National Weather Service Weather Forecast Office

Area Forecast Discussion

819
FXUS62 KJAX 021857
AFDJAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
257 PM EDT WED OCT 2 2013

.CURRENTLY...
AFTERNOON SURFACE ANALYSIS DEPICTS HIGH PRESSURE (1022 MILLIBARS)
HIGH PRESSURE (1020 MILLIBARS) COVERING THE SOUTHEASTERN UNITED
STATES. ALOFT...STACKED RIDGING PREVAILS FROM THE SOUTHEASTERN
STATES SOUTHWARD TO CUBA. A SLIGHTLY TIGHTER LOCAL PRESSURE
GRADIENT HAS INCREASED NORTHEASTERLY WINDS TO 10-15 MPH...WHICH
HAS ADVECTED A DECENT CUMULUS FIELD ONSHORE INTO NORTHEAST FL.
MOSTLY SUNNY SKIES PREVAILED OVER SOUTHEAST GA. TEMPERATURES
RANGED FROM THE MID 80S INLAND TO NEAR 80 ALONG THE COAST.
DEWPOINTS REMAIN COMFORTABLE...IN THE UPPER 50S TO THE MID 60S.

.SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)...
ANOTHER NIGHT OF RADIATIONAL COOLING IS ANTICIPATED INLAND AS
STACKED RIDGING REMAINS IN PLACE LOCALLY. A HIGH CIRRUS
SHIELD...THE OUTFLOW FROM INVEST 97L NEAR MEXICO`S YUCATAN
PENINSULA...SHOULD MOVE OVER NORTHEAST FL LATER TONIGHT.
HOWEVER...THIS WILL HAVE LITTLE IMPACT ON LOW TEMPS. NEAR OR
SLIGHTLY BELOW CLIMO LOWS ARE ANTICIPATED INLAND...WITH UPPER 50S
OVER INTERIOR SOUTHEAST GA...RANGING TO THE MID 60S OVER NORTH
CENTRAL FL. A LIGHT ONSHORE WIND WILL KEEP LOWS IN COASTAL
LOCATIONS NEAR 70 DEGREES.

DRY AIR ALOFT WILL PERSIST OVER SOUTHEAST GA ON THURS AS STACKED
RIDGING ONLY SLOWLY SINKS SOUTHWARD. DEEP LAYERED MOISTURE
ADVECTING NORTHWARD IN ADVANCE OF INVEST 97L MAY INCREASE ENOUGH
OVER NORTH CENTRAL FL ON THURS AFTERNOON TO DEVELOP A FEW LOW-
TOPPED SHOWERS. KEPT ISOLATED SHOWER CHANCES ON THURS AFTERNOON
CONFINED TO MARION COUNTY. OTHERWISE...EXPECT HIGH CIRRUS TO
THICKEN FROM SOUTH TO NORTH DURING THE DAY AS INVEST 97L MOVES
INTO THE SOUTHERN GULF OF MEXICO. NEAR OR SLIGHTLY ABOVE CLIMO
HIGHS WILL CONTINUE...WITH READINGS RANGING FROM THE MID/UPPER 80S
INLAND TO THE LOWER 80S AT THE COAST. INCREASED MID AND HIGH
ALTITUDE CLOUDS ON THURS NIGHT WILL KEEP LOWS ABOUT 5 DEGREES
WARMER THAN TONIGHT`S READINGS. ANY LATE AFTERNOON SHOWER ACTIVITY
OVER MARION COUNTY WILL QUICKLY FADE TOWARDS SUNSET.

.LONG TERM (FRIDAY THROUGH WEDNESDAY)...

FRI & FRI NIGHT...EXPECTED FILTERED SUNLIGHT OVER MUCH OF NE FL
AS ABUNDANT HIGH CLOUDINESS INCREASES FROM THE WSW WHILE INVEST
97L TRACKS NORTHWARD OVER THE CENTRAL GULF OF MEXICO. PARTLY
CLOUDY SKIES ARE EXPECTED OVER SE GA. MAX TEMPS WILL RANGE FROM
THE LOW TO MID 80S UNDER EASTERLY FLOW AND ONLY A LOW 20% CHANCE
OF SHOWERS IS FORECAST OVER NE FL. ADJUSTED LOW TEMPS FRI NIGHT
INTO THE LOW 60S FOR INLAND SE GA TO MID/UPPER 60S NE FL AS CLOUDS
INCREASE FROM THE SSW.

