Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 230242
AFDJAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
1042 PM EDT MON SEP 22 2014

...ONSHORE FLOW WILL BRING WET AND BREEZY CONDITIONS TO THE COAST
FROM TUESDAY THROUGH THE UPCOMING WEEKEND...

.UPDATE...
LATE EVENING SURFACE ANALYSIS DEPICTS A COLD FRONT CROSSING THE
FLORIDA/GEORGIA BORDER...WITH ANOTHER BOUNDARY EXTENDING FROM
NORTH CENTRAL FLORIA AND THE EASTERN GULF OF MEXICO TO THE
OFFSHORE ATLANTIC WATERS. ALOFT...A SHARP TROUGH IS PLUNGING
THROUGH THE FL PANHANDLE AND EXTENDS INTO THE CENTRAL GULF OF
MEXICO. SCATTERED SHOWERS AND THUNDERSTORMS WERE DEVELOPING ALONG
AND JUST BEHIND THE COLD FRONT THAT IS CROSSING THE FL/GA
BORDER...WITH SLOW MOVEMENT TO THIS ACTIVITY. CONVECTION
ASSOCIATED WITH THE BOUNDARY OVER NORTH CENTRAL FL IS SLOWLY
WANING SOUTH OF GAINESVILLE...WITH HEAVY SHOWERS AND EMBEDDED
STORMS OVER THE ADJACENT ATLANTIC COASTAL WATERS. THERE IS ALSO
WIDELY SCATTERED CONVECTION NEAR THE ALTAMAHA RIVER ASSOCIATED
WITH INCREASING ISENTROPIC ASCENT BEHIND THE COLD FRONT. A
NORTHEAST WIND SURGE BEHIND THE COLD FRONT IS ALREADY MAKING ITS
WAY INTO COASTAL SOUTHEAST GA...WHERE NORTHEAST WINDS ARE ALREADY
GUSTING TO NEAR 20 KNOTS AT SAINT SIMONS ISLAND.

LEFT SCATTERED POPS IN THE FORECAST GRIDS OVERNIGHT NEARLY REGION-
WIDE DUE TO THE APPROACHING DEEP TROUGH AND THE PRESENCE OF THE
DUAL SURFACE BOUNDARIES OVER OUR REGION. INDICATED DECREASING POPS
DURING THE PREDAWN HOURS OVER THE SUWANNEE VALLEY AND OUR FAR
WESTERN GA COUNTIES AS DRIER AIR BEGINS TO ADVECT IN FROM THE
WEST. SLOW MOVING CONVECTION DEVELOPING ALONG AND JUST BEHIND THE
BOUNDARY COULD PRODUCE SOME LOCALIZED FLOODING...PARTICULARLY OVER
COASTAL SOUTHEAST GA WHERE ONSHORE WINDS WILL BEGIN TO INCREASE
LOW-LEVEL CONVERGENCE LATER TONIGHT. WE EXPECT SHOWERS AND
EMBEDDED THUNDERSTORMS TO INCREASE OVER COASTAL NORTHEAST FL ON
TUES AS WINDS BECOME ONSHORE BEHIND THE COLD FRONT...WHICH IS
EXPECTED TO SLIP INTO CENTRAL FL BEFORE STALLING ON TUES EVENING.
ONSHORE WINDS AND SHOWERS WILL KEEP HIGHS IN THE COASTAL COUNTIES
NEAR 80...WITH MID 80S EXPECTED INLAND.

