379
FXUS62 KJAX 110809
AFDJAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
409 AM EDT SAT JUL 11 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
- DANGEROUS HEAT INDICES CONTINUE THIS WEEKEND. HEAT ADVISORY IN
EFFECT TODAY FOR NORTHEAST AND NORTH CENTRAL FL AND PORTIONS
OF SOUTHEAST GA. HIGH TEMPERATURES: 95-100. PEAK HEAT INDEX
VALUES: 105-110.
- INCREASING COVERAGE OF AFTERNOON AND EVENING THUNDERSTORMS
THROUGH EARLY NEXT WEEK. STRONG TO ISOLATED SEVERE STORMS AND
LOCALLY HEAVY DOWNPOURS ARE POSSIBLE EACH AFTERNOON AND
EVENING. STRONG WIND GUSTS, FREQUENT LIGHTNING STRIKES, AND
SMALL HAIL WILL BE POSSIBLE LATER THIS AFTERNOON.
NEAR TERM /THROUGH TONIGHT/
MAIN HIGHLIGHTS TODAY AND TONIGHT:
- HEAT ADVISORY FOR NORTHEAST AND NORTH CENTRAL FL AND PORTIONS
OF SOUTHEAST GA THIS AFTERNOON THROUGH EARLY THIS EVENING.
- SCATTERED TO NUMEROUS AFTERNOON AND EARLY EVENING
THUNDERSTORMS, MAINLY FOR LOCATIONS SOUTH AND EAST OF
WAYCROSS, GA.
- STRONG TO ISOLATED SEVERE STORMS ARE POSSIBLE LATER TODAY,
WITH STRONG WIND GUSTS, FREQUENT LIGHTNING STRIKES, AND
SMALL HAIL POSSIBLE.
EARLY MORNING SURFACE ANALYSIS DEPICTS ATLANTIC HIGH PRESSURE
(1021 MILLIBARS) THAT WAS CENTERED TO THE SOUTHEAST OF
BERMUDA, WITH THIS FEATURE EXTENDING ITS AXIS WESTWARD ACROSS
THE FL PENINSULA. MEANWHILE, A WAVY FRONTAL BOUNDARY EXTENDS
FROM COASTAL NEW ENGLAND WESTWARD ACROSS THE OHIO AND MISSOURI
VALLEYS AND THROUGH THE SOUTHERN PLAINS STATES. ALOFT...DEEP-
LAYERED RIDGING EXTENDING FROM THE SOUTHWESTERN ATLANTIC
WESTWARD ACROSS THE DEEP SOUTH WAS IN THE PROCESS OF SPLITTING
AS A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) WAS PUSHING
NORTHWARD ACROSS THE NORTHWESTERN BAHAMAS. OTHERWISE, A POTENT
SHORTWAVE TROUGH WAS PUSHING SLOWLY SOUTHEASTWARD ACROSS UPPER
PORTIONS OF THE MISSISSIPPI VALLEY. LATEST GOES-EAST DERIVED
TOTAL PRECIPITABLE WATER IMAGERY INDICATES THAT A SAHARAN AIR
LAYER (SAL) HAS OVERSPREAD OUR REGION, WITH PWATS MOSTLY IN THE
1.5 - 1.75 INCH RANGE. FAIR SKIES PREVAIL THROUGHOUT OUR REGION,
WITH TEMPERATURES IN THE 70S AT INLAND LOCATIONS, RANGING TO
AROUND 80 ALONG THE ATLANTIC COAST. DEWPOINTS WERE GENERALLY IN
THE UPPER 60S TO LOWER 70S.
RIDGING ALOFT OVER OUR AREA WILL WEAKEN TODAY AS THE
AFOREMENTIONED TUTT FEATURE OVER THE BAHAMAS CONTINUES MOVING
SLOWLY NORTHWARD OFF THE FL ATLANTIC COAST. MEANWHILE, SHORTWAVE
TROUGHING OVER THE UPPER MISSISSIPPI AND MISSOURI VALLEYS WILL
CONTINUE TO SLIDE SLOWLY SOUTHEASTWARD TOWARDS THE OZARKS AND
THE TENNESSEE VALLEY. A "COL" REGION WILL DEVELOP OVER OUR AREA
AS RIDGES CONSOLIDATE OVER THE LOWER MISSISSIPPI VALLEY AND THE
WESTERN ATLANTIC. OTHERWISE, ATLANTIC HIGH PRESSURE WILL
CONTINUE TO EXTEND ITS AXIS WESTWARD ACROSS THE FL PENINSULA,
MAINTAINING LOW LEVEL WEST-SOUTHWESTERLY FLOW. THE SAL LAYER IN
PLACE OVER OUR REGION WILL SHIFT NORTHWARD OVER INTERIOR
SOUTHEAST GA LATER THIS AFTERNOON, ALLOWING PWATS TO RECOVER TO
MID-JULY CLIMATOLOGY BY LATE THIS AFTERNOON.
