Area Forecast Discussion
Issued by NWS Jacksonville, FL

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000
FXUS62 KJAX 060802
AFDJAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
355 AM EDT WED MAY 6 2015

...BREEZY WITH PASSING SHOWERS GENERALLY ALONG AND EAST OF THE
ST. JOHNS RIVER BASIN THROUGH THU WITH WARMER AND MOSTLY DRY
CONDITIONS INLAND...

.NEAR TERM...TODAY THROUGH THU...

SYNOPSIS...00Z MODEL GUIDANCE IN GOOD AGREEMENT WITH THE NAM12 MODEL
SHIFTING ITS SOLUTION OF THE SUB-TROPICAL LOW DEVELOPING NEAR THE
BAHAMAS FARTHER EAST...MORE IN LINE WITH THE GFS/ECMWF SOLUTIONS.
MODEL CONSENSUS TRACKS THE STORM CENTER NORTHWARD WELL OFFSHORE OF
THE FL ATLANTIC COASTLINE THROUGH THU THEN MORE SLOWLY NORTHWARD
TOWARD THE CAROLINA COAST INTO THE WEEKEND. THE MAIN LOCAL HAZARDS
FROM THIS SYSTEM WILL BE FREQUENT RIP CURRENTS...ELEVATED SURF AND
SMALL CRAFT ADVISORY CONDITIONS OFFSHORE.

TODAY...BREEZY/WINDY ONSHORE FLOW WILL BRING WAVES OF BROKEN CLUSTERS
OF COASTAL SHOWERS INLAND WITH GRADUAL EROSION AS ACTIVITY INTERACTS
WITH DRIER AIR INLAND. COULD SEE A FEW ISOLATED STORMS OFFSHORE AND
ALONG THE ST JOHNS/FLAGLER COASTS LATER THIS MORNING...THEN ISOLATED
TS POTENTIAL SHIFTS FARTHER INLAND OVER NE FL GENERALLY FROM JAX
TO GNV SOUTHWARD INTO THE AFTERNOON HOURS WHERE DIURNAL INSTABILITY
INCREASES AS COOLER 500 MB TEMPS OF -11 TO -13 DEG C ROTATE OVERHEAD
ASSOCIATED WITH BROAD UPPER LEVEL LOW. RAINFALL ACTIVITY WILL DECREASE
FROM WEST TO EAST INTO THE EVENING AS THE SURFACE LOW LIFTS NWD FROM
THE BAHAMAS TO APPROXIMATELY 200-250 MILES EAST OF ST AUGUSTINE WHICH
WILL BACK LOCAL WINDS FROM THE NE TO N GRADUALLY SHUNTING PRECIP ACTIVITY
FARTHER EASTWARD AND OFFSHORE. HIGH TEMPS WILL WARM INTO THE LOW TO
MID 80S INLAND TO MID 70S COAST UNDER FRESH NE WINDS 20 MPH WITH GUSTS
TO 30 MPH.

TONIGHT...THE SFC LOW WILL CONTINUE TO TRACK NWD OFFSHORE OF THE
FL/GA ATLANTIC COAST WHICH WILL BACK LOW LEVEL WINDS TO THE NNW.
THIS PATTERN WILL ENABLE DRIER AIR FROM THE NW TO FUNNEL SOUTHWARD
AND DECREASE RAINFALL POTENTIAL ACROSS NE FL EVEN ALONG THE COAST.
TEMPS WILL COOL INTO THE LOW 60S INLAND TO MID/UPPER 60S TOWARD
THE ATLANTIC COAST UNDER LIGHTER NW WINDS 5-10 MPH INLAND TO 10-15
MPH COAST AFTER MIDNIGHT.

THU...A GORGEOUS DAY EXPECTED UNDER DRY AND BREEZY NW FLOW. A LOW
CHANCE 20-30% OF SHOWERS WAS ADVERTISED FOR MAINLY COASTAL SE GA
WHERE SOME LOW LEVEL MOISTURE WILL INFILTRATE FROM THE
N...OTHERWISE DRY AIR FROM THE NW AND INCREASED SUBSIDENCE WILL
GREATLY LIMIT CONVECTION. HIGH TEMPS WILL WARM INTO THE MID/UPPER 80S
INLAND TO LOWER 80 COAST.

