Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 221940
AFDJAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
240 PM EST MON DEC 22 2014

.NEAR TERM /THROUGH TUESDAY/...
A SURFACE WARM FRONT CONTINUES TO NUDGE SLOWLY NORTHWARD ACROSS
EXTREME SE GA. MID LEVEL IMPULSES COMING FROM THE EASTERN
GULF IN SW FLOW...ALONG WITH THE SURFACE BOUNDARY IS RESULTING
IN NUMEROUS SHOWERS/ISOLATED TSTMS ACROSS NE FL INTO SE GA.
FURTHER NORTH...THE STRATUS DECK/FOG IS STRUGGLING TO ERODE
TO THE NORTH OF THE FRONT...WITH VISIBILITIES JUST BEGINNING TO
IMPROVE ACROSS MOST OF SE GA.

FOR TNGT...THE BOUNDARY WILL CONTINUE TO SLOWLY LIFT NORTH WITH
THE FRONT MOVING NORTH OF THE ALTAMAHA RIVER BY THE OVERNIGHT
HOURS. NUMEROUS POPS ALONG THE BOUNDARY WILL EXIT SE GA LATER
THIS EVENING. THE REGION WILL BE FIRMLY IN THE WARM SECTOR
OVERNIGHT...WITH THE NEXT SIGNIFICANT IMPULSE WELL TO THE
WEST. WILL LOWER POPS FURTHER...WITH ISOLATED/WIDELY SCATTERED
POPS JUST TO THE SOUTH OF THE ALTAMAHA...AND LITTLE/NO PRECIP
FOR THE OVERNIGHT ACROSS NE FL. MODELS ALL POINT TO A LOW CLOUD
DECK COMING IN FROM THE GULF IN SW FLOW...WITH SOME MODELS
DEPICTING FOG DEVELOPMENT. WILL INCLUDE AREAS OF FOG ALONG
WITH THE LOW CLOUDS ACROSS MOST AREAS OVERNIGHT INTO TUESDAY
MORNING. ANOTHER MILD NIGHT IN STORE...WITH LOWS MAINLY IN THE
50S TO LOWER 60S.

TUESDAY...THE WARM FRONT WILL MOVE WELL NORTH OF THE AREA...WITH
THE COLD FRONT STILL WELL TO THE WEST. A MORE SIGNIFICANT WAVE
WILL APPROACH FROM THE WEST TUESDAY AFTN. MAINLY DRY CONDITIONS
WILL PREVAIL EARLY...WITH INITIAL PRECIP LIKELY ENTERING INTERIOR
SE GA BY LATE MORNING. PRECIP WILL INCREASE SUBSTANTIALLY
ACROSS SE GA IN THE AFTN AND WILL KEEP NUMEROUS TO WIDESPREAD POPS
AS THE WAVE IS JUST TO THE WEST BY LATE AFTN. WILL USE MAINLY
SCATTERED AFTN POPS FOR MOST OF NE FL...WITH A BIT HIGHER COVERAGE
SUWANNEE VALLEY. WITH THE GREATEST BULK LAYER SHEAR STILL TO THE
WEST THROUGH TUESDAY AFTN...WILL KEEP SEVERE WORDING OUT OF THE
FCST. WARMER AIR WILL SURGE NORTH...WITH HIGHS IN THE LOWER/MID
70S FOR SE GA...AND 75-80 FOR NE FL.


.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
TUE NIGHT...PRECIP COVERAGE AND RATES INCREASE ACROSS OUR
WESTERN TIER WHEN ANOTHER TROUGH AXIS/PSEUDO-WARM FRONT LIFTS
NORTHWARD FROM THE GULF COAST REGION AS THE SURFACE COLD FRONT
PUSHES DOWNSTREAM OF THE LOWER MS RIVER VALLEY. WIDESPREAD
MODERATE TO HEAVY RAINFALL IS EXPECTED TO OVERSPREAD THE GULF
COAST REGION INTO THE SUWANNEE RIVER VALLEY AND PARTS OF SE GA TUE
NIGHT THROUGH EARLY WED WITH THE PHASING OF STRONG LOW LEVEL
ISENTROPIC LIFT AND JET DYNAMICS INCLUDING A LOW LEVEL 850 MB JET
OF 40-50 KTS PUMPING GULF MOISTURE INLAND. WAVES OF A FEW STRONG
TO SEVERE STORMS MOVING INLAND FROM THE GULF ARE ALSO LIKELY
DURING THIS PERIOD AS THE PARENT UPPER LEVEL TROUGH CONTINUES TO
DIG SOUTHWARD OVER THE LOWER CONUS. THE STORM PREDICTION CENTER
HAS THE AREA FROM THE NE GULF COAST INLAND TO THE NEAR SUWANNEE
VALLEY REGION UNDER A SLIGHT RISK OF SEVERE WEATHER WITH
SUPERCELLS AND ISOLATED TORNADOES POSSIBLE.

