Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 040839
AFDJAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
439 AM EDT WED MAY 4 2016

...STRONG THUNDERSTORMS POSSIBLE THIS MORNING OVER NORTH CENTRAL
AND PORTIONS OF NORTHEAST FLORIDA...

.CURRENTLY...
OVERNIGHT SURFACE ANALYSIS DEPICTS A COLD FRONT EXTENDING FROM
JUST WEST OF THE OCMULGEE RIVER IN SOUTHEAST GA SOUTHWESTWARD
THROUGH THE FL BIG BEND REGION. ALOFT...A SHORTWAVE TROUGH WAS
PROGRESSING E-SE FROM THE ARKLATEX REGION. A POTENT SHORTWAVE WAS
DIGGING SOUTHWARD FROM THE GREAT LAKES STATES. DEEP W/SW FLOW
PREVAILS LOCALLY DOWNSTREAM OF THESE TWO SHORTWAVES. CONVECTION
HAS INCREASED OVERNIGHT OVER THE EASTERN GULF OF MEXICO AS
DIFFLUENCE ALOFT STRENGTHENED WITH THE APPROACH OF THE ARKLATEX
SHORTWAVE. THIS CONVECTION IS NOW MOVING ONSHORE ALONG THE NATURE
COAST...AND WILL IMPACT NORTH CENTRAL FL THROUGH THE PREDAWN
HOURS. LOW STRATUS CLOUDS ARE INCREASING AHEAD OF THE COLD FRONT
OVER INLAND SOUTHEAST GEORGIA AND THE WESTERN SUWANNEE
VALLEY...WITH FAIR SKIES ELSEWHERE. UNSEASONABLY WARM AND HUMID
WEATHER PREVAILS AREA-WIDE...WITH TEMPS AND DEWPOINTS RANGING FROM
THE MID 60S OVER INLAND SOUTHEAST GA TO THE MID 70S OVER PORTIONS
OF NORTHEAST FL.

.NEAR TERM /THROUGH THURSDAY/...
SHORT-TERM HIGH RESOLUTION GUIDANCE INDICATES THAT CONVECTION WILL
CONTINUE TO INCREASE IN COVERAGE OVER NORTH CENTRAL FL THROUGH THE
EARLY MORNING HOURS AS SHORTWAVE ENERGY APPROACHES FROM THE
NORTHWEST...WITH AT LEAST SCATTERED CONVECTION DEVELOPING AHEAD
OF THE FRONT OVER COASTAL NORTHEAST FL. FAIRLY IMPRESSIVE SPEED
SHEAR VALUES EXIST OVER OUR REGION...WITH BULK SHEAR VALUES AROUND
50 KNOTS OVER NORTHEAST FL. A MARGINALLY UNSTABLE AIR MASS
PREVAILS...WITH MIXED LAYER CAPE VALUES GENERALLY IN THE 1000-1500
J/KG RANGE OVER NORTHEAST AND NORTH CENTRAL FL. THIS ENVIRONMENT
WILL CREATE A RISK OF STRONG THUNDERSTORMS...MAINLY DURING THE
MORNING HOURS AHEAD OF THE COLD FRONT. SOME CONVECTION MAY TRY TO
DEVELOP OVER COASTAL SOUTHEAST GA AFTER SUNRISE...BUT MOST OF THE
ACTION WILL BE FOR LOCATIONS SOUTHEAST OF THE INTERSTATE 10
CORRIDOR FROM THE MID-MORNING THROUGH THE EARLY AFTERNOON.
STRONGER STORMS WILL BE CAPABLE OF PRODUCING GUSTS IN THE 40-55
MPH RANGE AND SMALL HAIL. CONVECTION WILL REMAIN POSSIBLE THROUGH
THE MID- AFTERNOON HOURS IN EASTERN MARION...SOUTHERN PUTNAM AND
FLAGLER COUNTIES...WHERE RAINFALL AMOUNTS MAY EXCEED ONE HALF
INCH. A DRIER AIR MASS WILL QUICKLY FILTER INTO SOUTHEAST GA IN
THE WAKE OF THE FRONT THIS AFTERNOON...WITH CLEARING SKIES TAKING
PLACE FROM NORTHWEST TO SOUTHEAST. COLD AIR ADVECTION WILL LAG THE
FRONTAL PASSAGE...WITH HIGHS THIS AFTERNOON STILL CLIMBING TO NEAR
80 IN SOUTHEAST GA...AND THE LOWER 80S IN NORTHEAST AND NORTH
CENTRAL FL.

