514
FXUS62 KJAX 181214
AFDJAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
814 AM EDT THU JUN 18 2026
KEY MESSAGES
FOR THE LATEST NE FL AND SE GA DAILY KEY MESSAGES PLEASE VISIT:
HTTPS:/WWW.WEATHER.GOV/MEDIA/JAX/BRIEFINGS/NWS-JAX-BRIEFING.PDF
- HOT AND HUMID THROUGH THE WEEKEND, WITH PEAK HEAT INDEX VALUES
OF 103-107 DEGREES EXPECTED ACROSS PORTIONS OF OUR REGION EACH
DAY.
- SCATTERED AFTERNOON & EARLY EVENING THUNDERSTORMS ALONG THE
I-95 AND U.S. HIGHWAY 17 CORRIDORS. STRONG TO ISOLATED SEVERE
T'STORMS ARE POSSIBLE, WITH WIND GUSTS OF 40-60 MPH, FREQUENT
LIGHTNING STRIKES, AND HEAVY DOWNPOURS.
- SQUALL LINE OF STRONG TO ISOLATED SEVERE THUNDERSTORMS WILL
TRAVERSE INLAND PORTIONS OF SOUTHEAST GA AND POSSIBLY THE
SUWANNEE VALLEY OVERNIGHT THROUGH THE PREDAWN HOURS ON FRIDAY.
WIND GUSTS OF 40-60 MPH, FREQUENT LIGHTNING STRIKES, AND
HEAVY DOWNPOURS WILL BE POSSIBLE.
- NUMEROUS SHOWERS AND THUNDERSTORMS EXPECTED ON FRIDAY AND
SATURDAY. STRONG TO ISOLATED SEVERE STORMS WILL BE POSSIBLE.
- HEAT INDEX VALUES INCREASING TO NEAR HEAT ADVISORY LEVELS NEXT
WEEK.
NEAR TERM /THROUGH TONIGHT/
MAIN HIGHLIGHTS TODAY AND TONIGHT:
- HOT AND HUMID THROUGH THE WEEKEND, WITH PEAK HEAT INDEX VALUES
OF 103-107 DEGREES EXPECTED ACROSS PORTIONS OF OUR REGION EACH
DAY.
- SCATTERED AFTERNOON & EARLY EVENING THUNDERSTORMS ALONG THE
I-95 AND U.S. HIGHWAY 17 CORRIDORS. STRONG TO ISOLATED SEVERE
T'STORMS ARE POSSIBLE, WITH WIND GUSTS OF 40-60 MPH, FREQUENT
LIGHTNING STRIKES, AND HEAVY DOWNPOURS.
- SQUALL LINE OF STRONG TO ISOLATED SEVERE THUNDERSTORMS WILL
TRAVERSE INLAND PORTIONS OF SOUTHEAST GA AND POSSIBLY THE
SUWANNEE VALLEY OVERNIGHT THROUGH THE PREDAWN HOURS ON FRIDAY.
WIND GUSTS OF 40-60 MPH, FREQUENT LIGHTNING STRIKES, AND HEAVY
DOWNPOURS WILL BE POSSIBLE.
ANOTHER DAY WITH A SOUTHWESTERLY CONDUIT GULF MOISTURE PUSHING
INTO THE AREA. THIS WILL SET UP ANOTHER EARLY START TO SHOWER
ACTIVITY THIS MORNING, MAINLY ACROSS THE SUWANNEE VALLEY BEFORE
THUNDERSTORM POTENTIAL INCREASES THIS AFTERNOON ALONG THE PINNED
ATLANTIC SEA BREEZE. HEAT WILL BUILD MORE TODAY WHICH WILL
LEVERAGE A STRONGER ATLANTIC SEA BREEZE THAT SHOULD MOVE A FEW
MILES INLAND EARLY THIS AFTERNOON, THE SOUTHWESTERLY FLOW AND
AMPLE INSTABILITY WILL BE SUFFICIENT FOR SCATTERED THUNDERSTORMS
TO DEVELOP ALONG THE COAST AND THEN PROCEED INTO THE COASTAL
WATERS DURING THE AFTERNOON HOURS. A FEW OF THE STORMS ALONG THE
COAST MAY PULSE TO STRONG TO MARGINALLY SEVERE LEVELS,
ESPECIALLY AS BOUNDARIES BEGIN TO COLLIDE. ADDITIONAL AFTERNOON
CONVECTION IS LIKELY ACROSS THE SUWANNEE VALLEY AND INLAND SE GA
AS A "MASKED" GULF BREEZE PUSHES INLAND.
