« Back
NWS Peachtree City, Ga » Text Product » JAX Area Forecast Discussion


Printer-friendly Version
Current Version              Previous Versions:   1  2  3  4  5  6  7  8  9  

Area Forecast Discussion

673
FXUS62 KJAX 282006
AFDJAX

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

...ERIKA MAY BRING FLOODING RAINS TO OUR REGION NEXT WEEK...

.CURRENTLY...
AFTERNOON SURFACE ANALYSIS DEPICTS A STATIONARY FRONTAL BOUNDARY
EXTENDING FROM COASTAL GEORGIA SOUTHWESTWARD THROUGH THE FLORIDA
PANHANDLE AND INTO THE CENTRAL GULF OF MEXICO. HIGH PRESSURE
(1023 MILLIBARS) WAS CENTERED OVER THE OHIO VALLEY.
MEANWHILE...TROPICAL STORM ERIKA REMAINS POORLY ORGANIZED AS IT
MOVES WESTWARD ALONG THE SOUTHERN COAST OF HISPANIOLA.
ALOFT...THE TROUGH OVER THE SOUTHEASTERN STATES HAS CUTOFF INTO AN
UPPER LEVEL LOW THAT WAS SPINNING OVER THE CENTRAL GULF COAST.
THIS WEATHER PATTERN IS CREATING STRONG SOUTHWEST FLOW LOCALLY
ABOVE 400 MILLIBARS (25000 FEET). ATLANTIC RIDGING CENTERED
SOUTHEAST OF BERMUDA WAS BUILDING WESTWARD TOWARDS THE BAHAMAS.
CONVECTION THAT INITIATED ALONG THE STATIONARY FRONTAL BOUNDARY
OVER COASTAL SOUTHEAST GEORGIA LATE THIS MORNING SENT A LARGE
OUTFLOW BOUNDARY SOUTH AND WESTWARD HAS SPARKED SLOW MOVING STRONG
TO SEVERE THUNDERSTORMS NEAR THE OCMULGEE/ALTAMAHA RIVER BASIN IN
INTERIOR SOUTHEAST GEORGIA. ADDITIONAL SLOW MOVING CONVECTION HAS
SUNK SOUTHWARD ALONG THE FL/GA BORDER. OUTSIDE OF THUNDERSTORM
ACTIVITY...MULTI-LAYERED CLOUDINESS HAS HELD TEMPERATURES TO THE
85-90 RANGE...WITH DEWPOINTS IN THE 70S.

.NEAR TERM (THIS AFTERNOON THROUGH SATURDAY)...
STRENGTHENING LOW-LEVEL ONSHORE FLOW WILL PUSH CONVECTION NEAR
THE FL/GA BORDER WESTWARD...WITH COLLIDING BOUNDARIES SETTING UP
NUMEROUS SHOWERS AND THUNDERSTORMS ALONG THE I-75 CORRIDOR BY
EARLY EVENING. A FEW STRONG THUNDERSTORMS CONVERGENT E-SE LOW-
LEVEL WINDS WILL REDEVELOP WIDESPREAD CONVECTION OVER THE COASTAL
WATERS THIS EVENING...WITH SCATTERED ACTIVITY MOVING ONSHORE INTO
THE COASTAL COUNTIES THROUGH THE OVERNIGHT HOURS. INLAND
CONVECTION THIS EVENING WILL QUICKLY WANE. MOIST SOUTHWEST FLOW
WILL KEEP PLENTY OF CLOUDS IN PLACE OVERNIGHT...LIMITING FOG
FORMATION. LOWS IN THE LOW TO MID 70S ARE EXPECTED.

A PLUME OF DEEP TROPICAL MOISTURE OVER THE FL PENINSULA WILL
ADVECT NORTHWARD INTO OUR REGION ON SATURDAY AS ATLANTIC RIDGING
BUILDS WESTWARD...SWITCHING OUR LOW LEVEL FLOW TO SOUTHEASTERLY
AND ESTABLISHING A VEERING WIND PROFILE. SCATTERED CONVECTION WILL
BE ONGOING IN THE COASTAL COUNTIES DURING THE MORNING...BECOMING
NUMEROUS OVER INLAND SECTIONS DURING THE AFTERNOON AS SHORTWAVE
ENERGY LIFTS NORTHWARD FROM THE NORTHEAST GULF OVER THE FL BIG
BEND AND INLAND SOUTH GA. SOME DECREASE IN CONVECTIVE COVERAGE IS
POSSIBLE TOWARDS SUNSET. COOL MID-LEVEL TEMPERATURES MAY AGAIN
PROMOTE STRONG THUNDERSTORMS...WITH GUSTY WINDS OF 30-50 MPH AND
LOCALIZED FLOODING POSSIBLE WITH HEAVIER AND/OR SLOWER MOVING
ACTIVITY. PLENTY OF CLOUDS AND CONVECTION WILL KEEP HIGHS MOSTLY
IN THE UPPER 80S.

