799
FXUS62 KJAX 181812
AFDJAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
212 PM EDT FRI JUL 18 2025
..HEAT ADVISORY THROUGH 6 PM FOR PORTIONS OF INLAND NE FL
..A FEW STRONG STORMS POSSIBLE LATE THIS AFTERNOON AND EVENING
...DANGEROUSLY HIGH HEAT INDICES AREA-WIDE THIS WEEKEND AND EARLY
NEXT WEEK...
FOR THE LATEST NE FL AND SE GA DAILY KEY MESSAGES PLEASE VISIT:
HTTPS://WWW.WEATHER.GOV/MEDIA/JAX/BRIEFINGS/NWS-JAX-BRIEFING.PDF
SYNOPSIS
ISSUED AT 213 PM EDT FRI JUL 18 2025
NOON SURFACE ANALYSIS DEPICTS HIGH PRESSURE (1024 MILLIBARS)
POSITIONED TO THE EAST OF THE GULF STREAM WATERS OFF THE
SOUTHEASTERN SEABOARD. MEANWHILE, THE REMNANT CIRCULATION OF
INVEST 93L WAS MEANDERING THROUGH THE LOWER MISSISSIPPI VALLEY.
ALOFT...RIDGING CENTERED FROM THE SOUTHEASTERN SEABOARD SOUTHWARD
THROUGH THE BAHAMAS CONTINUES TO GRADUALLY RETROGRADE WESTWARD,
WITH THIS FEATURE STEERING A WEAK TROUGH SLOWLY NORTHWARD ACROSS
EASTERN PORTIONS OF THE GULF AND FL PENINSULA. LATEST GOES-EAST
DERIVED TOTAL PRECIPITABLE WATER IMAGERY INDICATES THAT DEEP
TROPICAL MOISTURE REMAINS IN PLACE ACROSS OUR AREA, WITH PWATS
GENERALLY AROUND OR JUST ABOVE 2 INCHES, WHILE LOWER VALUES IN THE
1.6 - 1.8 INCH RANGE WERE ADVECTING NORTHWARD FROM THE INTERSTATE
4 CORRIDOR IN CENTRAL FL. TEMPERATURES HAVE SOARED TO THE 90-95
DEGREE RANGE AT MOST INLAND LOCATIONS AS OF 18Z, WITH DEWPOINTS
IN THE 70S YIELDING HEAT INDEX VALUES IN THE 100-108 DEGREE
RANGE THUS FAR THIS AFTERNOON. WHILE A HEALTHY CUMULUS FIELD WAS
BUILDING ACROSS OUR REGION, CONVECTION THUS FAR AS REMAINED TO THE
WEST OF THE SUWANNEE AND ALAPAHA RIVERS, WHERE INITIATION WAS
BEING TRIGGERED BY THE INLAND MOVING GULF COAST SEA BREEZE
BOUNDARY.
NEAR TERM
(THROUGH TONIGHT)
ISSUED AT 213 PM EDT FRI JUL 18 2025
ALTHOUGH SUBSIDENCE WILL BE STRENGTHENING WITH THE RETROGRADING
RIDGE APPROACHING OUR REGION, SOME COOLING ALOFT ASSOCIATED WITH
WEAK TROUGHING ALOFT APPROACHING FROM THE SOUTH AND PLENTY OF LOW
LEVEL MOISTURE SHOULD RESULT IN SCATTERED LATE AFTERNOON AND
EVENING CONVECTION DEVELOPING ALONG INLAND MOVING SEA AND RIVER
BREEZE BOUNDARIES, WITH A SLIGHTLY HIGHER COVERAGE POSSIBLE
TOWARDS SUNSET ALONG THE U.S. HIGHWAY 301 CORRIDOR, WHERE
MESOSCALE BOUNDARIES ARE LIKELY TO COLLIDE. SOUTHWESTERLY STEERING
FLOW COULD BRING SOME OF THIS ACTIVITY BACK TOWARDS THE I-95
CORRIDOR AFTER SUNSET BEFORE ACTIVITY DIMINISHES LATER THIS
EVENING, OR BEFORE MIDNIGHT. A FEW STORMS WILL PULSE AS
CONVECTIVE BOUNDARIES COLLIDE AND MAY BRIEFLY BECOME STRONG EARLY
THIS EVENING, WITH STRONGER STORMS BEING CAPABLE OF PRODUCING
DOWNBURST WINDS OF 40-50 MPH, FREQUENT LIGHTNING STRIKES, AND
LOCALLY HEAVY DOWNPOURS. DEBRIS CLOUDINESS FROM THIS EVENING'S
SCATTERED CONVECTION WILL THEN GRADUALLY THIN OUT OVERNIGHT, WITH
LOWS ONLY FALLING TO THE MID 70S INLAND, RANGING TO AROUND 80 AT
AREA BEACHES.
