAR SHORE
AND OFFSHORE FROM THURSDAY THROUGH FRIDAY. 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. WINDS AND SEAS MAY APPROACH SMALL CRAFT ADVISORY
LEVELS LATE THIS WEEKEND AND EARLY NEXT WEEK.
RIP CURRENTS: A PERSISTENT EASTERLY OCEAN SWELL AND BREAKERS OF
3-5 FEET WILL KEEP A MODERATE RIP CURRENT RISK IN PLACE AT ALL
AREA BEACHES ON THURSDAY. THIS PERSISTENT SWELL SHOULD KEEP A
LOWER END MODERATE RISK GOING INTO FRIDAY AS BREAKER HEIGHTS
SUBSIDE TO 2-4 FEET AT AREA BEACHES.
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 72 46 65 / 20 10 0 0
SSI 59 69 53 65 / 20 10 0 0
JAX 60 75 52 69 / 20 10 0 0
SGJ 61 73 55 71 / 30 10 0 0
GNV 61 77 53 69 / 20 20 0 0
OCF 61 78 54 72 / 20 20 0 0
JAX WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GA...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR AMZ452-454-472-
474.
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