AS MENTIONED THE HEAT WILL BUILD TODAY BUT DECENT MIXING SHOULD
MIX NEAR-SURFACE MOISTURE ENOUGH TO KEEP PEAK HEAT INDEX JUST
A BIT BELOW HEAT ADVISORY LEVELS THIS AFTERNOON. BUT IT WILL
STILL BE SEASONABLY HOT WITH HEAT INDEX IN THE 102-107 DEGREE
RANGE WITH THE HIGH END OF THAT RANGE FAVORED ALONG THE COAST.
LOW LEVEL TEMPERATURES WILL BE ABOVE THE CLIMO 90TH PERCENTILE,
SO ACTUAL HIGHS TEMPERATURES IN THE MID/UPPER 90S ARE VERY
LIKELY TO MATERIALIZE ACROSS MUCH OF NE FL THIS AFTERNOON WHERE
CLOUD COVER SHOULD BE LESS.
TONIGHT, ATTENTION TURNS TOWARD THE UPPER SHORTWAVE TROUGH
ASSOCIATED WITH THE POST-TROPICAL REMNANTS OF ARTHUR. THAT
SHORTWAVE WILL GRAZE OUR INLAND AREAS LATE TONIGHT AS IT EJECTS
NORTHEASTWARD. HIGH RESOLUTION HAS BEEN CONSISTENTLY BRINGING A
DECAYING CONVECTIVE COMPLEX OF THUNDERSTORMS INTO INLAND SE GA
ZONES AROUND MIDNIGHT AND THEN FADE IN INTENSITY AS IT MOVES
EAST- SOUTHEASTWARD TOWARD THE ATLANTIC COAST THROUGH THE EARLY
MORNING HOURS FRIDAY. GIVEN THE LOW LEVEL JET AT 850MB, AROUND
40-50 KTS, THE MAIN CONCERN WILL BE STRONG OUTFLOW WINDS,
POSSIBLY AT SEVERE LEVELS FOR IN "BOWING" SEGMENTS EMBEDDED
WITHIN THE CLUSTER. THOUGH PROBS ARE LOW, CAN'T RULE OUT THE
POSSIBILITY OF AN ISOLATED QUICK-SPIN UP TORNADO, ESPECIALLY
ACROSS INLAND SE GA. THERE'S STILL CONSIDERABLE UNCERTAINTY IN
HOW LONG CONVECTION WILL BE SUSTAINED GIVEN THE DEGRADED SURFACE
INSTABILITY BUT IT COULD MAINTAIN AND EXTEND A SEVERE
THUNDERSTORM THREAT INTO DAYBREAK FRIDAY, MAINLY FROM I-10
NORTHWARD.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/
- ISOLATED STRONG TO SEVERE T'STORMS FRIDAY.
- NUMEROUS TO WIDESPREAD SHOWERS AND T'STORMS SATURDAY.
- HOT AND HUMID CONDITIONS FRIDAY INTO SATURDAY.
FRIDAY, A COLD FRONT WILL SINK SE TOWARDS THE AREA, TRAILING THE
REMNANTS OF TROPICAL STORM ARTHUR, BRINGING HIGH MOISTURE VALUES
INTO THE AREA WITH PRECIPITABLE WATER LEVELS (PWATS) IN EXCESS
OF 2 INCHES (ABOVE THE 90TH PERCENTILE COMPARED TO CLIMATOLOGY).
THE ABUNDANCE OF MOISTURE WILL CREATE MOSTLY CLOUDY SKIES, BUT
LIFT FROM THE INCOMING FRONT AT THE SURFACE AND INSTABILITY
ALOFT FROM SHORTWAVE ENERGY OVER AREA WILL CREATE NUMEROUS TO
WIDESPREAD SHOWERS AND T'STORMS OVER SE GA. MORE BREAKS IN THE
CLOUDS FURTHER SOUTH AND WSW LOW LEVEL FLOW WILL ALLOW THE GULF
SEABREEZE A HEAD START TOWARDS THE NE FL COAST, SPURRING
AFTERNOON/EARLY EVENING SCATTERED TO NUMEROUS T'STORMS. DESPITE
A LACK OF STRONG SHEAR, WATER LOADING FROM A NEAR SATURATED
ATMOSPHERIC COLUMN AND STRONG LOW LEVEL INSTABILITY WILL ALLOW
FOR ISOLATED STRONG TO SEVERE T'STORMS DEVELOPING ALONG
SEABREEZE INTERACTIONS AND OUTFLOW/STORM MERGERS CAPABLE OF WET
DOWNBURST WIND GUSTS UP TO 50-60 MPH. OTHER T'STORM HAZARDS OF
LOCALLY HEAVY DOWNPOURS AND FREQUENT LIGHTNING ALSO EXPECTED.
