Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 300842
AFDJAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
442 AM EDT WED JUL 30 2014

...UNSEASONABLY DRY AIR PERSISTS AT INLAND LOCATIONS TODAY...

.CURRENTLY...
EARLY MORNING SURFACE ANALYSIS DEPICTS A COLD FRONT PUSHING INTO
CENTRAL FLORIDA...WITH WEAK LOW PRESSURE (1012 MILLIBARS) LOCATED
OFF THE NORTH CAROLINA OUTER BANKS. WEAK HIGH PRESSURE COVERS MOST
OF THE EASTERN AND SOUTHERN UNITED STATES IN THE WAKE OF THE
FRONTAL BOUNDARY. ALOFT...DEEP-LAYERED TROUGHING REMAINS IN PLACE
FROM HUDSON BAY CANADA SOUTHWARD TO THE CENTRAL GULF
COAST...CREATING A DEEP WEST TO NORTHWEST FLOW LOCALLY. WEAK
SURFACE CONVERGENCE AND ISENTROPIC LIFT DEVELOPED A FEW SHOWERS
OVER COASTAL GLYNN AND WAYNE COUNTIES IN SOUTHEAST GEORGIA
OVERNIGHT...BUT ACTIVITY HAS SINCE DISSIPATED. TEMPERATURES AT 08Z
RANGED FROM THE MID/UPPER 60S IN INTERIOR SOUTHEAST GEORGIA AND THE
WESTERN SUWANNEE VALLEY TO THE UPPER 70S IN COASTAL LOCATIONS.
DEWPOINTS WERE GENERALLY IN THE LOW TO MID 60S...EXCEPT NEAR 70 IN
COASTAL LOCATIONS. THE WEAK ISENTROPIC LIFT IS PRODUCING ENOUGH
MID-LEVEL CLOUDINESS TO PRECLUDE ANY THREAT OF RECORD LOW
TEMPERATURES AT OUR CLIMATE SITES THIS MORNING.

.SHORT TERM (TODAY THROUGH FRIDAY NIGHT)...
THE FRONTAL BOUNDARY WILL REMAIN STALLED ALONG THE INTERSTATE 4
CORRIDOR IN CENTRAL FLORIDA TODAY...WITH A DRY AND SUBSIDENT AIR
MASS REMAINING IN PLACE OVER INTERIOR LOCATIONS. WEAK HIGH
PRESSURE OVER THE SOUTHEASTERN STATES WILL ALLOW THE SEA BREEZE TO
PUSH INLAND PAST THE INTERSTATE 95 CORRIDOR BY THE LATE AFTERNOON
HOURS. MODEL SOUNDINGS DEPICT RECOVERING LOW-LEVEL MOISTURE
LEVELS IN THE COASTAL COUNTIES AS THE AFTERNOON PROGRESSES...WITH
PRECIPITABLE WATER VAPOR (PWAT) VALUES CLIMBING ABOVE 1.5 INCHES
TOWARDS SUNSET...WHICH IS STILL WELL BELOW NORMAL FOR LATE JULY.
SHORT TERM HIGH RESOLUTION GUIDANCE SUCH AS THE HRRR AND ARW
DEPICT ISOLATED CONVECTION DEVELOPING ALONG THE ATLANTIC SEA
BREEZE THIS AFTERNOON...MAINLY FOR AREAS ALONG OR EAST OF THE I-95
CORRIDOR/ST. JOHNS RIVER BASIN. DRY AIR ALOFT WILL LIKELY KEEP ANY
CONVECTION THAT MANAGES TO BREAK THROUGH A SUBSTANTIAL INVERSION
BASED AROUND 800 MILLIBARS (6500 FEET) BRIEF IN DURATION.
OTHERWISE...PLENTY OF INSOLATION WILL ALLOW HIGHS TO CLIMB INTO
THE LOWER 90S INLAND...WITH THE AFTERNOON SEA BREEZE KEEPING HIGHS
IN THE UPPER 80S AT THE BEACHES. DRY AIR MIXING TO THE SURFACE
THIS AFTERNOON WILL RESULT IN WELL BELOW NORMAL HUMIDITY LEVELS.
ISOLATED CONVECTION THAT MANAGES TO DEVELOP ALONG THE ATLANTIC SEA
BREEZE WILL FADE QUICKLY TOWARDS SUNSET. SOME PATCHY LIGHT FOG
WILL BE POSSIBLE LATER TONIGHT ALONG THE ST. JOHNS RIVER BASIN AS
ONSHORE FLOW CONTINUES TO MOISTEN THE LOW LEVELS.
OTHERWISE...EXPECT FAIR SKIES AND LIGHT WINDS WITH BELOW NORMAL
TEMPS INLAND...AS LOWS FALL INTO THE UPPER 60S INLAND...RANGING
TO THE MID/UPPER 70S AT THE COAST.

