120
FXUS62 KJAX 130809
AFDJAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
409 AM EDT MON JUL 13 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
- STRONG TO ISOLATED SEVERE THUNDERSTORMS AND LOCALIZED FLOODING
POSSIBLE ACROSS SOUTHEAST GA LATE THIS AFTERNOON AND EVENING.
- STRONG THUNDERSTORM POTENTIAL ALONG THE NORTHEAST FL COAST
DURING THE EARLY TO MID-AFTERNOON HOURS TODAY.
- ADDITIONAL ROUNDS OF SHOWERS AND THUNDERSTORMS POSSIBLE
OVERNIGHT TONIGHT, WITH WIDESPREAD ACTIVITY CONTINUING ON
TUESDAY.
- HEAT AND HUMIDITY RETURNS LATE THIS WEEK AND INTO THE
UPCOMING WEEKEND AS THUNDERSTORM COVERAGE DECREASES.
NEAR TERM /THROUGH TONIGHT/
MAIN HIGHLIGHTS THIS AFTERNOON AND TONIGHT:
- STRONG TO ISOLATED SEVERE THUNDERSTORMS AND LOCALIZED FLOODING
POSSIBLE ACROSS INLAND SOUTHEAST GA LATE THIS AFTERNOON AND
EVENING.
- STRONG THUNDERSTORM POTENTIAL AT COASTAL LOCATIONS THIS
AFTERNOON.
- ADDITIONAL ROUNDS OF SHOWERS AND THUNDERSTORMS POSSIBLE
OVERNIGHT TONIGHT, ESPECIALLY ALONG THE I-10 CORRIDOR.
EARLY MORNING SURFACE ANALYSIS DEPICTS A WAVY FRONTAL BOUNDARY
STRETCHING FROM COASTAL SOUTH CAROLINA WESTWARD ACROSS THE
SOUTHERN APPALACHIANS AND THE TENNESSEE VALLEY THROUGH THE
OZARKS AND SOUTHERN PLAINS STATES. MEANWHILE, ATLANTIC HIGH
PRESSURE (1021 MILLIBARS) POSITIONED EAST OF THE BAHAMAS
CONTINUES TO EXTEND ITS AXIS WESTWARD ACROSS SOUTH FL AND THE
SOUTHEASTERN GULF. OTHERWISE, STRENGTHENING HIGH PRESSURE (1024
MILLIBARS) WAS EXPANDING FROM THE UPPER MIDWEST EASTWARD ACROSS
THE OHIO VALLEY AND THE MID-ATLANTIC STATES IN THE WAKE OF THE
FRONTAL BOUNDARY THAT WAS PUSHING SLOWLY SOUTHWARD TOWARDS OUR
AREA. ALOFT...A POTENT SHORTWAVE TROUGH OVER THE SOUTHERN
APPALACHIANS WAS IN THE PROCESS OF CUTTING OFF FROM THE MAIN
FLOW PATTERN AS IT MEANDERS SOUTHWARD, WITH THIS FEATURE
SUPPRESSING DEEP-LAYERED RIDGING SOUTH OF OUR AREA. A "HEAT
WAVE" RIDGE EXPANDING FROM THE EASTERN ROCKIES AND THE NORTHERN
PLAINS STATES TOWARDS THE UPPER MIDWEST AND THE GREAT LAKES
STATES WAS OTHERWISE CREATING A HIGHLY AMPLIFIED "BLOCKING"
PATTERN OVER THE EASTERN HALF OF THE NATION. LATEST GOES-EAST
DERIVED TOTAL PRECIPITABLE WATER IMAGERY INDICATES THAT DEEP
TROPICAL MOISTURE HAS OVERSPREAD OUR REGION, WITH PWATS RANGING
FROM 1.9 - 2.2 INCHES. MID AND HIGH ALTITUDE CLOUD COVER WAS
SLOWLY THINNING OUT ACROSS OUR AREA AS OF 08Z, WITH TEMPERATURES
AND DEWPOINTS IN THE 70S AREA-WIDE.