.SHORT TERM (SATURDAY NIGHT THROUGH SUNDAY NIGHT)... WEAK MID
LEVEL TROUGH CONTINUES TO RETROGRADE TO OUR WEST AS WESTERN EXTENT
OF SUBTROPICAL RIDGE EXTENDS OVER THE FL PENINSULA SAT NIGHT
THROUGH SUN NIGHT. MOIST AIRMASS WILL BE IN PLACE OVER THE AREA
WITH PWATS AROUND 2 INCHES WHICH COMBINED WITH DIURNAL HEATING
WILL LIKELY PRODUCE NUMEROUS SHOWERS AND TSTORMS THROUGHOUT THE
DAY ON SUNDAY. HEAVY RAIN AND LOCALIZED FLOODING WILL BE POSSIBLE
WITH ANY SLOW MOVING STORMS. ONSHORE FLOW WILL ALLOW HIGHEST
PRECIP CHANCES ON SUNDAY TO START THE DAY OVER THE COASTAL WATERS
AND COASTAL COUNTIES AND SPREAD INLAND DURING THE MID/LATE
AFTERNOON. BREEZY CONDITIONS WILL BE POSSIBLE SUNDAY AFTERNOON
ALONG THE COAST WITH EASTERLY WINDS OF 10 TO 15 MPH GUSTING 15 TO
20 MPH. AFTERNOON CONVECTION WILL BEGIN TO DECREASE IN COVERAGE
AND INTENSITY AFTER SUNSET SUNDAY WITH RAIN CHANCES INCREASING
OVER THE COASTAL WATERS AND ADJACENT COASTAL AREAS LATE SUNDAY
NIGHT. INCREASED CLOUD COVER WILL KEEP MAX TEMPS IN THE UPPER 80S
TO LOW 90S AND LOWS IN THE LOW/MID 70S.

.LONG TERM (MONDAY THROUGH THURSDAY NIGHT)...LONG TERM PERIOD
FORECAST IS STILL VERY UNCERTAIN AS MODELS ARE STILL INCONSISTENT
WITH HANDLING THE PROGRESSION OF T.S ERIKA INTO EARLY NEXT WEEK.
CURRENT NHC TRACK BRINGS THE LOW ACROSS THE SOUTHERN FL PENINSULA
LATE IN THE WEEKEND TURNING TO THE NORTH AND MOVING UP THE FLORIDA
PENINSULA INTO THE LOCAL AREA TUESDAY INTO WEDNESDAY AS A TROPICAL
STORM. THIS COULD CHANGE SIGNIFICANTLY IF THE STORM WEAKENS AS IT
PASSES OVER HISPANIOLA AND INTERACTS WITH A PERSISTENT VERTICAL
WIND SHEAR PROFILE...POSSIBLY WEAKENING INTO A TROPICAL WAVE THIS
WEEKEND. THE 12Z RUNS OF THE GFS AND ECMWF SHOW A SOLUTION SIMILAR
TO THIS WITH AN OPEN WAVE PASSING OVER THE KEYS AND SOUTHERN FL
PENINSULA ON SUNDAY THEN ENTERING THE GULF BY EARLY NEXT WEEK
WHERE IT BECOMES MOSTLY STATIONARY. EVEN IF THE 12Z RUNS PLAY OUT
AND THE LOW MOVES INTO THE GOMEX THE LOCAL AREA COULD STILL SEE
ISSUES WITH HEAVY RAINFALL AND FLOODING AS MOIST TROPICAL AIRMASS
ON THE EAST SIDE OF THE LOW BLANKETS THE FL PENINSULA. CONFIDENCE
IN THE TRACK...STRENGTH...AND TIMING SHOULD INCREASE THROUGHOUT
THE WEEKEND AT WHICH POINT ACTUAL IMPACTS FOR THE LOCAL AREA CAN
BE ESTABLISHED. UNTIL THEN...IT IS IMPORTANT TO CONTINUE TO
MONITOR T.S ERIKA AND ITS PROGRESSION.

