Area Forecast Discussion
Issued by NWS Jacksonville, FL

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000
FXUS62 KJAX 201849
AFDJAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
148 PM EST SAT DEC 20 2014

...WIDESPREAD RAINFALL EXPECTED LATE SUNDAY THROUGH EARLY WED...

.NEAR TERM /THROUGH TONIGHT/...

REST OF THIS AFTERNOON/EVENING...LIGHT SHOWER ACTIVITY ACROSS SE GA
ASSOCD WITH ISENTROPIC LIFT CONTINUES TO FADE AND EXPECT JUST PARTLY
TO MOSTLY CLOUDY SKIES ACROSS SE GA/NE FL THROUGH SUNSET. WIDE RANGE
OF TEMPS FROM CLOSE TO 60 DEGREES ACRS SE GA TO WELL INTO THE
60S/LOWER 70S ACROSS NE FL WHERE MORE SUNNY BREAKS HAVE OCCURRED.

REST OF TONIGHT...NEXT WAVE OF ISENTROPIC LIFT WILL BEGIN TO SET
IN...MAINLY AFTER MIDNIGHT WITH LIGHT RAINFALL IN SHOWER ACTIVITY
CENTERED ALONG THE FL/GA BORDER AND POINTS NORTH ACROSS SE GA
ALTHOUGH BETTER CHANCES (20-30%) EXIST TONIGHT TO SEE SOME LIGHT
MEASURABLE AMOUNTS OF PCPN ACRS NE FL AS WELL. THE ABUNDANT CLOUD
COVER WILL PREVENT MUCH IN THE WAY OF ANY SIGNIFICANT FOG BUT
THROUGH THE EVENING AND OVERNIGHT HOURS EXPECT A LOW OVERCAST DECK
TO DEVELOP ALONG WITH THE SLIGHT INCREASE IN SHOWER ACTIVITY FOR ALL
AREAS...AND IF ANY SIGNIFICANT FOG DOES TRY TO DEVELOP IT WILL AT
THE SOUTH END OF THE OVERCAST DECK IN THE REGION FROM OCALA EAST TO
PALM COAST AND ACROSS THE OCALA NATIONAL FOREST.

.SHORT TERM /SUN-WED/...

SUNDAY...ISENTROPIC LIFT EVENT SLOWLY STRENGTHENS ALONG FRONTAL
BOUNDARY AND EXPECT PCPN CHANCES TO SLOWLY INCREASE THROUGH THE DAY
TO 50-60% BY THE AFTERNOON AND ENOUGH LIFT/ENERGY TO TRIGGER A FEW
ISOLATED STORMS POSSIBLE LATE IN THE DAY. WIDE RANGE OF TEMPS ACROSS
THE FRONTAL BOUNDARY FROM THE 50S SE GA TO 60S/70S ACRS NE FL.
RAINFALL AMOUNTS WILL SLOWLY INCREASE BUT WILL STILL REMAIN
GENERALLY IN THE TENTH TO QUARTER OF AN INCH RANGE WITH A FEW HIGHER
AMOUNTS.

SUNDAY NIGHT/MONDAY...A WARM FRONTAL BOUNDARY WILL LIFT NORTH ACROSS
THE AREA SUNDAY NIGHT...EXITING TO THE NORTH ON MONDAY. MODELS
CONTINUE TO AGREE THAT A WAVE WILL FORM IN THE EASTERN GULF AND
TRACK ALONG THE BOUNDARY. PRECIP COVERAGE WILL INCREASE SUNDAY
EVENING AS THE WAVE MOVES ONSHORE...WITH CATEGORICAL POPS FOR MOST
AREAS OVERNIGHT INTO MONDAY MORNING. BY MONDAY AFTN...AS THE
BOUNDARY MOVES TO THE NORTH...EXPECT PRECIP COVERAGE TO LOWER
SOME...BUT WITH DEEP MOISTURE STILL OVERHEAD AND SOME FORCING...WILL
KEEP MAINLY CHANCE TO LOW END LIKELY POPS. WILL RETAIN SLIGHT
CHANCES OF THUNDERSTORMS GIVEN MARGINAL INSTABILITY. ABOVE NORMAL
TEMPERATURES CAN BE EXPECTED GIVEN THICK CLOUD COVER SUNDAY
NIGHT...AND MOST OF THE AREA IN THE WARM SECTOR MONDAY.

MONDAY NIGHT/TUESDAY...THE REGION WILL BE FIRMLY POSITIONED IN
THE WARM SECTOR OF THE SYSTEM...WITH THE WARM FRONT NORTH OF THE
ALTAMAHA RIVER AND THE COLD FRONT STILL WELL TO THE WEST. COULD
SEE A BREAK FROM SIGNIFICANT PRECIP MONDAY EVENING BETWEEN
WAVES OF LOW PRESSURE...WITH THE NEXT IMPULSE APPROACHING
LATE MONDAY NIGHT/TUESDAY. WILL USE CHANCE POPS MONDAY NIGHT WITH
PRECIP COVERAGE INCREASING TO LIKELY/CATEGORICAL TUESDAY. ABOVE
NORMAL TEMPERATURES WILL CONTINUE.