.SHORT TERM...THU NIGHT AND FRI...

THU NIGHT...SUBTROPICAL LOW PRES SYSTEM EXPECTED TO BE ENE OF THE
FORECAST REGION SOME 250 TO 300 MILES FROM JAX WITH A GENERALLY NWD
MOTION COMPONENT. PREVAILING NW FLOW LOW LEVEL EXPECTED WITH
GENERALLY DRY CONDITIONS...THOUGH GFS AND SREF ENSEMBLE SOLUTIONS
SHOW PWATS INCREASING FROM THE N AS A SLUG OF MOISTURE HEADS SWD
FROM SC AND ERN GA. THE EURO SHOWS A HINT OF THIS TOO. THUS WILL
RETAIN SOME SLIGHT RAIN SHOWER CHANCE FOR THE NERN QUARTER OF THE
FORECAST AREA. LOWS WILL BE IN THE 60S.

FRIDAY...THE SFC LOW DEPICTED BY MOST 00Z GUIDANCE CONTINUES TO
WOBBLE NWD WHILE NAM AND GFS SHOW BROAD SFC TROUGH EXTENDING SW OVER
THE COASTAL WATERS AND INTO NERN FL AND EXTREME SE GA. COMBINATION
OF PWATS NEARING 1.3 INCHES AND BOUNDARY LAYER DESTABILIZATION...SFC
TROUGH AND SEA BREEZES EXPECTED TO RESULT IN A ISOLD TO POSSIBLY SCT
SHOWERS AND TSTMS IN THE AFTN. BASED ON SOUNDING GUIDANCE...DECIDED
TO CAP POPS IN THE ERN ZONES IN THE LOWER END OF THE LATEST MOS
GUIDANCE OF 25-30%. HIGHS IN THE MID 80S EXPECTED. BY FRI
NIGHT...ONLY ISOLD COVERAGE OF CONVECTION IN THE EVENING WITH
OVERNIGHT LOWS A BIT HIGHER IN THE MID 60S.

.LONG TERM...SATURDAY THROUGH TUESDAY...

DURING THE WEEKEND WEAK HIGH PRES EXPECTED TO REMAIN NEARLY
STATIONARY ACROSS CENTRAL FL WHILE MEAN LOW LEVEL FLOW REMAINS SW TO
S. AS ANY LOW PRES SYSTEM NEAR THE CAROLINAS LIFTS GENERALLY
NWD...HEIGHTS EXPECTED TO RISE WITH 850 MB TEMPS WARMING. THUS
SHOULD SEE A GOOD CHANCE OF HIGHER MAX TEMPS...WITH MID TO UPPER 80S
LIKELY...WITH 90 DEG READINGS FCST ON SUNDAY FOR INLAND AREAS. W AND
E COAST SEAS BREEZES LIKELY BUT LOW LEVEL MOISTURE IS GENERALLY
LACKING SO AT BEST THINK ISOLD AFTN CONVECTION WOULD
DEVELOP...MAINLY FOR THE ERN ZONES. LOWS FCST TO BE MID 60S TO
AROUND 70 THROUGHOUT EXTENDED PERIOD.

MONDAY...MORE PERSISTENCE WITH BROAD 500 MB RIDGING ALOFT. WARM
TEMPS AND MAINLY DRY CONDS WITH HIGHS IN THE UPPER 80S TO AROUND 90.
PERHAPS A RELIEF FOR THE NE FL/SE GA BEACHES AS SEA BREEZE DEVELOPS
INT EH AFTN GIVING HIGHS IN THE MID 80S. ONLY ISOLD CONVECTION FCST
AT THIS TIME FOR AFTN HOURS...WHICH SHOULD FADE IN THE EVENING HOURS.