THE POTENT SHORTWAVE TROUGH OVER THE SOUTHERN APPALACHIANS WILL
CUTOFF TODAY AS IT SINKS SOUTHWARD ACROSS THE TENNESSEE VALLEY,
WITH THIS FEATURE THEN BECOMING STEERED SOUTHWESTWARD TOWARDS
THE LOWER MISSISSIPPI VALLEY TONIGHT AS IT BECOMES CAPTURED BY
THE EXPANDING "HEAT WAVE" RIDGE OVER THE UPPER MIDWEST AND THE
GREAT LAKES STATES. TROUGHING ALOFT WILL CONTINUE TO SUPPORT A
SLOW MOVING, WAVY FRONTAL BOUNDARY THAT WILL SLIDE TOWARDS THE
DEEP SOUTH AND THE LOWER MISSISSIPPI VALLEY TODAY AND TONIGHT.
DEEPENING WESTERLY FLOW TO THE SOUTH OF THIS TROUGH AND ITS
ASSOCIATED FRONTAL BOUNDARY IS EXPECTED TODAY, WHICH WILL
CONTINUE TO ADVECT TROPICAL MOISTURE ACROSS OUR AREA.
THE MAIN FORECAST QUESTION WILL BE CLOUD COVER THIS MORNING,
WHICH WILL DETERMINE HOW UNSTABLE OUR ATMOSPHERE WILL BECOME
TODAY, PARTICULARLY OVER NORTHEAST AND NORTH CENTRAL FL. THERE
IS NOT MUCH IN THE WAY OF SHOWER ACTIVITY UPSTREAM OF OUR AREA
OVER APALACHEE BAY AND THE NORTHEAST GULF, AND RECENT SATELLITE
TRENDS DEPICT A SLOW THINNING OF MID AND HIGH ALTITUDE
CLOUDINESS. CONVECTION MAY NOT BEGIN OVER AREAS UPSTREAM FROM
OUR REGION UNTIL THE MID-MORNING HOURS, ALLOWING FOR ENOUGH
HEATING AN INSTABILITY TO CREATE NUMEROUS SHOWERS AND
THUNDERSTORMS ALONG THE INLAND MOVING GULF SEA BREEZE BOUNDARY
BY THE LATE MORNING AND EARLY AFTERNOON HOURS. ACTIVITY SHOULD
RACE TOWARDS THE ATLANTIC COAST DURING THE MID-AFTERNOON HOURS,
WHERE CONVECTION MAY INTERACT WITH A PINNED ATLANTIC SEA BREEZE
BOUNDARY EAST OF THE I-95 CORRIDOR THAT COULD CAUSE A FEW STORMS
TO "PULSE" AND BECOME STRONG ACROSS COASTAL NORTHEAST FL BEFORE
MOVING OFFSHORE LATE THIS AFTERNOON. STRONGER ACTIVITY COULD
PRODUCE BRIEF WIND GUSTS OF 35-45 MPH, FREQUENT LIGHTNING
STRIKES, AND BRIEFLY HEAVY DOWNPOURS. HIGHS TODAY WILL BE HELD
TO THE 85-90 DEGREE RANGE ACROSS INLAND NORTHEAST AND NORTH
CENTRAL FL, RANGING TO THE LOWER 90S AT COASTAL LOCATIONS, WHERE
CONVECTION MAY NOT ARRIVE UNTIL THE MID-AFTERNOON. HEAT INDEX
VALUES WILL GENERALLY RISE TO THE 100-105 DEGREE RANGE ALONG AND
EAST OF THE U.S. HIGHWAY 301 CORRIDOR.