TUESDAY NIGHT/WEDNESDAY...STILL LOOKS LIKE THE GREATEST PRECIP
OF THE EVENT WILL OCCUR TUESDAY NIGHT INTO WEDNESDAY AS THE
COLD FRONT MAKES ITS APPROACH. DEEPEST POOLING OF MOISTURE ALONG
WITH A DECENT LOW LEVEL JET WILL LIKELY RESULT IN A PERIOD
OF MODERATE RAINFALL WITH AN ISOLATED STRONG STORM POSSIBLE
ESPECIALLY WEST OF JAX. STORM TOTAL PRECIP FROM SUNDAY NIGHT
INTO WEDNESDAY OF 2-4 INCHES WILL BE LIKELY...BUT WITH RAINFALL
RATES NOT EXPECTED TO BE VERY HIGH...EXCESSIVE RAINS/FLOODING
ISSUES STILL LOOK UNLIKELY. PRECIP WILL DECREASE WEDNESDAY AFTN
AS THE FRONT SWEEPS ACROSS AND BEGINS TO EXIT. LOW TEMPERATURES
TUESDAY NIGHT WILL REMAIN WELL ABOVE NORMAL...WITH NOT MUCH
ADDITIONAL WARMING WEDNESDAY AS THE FRONT CROSSES.

.LONG TERM /WED NGT-SAT/...

THE FRONT WILL EXIT TO THE SE WEDNESDAY NIGHT...WITH CLEARING
SKIES...BREEZY CONDITIONS...AND MUCH COOLER TEMPERATURES. EXPECT
LOWS EARLY CHRISTMAS MORNING IN THE UPPER 30S/LOWER 40S INLAND WITH
MID/UPPER 40S COAST. COOL AND DRY CONDITIONS WILL PREVAIL CHRISTMAS
DAY INTO NEXT WEEKEND UNDER HIGH PRESSURE. PERHAPS A FEW MORE CLOUDS
AND A SMALL CHANCE OF SHOWERS POSSIBLE NEXT SATURDAY AS MODELS
INDICATE SOME BREAKING DOWN OF THE RIDGE.

&&

.AVIATION...
VFR CONDS ATTM...BUT IFR CIGS AROUND 800 FEET ARE STEADILY MOVING
SOUTHWARD ALONG THE SC/SE GA COAST IN THE N/NE SURGE AND HAVE MADE
IT INTO THE SAVANNAH AREA AROUND 16-17Z...SO HAVE TIMED THIS BROKEN
IFR DECK INTO KSSI AROUND 20Z AND JAX METRO TAF SITES IN THE 23-00Z
TIME FRAME...THEN EVENTUALLY INTO KGNV BY 04Z. THE IFR DECK SHOULD
BECOME OVERCAST A FEW HOURS LATER WITH A FEW LIGHT SHOWERS POSSIBLE
OVERNIGHT INTO TOMORROW MORNING AND HAVE INCLUDED VCSH FOR THIS
WHILE ALSO LOWERING IFR CIG TO 500-600 FEET OVERNIGHT. HI-RES MODELS
IN GENERAL AGREEMENT WITH THIS SCENARIO AND SREF HAS >90% CHANCE OF
500-1000 FT CIGS AT LOCAL TAF SITES...BUT ONLY 20-40% CHANCE OF CIGS
FALLING BELOW 500 FT ATTM.

&&

.MARINE...
N/NE FLOW WILL STEADILY INCREASE ON THE NW SIDE OF OFFSHORE COASTAL
TROF AND PINCHED GRADIENT WILL BE STRONGEST ACROSS THE SE GA COASTAL
WATERS AND WILL RAISE SCEC HEADLINE FOR 15-20 KNOT WINDS TONIGHT
WHILE THE NE FL COASTAL WATERS WILL REMAIN AROUND 15 KNOTS OR LESS.
THIS PATTERN WILL REMAIN IN PLACE THROUGH SUNDAY BEFORE SHIFTING
WINDS AROUND 15 KNOTS OR LESS IN VICINITY OF FRONTAL ZONE CAN BE
EXPECTED SUNDAY NIGHT INTO MONDAY. S/SW WINDS INCREASE STEADILY ON
TUESDAY AND ADVISORY CONDS WILL BE POSSIBLE BY TUESDAY NIGHT AS
STRONG COLD FRONT APPROACHES. STRONG WESTERLY FLOW EXPECTED ON
WEDNESDAY WITH FRONTAL PASSAGE AND GALE FORCE GUSTS WILL BE POSSIBLE
ESPECIALLY ACROSS THE OFFSHORE WATERS.

RIP CURRENTS: LOW TO MOD RISK CONTINUES THROUGH THE WEEKEND IN THE
DEVELOPING N/NE FLOW.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  47  57  52  65 /  40  70  70  60
SSI  52  59  56  64 /  40  50  90  70
JAX  52  65  59  72 /  30  50  90  80
SGJ  56  68  61  71 /  20  40  90  70
GNV  53  70  62  73 /  20  50  90  70
OCF  56  74  62  75 /  10  50  80  60

&&

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

$$

HESS/ALLEN/PETERSON







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