THURSDAY THROUGH FRIDAY NIGHT...MORE MOIST AIR WILL BEGIN TO
FILTER INTO AREA ON THURSDAY BUT STILL REMAIN DRY ENOUGH TO ONLY
SUPPORT ISOLATED SHOWERS AND THUNDERSTORMS ALONG THE ATLANTIC SEA
BREEZE. FRIDAY WILL SEE A MORE NORMAL COVERAGE PATTERN OF
CONVECTION AS MOISTURE LEVELS CONTINUE TO RISE AND UPPER LEVEL
SHORTWAVE PROVIDES SUPPORT FOR SHOWERS AND THUNDERSTORMS DURING
THE AFTERNOON AND EVENING. TEMPS WILL REMAIN IN THE LOW 90S EACH
AFTERNOON AND LOW 70S EACH NIGHT.

.LONG TERM (SATURDAY THROUGH WEDNESDAY)...
UPPER TROUGH OVER THE EASTERN UNITED STATES WILL BECOME MORE
DEFINED ON SATURDAY AS IT MOVES OFF SLOWLY TO THE NORTHEAST INTO
EARLY NEXT WEEK. THIS FEATURE WILL BRING A SWATH OF THE DEEP LAYER
MOISTURE INTO THE LOCAL AND SURROUNDING AREAS WITH WEAK SOUTH TO
SOUTHEASTERLY FLOW AT THE SFC. EXPECT A TYPICAL SUMMER PATTERN TO
COMMENCE WITH THE SUPPORT OF A SERIES OF SHORTWAVES TRAVELING
THROUGH GEORGIA AND THE ATLANTIC STATES WITH SHOWERS AND
THUNDERSTORMS DEVELOPING EACH DAY ALONG WEST AND EAST COAST SEA
BREEZE THEN DIMINISHING SLOWLY AFTER SUNSET. TEMPERATURES AND
HUMIDITY LEVELS WILL BE BACK NEAR SEASONAL NORMALS.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL. A FEW SHOWERS OR ISOLATED
THUNDERSTORMS MAY DEVELOP ALONG THE ATLANTIC SEA BREEZE FROM 18Z-
23Z AND COULD IMPACT SSI AND THE DUVAL COUNTY TERMINALS...BUT
CONFIDENCE IS TOO LOW TO CURRENTLY INCLUDE IN THE TAFS.

&&

.MARINE...
LIGHT OFFSHORE FLOW THIS MORNING WILL BECOME ONSHORE THIS
AFTERNOON AS THE SEA BREEZE DEVELOPS ALONG COASTAL LOCATIONS. WEAK
HIGH PRESSURE OVER THE EASTERN UNITED STATES WILL KEEP ONSHORE
WINDS IN PLACE THROUGH SATURDAY AS A FRONTAL BOUNDARY OVER CENTRAL
FLORIDA WEAKENS AND LIFTS NORTHWARD INTO OUR REGION DURING THE
WEEKEND. WIND SPEEDS SHOULD REMAIN JUST BELOW CAUTION CRITERIA
DURING EVENING WIND SURGES. HIGH PRESSURE OVER THE WESTERN
ATLANTIC WILL THEN BUILD WESTWARD INTO OUR COASTAL WATERS LATE
THIS WEEKEND AND EARLY NEXT WEEK...PRODUCING A SOUTHERLY WIND FLOW
AND POSSIBLE CAUTION CONDITIONS DURING EVENING WIND SURGES. SEAS
WILL BUILD TO 3-5 FEET OFFSHORE BY LATE IN THE WEEKEND.

RIP CURRENTS: LOW RISK EXPECTED THROUGH THURSDAY.

&&

.FIRE WEATHER...
AN UNSEASONABLY DRY AIR MASS WILL REMAIN IN PLACE OVER SOUTHEAST
GEORGIA TODAY AND WILL FILTER INTO NORTH CENTRAL FLORIDA. EXPECT
MINIMUM RELATIVE HUMIDITY VALUES TO RANGE FROM 25 TO 30 PERCENT
OVER INTERIOR SOUTHEAST GA...WITH 30 TO 35 PERCENT EXPECTED FOR
INLAND NORTHEAST AND NORTH CENTRAL FL. LIGHT WINDS ARE
EXPECTED...AND MOISTURE LEVELS/ERC VALUES WILL PRECLUDE RED FLAG
CONDITIONS. THE AFTERNOON SEA BREEZE WILL MOISTEN CONDITIONS IN
THE COASTAL COUNTIES BY THE MID TO LATE AFTERNOON HOURS. RELATIVE
HUMIDITY VALUES WILL REMAIN WELL ABOVE CRITICAL THRESHOLDS FOR THE
REMAINDER OF THE FORECAST.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  92  68  92  73 /   0  10  20  30
SSI  87  76  87  78 /  20  10  30  40
JAX  91  71  89  75 /  20  10  20  30
SGJ  90  75  87  76 /  20  10  20  30
GNV  93  69  91  72 /  10  10  20  20
OCF  93  70  92  73 /  10  10  20  20

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&

$$

NELSON/GUILLET






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