A POTENT SHORTWAVE TROUGH DIGGING S-SE FROM THE GREAT LAKES
STATES THIS MORNING WILL PROGRESS INTO THE APPALACHIANS TONIGHT.
LOW PRESSURE WILL ORGANIZE NEAR THE NORTH CAROLINA OUTER BANKS
TONIGHT. THIS WILL RESULT IN CYCLOGENESIS ALONG THE FRONTAL
BOUNDARY NEAR THE NORTH CAROLINA OUTER BANKS...TIGHTENING OUR
LOCAL PRESSURE GRADIENT. NORTHWEST WINDS WILL REMAIN NEAR 10 MPH
INLAND OVERNIGHT...AND NEAR 15 MPH AT THE COAST. THESE WINDS WILL
BRING A MUCH COOLER AIR MASS INTO OUR AREA...WITH INLAND LOWS
FALLING TO THE MID 50S...RANGING TO NEAR 60 AT THE BEACHES.

LOW PRESSURE WILL CONTINUE TO STRENGTHEN OFF THE VIRGINA CAPES ON
THURS AS THE POTENT SHORTWAVE TROUGH PIVOTS EASTWARD THROUGH THE
CAROLINAS. SOME WRAP-AROUND MOISTURE WILL DIVE INTO INLAND
SOUTHEAST GA DURING THE AFTERNOON HOURS...WITH AN INCREASING
CUMULUS FIELD DEVELOPING. OTHERWISE...SUNNY SKIES WILL PREVAIL. A
TIGHT PRESSURE GRADIENT WILL CREATE BREEZY TO WINDY CONDITIONS
AREA-WIDE...WITH NORTHWESTERLY WINDS QUICKLY INCREASING TO 20-25
MPH OVER INLAND SOUTHEAST GA...WHERE GUSTS UP TO 35 MPH ARE
POSSIBLE DURING THE AFTERNOON HOURS. WIND SPEEDS ELSEWHERE WILL
GENERALLY BE IN THE 15-25 MPH RANGE FROM THE MID-MORNING THROUGH
THE AFTERNOON HOURS. DESPITE SUNSHINE...COLD AIR ADVECTION WILL
KEEP HIGHS 5-10 DEGREES BELOW EARLY MAY CLIMO. HIGHS OVER
SOUTHEAST GA WILL ONLY CLIMB TO THE LOWER 70S...WITH MID TO UPPER
70S FOR MOST OF NORTHEAST AND NORTH CENTRAL FL.

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
DRY CONDITIONS WILL PREVAIL UNDER MEAN LAYER AND STABLE NW FLOW AS
STACKED RIDGING DOMINATES ACROSS THE CENTRAL CONUS. NEAR RECORD
LOW TEMPS ARE EXPECTED FRI MORNING WITH VALUES IN THE 40S WELL
INLAND AND 50S TOWARD THE ATLANTIC COAST. HIGH TEMPS WILL RANGE IN
THE 70S FRI THEN WARM TO NEAR CLIMO VALUES BY SAT AS RIDGING
BUILDS EASTWARD WITH MOSTLY CLEAR TO PARTLY CLOUDY SKIES.

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SUN-MON...DRY CONDITIONS AND MODERATING TEMPS AS STACKED RIDGING
BUILDS ACROSS THE FL PENINSULA. HIGH TEMPS WILL WARM BACK INTO THE
MID/UPPER 80S WITH LOWS IN THE UPPER 50S TO LOWER 60S WITH SOME
LATE NIGHT FOG POTENTIAL.

TUE-WED...RIDGING BUILDS OFFSHORE OF THE FL ATLANTIC COAST AS THE
UPPER RIDGE BREAKS DOWN. MEAN LAYER SOUTHERLY FLOW DEVELOPS WITH
AN INCREASE IN MOISTURE...DIURNAL INSTABILITY AND STRONGER SEA
BREEZE FORCING. ADVERTISED A LOW 20% CHANCE OF SEA BREEZE INDUCED
SHOWERS/ISOLATED TSTORMS. HIGH TEMPS WILL MODERATE BACK ABOVE
CLIMO WITH HIGHS NEAR 90 INLAND AND LOWS IN THE MID 60S INLAND TO
NEAR 70 COAST.