HIGHS ON FRIDAY WILL BE NEAR NORMAL OVER NE FL INTO THE UPPER
80S AND LOW 90S WHILE STAYING BELOW NORMAL OVER SE GA DUE TO
THE CLOUDS AND SHOWERS AND T'STORMS WITH HIGHS ONLY IN THE MID
80S. MAX HEAT INDEX VALUES WILL BE 100-104 FOR PORTIONS OF NE FL
SOUTH OF I-10.
FRIDAY NIGHT, CONVECTION WILL DISSIPATE BUT SCATTERED SHOWERS
WILL REMAIN DRIFTING EASTWARD ACROSS THE AREA AS THE FRONTAL
BOUNDARY SINKS TO THE FL/GA BORDER THROUGH THE PRE-DAWN MORNING
HOURS. LOWS WILL BE MUGGY IN THE MID TO UPPER 70S.
SATURDAY, THE FRONTAL BOUNDARY WILL SINK INTO NE FL AS WEAK HIGH
PRESSURE MOVES NORTH OF THE REGION INTO THE UPPER OH/TN VALLEYS.
THIS WILL PROMOTE THE HIGHEST CHANCES FOR SHOWERS AND T'STORMS
MORE OVER NE FL AS LIFT FROM THE FRONT, SHORTWAVE ENERGY ALOFT,
AND HIGH MOISTURE CONTENT COMBINE TO CREATE WIDESPREAD SHOWERS
AND T'STORMS FROM MID TO LATE MORNING PERSISTING THROUGH THE
EARLY EVENING HOURS WITH DIMINISHED COVERAGE BEHIND THE FRONT
ACROSS SE GA. WINDS WILL SHIFT FROM WESTERLY TO WNW WITH SKIES
STAYING MOSTLY CLOUDY. CLOUDS WILL LIMIT THE DEGREE OF LOW LEVEL
INSTABILITY COMPARED TO FRIDAY, BUT GUSTY WINDS TO 40 MPH,
FREQUENT LIGHTNING, AND LOCALLY HEAVY DOWNPOURS WILL BE THE MAIN
HAZARDS. SOME PONDING OF WATER AND MINOR FLOODING POTENTIAL
EXPECTED FOR NE FL SATURDAY WITH SLOWER STORM MOTIONS PUSHING
ACTIVITY ESE. HIGHS ON SATURDAY WILL BE IN THE LOW 90S OVER NE
FL AND AROUND 90 OVER SE GA.
SATURDAY NIGHT, SKIES WILL BECOME PARTIALLY CLEAR WITH T'STORMS
ENDING BY 10PM AND ANY LINGERING SCATTERED SHOWERS ENDING A
LITTLE AFTER MIDNIGHT, LOWS WILL FALL TO THE LOWER 70S OVER SE
GA AND THE MID 70S OVER NE FL. LIGHT WESTERLY WINDS WILL BECOME
CALM INLAND.
LONG TERM /SUNDAY THROUGH WEDNESDAY/
MAIN HIGHLIGHTS THIS PERIOD:
- HEAT INDEX VALUES INCREASING TO NEAR HEAT ADVISORY LEVELS NEXT
WEEK.
- DECREASING CHANCES FOR SHOWERS AFTERNOON AND EVENING T'STORMS
SUNDAY THROUGH NEXT WEEK.
SUNDAY, SLIGHTLY DRIER AIR ALOFT WILL ARRIVE ACROSS SE GA AND
INTO PORTIONS OF NE FL AS THE FRONT STALLS NEAR NORTH CENTRAL
FL. LIGHT WESTERLY WINDS WILL PUSH THE GULF SEABREEZE EASTWARD
TOWARDS THE SE GA AND NE FL COAST, KICKING OFF WIDELY SCATTERED
T'STORMS IN THE STRONG DIURNAL HEATING. BUT, THE WESTERLY FLOW
WILL LIMIT THE ADVANCEMENT OF THE ATLANTIC SEABREEZE TO EAST OF
I-95.