THE SAL OVERHEAD THIS MORNING SHOULD CONTINUE TO PROVIDE STRONG
SUBSIDENCE THAT WILL SUPPRESS CLOUD DEVELOPMENT, WITH PLENTY OF
SUNSHINE BOOSTING HIGHS TO THE 95-100 DEGREE RANGE AT INLAND
LOCATIONS, WITH ENOUGH WESTERLY FLOW TO DELAY THE DEVELOPMENT OF
THE ATLANTIC SEA BREEZE BOUNDARY UNTIL EARLY THIS AFTERNOON.
THIS WILL ALLOW HIGHS TO SOAR TO THE MID 90S AT COASTAL
LOCATIONS, WITH DEWPOINTS THEN SPIKING TO THE MID AND UPPER 70S
AS THE SEA BREEZE MIGRATES SLOWLY INLAND BY THE MID AND LATE
AFTERNOON. HEAT INDICES SHOULD INCREASE TO ADVISORY LEVELS (108
DEGREES) AT COASTAL LOCATIONS AS THIS SPIKE IN DEWPOINTS OCCURS.
THE SUBSIDENT SAL LAYER SHOULD MIX DEWPOINTS DOWN THROUGH THE
60S ACROSS INLAND PORTIONS OF SOUTHEAST GA, BUT THE INLAND
MOVING SEA BREEZE BOUNDARY COULD INCREASE DEWPOINTS ENOUGH LATER
THIS AFTERNOON TO ALLOW HEAT INDICES TO REACH CRITERIA TO REACH
ADVISORY LEVELS FOR INLAND LOCATIONS SOUTH AND EAST OF
WAYCROSS, BLACKSHEAR, AND JESUP. HEAT ADVISORIES INCLUDE ALL OF
NORTHEAST AND NORTH CENTRAL FL, ALTHOUGH CONFIDENCE IS NOT AS
HIGH FOR INLAND LOCATIONS, WHERE DEWPOINTS COULD ALSO MIX DOWN
INTO THE 60S BEFORE CONVECTION DEVELOPS LATER THIS AFTERNOON.
ALTHOUGH THERE WILL BE LITTLE IN THE WAY OF WIND SHEAR TODAY,
LINGERING DRY AIR ALOFT PROVIDED BY THE RETREATING SAL WILL
AGAIN ENHANCE THE DOWNDRAFT POTENTIAL AS THUNDERSTORMS DEVELOP
ALONG MESOSCALE BOUNDARIES DURING THE MID TO LATE AFTERNOON
HOURS , WITH ACTIVITY "PULSING" AS MESOSCALE BOUNDARIES COLLIDE.
SCATTERED ACTIVITY WILL POTENTIALLY LAST INTO THE EVENING
HOURS, ESPECIALLY FOR LOCATIONS ALONG AND NORTH OF I-10, WHERE
OUTFLOW BOUNDARIES PROGRESSING NORTHWARD SHOULD IGNITE
ADDITIONAL CONVECTION. STRONG TO ISOLATED SEVERE THUNDERSTORMS
WILL BE POSSIBLE ACROSS MUCH OF OUR AREA LATE THIS AFTERNOON AND
EARLY THIS EVENING, WITH DOWNBURST WINDS OF 40-60 MPH, SMALL
HAIL, AND FREQUENT LIGHTNING STRIKES POSSIBLE WITHIN STRONGER
STORMS. ACTIVITY WILL INITIALLY DEVELOP ALONG THE INLAND MOVING
GULF SEA BREEZE BOUNDARY OVER NORTH CENTRAL FL AND SOUTHERN
PORTIONS OF THE SUWANNEE VALLEY EARLY THIS AFTERNOON, WITH
MESOSCALE BOUNDARIES COLLIDING OVER INLAND NORTH CENTRAL AND
NORTHEAST FL, WHERE POPS ARE LIKELY BY LATE AFTERNOON AND EARLY
THIS EVENING.
