Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 281846
AFDJAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
246 PM EDT MON JUL 28 2014

...HEAT ADVISORY WITH A SLIGHT RISK OF SEVERE TSTORMS...

.SHORT TERM...THIS AFTN AND TONIGHT...

SMALL QUICK MOVING SHOWERS WILL CONTINUE TO PUSH EAST ACROSS NORTHEAST
FL THROUGH THE EARLY EVENING WITH A RECENT INCREASE IN TSTORM ACTIVITY
NOTED WITH THE WEST COAST SEA BREEZE STARTING TO SHIFT INLAND OVER
THE SUWANNEE RIVER VALLEY. STORMS OVER FL WILL BE CAPABLE OF PRODUCING
GUSTY WINDS OF 30-40 MPH AS WELL AS FREQUENT LIGHTNING AS THEY
TRACK OFF TOWARD THE EAST AROUND 20 MPH.

JUST NORTH OF THE ALTAMAHA RIVER BASIN SHOWERS AND ISOLD TSTORMS
STARTED TO BREAK OUT AHEAD OF AN APPROACHING FRONTAL ZONE. THIS
ACTIVITY IS EXPECTED TO INCREASE IN COVERAGE AND INTENSITY AS IT
NEARS THE ALTAMAHA RIVER BASIN THROUGH 00Z...WITH A GRADUAL
DECREASE IN COVERAGE AND INTENSITY THROUGH THE NIGHT AS SHEARED
OUT PRE- FRONTAL DYNAMICS AND MOISTURE SHIFT SOUTHWARD OVER NE FL.
THE LIMITING FACTOR FOR CONVECTION TODAY AND TONIGHT IS DEEP LAYER
MOISTURE...AND THUS CONTINUED TO CAP RAIN CHANCES IN THE 30-40%
RANGE FOR MOST AREAS THROUGH TONIGHT EXCEPT FOR A SWATH OF 50-60%
NEAR THE ALTAMAHA RIVER BASIN THIS EVENING. GIVEN THE PRESENCE OF DRY
POCKETS IN THE LOW/MID LEVELS AND INCREASED SHEAR...THERE REMAINS
A SLIGHT CHANCE OF SEVERE STORMS CAPABLE OF PRODUCING STRONG
DOWNBURSTS AND EVEN HAIL ESPECIALLY ACROSS SE GA LATE THIS AFTN
INTO THE EARLY EVENING HOURS. A FEW STRONG CELLS WILL ALSO BE
POSSIBLE OVER NE FL THROUGH THE LATE AFTN.

HEAT INDICES RANGED FROM GENERALLY BETWEEN 105-110 DEG THIS AFTN...WITH
A DRY BULB READING OF 100 DEG AT WAYCROSS TO EVEN 95 DEG AT SSI UNDER
A VERY WARM AND BREEZY WEST WIND. THE HEAT ADVISORY LOOKS REASONABLE
AND WILL LEAVE IN PLACE THROUGH 7 PM EDT. DRIER AIR WILL FILTER IN
FROM THE NW TRAILING THE FRONT TONIGHT OVER OUR EXTREME NW GA
ZONES NEAR HAZLEHURST AND PLANT HATCH WITH DEW PTS IN THE MID/UPPER
60S BY DAYBREAK TUE...BUT TEMPS WILL REMAIN RATHER WARM WITH MINS
IN THE LOW/MID 70S INLAND TO UPPER 70S RIVER/COAST UNDER PARTLY TO
AT TIMES MOSTLY CLOUDY SKIES THE FRONTAL BOUNDARY PRESSES
SOUTHWARD OVER THE FORECAST AREA.

TUESDAY THROUGH THURSDAY...

THE COLD FRONT WILL BECOME QUASI-STATIONARY OVER NORTHERN FLORIDA ON
TUESDAY. SIGNIFICANTLY DRIER MID TO UPPER LEVEL AIR NORTH OF THIS
FRONT WILL BRING AN END TO PRECIP ACROSS SOUTHEAST GEORGIA. MOISTURE
LEVELS WILL REMAIN SUFFICIENT ALONG AND SOUTH OF THIS BOUNDARY TO
SUPPORT SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. THE HIGHEST
CHANCES WILL BE SOUTH OF A LINE FROM GAINESVILLE TO ST AUGUSTINE.
UPPER LEVEL SUPPORT WILL BE GREATLY LACKING BUT INSTABILITY AND
MOISTURE WILL BE ADEQUATE FOR PERHAPS AN ISOLATED PULSE STRONG TO
SEVERE STORM ACROSS OUR SOUTHERN ZONES ON TUESDAY. DRY UPPER LEVEL
AIR WILL CONTINUE TO FILTER SOUTH DURING THE DAY AND EVENTUALLY
BRING AN END TO ALL PRECIP CHANCES ACROSS ALL OF OUR ZONES EARLY
TUESDAY EVENING. COOLER TEMPS WILL PREVAIL TUESDAY NIGHT WITH TEMPS
DIPPING DOWN INTO THE MID 60S AT MANY LOCALES WELL
INLAND...PARTICULARLY ACROSS OUR INLAND GEORGIA COUNTIES.

