Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 281616
AFDJAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
1216 PM EDT FRI AUG 28 2015

.UPDATE...
LATE MORNING SURFACE ANALYSIS DEPICTS A STATIONARY FRONTAL
BOUNDARY EXTENDING FROM COASTAL GEORGIA SOUTHWESTWARD THROUGH THE
FLORIDA BIG BEND AND INTO THE CENTRAL GULF OF MEXICO. HIGH
PRESSURE (1024 MILLIBARS) WAS CENTERED OVER THE NORTHEASTERN U.S.
MEANWHILE...TROPICAL STORM ERIKA REMAINS POORLY ORGANIZED AS IT
MOVES TOWARDS THE COAST OF HISPANIOLA. ALOFT...THE TROUGH OVER THE
SOUTHEASTERN STATES HAS CUTOFF INTO AN UPPER LEVEL LOW THAT WAS
SPINNING NEAR MOBILE BAY. THIS WEATHER PATTERN IS CREATING STRONG
SOUTHWEST FLOW LOCALLY ABOVE 400 MILLIBARS (25000 FEET). THE
MORNING SOUNDING AT JACKSONVILLE DISPLAYED WEAK FLOW BELOW 25000
FT...WITH AN UNSTABLE SOUNDING FEATURING A VERY MOIST LOWER
ATMOSPHERE UP THROUGH 700 MILLIBARS (10000 FT).

HIGH RESOLUTION SHORT TERM GUIDANCE INDICATES THAT A DEVELOPING
NORTHEAST WIND SURGE OVER THE COASTAL GEORGIA WATERS WILL ENHANCE
CONVERGENCE ALONG THE STALLED FRONTAL BOUNDARY ALONG THE I-95
CORRIDOR IN SOUTHEAST GA...WITH CONVECTION SPREADING SOUTHWARD
INTO NORTHEAST FLORIDA AND THE SUWANNEE VALLEY THIS AFTERNOON.
STRENGTHENING EASTERLY FLOW IN THE LOW LEVELS WILL PUSH ACTIVITY
INLAND TOWARDS THE HIGHWAY 301 CORRIDOR BY LATE AFTERNOON...AND
TOWARDS THE I-75 CORRIDOR THIS EVENING. A FEW STRONG THUNDERSTORMS
ARE POSSIBLE DUE TO INCREASED INSTABILITY ALOFT...WITH STRONG WIND
GUSTS OF 30-50 MPH POSSIBLE IN HEAVIER ACTIVITY DURING THE MID
AFTERNOON THROUGH EARLY EVENING HOURS...MAINLY AT INLAND
LOCATIONS. NEAR CLIMO LATE AUGUST HIGHS ARE EXPECTED...RANGING
FROM THE UPPER 80S AT THE COAST TO THE LOWER 90S INLAND.

ERIKA PRODUCED A PROLIFIC RAINFALL EVENT OVER PORTIONS OF THE
NORTHERN LEEWARD ISLANDS. WITH STEERING CURRENTS ALOFT EXPECTED TO
COLLAPSE NEXT WEEK OVER OUR REGION...THERE IS THE POTENTIAL THAT
ERIKA OR ITS REMNANTS WILL SLOW DOWN SIGNIFICANTLY...POSSIBLY
BRINGING AN EXTENDED PERIOD OF HEAVY DOWNPOURS TO OUR REGION FOR
MUCH OF NEXT WEEK. WE HAVE HIGHLIGHTED THIS THREAT THIS MORNING IN
A HYDROLOGIC OUTLOOK PRODUCT...WITH THE THREAT FOR MAJOR FLOODING
ON FAST RISING TRIBUTARIES SUCH AS BLACK CREEK AND THE UPPER SANTA
FE RIVER...WHICH ALREADY HAVE ENHANCED FLOWS LEADING INTO THIS
POTENTIAL EVENT.

&&

.AVIATION...
MVFR CONDITIONS ARE POSSIBLE THROUGH THE EARLY TO MID AFTERNOON
HOURS AT SSI AS THUNDERSTORMS DEVELOP NEAR OR OVER THE TERMINAL.
WILL INCLUDE TEMPO GROUPS AT THE FLORIDA TERMINALS FOR MVFR
CONDITIONS THIS AFTERNOON...WITH SUB-VFR CONDITIONS POSSIBLY
PERSISTING TO THE EARLY EVENING HOURS AT GNV. SURFACE WINDS WILL
INCREASE TO NEAR 15 KNOTS AT SSI OUTSIDE OF THUNDERSTORM
ACTIVITY...AND NEAR 10 KNOTS ELSEWHERE AFTER 18Z.

&&

.MARINE...
AS HIGH PRESSURE BUILDS TO THE NORTH OF OUR REGION...ONSHORE
WINDS WILL INCREASE TO NEAR 15 KNOTS LATE THIS AFTERNOON AND
TONIGHT WITH SEAS INTO THE 3-5 FT RANGE BY SAT...WITH FURTHER
INCREASES ON SUNDAY POSSIBLY TO CAUTION CONDITIONS. EARLY NEXT
WEEK...STILL TOO MUCH UNCERTAINTY IN LONG RANGE PREDICTIONS OF
ERIKA AND POTENTIAL FOR HIGH WINDS/SEAS FOR ANY DETAILS AND WILL
CONTINUE WITH WORDING FOR TROPICAL STORM CONDITIONS POSSIBLE AND
ANY CHANGES WILL DEPEND ON TRACK UPDATES FROM THE NATIONAL
HURRICANE CENTER IN THE NEXT COUPLE OF DAYS.

RIP CURRENTS: EASTERLY FLOW INCREASES JUST ENOUGH TODAY AND
SATURDAY TO WARRANT A MARGINAL MODERATE RISK OF RIPS WITH SWELLS
OF 2 TO POSSIBLY 3 FEET AT TIMES.

SURF ZONE/TIDES: COMING UP ON FULL MOON SAT 8/29 AND EXPECT THE
EASTERLY FLOW TO ENHANCE ALREADY ELEVATED TIDAL LEVELS ALONG THE
COAST BUT NOT LIKELY ENOUGH TO PRODUCE COASTAL FLOODING AT THIS
TIME.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  90  72  87  72 /  70  10  60  40
SSI  88  77  85  75 /  50  40  60  40
JAX  89  74  87  73 /  40  30  60  30
SGJ  88  75  86  75 /  50  40  60  30
GNV  91  72  88  71 /  60  20  60  20
OCF  91  73  89  72 /  60  30  60  20

&&

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

$$

NELSON/GUILLET/KENNEDY/COMBS



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