&&

.AVIATION...
PERIODS OF MVFR CIGS WILL PREVAIL AHEAD OF A COLD FRONT AT SSI
THROUGH AROUND 12Z. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
IMPACT THE NORTHEAST FL TERMINALS AFTER 11Z...WITH A PERIOD OF
SUB-VFR CONDITIONS EXPECTED. ACTIVITY WILL MOVE QUICKLY
EASTWARD...ENDING AT GNV TOWARDS 14Z...ENDING AT THE DUVAL COUNTY
TERMINALS AROUND 15Z...AND MOVING OFFSHORE OF SGJ AROUND 17Z. A
FEW STRONG THUNDERSTORMS WILL BE POSSIBLE AT THE NORTHEAST FL
TERMINALS THIS MORNING...WITH STRONG WIND GUSTS POSSIBLE. VFR
CONDITIONS WILL PREVAIL REGION-WIDE BY 18Z.

&&

.MARINE...
A COLD FRONT WILL CROSS THE GEORGIA WATERS THIS MORNING...AND WILL
PASS THROUGH THE OFFSHORE FLORIDA WATERS BY LATE THIS AFTERNOON.
SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE FRONTAL PASSAGE OVER
THE FLORIDA WATERS. LOW PRESSURE WILL THEN ORGANIZE NEAR THE NORTH
CAROLINA OUTER BANKS TONIGHT...TIGHTENING OUR LOCAL PRESSURE
GRADIENT WITH WEST/NORTHWEST WINDS INCREASING TO CAUTION SPEEDS
OVER BOTH THE NEAR SHORE AND OFFSHORE WATERS. SMALL CRAFT ADVISORY
CONDITIONS MAY DEVELOP OVER THE OFFSHORE GEORGIA WATERS DURING THE
PREDAWN HOURS ON THURS MORNING...AND WILL OVERSPREAD THE REST OF
THE GEORGIA AND FLORIDA WATERS BY THE LATE MORNING AND EARLY
AFTERNOON HOURS. SEAS OFFSHORE WILL PEAK IN THE 5-7 FT RANGE
THURS NIGHT. WINDS WILL LIKELY SUBSIDE BACK TO CAUTION LEVELS ON
THURS NIGHT IN THE NEAR SHORE WATERS...WITH SCA CONDITIONS
CONTINUING THROUGH AROUND SUNRISE ON FRI OFFSHORE. HIGH PRESSURE
CENTERED OVER TEXAS ON FRIDAY WILL BUILD EAST/SOUTHEASTWARD OVER
THE GULF OF MEXICO THIS WEEKEND. CAUTION CONDITIONS MAY CONTINUE
THROUGH FRI NIGHT OFFSHORE...WITH OFFSHORE WINDS CONTINUING THIS
WEEKEND BUT SPEEDS REMAINING BELOW CAUTION CRITERIA.

RIP CURRENTS: LOW RISK EXPECTED THROUGH AT LEAST FRIDAY DUE TO
OFFSHORE WINDS.

&&

.FIRE WEATHER...
ELEVATED FIRE DANGER IS LIKELY FOR PORTIONS OF NE FL THU DUE TO
HUMIDITY NEAR 28% AND BREEZY WNW WINDS 15 MPH WITH GUSTS TO 25
MPH POSSIBLE. IF ERC VALUES RISE TO TO NEAR 26 UNITS ACROSS NE
FL...THEN A FIRE WEATHER WATCH MAY BE NEEDED FOR THU FOR PORTIONS
OF THE AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  80  54  72  49 /  20  10  10   0
SSI  79  59  73  52 /  50  10   0   0
JAX  83  56  76  52 /  50  10   0   0
SGJ  81  60  76  56 /  70  20   0   0
GNV  82  56  77  50 /  60  10   0   0
OCF  81  56  80  52 /  80  10   0   0

&&

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

$$

NELSON/ENYEDI



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