SAT & SUN...LATEST 12Z GFS GUIDANCE WAS MUCH STRONGER IN
DEVELOPING INVEST 97L AS IT APPROACHES THE FL PANHANDLE
SAT...WHILE THE ECMWF AND NAM CONTINUED TO BE WEAKER AND FARTHER
WEST WITH THE STORM AS IT NEARS THE MS/LA COAST. THERE IS STILL
MUCH UNCERTAINTY WITH THE FORECAST EVOLUTION AND TRACK OF
97L...AND LOCAL INTERESTS SHOULD CONTINUE TO MONITOR THE LATEST
OFFICIAL FORECAST INFORMATION FROM THE NATIONAL HURRICANE CENTER &
LOCAL NATIONAL WEATHER SERVICE OFFICES. FOR NOW...THE ONLY CHANGE
TO THE EXTENDED FORECAST WAS TO DECREASE RAIN CHANCES SLIGHTLY SAT
AND SAT NIGHT WITH STACKED RIDGING EXPECTED TO HOLD A BIT LONGER
TO OUR NE WITH LOW 20% RAIN CHANCES ADVERTISED OVER OUR COASTAL GA
ZONES SAT TO 50% BY SAT AFTN OVER OUR INLAND SE GA ZONES AND THE
SUWANNEE RIVER VALLEY. LOWERED MAX TEMPS SAT INTO THE LOW/MID 80S
UNDER MOSTLY CLOUDY SKIES AS MULTI-LAYERED CLOUDINESS CONTINUES TO
INCREASE.

SUN & MON...MOISTURE ASSOCIATED WITH THE LOW AS IT TRACKS NNE OF
THE AREA WILL LINGER OVER THE AREA...WITH A TRAILING COLD FRONT
EXPECTED TO PRESS SOUTH OF THE AREA LATE MONDAY WHICH WILL BRING A
CHANCE OF STRONG TSTMS. PERIODS OF LOCALLY HEAVY RAINFALL WILL BE
POSSIBLE...AND AT THIS TIME THE WEATHER PREDICTION CENTER
ADVERTISED WIDESPREAD 7-DAY RAINFALL (TODAY THROUGH WED 10/9)
AMOUNTS OF 0.5 INCHES WITH LOCALLY HIGHER AMOUNTS ESPECIALLY OVER
INLAND SE GA AND THE SUWANNEE RIVER VALLEY OF NE FL WHERE MOST
RAINFALL WILL OCCUR LATE SAT THROUGH LATE MON. WILL CONTINUE WITH
THE ONGOING FORECAST OF 40-50% RAIN CHANCES SUN...DECREASING TO
30-40% ON MON.

DRIER AIR IS EXPECTED TO FILTER IN FROM THE WNW TRAILING THE
FRONTAL PASSAGE TUE & WED AS HIGH PRESSURE BUILDS FROM THE MID MS
RIVER VALLEY TOWARD THE NE. EXPECT A DECREASE IN RAIN CHANCES
BELOW 15% AND NEAR TO SLIGHTLY ABOVE NORMAL TEMPS WITH LOWS IN THE
60S AND HIGHS IN THE 80S.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL AT THE REGIONAL TERMINALS. NORTHEAST
TO EAST WINDS OF 10 TO 15 KNOTS FROM JUST OFF THE SURFACE UP
THROUGH 2000 FEET WILL THEN DECREASE TO NEAR 10 KNOTS AFTER 00Z.

&&

.MARINE...
NORTHEAST WINDS IN THE 10-15 KT RANGE WILL GRADUALLY DIMINISH THIS
EVENING. HIGH PRESSURE WILL REMAIN ANCHORED TO THE NORTH OF OUR
REGION INTO THE UPCOMING WEEKEND...WHILE LOW PRESSURE (POTENTIAL
TROPICAL CYCLONE) MOVES INTO THE SOUTHERN GULF OF MEXICO ON THURS.
THIS SYSTEM IS EXPECTED TO MOVE NORTHWARD TOWARDS THE CENTRAL GULF
COAST STATES OR THE FL PANHANDLE THIS WEEKEND. HEADLINES ARE NOT
ANTICIPATED THROUGH AT LEAST SATURDAY. SOUTHEAST TO SOUTHERLY
WINDS MAY APPROACH CAUTION SPEEDS BY LATE IN THE WEEKEND...BUT
SEAS SHOULD REMAIN IN THE 3-5 FT RANGE.

RIP CURRENTS: LONG PERIOD EASTERLY SWELLS AND ONSHORE WINDS WILL
MAINTAIN A MODERATE RISK OF RIP CURRENTS AT AREA BEACHES THROUGH
THURSDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  58  86  62  86 /   0  10  10  10
SSI  66  82  68  82 /   0  10  10  20
JAX  62  84  65  85 /   0  10  10  20
SGJ  69  83  70  83 /   0  10  10  20
GNV  63  86  66  86 /  10  10  10  20
OCF  65  87  68  86 /  10  20  20  20

&&

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

$$

NELSON/ENYEDI/GUILLET