CONVECTIVE OUTFLOWS MOVING NORTHWARD WILL IGNITE NUMEROUS
SHOWERS AND THUNDERSTORMS DURING THE MID TO LATE AFTERNOON
HOURS ACROSS SOUTHEAST GA, WHERE ACTIVITY COULD BE ENHANCED BY A
DEVELOPING 35-45 KNOT WEST-SOUTHWESTERLY LOW LEVEL JET
POSITIONED AT 850 MILLIBARS (AROUND 5,000 FEET). STRONG TO
ISOLATED SEVERE THUNDERSTORMS WILL BE POSSIBLE ACROSS SOUTHEAST
GA LATER THIS AFTERNOON, WITH HEAVY DOWNPOURS POTENTIALLY
FOCUSING OVER INLAND SOUTHEAST GA, WHERE DEEPER TROPICAL
MOISTURE WILL BE POOLING AHEAD OF THE APPROACHING FRONTAL
BOUNDARY. THE WEATHER PREDICTION CENTER HAS INDICATED A "SLIGHT"
RISK (LEVEL 2 OF 4) FOR EXCESSIVE RAINFALL THIS AFTERNOON FROM
AREAS AROUND WAYCROSS AND POINTS NORTHWARD IN INTERIOR SOUTHEAST
GA THIS AFTERNOON, WHILE A "MARGINAL" RISK (LEVEL 1 OF 4) IS IN
PLACE ELSEWHERE ACROSS OUR AREA. LOCALIZED FLOODING WILL BE
POSSIBLE TODAY, MAINLY AT MORE URBAN AND NORMALLY FLOOD PRONE
LOCATIONS ACROSS SOUTHEAST GA, WHERE CONVECTION COULD LINGER
SLIGHTLY PAST SUNSET THIS EVENING. STRONGER STORMS PULSING OVER
SOUTHEAST GA COULD PRODUCE DOWNBURST WINDS OF 40-60 MPH, ALONG
WITH FREQUENT LIGHTNING STRIKES AND TORRENTIAL DOWNPOURS. HIGHS
WILL GENERALLY CLIMB TO THE UPPER 80S AND LOWER 90S, WITH HEAT
INDEX VALUES PEAKING IN THE 100-105 DEGREE RANGE FOR LOCATIONS
EAST OF U.S.-301.
STRONG STORMS AND TORRENTIAL DOWNPOURS MAY LINGER INTO THE EARLY
EVENING HOURS ACROSS INTERIOR SOUTHEAST GA BEFORE ACTIVITY LIFTS
NORTH OF THE ALTAMAHA / OCMULGEE RIVER BASINS BY MIDNIGHT.
MEANWHILE, THE AFOREMENTIONED STRONG LOW LEVEL WESTERLY JET
COULD PROPEL ANOTHER ROUND OF CONVECTION ACROSS APALACHEE BAY
EARLY THIS EVENING, WITH A SECOND EPISODE OF SHOWERS AND
THUNDERSTORMS POTENTIALLY IMPACTING THE SUWANNEE VALLEY AND THE
I-10 CORRIDOR LATE THIS EVENING. CYCLONIC FLOW AROUND THE TROUGH
DIGGING TOWARDS THE DEEP SOUTH AND THE LOWER MISSISSIPPI VALLEY
MAY ALSO IGNITE CONVECTION ALONG THE FL NATURE COAST TOWARDS
SUNRISE ON TUESDAY. CLOUD COVER AND LOW LEVEL WESTERLY FLOW WILL
GENERALLY KEEP LOW TEMPERATURES IN THE LOW AND MID 70S AREA-
WIDE TONIGHT.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
MAIN HIGHLIGHTS DURING THIS PERIOD:
-INCREASED STORM POTENTIAL ON TUESDAY WITH GREATEST CHANCE FOR
STRONG TO SEVERE THUNDERSTORMS AND HEAVY RAINFALL NORTH OF
I-10.