TUESDAY...MID TO UPPER LEVEL RIDGE ALOFT FCST TO WEAKEN AND SHIFT
SWD TO SEWD AS SHORTWAVE TROUGHS LEAD TO INCREASED CONVECTIVE
POTENTIAL ACROSS THE SE STATES. AN ASSOCD SFC COLD FRONT EXPECTED TO
PUSH INTO GA BY LATE TUE/TUE NIGHT. BEST FORCING AND MOISTURE
APPEARS TO REMAINS TO OUR NW AND N SO WILL MAINTAIN LOW POPS...ABOUT
20 PERCENT FOR NOW. TEMPS CONTINUE WARM IN THE MID 80S TO ABOUT 90
WITH LIGHT W-SW FLOW.

&&

.AVIATION...

WAVES OF MVFR CIGS WILL CONTINUE IN SHOWER ACTIVITY TODAY AS IT
MOVES INLAND FROM THE ATLANTIC UNDER BREEZY NE WINDS WITH GUSTS UP
TO 25 KTS BY MID-MORNING. LOCALLY HEAVY BUT BRIEF POCKETS OF
HEAVY RAINFALL COULD BRING TEMPO IFR. THIS AFTERNOON WINDS WILL
BEGIN TO BACK N THEN NW TONIGHT WITH DRIER AIR FILTERING IN AND
DECREASING RAINFALL POTENTIAL ACROSS NE FL SITES.

&&

.MARINE...

SMALL CRAFT ADVISORY CONDITIONS EXPECTED TODAY FOR BOTH NEAR AND
OFFSHORE WATERS AS THE PRESSURE GRADIENT STRENGTHENS IN RESPONSE
OT LOW PRESSURE DEVELOPING NEAR THE BAHAMAS. INCLUDED OCCASIONAL
GUSTS TO GALE FORCE OVER THE OUTER WATERS THIS EVENING AS SURFACE
LOW MAKES ITS CLOSEST PASS...BUT STILL BEYOND 200 NM OFFSHORE. WINDS
WILL RELAX OVER THE NEARSHORE WATERS TONIGHT WHILE BACKING NNW AS
THE LOW TRACKS NNE OF THE LOCAL AREA INTO THU...HOWEVER ELEVATED
WINDS AND SEAS WILL CONTINUE OVER THE OFFSHORE WATERS. WINDS RELAX
LATE THU HOWEVER WAVES WILL REMAIN ELEVATED AS NNE SWELLS CONTINUE
FROM THE LOW FORECAST TO LINGER NEAR THE BAHAMAS INTO THE WEEKEND.

RIP CURRENTS:

MODERATE RISK TODAY AND THU. WILL NEED TO MONITOR BEACH REPORTS
TODAY FOR POTENTIAL OF ELEVATING RIP CURRENT RISK TO HIGH.

&&

.HYDROLOGY...

MINOR TO MODERATE FLOODING ON PORTIONS OF THE ALTAMAHA RIVER WILL
CONTINUE THROUGH THE END OF THE WEEK. RECENT OBSERVATIONS INDICATED
MINOR FLOODING ALONG THE LITTLE SATILLA RIVER NEAR OFFERMAN.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  84  61  84  62 /  10  10  10  10
SSI  77  65  79  63 /  20  20  30  20
JAX  81  63  84  63 /  30  20  20  20
SGJ  78  65  82  65 /  50  20  20  20
GNV  84  61  86  61 /  20  20  10  10
OCF  86  63  87  62 /  30  20  10  10

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THURSDAY FOR WATERS FROM
     ALTAMAHA SOUND GA TO FERNANDINA BEACH FL FROM 20 TO 60 NM-
     WATERS FROM FERNANDINA BEACH TO ST. AUGUSTINE FL FROM 20 TO
     60 NM-WATERS FROM ST. AUGUSTINE TO FLAGLER BEACH FL FROM 20
     TO 60 NM.

     SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR COASTAL
     WATERS FROM ALTAMAHA SOUND TO FERNANDINA BEACH FL OUT 20 NM-
     COASTAL WATERS FROM FERNANDINA BEACH TO ST. AUGUSTINE FL
     OUT 20 NM-COASTAL WATERS FROM ST. AUGUSTINE TO FLAGLER
     BEACH FL OUT 20 NM.

&&

$$

ENYEDI/SHASHY


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