SHORT TERM
(SATURDAY THROUGH SUNDAY)
ISSUED AT 213 PM EDT FRI JUL 18 2025
THIS WEEKEND, LOW/MID LEVEL RIDGING WILL SHIFT FROM THE ATLANTIC
OVER SOUTHERN PORTIONS OF THE AREA CENTERED OVER CENTRAL TO NORTH
CENTRAL FL AND THEN SHIFT WESTWARD INTO THE NE GULF WATERS. THIS
WILL LIMIT CHANCES FOR T'STORMS TO MAINLY UNDER 30 PERCENT OVER
NORTH CENTRAL FL AND UNDER 20 PERCENT OVER NE FL WITH SILENT POPS
UNDER 10 PERCENT OVER MOST OF SE GA. SKY COVER WILL BE MOSTLY SUNNY
UNDER THE HIGH AND ALONG WITH RISING HEIGHTS UNDER THE RIDGE WILL
ALLOW HIGH TEMPERATURES TO RISE INTO THE MID TO UPPER 90S ON
SATURDAY AND UPPER 90S TO AROUND 100 DEGREES INLAND. WEST TO SW
FLOW WILL WILL PIN THE ATLANTIC SEABREEZE TO THE IMMEDIATE COAST
SATURDAY AND OFFSHORE ON SUNDAY ALLOWING HIGHS TO REACH THE LOW TO
MID 90S EVEN AT THE BEACHFRONT.
THE MAIN STORY WILL BE THE HEAT INDEX VALUES THIS WEEKEND AS THE
HIGH TEMPERATURES ALSO COMBINE WITH DEWPOINTS IN THE MID 70S TO
CREATE HEAT INDEX VALUES 108-112 DEGREES ACROSS MUCH OF THE AREA,
EXCEPT GENERALLY NORTH AND WEST OF WAYCROSS. THEREFORE, HEAT
ADVISORIES ARE LIKELY FOR A MAJORITY OF NE FL AND ALONG THE SE GA
COAST.
LONG TERM
(MONDAY THROUGH THURSDAY)
ISSUED AT 213 PM EDT FRI JUL 18 2025
NEXT WEEK, THE LOW/MID LEVEL RIDGE WILL SLIDE WESTWARD INTO THE
NORTH CENTRAL GULF AS A TROUGH/WEAK FRONTAL BOUNDARY SETTLES
SOUTHWARD ALONG THE SOUTHEAST U.S. COAST TOWARDS THE AREA.
FOR MONDAY, SCATTERED TO NUMEROUS SHOWERS AND T'STORMS WILL
DEVELOP AS MOISTURE POOLS AHEAD OF THE TROUGH/FRONT WITH PWATS
CLIMBING TO 2.0 - 2.25 INCHES (90TH PERCENTILE THIS TIME OF
YEAR). WINDS WILL SHIFT MORE EASTERLY AS THE FRONT APPROACHES FROM
THE NORTH WITH HIGHEST T'STORM CHANCES WEST OF HIGHWAY 301.
BY TUESDAY AND WEDNESDAY, THE FRONT WILL SLIDE INTO THE AREA WITH
PWATS REACHING NEAR DAILY MAX VALUES (ABOVE 2.3-2.4 INCHES). THE
COMBINATION OF HIGH MOISTURE, LIFT FROM THE FRONT AND SHORTWAVE
ENERGY ALOFT WITH A MID/UPPER TROUGH MOVING SE OFF THE EASTERN
SEABOARD WILL PROMOTE WIDESPREAD SHOWERS AND T'STORMS OVER OUR
AREA EACH DAY. WHILE MID LEVEL TEMPS WILL STAY NEAR TO SLIGHTLY
WARMER THAN CLIMATOLOGY (ABOUT -5 TO -7 CELSIUS), STEEP LOW LEVEL
LAPSE RATES AND HIGH MOISTURE WILL ALLOW FOR STRONG DOWNBURST
WINDS TO OCCUR BETWEEN SEABREEZE AND STORM OUTFLOW COLLISIONS
ALONG WITH LOCALLY HEAVY RAINFALL FROM HEAVY DOWNPOURS AND
FREQUENT LIGHTNING.