PREDOMINANTLY WESTERLY FLOW THROUGH TUESDAY AND THEN SHIFTING TO
BECOME MORE OUT OF THE NORTHWEST ON WEDNESDAY AS HIGH PRESSURE
OVER THE FLORIDA PENINSULA MOVES EASTWARD AND DRIFTS NORTHWARD
TOWARDS THE GULF. PATTERN OF DAILY SHOWERS AND STORMS WILL
CONTINUE THROUGH MIDWEEK WITH CONVECTION EXPECTED TO BE MORE
WIDESPREAD ON TUESDAY WITH MORE DENSE DEVELOPMENTS EXPECTED TO
OCCUR OVER SOUTHEAST GEORGIA, NEARER TO THE FRONTAL BOUNDARY TO
THE NORTH. HIGH TEMPERATURES THROUGH MIDWEEK WILL RISE INTO THE
UPPER 80S AND LOWER 90S FOR SOUTHEAST GEORGIA AND IN THE LOWER
TO MID 90S OVER NORTHEAST FLORIDA WITH TEMPS BEGINNING TO
INCREASE ON WEDNESDAY. OVERNIGHT LOW TEMPERATURES DROPPING DOWN
INTO THE LOWER TO MID 70S. HEAT INDEX VALUES WILL ARE EXPECTED
TO RANGE UPWARDS OF ABOVE 100, BUT IS LIKELY TO REMAIN BELOW
HEAT ADVISORY CRITERIA.
LONG TERM /THURSDAY THROUGH SUNDAY/
MAIN HIGHLIGHTS DURING THIS PERIOD:
- REDUCED CHANCES FOR AFTERNOON AND EVENING THUNDERSTORMS.
- HEAT AND HUMIDITY RETURNS LATE THIS WEEK AND INTO THE
UPCOMING WEEKEND.
EASTERLY PREVAILING FLOW WILL CONTINUE THROUGH THE WEEK AS HIGH
PRESSURE SITUATED TO THE SOUTH CONTINUES TO EXTEND TO TO THE WEST
AND NORTH WITH FLOW BECOMING LESS UNIFORM BY THE WEEKEND AS HIGH
PRESSURE OVER WATERS TO THE EAST STRENGTHENS OFF THE COAST. DAILY
BOUTS OF SHOWERS AND STORMS WILL CONTINUE THROUGH INTO THE WEEKEND
WITH CONVECTION EXPECTED TO BE LESS WIDESPREAD THAN EARLIER IN THE
WEAK AS THE FRONT TO THE NORTH BECOME LESS DEFINED. ABOVE AVERAGE
TEMPERATURES, WITH MAX TEMPS RISING INTO THE MID 90S, WILL CONTINUE
THROUGH THE END OF THE WEEK AND INTO THE WEEKEND WITH HEAT INDEX
VALUES POTENTIALLY RISING TO HEAT ADVISORY LEVELS THROUGH THE
PERIOD.
AVIATION /06Z MONDAY THROUGH 06Z TUESDAY/
PERIODS OF MVFR TO IFR CONDITIONS ARE EXPECTED OVERNIGHT AT VQQ.
OTHERWISE, VFR CONDITIONS WILL PREVAIL AT THE REGIONAL TERMINALS
THROUGH AT LEAST 15Z. SHOWERS AND THUNDERSTORMS DEVELOPING ON
MONDAY MORNING ALONG THE FL BIG BEND AND NATURE COASTS WILL PUSH
QUICKLY EASTWARD, WITH CONVECTION EXPECTED TO APPROACH GNV
AFTER 15Z. TEMPO GROUPS WERE INTRODUCED DURING THIS TAF CYCLE
DUE TO INCREASING CONFIDENCE IN TIMING BETWEEN 16Z-19Z AT GNV,
WHERE BRIEF WIND GUSTS UP UP 30 KNOTS AND IFR VISIBILITIES
DURING HEAVIER DOWNPOURS ARE FORECAST. THE TEMPO PERIOD FOR
THESE IMPACTS SHOULD BE NARROWED DOWN FURTHER DURING THE 12Z TAF
CYCLE. CONVECTION SHOULD THEN APPROACH VQQ AFTER 16Z AND THEN
JAX AND CRG AFTER 17Z, WITH ACTIVITY THEN REACHING THE SSI AND
SGJ COASTAL TERMINALS TOWARDS OR JUST AFTER 18Z. TEMPO GROUPS
WERE ALSO INTRODUCED AT THE DUVAL COUNTY TERMINALS AND THE
COASTAL TERMINALS FOR BRIEF WIND GUSTS UP TO 30 KNOTS AND IFR
VISIBILITIES DURING HEAVIER DOWNPOURS, WITH ACTIVITY EXPECTED TO
PUSH OFFSHORE BEFORE 23Z. SHOWERS COULD LINGER INTO THE EARLY
EVENING HOURS AT SSI, BUT VFR CONDITIONS WILL GENERALLY PREVAIL
AFTER 00Z TUESDAY, WITH VISIBILITY RESTRICTIONS POSSIBLE AT VQQ
TOWARDS THE END OF THIS TAF CYCLE ON MONDAY NIGHT. WEST-
SOUTHWESTERLY SURFACE WINDS WILL REMAIN SUSTAINED AROUND OR LESS
THAN 5 KNOTS OVERNIGHT AT THE REGIONAL TERMINALS. WESTERLY
SURFACE WINDS ARE EXPECTED TO DEVELOP TOWARDS 14Z, WITH SPEEDS
INCREASING TO AROUND 10 KNOTS BY 16Z. A PINNED ATLANTIC SEA
BREEZE BOUNDARY MAY SHIFT SURFACE WINDS TO SOUTHERLY AROUND 18Z
BEFORE CONVECTION ARRIVES AT THE COASTAL TERMINALS.