CONVECTION WILL DIMINISH TOWARDS MIDNIGHT FOR LOCATIONS NORTH OF
I-10, WITH DEBRIS CLOUD COVER THEN GRADUALLY THINNING OUT AFTER
MIDNIGHT. LOWS TONIGHT WILL GENERALLY FALL TO THE MID 70S
INLAND AND THE UPPER 70S AT COASTAL LOCATIONS AS LOW LEVEL WEST-
SOUTHWESTERLY FLOW CONTINUES OVERNIGHT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
MAIN HIGHLIGHTS DURING THIS PERIOD:
- INCREASED STORM CHANCES SUNDAY ONWARD.
STEERING FLOW OFF THE GULF COUPLED WITH AN APPROACHING FRONT
FROM THE NORTH WILL INCREASE MOISTURE ACROSS THE AREA SUNDAY
AND MONDAY, PROMPTING HIGHER CONVECTIVE CHANCES THEN WE'VE SEEN
THIS PAST WEEK. WESTERLY SURFACE WINDS WILL ALLOW THE GULF SEA
BREEZE TO PUSH FAR INLAND, REACHING THE ATLANTIC SEA BREEZE
CLOSER TO I-95, LEAVING HIGHER STRONG STORM POTENTIAL IN THAT
REGION AS WELL AS CLOSER TO THE FRONT ACROSS SOUTHEAST GEORGIA.
STILL GOING TO BE PRETTY HOT ON SUNDAY, WITH HIGHS IN THE MID TO
UPPER 90S, WITH THE HOTTEST APPARENT TEMPERATURES NEAR THE EAST
COAST, WHERE VALUES WILL APPROACH HEAT ADVISORY CRITERIA.
MONDAY, SHOWER AND STORM COVERAGE INCREASES FURTHER AS THE
AFOREMENTIONED FRONT SINKS FURTHER SOUTH INTO CENTRAL GEORGIA.
HIGHEST STORM CHANCES WILL AGAIN BE CLOSER TO THE FRONT, ALONG
AND NORTH OF I-10, AND ALSO ALONG THE NORTHEAST FLORIDA COAST
WHERE THE SEA BREEZES INTERACT. THE PRIMARY STRONG STORM THREATS
WILL BE GUSTY WINDS AND HEAVY RAINFALL POTENTIALLY CAUSING
FLOODING CONCERNS. AGAIN, CONVECTION MAY LINGER PAST SUNSET
ACROSS SOUTHEAST GEORGIA MAINLY. TEMPERATURES WILL LOWER A FEW
DEGREES MONDAY, WITH HIGHS IN THE LOWER TO MID 90S.
ISOLATED STORMS MAY LINGER AFTER SUNSET BOTH SUNDAY AND MONDAY
NIGHTS CLOSER TO WHERE THE FRONT IS, OVER SOUTHEAST GEORGIA.
LONG TERM /TUESDAY THROUGH FRIDAY/
MAIN HIGHLIGHTS DURING THIS PERIOD:
- HIGH STORM CHANCES CONTINUE TUESDAY.
NUMEROUS SHOWERS AND STORMS ARE FORECAST AGAIN FOR TUESDAY AS
THE FRONT SITS NEAR THE FLORIDA/GEORGIA STATE BORDER, THEN
SLOWLY DISSIPATES THROUGH THE REST OF THE WEEK. MOST OF THE AREA
IS UNDER A 'MARGINAL' RISK OF EXCESSIVE RAINFALL ON TUESDAY,
AFTER SEVERAL DAYS OF HEAVY RAIN THERE WILL BE A THREAT OF
LOCALIZED FLOODING, ESPECIALLY NEAR THE FRONT AND OVER FLOOD
PRONE AREAS.
STORM CHANCES ARE GENERALLY LOWER WEDNESDAY ONWARD AS
NORTHWESTERLY STEERING FLOW BRINGS IN DRIER AIR, PRECIPITATION
CHANCES WILL BE AROUND 20-40%. TEMPERATURES WILL GRADUALLY RISE
AGAIN EACH DAY THROUGH FRIDAY.