WITH LITTLE CONFIDENCE IN THE LONG TERM HAVE KEPT THE FORECAST IN
THIS PERIOD CONSISTENT WITH PREVIOUS ISSUANCE. ELEVATED RAIN
CHANCES BEGIN ON MONDAY AND CONTINUE THROUGH THE
WEDNESDAY/THURSDAY TIME FRAME WITH HIGHEST CHANCES IN COASTAL
AREAS AND ACROSS NE FL. BREEZY NORTHEASTERLY WINDS WILL BEGIN ON
MONDAY WITH HIGHER WINDS CLOSER TO THE CENTER OF THE LOW WHICH
WHERE THE ACTUAL CENTER WILL BE IS UP IN THE AIR AT THIS TIME.
CLOUD SHIELD IN PLACE SHOULD KEEP TEMPS DOWN INTO THE MID/UPPER
80S EACH DAY AND LOWS IN THE MID 70S.

&&

.AVIATION...
TEMPO MVFR CONDITIONS...WITH POSSIBLE BRIEF IFR VISIBILITIES...ARE
POSSIBLE THROUGH AROUND SUNSET AT THE DUVAL COUNTY
TERMINALS...GNV...AND SSI AS SLOW MOVING THUNDERSTORMS POTENTIALLY
BRING WIND GUSTS UP TO 30 KNOTS AND HEAVY DOWNPOURS. OCCASIONAL
MVFR CIGS ARE POSSIBLE THROUGH SATURDAY AT SGJ...ALTHOUGH
THUNDERSTORM ACTIVITY WILL LIKELY AVOID THAT TERMINAL THROUGH AT
LEAST 00Z. KEPT VICINITY SHOWERS IN THE TAFS OVERNIGHT...ALTHOUGH
VFR CONDITIONS SHOULD PREVAIL AT MOST TERMINALS AFTER 00Z.
OUTSIDE OF THUNDERSTORM ACTIVITY...MOSTLY EAST WINDS NEAR 10 KNOTS
WILL DECREASE AT VQQ AND GNV OVERNIGHT...AND WILL PERSIST AT
SSI...CRG...AND SGJ.

&&

.MARINE...
AS HIGH PRESSURE BUILDS TO THE NORTH OF OUR REGION...ONSHORE
WINDS WILL INCREASE TO NEAR 15 KNOTS TONIGHT. SEAS WILL BUILD TO
3-4 FT RANGE TONIGHT AND SATURDAY. AS OUR GRADIENT TIGHTENS LATE
THIS WEEKEND WITH THE POTENTIAL APPROACH OF ERIKA TOWARDS THE FL
PENINSULA...ONSHORE WINDS WILL INCREASE TO NEAR 20 KNOTS WITH
SEAS BUILDING TO 5-8 FT BY LATE SUNDAY. TIMING OF THESE INCREASES
REMAINS UNCERTAIN AND ARE PREDICATED ON THE LOCATION AND INTENSITY
OF ERIKA...BUT A SMALL CRAFT ADVISORY MAY BE REQUIRED BY SUNDAY
AFTERNOON OR EVENING. 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: ELEVATED RISK ANTICIPATED THIS WEEKEND INTO NEXT
WEEK DUE TO PERSISTENT ONSHORE WINDS AND BUILDING SEAS.

SURF ZONE/TIDES: FULL MOON THIS SATURDAY...COMBINED WITH DEEPENING
ONSHORE WINDS WILL ENHANCE ALREADY ELEVATED TIDAL LEVELS ALONG
THE COAST...BUT COASTAL FLOODING IS NOT EXPECTED AT THIS TIME.

&&

.HYDROLOGY...
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 NEAR OR OVER
THE FLORIDA PENINSULA...POSSIBLY BRINGING AN EXTENDED PERIOD OF
HEAVY DOWNPOURS TO OUR REGION FOR MUCH OF NEXT WEEK. WE HIGHLIGHTED
THIS THREAT THIS MORNING IN A HYDROLOGIC OUTLOOK PRODUCT...WITH
THE THREAT FOR MAJOR FLOODING OCCURRING INITIALLY ON FAST RISING
TRIBUTARIES SUCH AS BLACK CREEK AND THE UPPER SANTA FE
RIVER...WHICH ALREADY HAVE ENHANCED FLOWS LEADING INTO THIS
POTENTIAL EVENT.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  72  89  73  89 /  20  60  30  60
SSI  76  87  76  85 /  50  60  40  60
JAX  72  89  74  87 /  40  60  30  60
SGJ  75  87  77  86 /  40  60  30  60
GNV  71  89  73  89 /  20  60  20  60
OCF  72  89  73  89 /  30  70  20  60

&&

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

$$

GUILLET/NELSON/WALSH/KENNEDY



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.