MARINE
A FRONTAL BOUNDARY PUSHING SLOWLY SOUTHWARD DOWN THE SOUTH
CAROLINA COAST WILL APPROACH THE GEORGIA WATERS BY MONDAY
EVENING, WITH THIS FEATURE THEN STALLING OVER THE GEORGIA WATERS
ON TUESDAY BEFORE WEAKENING ON WEDNESDAY. SHOWERS AND
THUNDERSTORMS WILL IMPACT OUR LOCAL WATERS EARLIER DURING THE
AFTERNOON HOURS THROUGH WEDNESDAY, WITH A FEW STRONG STORMS
CONTAINING BRIEFLY GUSTY WESTERLY WINDS AND FREQUENT LIGHTNING
STRIKES POSSIBLE. COVERAGE OF SHOWERS AND THUNDERSTORMS WILL
THEN DECREASE BY THURSDAY AND ESPECIALLY ON FRIDAY AND SATURDAY
AS THE FRONTAL BOUNDARY DISSIPATES, WITH ONLY ISOLATED TO WIDELY
SCATTERED LATE AFTERNOON AND EARLY EVENING ACTIVITY POSSIBLE
FOR THE NEAR SHORE WATERS AS A PREVAILING WESTERLY FLOW
CONTINUES DURING THE OVERNIGHT AND MORNING HOURS EACH DAY.
RIP CURRENTS:
PREVAILING OFFSHORE WINDS AND LOW SURF HEIGHTS WILL KEEP THE RIP
CURRENT RISK LOW AT AREA BEACHES THROUGHOUT THIS WEEK.
FIRE WEATHER
- AREAS OF HIGH DISPERSIONS TUESDAY THROUGH THURSDAY.
THE REGION WILL BE BETWEEN HIGH PRESSURE TO THE SOUTH AND A
GRADUALLY WEAKENING FRONTAL ZONE TO THE NORTH THIS WEEK. WHILE
DAILY THUNDERSTORM CHANCES ARE FORECAST, ABOVE AVERAGE CHANCES
CAN BE EXPECTED EARLY IN THE WEEK. TEMPERATURES WILL BE ABOVE
AVERAGE, WITH A TREND UPWARD LATER IN THE WEEK.
FOG POTENTIAL AND OTHER REMARKS: SIGNIFICANT FOG POTENTIAL IS
NOT EXPECTED TONIGHT. ERRATIC WIND GUSTS POSSIBLE IN AND NEAR
THUNDERSTORMS, AND AT TIMES, AT A DISTANCE DUE TO OUTFLOWS.
PRELIMINARY POINT TEMPS/POPS
AMG 90 73 88 72 / 80 60 70 40
SSI 90 76 90 76 / 70 50 80 50
JAX 90 74 91 73 / 70 30 70 40
SGJ 91 75 92 75 / 70 20 70 30
GNV 88 73 91 73 / 70 30 60 10
OCF 89 74 92 75 / 60 20 40 10
JAX WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GA...NONE.
MARINE...NONE.
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