AVIATION /06Z SATURDAY THROUGH 06Z SUNDAY/
VFR CONDITIONS WILL PREVAIL AT THE REGIONAL TERMINALS THROUGH AT
LEAST 19Z. SHOWERS AND THUNDERSTORMS WILL BEGIN DEVELOPING NEAR
THE TERMINALS AFTER 20Z, AND WE HAVE INCLUDED PROB30 GROUPS
THROUGH AROUND 02Z SUNDAY FOR BRIEF WIND GUSTS UP TO 35 KNOTS
AND IFR TO MVFR VISIBILITIES DURING HEAVIER DOWNPOURS AT EACH
TERMINAL. CONFIDENCE WAS A LITTLE TOO LOW TO INCLUDE PREVAILING
VICINITY THUNDERSTORMS AT SGJ DURING THIS TIME FRAME, WHILE
PREVAILING VCTS ARE EXPECTED ELSEWHERE. STRONGER WIND GUSTS AND
POSSIBLY SMALL HAIL WILL BE POSSIBLE AFTER 21Z AT THE REGIONAL
TERMINALS, AND TEMPO GROUPS WILL LIKELY BE ADDED IN FUTURE TAF
ISSUANCES AS TIMING AND CONFIDENCE IN COVERAGE AND INTENSITY
INCREASES. VFR CONDITIONS WILL THEN PREVAIL AT THE REGIONAL
TERMINALS BY 04Z SUNDAY. SOUTHWEST TO WESTERLY SURFACE WINDS
WILL REMAIN SUSTAINED AROUND 5 KNOTS AT THE REGIONAL TERMINALS
THROUGH AROUND 14Z, FOLLOWED BY SURFACE WINDS SHIFTING TO
NORTHWESTERLY AT 5-10 KNOTS BY 15Z. THE ATLANTIC AND GULF SEA
BREEZES WILL MOVE INLAND ON SATURDAY AFTERNOON, SHIFTING SURFACE
WINDS TO SOUTHEASTERLY AT 10-15 KNOTS AT SGJ TOWARDS 18Z AND
SOUTHERLY AT 10-15 KNOTS AT SSI TOWARDS 19Z. OUTSIDE OF
DEVELOPING THUNDERSTORM ACTIVITY, SURFACE WINDS AT GNV WILL
SHIFT TO SOUTHWESTERLY AT 5-10 KNOTS TOWARDS 20Z, WHILE SURFACE
WINDS ELSEWHERE AT THE DUVAL COUNTY TERMINALS WILL GENERALLY
BECOME SOUTHERLY AROUND 10 KNOTS TOWARDS 20Z. SURFACE WINDS WILL
THEN SHIFT TO SOUTHWESTERLY TOWARDS 03Z SUNDAY AT THE REGIONAL
TERMINALS, WITH SUSTAINED SPEEDS REMAINING AROUND 10 KNOTS AT
THE SSI AND SGJ COASTAL TERMINALS AND AROUND 5 KNOTS AT THE
INLAND TERMINALS.
MARINE
ATLANTIC HIGH PRESSURE WILL CONTINUE TO EXTEND ITS AXIS WESTWARD
ACROSS THE FLORIDA PENINSULA THIS WEEKEND, MAINTAINING A
PREVAILING WEST SOUTHWESTERLY WIND FLOW DURING THE OVERNIGHT AND
MORNING HOURS, WITH SOUTHEAST AND SOUTHERLY WINDS THEN SURGING
TO CAUTION LEVELS DURING THE LATE AFTERNOON AND EVENING HOURS AS
THE ATLANTIC SEA BREEZE SHIFTS INLAND. A FEW STRONG OR EVEN
SEVERE THUNDERSTORMS MAY IMPACT THE NEAR SHORE WATERS LATE THIS
AFTERNOON AND EARLY THIS EVENING, POSSIBLY CONTAINING STRONG
WIND GUSTS, HAIL, AND FREQUENT LIGHTNING STRIKES. TROUGHING
DEVELOPING OVER THE SOUTHEASTERN STATES LATE SUNDAY AND EARLY
NEXT WEEK WILL CREATE A LIGHTER SOUTHWESTERLY WIND FLOW, WITH
NUMEROUS MAINLY AFTERNOON AND EVENING THUNDERSTORMS FORECAST
THROUGH TUESDAY AS A FRONTAL BOUNDARY SINKS INTO THE
SOUTHEASTERN STATES. THIS FEATURE WILL LIKELY STALL OVER THE
SOUTHEAST GEORGIA WATERS BEFORE WEAKENING TOWARDS MIDWEEK.