MONDAY, DRIER AIR WILL LOWER PWATS TO 1.50 TO 1.75 INCHES AND
ALONG WITH LOW TO MID LEVEL SUBSIDENCE DUE TO RIDGING BUILDING
OVER THE GULF AND FL PENINSULA WILL WIDELY ISOLATED T'STORM
ACTIVITY TO NEAR THE ALTAMAHA RIVER AS A FAST MOVING TROUGH
MOVES NORTH OF THE REGION. MOSTLY SUNNY SKIES WILL ALLOW FOR HOT
CONDITIONS WITH HIGHS INTO THE MID TO UPPER 90S, LIKELY PUSHING
HEAT INDEX VALUES TO 104-108 VERY CLOSE TO HEAT ADVISORY
LEVELS.
TUESDAY, A FRONT WILL APPROACH FROM THE NORTH WITH WSW FLOW AND
AN UPTICK IN MOISTURE ALLOWING FOR WIDELY SCATTERED T'STORMS.
BUT, THE VERY HOT CONDITIONS WILL CONTINUE WITH POTENTIAL HEAT
ADVISORY CONDITIONS AS VALUES CLIMB TO 106-110 AS DEWPOINTS
REMAIN IN THE MID TO UPPER 70S AHEAD OF THE FRONT.
WEDNESDAY, THE FRONT WILL SINK INTO THE AREA WITH MORE CLOUDS
AND WNW FLOW, BUT ALSO HIGHS DECREASING BACK TO THE LOW 90S
WHICH MAY CURVE HEAT ADVISORY CONDITIONS. UNCERTAINTY REMAINS ON
EXACTLY WHERE THE FRONT STALLS, SO KEEPING SCATTERED CHANCES
FOR T'STORMS AT THIS TIME.
NEAR NORMAL TEMPERATURES SUNDAY WILL RISE TO ABOVE NORMAL NEXT
WEEK.
AVIATION /12Z THURSDAY THROUGH 12Z FRIDAY/
VFR CONDITIONS WILL PREVAIL THROUGH AT LEAST 18Z AT THE REGIONAL
TERMINALS. SHOWERS AND THUNDERSTORMS WILL BEGIN TO DEVELOP ALONG
THE ST. JOHNS RIVER BREEZE AND A SLOW MOVING ATLANTIC SEA
BREEZE BOUNDARY ALONG OR EAST OF INTERSTATE 95 TOWARDS 19Z, WITH
CONFIDENCE REMAINING HIGH ENOUGH TO MAINTAIN AT TEMPO GROUP AT
SGJ THROUGH 00Z FOR POTENTIAL WIND GUSTS UP TO 30 KNOTS AND IFR
VISIBILITIES DURING HEAVIER DOWNPOURS. CONFIDENCE WAS ONLY HIGH
ENOUGH FOR PROB30 GROUPS AT THE DUVAL COUNTY TERMINALS AND SSI
FROM AROUND 20Z-00Z FOR BRIEF WIND GUSTS UP TO 30 KNOTS AND MVFR
VISIBILITIES DURING HEAVIER DOWNPOURS. MOST ACTIVITY WILL
DEVELOP EAST OF THE U.S. HIGHWAY 301 CORRIDOR IN NORTH CENTRAL
FL LATE THIS AFTERNOON, SO WE HAVE MAINTAINED ONLY VICINITY
SHOWER COVERAGE FOR NOW. SCATTERED THUNDERSTORMS THAT DEVELOP
ALONG THE I-95 CORRIDOR LATE THIS AFTERNOON WILL MOVE OFFSHORE
BEFORE 02Z THIS EVENING, WITH ANOTHER ROUND OF THUNDERSTORMS
EXPECTED TO IMPACT INLAND PORTIONS OF SOUTHEAST GA TOWARDS 06Z
FRIDAY. THIS ACTIVITY COULD APPROACH SSI AFTER 08Z AND POSSIBLY
THE DUVAL COUNTY TERMINALS AFTER 10Z. CONFIDENCE REMAINS TOO LOW
FOR ANYTHING OTHER THAN VICINITY SHOWER MENTIONS DURING THE
OVERNIGHT AND PREDAWN HOURS ON FRIDAY AT THIS TIME. SOUTHERLY
SURFACE WINDS SUSTAINED AT 5-10 KNOTS WILL BECOME SOUTH-
SOUTHWESTERLY TOWARDS 15Z, WITH SPEEDS INCREASING TO 10-15
KNOTS. THE ATLANTIC SEA BREEZE BOUNDARY WILL MOVE SLOWLY INLAND
THIS AFTERNOON, SHIFTING SURFACE WINDS TO SOUTHEASTERLY AT SGJ
AND SOUTHERLY AT SSI AT 10-15 KNOTS TOWARDS 19Z. SOUTHERLY
SURFACE WINDS WILL REMAIN SOMEWHAT ELEVATED OVERNIGHT, WITH
SUSTAINED SPEEDS GENERALLY REMAINING AROUND 10 KNOTS.