&&

.AVIATION...
TWO SFC BOUNDARIES WILL CONVERGE OVER THE AREA TONIGHT WHICH WILL
KEEP THUNDERSTORMS POSSIBLE AT ALL TERMINALS FOR A MAJORITY OF THE
OVERNIGHT PERIOD. GNV IS SEEING ACTIVITY IN THE VCNTY CURRENTLY SO
HAVE INCLUDED A TEMPO FOR MVFR VIS/CIG RESTRICTIONS WITH HEAVIER
ACTIVITY THROUGH 02Z. PATCHY FOG FORMATION WILL BE POSSIBLE AT VQQ
AND GNV LATE TONIGHT FOLLOWING PERSISTENCE AT VQQ AND THE PRESENCE
OF A MOIST SFC FOLLOWING RAINFALL AT GNV. TOMORROW...THE BEST
CHANCES FOR PRECIPITATION WILL BE IN COASTAL COUNTIES SO HAVE
INCLUDED VCSH IN THE MORNING AND VCTS DURING THE AFTERNOON  AT
THE DUVAL COUNTY TERMINALS AND VCSH AT SSI FOR TUESDAY.

&&

.MARINE...
NORTHEAST WINDS ARE ALREADY SURGING IN THE WAKE OF THE COLD FRONT
AT THE GRAY`S REEF BUOY 41008...WITH SPEEDS REACHING 15-20 KNOTS
DURING THE PAST FEW HOURS. WE SPLIT OFF THE NEAR SHORE AND
OFFSHORE GA WATERS IN THE EVENING COASTAL WATERS FORECAST TO
INDICATE SMALL CRAFT EXERCISE CAUTION CONDITIONS FOR THE OVERNIGHT
HOURS. THE FRONT WILL TAKE MOST OF THE OVERNIGHT TO MAKE IT TO THE
WATERS SOUTH OF ST. AUGUSTINE...WHERE MAINLY SOUTH TO SOUTHEAST
WINDS WILL REMAIN BELOW 15 KNOTS OUTSIDE OF SHOWER AND
THUNDERSTORM ACTIVITY.

SMALL CRAFT ADVISORY CONDITIONS ARE POSSIBLE IN THE GEORGIA
COASTAL WATERS BY TUESDAY AFTERNOON...AND WE WILL EVALUATE THE
OVERNIGHT MODELS BEFORE HOISTING THE SCA FOR TOMORROW. WE WILL
LIKELY NEED TO BREAK OFF THE COASTAL ZONES NORTH OF ST. AUGUSTINE
FOR SCEC CONDITIONS BY TOMORROW AFTERNOON IN THE EARLY MORNING
FORECAST UPDATE. WEAK LOW PRESSURE WILL DEVELOP OFF THE NORTHEAST
FL COAST BY TOMORROW EVENING...WITH SCEC CONDITIONS POSSIBLY
OVERSPREADING THE REST OF COASTAL NORTHEAST FL...AND POSSIBLE SCA
CONDITIONS NORTH OF ST. AUGUSTINE. STRONG HIGH PRESSURE OVER NEW
ENGLAND WILL KEEP A TIGHT LOCAL PRESSURE GRADIENT IN PLACE OVER
THE COASTAL WATERS INTO THE UPCOMING WEEKEND...WITH ELEVATED WATER
LEVELS AT THE COAST POSSIBLE BY MID AND LATE WEEK DUE TO
ASTRONOMICALLY HIGH TIDE LEVELS AND PERSISTENT MODERATE TO STRONG
ONSHORE WINDS. SMALL CRAFT EXERCISE CAUTION WIND SPEEDS ARE
EXPECTED FOR MUCH OF THIS PERIOD...WITH INTERLUDES OF ADVISORY
LEVEL WIND SPEEDS POSSIBLE AS SEAS BUILD TO 4-6 FT.

RIP CURRENTS: MODERATE RISK DEVELOPING ON TUESDAY DUE TO ONSHORE
WINDS...WITH AN ELEVATED RISK EXPECTED TO PERSIST THROUGH THE
UPCOMING WEEKEND AS MODERATE TO STRONG ONSHORE WINDS PREVAIL.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  66  84  64  79 /  50  20  20  10
SSI  70  80  68  77 /  50  50  50  50
JAX  68  81  68  80 /  40  40  40  50
SGJ  72  81  71  82 /  60  60  60  60
GNV  68  82  67  82 /  60  40  40  40
OCF  69  83  69  86 /  50  60  50  60

&&

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

$$

NELSON/GUILLET/SHASHY





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