COVERAGE OF SHOWERS AND THUNDERSTORMS WILL THEN DECREASE BY
WEDNESDAY AND ESPECIALLY ON THURSDAY AND FRIDAY AS THE FRONTAL
BOUNDARY DISSIPATES.
RIP CURRENTS:
SOUTHEASTERLY WINDS STRENGTHENING LATE THIS AFTERNOON WILL
CREATE A LOWER END MODERATE RISK AT THE NORTHEAST FL BEACHES,
WITH SURF INCREASING TO AROUND 2 FEET TOWARDS SUNSET. LOWER SURF
OF ONLY 1-2 FEET AT THE SOUTHEAST GA BEACHES SHOULD YIELD A LOW
RISK THROUGHOUT THE WEEKEND AND EARLY NEXT WEEK. SURF HEIGHTS
OF LESS THAN 2 FEET AT THE NORTHEAST FL BEACHES ON SUNDAY AND
EARLY NEXT WEEK SHOULD ALSO YIELD A LOW RISK.
FIRE WEATHER
- AREAS OF HIGH DISPERSIONS TODAY AND SUNDAY NORTH OF I-10.
DRIER THAN NORMAL CONDITIONS ARE FORECAST THROUGH SATURDAY
BEFORE RAIN CHANCES BEGIN TO INCREASE LATE WEEKEND AND INTO
EARLY NEXT WEEK AS A FRONTAL BOUNDARY APPROACHES FROM THE NORTH.
SOUTHWESTERLY SURFACE WINDS CONTINUE THROUGH SUNDAY, WITH AREAS
OF HIGH AFTERNOON DISPERSION ALONG AND NORTH OF I-10. DESPITE
DRIER AIR IN PLACE, MINRH WILL REMAIN JUST ABOVE CRITICAL
VALUES, IN THE 30 TO 40% RANGE AWAY FROM THE COAST. HEAVY RAIN
POTENTIAL SUNDAY THROUGH TUESDAY AS WE EXPECTED NUMEROUS SHOWERS
AND STORMS EACH AFTERNOON AND EVENING.
FOG POTENTIAL AND OTHER REMARKS: SIGNIFICANT FOG POTENTIAL IS
NOT EXPECTED. ERRATIC WIND GUSTS POSSIBLE IN AND NEAR
THUNDERSTORMS, AND AT TIMES, AT A DISTANCE DUE TO OUTFLOWS.
CLIMATE
DAILY RECORD HIGH TEMPERATURES AT OUR DESIGNATED CLIMATE SITES
FOR THIS WEEKEND, JULY 11TH-12TH.
JULY 11TH:
KJAX: 104/1879
KGNV: 100/1900
KAMG: 100/1980
KCRG: 99/1998
JULY 12TH:
KJAX: 102/1879
KGNV: 99/1902
KAMG: 102/1966
KCRG: 99/2015
PRELIMINARY POINT TEMPS/POPS
AMG 97 75 96 74 / 10 10 40 60
SSI 96 79 97 78 / 30 30 40 40
JAX 98 76 97 76 / 50 30 60 40
SGJ 94 77 95 77 / 30 20 60 20
GNV 97 74 95 75 / 50 30 40 10
OCF 97 74 94 76 / 40 40 30 10
JAX WATCHES/WARNINGS/ADVISORIES
FL...HEAT ADVISORY FROM NOON TODAY TO 7 PM EDT THIS EVENING FOR
FLZ021-023-024-030-031-035-038-120-124-125-132-136>138-
140-220-225-232-233-236-237-240-322-325-333-340-422-425-
433-522-533-633.
GA...HEAT ADVISORY FROM NOON TODAY TO 7 PM EDT THIS EVENING FOR
GAZ152>154-162-163-165-166-264-350-364.
MARINE...NONE.
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