ON THURSDAY, THE FRONT WILL BEGIN TO WEAKEN WITH SOME DRIER AIR
WORKING IN FROM THE NORTH INTO SE GA AS WEAK HIGH PRESSURE EXTENDS
FROM NEAR COASTAL NEW ENGLAND INTO THE CAROLINAS. THIS WILL LIMIT
CHANCES TO SCATTERED T'STORMS OVER SE GA AND SCATTERED TO NUMEROUS
T'STORMS ACROSS NE FL.
TEMPERATURES WILL BEGIN THE PERIOD ABOVE NORMAL AS HIGHS REMAIN IN
THE MID TO UPPER 90S AWAY FROM THE COAST WITH HIGH HEAT INDEX VALUES
POTENTIALLY INTO HEAT ADVISORY LEVELS MONDAY BEFORE HIGHS TREND BACK
TO NEAR TO SLIGHTLY ABOVE NORMAL TUESDAY THROUGH THURSDAY.
AVIATION
(18Z TAFS)
ISSUED AT 125 PM EDT FRI JUL 18 2025
VFR CONDITIONS WILL PREVAIL AT THE REGIONAL TERMINALS THROUGH AT
LEAST 20Z. SCATTERED SHOWERS AND THUNDERSTORMS WILL BEGIN
DEVELOPING ALONG THE INLAND MOVING ATLANTIC AND GULF COAST SEA
BREEZE BOUNDARIES AFTER 20Z, LIKELY ALONG THE I-95 AND I-75
CORRIDORS. CONFIDENCE WAS HIGH ENOUGH TO MAINTAIN PROB30 GROUPS
FOR BRIEFLY GUSTY WINDS AND MVFR CONDITIONS DURING HEAVIER
DOWNPOURS AT THE REGIONAL TERMINALS, EXCEPT AT GNV, WHERE
CONFIDENCE WAS ONLY HIGH ENOUGH FOR VICINITY COVERAGE LATE THIS
AFTERNOON AND EARLY THIS EVENING. ACTIVITY MAY LINGER AT THE
REGIONAL TERMINALS THROUGH AROUND 03Z. VFR CONDITIONS SHOULD
THEN PREVAIL BY 04Z. PERIODS OF MVFR VISIBILITIES ARE THEN
EXPECTED AT VQQ DURING THE PREDAWN AND EARLY MORNING HOURS ON
SATURDAY. SOUTHEASTERLY SURFACE WINDS SUSTAINED AT 10-15 KNOTS
WILL CONTINUE THROUGH AROUND 23Z AT THE SSI AND SGJ COASTAL
TERMINALS. THE ATLANTIC SEA BREEZE BOUNDARY WILL PROGRESS SLOWLY
INLAND THIS AFTERNOON, WITH SURFACE WINDS AT THE DUVAL COUNTY
TERMINALS SHIFTING TO SOUTHEASTERLY AROUND 10 KNOTS BY 22Z. THE
GULF COAST SEA BREEZE BOUNDARY WILL CROSS THE GNV TERMINAL TOWARDS
21Z, SHIFTING SURFACE WINDS TO SOUTHWESTERLY AT 10-15 KNOTS.
SURFACE WINDS WILL THEN SHIFT TO SOUTHERLY AFTER 00Z AT THE
REGIONAL TERMINALS, WITH SPEEDS DIMINISHING OVERNIGHT AT THE
INLAND TERMINALS AND REMAINING SUSTAINED AROUND 5 KNOTS AT THE
COASTAL TERMINALS. WESTERLY SURFACE WINDS WILL THEN DEVELOP
TOWARDS SUNRISE AT THE COASTAL TERMINALS AND BY 14Z AT THE INLAND
TERMINALS.
MARINE
ISSUED AT 1229 PM FRI JUL 18 2025
HIGH PRESSURE CENTERED OFF THE SOUTHEASTERN SEABOARD WILL SHIFT
SLOWLY WESTWARD TOWARDS OUR LOCAL WATERS TONIGHT AND SATURDAY.