WED/WED NIGHT...AGREEMENT AMONG THE MODELS ON WIDESPREAD RAIN
RAPIDLY OVERSPREADING THE AREA AND A PRE-FRONTAL SQUALL LINE
TRAVERSING THE AREA DURING THE AFTERNOON INTO THE EARLY EVE. JET
DYNAMICS WILL BE IMPRESSIVE (STRONG DEEP LAYER SHEAR) BUT AMOUNT
OF SURFACE BASED INSTABILITY WILL BE IN QUESTION GIVEN ONGOING
PCP. THE STORM PREDICTION CENTER HAS OUR AREA UNDER A MARGINAL
RISK OF SEVERE WX WITH DAMAGING WINDS THE MAIN CONCERN. ISOLATED
TORNADOES WILL ALSO BE POSSIBLE BUT THAT WILL DEPEND ON THE AMOUNT
OF DESTABILZATION...MOST LIKELY ACROSS THE SOUTHERN AND SOUTHEAST
ZONES.

CHRISTMAS DAY/THU NIGHT...POST-FRONTAL CLOUDS WILL PUSH SE OVER
NE FL DURING THE MORNING WITH CLEAR SKIES EXPECTED OVER SE GA.
HIGH TEMPS WILL COOL INTO THE UPPER 50S NEAR THE ALTAMAHA RIVER
BASIN TO LOWER 70S OVER NE FL. MINS THU NIGHT WILL FALL INTO THE
MID 30S INLAND TO MID 40S COAST AS SURFACE HIGH PRESSURE BUILDS
OVER THE REGION FROM THE GULF COAST REGION. INCLUDED AREAS OF
FROST FOR INLAND LOCATIONS GIVEN NEAR CALM WINDS AND CLEAR SKIES.


.LONG TERM /FRIDAY THROUGH MONDAY/...
MODERATING TEMPERATURES FRI/SAT AS HIGH PRESSURE BUILDS OVER
THE REGION WITH DRY CONDITIONS EXPECTED. MODELS DIVERGE IN THE
TIMING OF THE NEXT FRONTAL SYSTEM EARLY NEXT WEEK THUS CAPPED
RAIN CHANCES AT 14% OR LESS FOR NOW UNDER PARTLY CLOUDY SKIES.
GUIDANCE SUGGESTS A COOLER NLY FLOW SUN/MON ASSOCIATED WITH A
WEAK BACKDOOR COLD FRONT. TEMPS WILL RANGE NEAR TO ABOVE NORMAL
FRI/SAT THEN NEAR TO SLIGHTLY BELOW NORMAL SUN/MON.

&&

.AVIATION...
QUITE A TRICKY FCST...WITH LINGERING IFR/LIFR CONDITIONS FOR
SSI...AND MVFR/VFR CONDITIONS FOR NE FL THIS AFTN. WITH THE
WARM FRONT SLOW TO EXIT TO THE NORTH...THINK SSI WILL GENERALLY
REMAIN IFR/LIFR THROUGH TUESDAY MORNING...WITH SOME IMPROVEMENT
TO MVFR IN THE AFTN. FOR THE NF FL PORTS...THINK THE IMPROVEMENT
THIS AFTN WILL BE SHORT-LIVED...WITH AT LEAST LOW CLOUDS EITHER
REFORMING AND/OR ADVECTING IN FROM THE GULF IN SW FLOW WILL
RESULT IN ANOTHER ROUND OF IFR/LIFR CONDITIONS LATER THIS
EVENING THROUGH TUESDAY MORNING. PRECIP COVERAGE WILL DECREASE
AND WILL MAINLY USE VCSH INTO THIS EVENING.

&&

.MARINE...
A WARM FRONTAL BOUNDARY WILL SLOWLY LIFT NORTH OF THE GA WATERS
LATER TONIGHT...WITH NEARSHORE FOG DECREASING. WINDS/SEAS WILL
REMAIN UNDER CAUTION THROUGH TUESDAY. WINDS WILL INCREASE TO
CAUTION LEVELS AHEAD OF A COLD FRONT WEDNESDAY...WITH SCA
CONDITIONS POSSIBLE IN THE WAKE OF THE FRONT WEDNESDAY NIGHT.
WINDS/SEAS WILL SUBSIDE CHRISTMAS DAY...WITH BENIGN CONDITIONS
EXPECTED FRIDAY INTO THE UPCOMING WEEKEND.


RIP CURRENTS: LOW RISK THROUGH TUESDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  54  72  63  72 /  60  90 100 100
SSI  58  68  64  71 /  60  70  70 100
JAX  60  76  64  75 /  50  40  70 100
SGJ  62  74  66  74 /  40  30  50  80
GNV  63  77  65  75 /  40  40  70 100
OCF  62  78  67  76 /  30  30  70  90

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...DENSE FOG ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR ALTAMAHA
     SOUND GA TO FERNANDINA BEACH FL OUT 20 NM.

&&

$$

ALLEN/PETERSON






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