MARINE
PERSISTENT OFFSHORE FLOW CONTINUES ACROSS THE WATERS INTO THE
WEEKEND. OFFSHORE WINDS WILL BECOME QUITE BREEZY THIS AFTERNOON,
POSSIBLY NEAR 20 KNOTS IN THE OUTER COASTAL WATERS. A WEAK FRONT
TRAILING A WEAK LOW PRESSURE TO THE NORTH WILL STALL ACROSS THE
GEORGIA'S COASTAL WATERS FRIDAY NIGHT. NUMEROUS SHOWERS AND
AFTERNOON THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG FRONT AS
IT DISSIPATES OVER THE WEEKEND. WEAKER OFFSHORE FLOW IS LIKELY
THROUGH THE FIRST HALF OF NEXT WEEK AS ANOTHER FRONT APPROACHES
AND LIKELY STALLS JUST NORTH OF THE WATERS.
RIP CURRENTS:
A GENERAL LOW RISK OF RIP CURRENTS CONTINUES TODAY AND LIKELY
THROUGH THE END OF THE WEEK AS SURF REMAINS ONLY IN THE 1-2 FT
RANGE IN OFFSHORE FLOW.
FIRE WEATHER
- HIGH DISPERSION FOR INLAND LOCATIONS JUST WEST OF I-95 TODAY.
MOIST AND UNSTABLE AIRMASS WILL CONTINUE AFTERNOON/EARLY EVENING
SCATTERED TO NUMEROUS T'STORMS TODAY AS WEST TO SOUTHWEST WINDS
ALLOW THE GULF SEABREEZE TO MOVE QUICKLY EASTWARD TO THE
ATLANTIC COAST BEFORE INTERACTING WITH THE PINNED ATLANTIC
SEABREEZE NEAR THE ATLANTIC COAST. T'STORMS WILL INCLUDE HEAVY
DOWNPOURS AND LOCALLY HEAVY RAINFALL, FREQUENT LIGHTNING, AND
GUSTY WINDS WITH ISOLATED STRONG TO SEVERE T'STORMS THIS
AFTERNOON. A FRONT WILL SINK TOWARDS THE AREA FRIDAY AND MOVE
THROUGH NORTHEAST FLORIDA SATURDAY WITH WIDESPREAD SHOWERS AND
T'STORMS. THE FRONT WILL STALL NEAR NORTH CENTRAL OR CENTRAL
FLORIDA SUNDAY WITH LESS COVERAGE OF T'STORMS.
FAVORABLE TRANSPORT WINDS AND MIXING HEIGHTS WILL LEAD TO AREAS
OF HIGH AFTERNOON DISPERSION VALUES TODAY ALONG AND WEST OF
I-95. GOOD LEVEL DISPERSIONS EXPECTED DURING EACH AFTERNOON
FRIDAY INTO THE WEEKEND AS MORE CLOUDS LIMIT MIXING HEIGHTS
WHILE TRANSPORT WINDS DECREASE SLIGHTLY AS THE FRONT SETTLES
SOUTH OF THE AREA BY SUNDAY.
TEMPERATURES WILL BE HOT TODAY AND ALONG WITH ELEVATED HUMIDITY WILL
CREATE HEAT INDEX VALUES UP TO 102-106 NEAR THE COAST AND ACROSS
NORTHEAST FL. HIGHS WILL DECREASE TO THE LOW 90S FRIDAY INTO THE
WEEKEND, BUT HIGH HUMIDITY LEVELS WILL CONTINUE.
FOG POTENTIAL AND OTHER REMARKS: AREAS THAT RECEIVE HEAVIER
RAINFALL MAY ALSO EXPERIENCE PATCHY LATE-NIGHT AND EARLY-MORNING
FOG.
PRELIMINARY POINT TEMPS/POPS
AMG 90 75 85 73 / 70 60 90 40
SSI 93 80 91 77 / 70 30 70 40
JAX 96 79 92 76 / 50 20 60 40
SGJ 96 78 93 77 / 60 20 50 20
GNV 95 79 92 75 / 20 10 50 30
OCF 94 79 91 77 / 20 10 30 20
JAX WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GA...NONE.
MARINE...NONE.
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