ON WEDNESDAY...ALTHOUGH WEAK CYCLONIC FLOW WILL PREVAIL WITH
BROAD TROUGHING CENTERED OVER THE FORECAST AREA...SIGNIFICANT DRY
AIR IN THE MID AND UPPER LEVELS WILL SUPPRESS ACTIVITY. AS A
RESULT...MOSTLY SUNNY AND DRY CONDITIONS WILL PREVAIL. TEMPS WILL
MAX OUT IN THE LOW TO MID 90S BUT SOME MUCH DRIER AIR WILL MIX
DOWN TO THE SURFACE AND IT WILL NOT BE NEARLY AS HUMID. LOWS
WEDNESDAY NIGHT WILL DROP INTO THE UPPER 60S TO LOWER 70S...A
LITTLE BELOW NORMAL...BUT AGAIN NOT NEARLY AS MUGGY AS RECENT
DAYS.

ON THURSDAY...THE SURFACE TROUGH WILL SHIFT TO OUR WESTERN ZONES
AND MOISTURE LEVELS WILL REBOUND SLIGHTLY TO BRING A RETURN TO A
LOW CHANCE OF THUNDERSTORMS...MAINLY ALONG THE ATLANTIC COAST
SEABREEZE AS IT MOVES INLAND DURING THE DAY.

.LONG TERM /FRIDAY THROUGH MONDAY/...

NO CHANGES TO THIS PART OF THE FORECAST AS THE MODELS REMAIN IN
PRETTY GOOD AGREEMENT THAT THE SRN EXTENT OF MID TO UPPER LEVEL
TROUGH ACROSS GA AND THE CAROLINAS WILL SHIFT WESTWARD TO SRN MS
VALLEY WHICH WILL TRANSITION DEEP LAYER MEAN FLOW TO THE SW. AT
THE SAME TIME...MOISTURE LEVELS WILL INCREASE AND TEMPS ALOFT MAY
COOL A COUPLE OF DEGREES. THIS ALL INDICATES A RETURN TO A MORE
UNSETTLED WEATHER PATTERN...ESPECIALLY SAT THROUGH MON WITH THE W
COAST SEA BREEZE THE DOMINATE BOUNDARY HELPING TO FOSTER AT LEAST
SCATTERED DAILY CONVECTION. MAX/MIN TEMPS WILL BE NEAR NORMAL
DURING THIS PERIOD. SOME HEAVIER PRECIP PERIODS WILL BE POSSIBLE
SAT THROUGH MONDAY DUE TO SHORTWAVES ROTATING THROUGH THE BASE OF
THE MID TO UPPER LEVEL TROUGH.

&&

.AVIATION...PREVAILING VFR EXPECTED THIS AFTN AT ALL TERMINALS
WITH MOST CLOUD BASES JUST ABOVE 3 KFT. COULD SEE TEMPO MVFR CIGS
ASSOCIATED WITH SHOWER AND ISOLATED TS ACTIVITY AND ADVERTISED
VCSH ALL ZONES BETWEEN NOW AND 20Z WITH TEMPO MVFR. SSI WILL HAVE
THE BEST CHANCE OF AN EVENING TS AND CONTINUED WITH VCTS AT 22Z.
EAST COAST SEA BREEZE NOT EXPECTED WITH SW WINDS PREVAILING EVEN
AT SSI AND CRG. OVERNIGHT FRONT WILL SHIFT SOUTH OVER THE
TERMINALS AND POSITION NEAR THE FL-GA STATE LINE EARLY TUE
MORNING. THIS COULD BRING SOME LOW STRATUS TO THE FL TAF
SITES...AND FOR NOW INDICATED SCT 1-1.5 KFT IN THE TAFS WITH VCSH
AROUND 07-13Z. BEST CHANCES OF PRECIP TUE WILL BE AT GNV AS THE
FRONT SHIFTS SOUTHWARD THROUGH THE DAY.

&&

.MARINE...SW WINDS WILL REMAIN ELEVATED OVER THE WATERS TONIGHT AS
FRONTAL ZONES SHIFTS SOUTHWARD. WILL CARRY SMALL CRAFT EXERCISE
CAUTION OFFSHORE LEGS WITH A SOLID 15 KTS NEARSHORE. CAPPED SEAS A
3-4 FT OFFSHORE 2-3 FT NEARSHORE BASED ON OFFSHORE FLOW. WINDS
WILL RELAX LATE TUE AS THE FRONT SHIFTS SOUTH OF THE WATERS AND
LIGHT ONSHORE FLOW DEVELOPS WED-FRI WITH EASTERLY FLOW 10-15 KTS.
WINDS VEER SOUTHERLY NEXT WEEKEND AS A LOW DEVELOPS OVER THE GULF
COAST REGION.

RIP CURRENTS: LOW RISK TODAY AND TUE.

&&

.CLIMATE...MORNING LOWS AT ALMA (AMG) AND GAINESVILLE (GNV) SET
RECORD HIGH MINIMUMS FOR THE DATE.

SITE NEW RECORD OLD RECORD/YEAR
AMG 78 76/2011
GNV7776/1992

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  73  90  65  93 /  60   0  10  10
SSI  76  91  74  89 /  50  10  10  10
JAX  75  92  71  92 /  30  30  10  10
SGJ  77  91  74  90 /  30  50  20  10
GNV  75  92  69  93 /  30  50  20  10
OCF  75  92  71  94 /  30  60  30  10

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR BAKER-CLAY-
     COLUMBIA-DUVAL-FLAGLER-HAMILTON-NASSAU-PUTNAM-ST JOHNS-
     SUWANNEE.

GA...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR APPLING-ATKINSON-
     BACON-BRANTLEY-CHARLTON-CLINCH-COASTAL CAMDEN-COASTAL GLYNN-
     COFFEE-ECHOLS-INLAND CAMDEN-INLAND GLYNN-JEFF DAVIS-PIERCE-
     WARE-WAYNE.

AM...NONE.
&&

$$

ENYEDI/SHULER/






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