ONLY ISOLATED LATE AFTERNOON AND EVENING THUNDERSTORMS ARE
POSSIBLE ACROSS THE NEAR SHORE WATERS THROUGH SATURDAY. TROUGHING
WILL THEN DEVELOP ON SUNDAY OVER THE SOUTHEASTERN STATES, WITH
THIS FEATURE POTENTIALLY SHARPENING NEAR OUR LOCAL WATERS EARLY
NEXT WEEK. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE
BEGINNING LATE SUNDAY AFTERNOON, WITH STRONG TO ISOLATED SEVERE
AFTERNOON AND EVENING THUNDERSTORMS POTENTIALLY IMPACTING OUR
LOCAL WATERS EACH DAY NEXT WEEK. SEAS OF 2 TO 3 FEET WILL PREVAIL
BOTH NEAR SHORE AND OFFSHORE DURING THE NEXT SEVERAL DAYS.
RIP CURRENTS: A PERSISTENT EAST-SOUTHEASTERLY OCEAN SWELL WILL
COMBINE WITH DEVELOPING ONSHORE WINDS THIS AFTERNOON TO CREATE A
LOWER END MODERATE RISK AT ALL AREA BEACHES. SIMILAR CONDITIONS
ARE EXPECTED ON SATURDAY, WITH A LOW RISK POSSIBLE BY SUNDAY AND
MONDAY DUE TO LOW SURF HEIGHTS.
FIRE WEATHER
ISSUED AT 1229 PM FRI JUL 18 2025
SOUTHWESTERLY TRANSPORT SPEEDS AROUND 10 MPH THIS AFTERNOON WILL
COMBINE WITH ELEVATED MIXING HEIGHTS TO CREATE GENERALLY FAIR
DAYTIME DISPERSION VALUES, EXCEPT GOOD VALUES FOR LOCATIONS NORTH
OF WAYCROSS IN SOUTHEAST GA AND POOR VALUES AT COASTAL LOCATIONS,
WHERE ONSHORE SURFACE WINDS WILL DEVELOP BY MID-AFTERNOON. SURFACE
AND TRANSPORT WINDS WILL BECOME WEST-SOUTHWESTERLY ON SATURDAY,
WITH BREEZY TRANSPORT SPEEDS DEVELOPING NORTH OF THE I-10 CORRIDOR
DURING THE AFTERNOON HOURS. THESE BREEZY CONDITIONS WILL COMBINE
WITH ELEVATED MIXING HEIGHTS TO CREATE HIGH DAYTIME DISPERSION
VALUES ACROSS MOST OF INLAND SOUTHEAST GA, WHILE GOOD VALUES
PREVAIL ELSEWHERE FOR INLAND LOCATIONS, EXCEPT FAIR VALUES FOR
LOCATIONS SOUTH OF THE I-10 CORRIDOR, WHERE SPEEDS WILL REMAIN
LIGHT. SURFACE AND TRANSPORT WINDS WILL THEN SHIFT TO WESTERLY ON
SUNDAY, WITH BREEZY TRANSPORT SPEEDS COMBINING WITH ELEVATED
MIXING HEIGHTS TO CREATE HIGH DAYTIME DISPERSION VALUES FOR INLAND
LOCATIONS ALONG AND NORTH OF I-10, WITH GOOD VALUES FORECAST
ELSEWHERE. AFTERNOON AND EVENING THUNDERSTORM COVERAGE WILL
INCREASE NEXT WEEK.
CLIMATE
ISSUED AT 1229 PM FRI JUL 18 2025
DAILY RECORD HIGH TEMPERATURES AT OUR DESIGNATED CLIMATE SITES
THROUGH TUESDAY, JULY 22
TODAY SATURDAY SUNDAY MONDAY TUESDAY
---------------------------------------------------
JACKSONVILLE 100/1887 101/2000 103/2000 102/1942 101/1942
GAINESVILLE 100/1889 101/1899 100/1942 102/1942 99/1907
ALMA, GA 102/2000 102/2002 104/2000 102/1942 100/1942
CRAIG AIRPORT 98/1981 99/1993 100/2000 98/2015 99/1977
PRELIMINARY POINT TEMPS/POPS
AMG 74 98 75 98 / 10 10 0 10
SSI 79 95 79 96 / 10 10 0 10
JAX 76 99 77 100 / 10 20 0 10
SGJ 76 95 77 96 / 10 20 0 10
GNV 74 97 74 98 / 10 20 0 10
OCF 75 95 75 96 / 10 30 0 20
JAX WATCHES/WARNINGS/ADVISORIES
FL...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR FLZ023-030-031-038-
132-137-225-232-237-325-425-433-533-633.
GA...NONE.
AM...NONE.
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