Area Forecast Discussion
Issued by NWS Jacksonville, FL

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000
FXUS62 KJAX 180910
AFDJAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
410 AM EST THU DEC 18 2014


.SYNOPSIS...STRONG MID AND UPPER LEVEL TROUGH IS LOCATED OVER THE
WRN U.S. WITH DOWNSTREAM UPPER LEVEL JET LOCATED ACROSS TX TO THE TN
VALLEY. WEAK MID TO UPPER LEVEL RIDGE ACROSS OUR FORECAST AREA WITH
UPPER LEVEL DISTURBANCES AND JET HELPING TO SPREADING AN OCNL
BROKEN-OVERCAST CIRRUS CLOUDS OVERHEAD. SFC HIGH PRES CENTRAL PLAINS
TO CENTRAL GULF COAST WITH LIGHT W TO NW FLOW OVER OUR AREA. TEMPS
ARE IN THE 40S MOST LOCATIONS WITH A FEW UPPER 30S OVER INLAND SE
GA. PATCHY FOG NOTED OVER THE SUWANNEE VALLEY PER SFC OBS AS PASSING
HIGH CLOUDS ARE MASKING ANY LOW CLOUD OR FOG DETECTION. FOG IS ALSO
INDICATED IN LATEST HRRR AND NARRE FCST GUIDANCE FROM AROUND LIVE
OAK TO OCALA. WILL CONTINUE MENTION OF FOG INTO THE EARLY MORNING
FCST...AND VSBY MAY BE BELOW 1 MI AT TIMES.

.SHORT TERM...FOR TODAY...ONE MID AND UPPER LEVEL SHORTWAVE TROUGH
WILL SHIFT EWD FROM CENTRAL PLAINS TO THE OHIO VALLEY WHILE
DE-AMPLIFYING. WE ANTICIPATE HIGH CLOUDS TO CONTINUE TO AFFECT THE
REGION THROUGH FIRST OF THE HALF OF THE DAY...WITH THINNING OF
CLOUDS IN THE AFTN FROM THE NW TO SE. SFC HIGH PRES NW OF THE AREA
WILL ALLOW FOR PREVAILING LIGHT NW TO N WINDS. MAX TEMPS TODAY
EXPECTED TO BE IN THE 60S AREA-WIDE BUT PERHAPS A TOUCH BELOW
CLIMATOLOGY. TONIGHT...A MORE SIGNIFICANT MID AND UPPER LEVEL SHORTWAVE
LOCATED ACROSS THE FOUR CORNERS WILL TRANSLATE TO LOWER CONUS
GENERATING SFC CYCLOGENESIS OVER THE WRN GULF. THIS DIGGING
SHORTWAVE TROUGH WILL ENHANCE MOISTURE OVER THE AREA LATER TONIGHT
THROUGH FRIDAY WITH PWATS INCREASING FROM ABOUT HALF AN INCH TO 3/4
OF AN INCH. GUIDANCE TEMPS ARE IN GOOD AGREEMENT WITH SIMILAR
READINGS TO THIS MORNING...MAINLY IN UPPER 30S TO LOWER 40S. COOLEST
READINGS WELL INTERIOR LOCATIONS. LOCAL TOOLS AND MODEL SOUNDINGS
DON`T SUPPORT MENTION OF FOG ATTM.

FRIDAY...STRONG MID AND UPPER SHORTWAVE TROUGH WILL MOVE INTO THE MS
RIVER VALLEY AND ASSOCD SFC LOW PRES WILL MOVE TOWARD THE LA COAST.
SFC HIGH PRES DUE N OF THE AREA WILL OOZE EWD ALLOWING WINDS TO
SLOWLY TURN TO THE NELY BUT LIGHT WIND SPEEDS. THE TAIL END OF A
WEAK FRONT WILL MOVE THROUGH PARTS OF SE GA BUT LITTLE SENSIBLE WX
NOTED BESIDES THE WIND SHIFT WITH SLIGHT BUMP IN SPEEDS AND
INCREASED DEWPOINTS. EXPECT PARTLY CLOUDY SKIES INCREASING DURING
THE DAY AS ISENTROPIC LIFT INCREASES FROM THE W AND NW. A SLIGHT
CHANCE AROUND 20 PRCT IS INDICATED OVER OUR FAR NW ZONES AS LIFT
INCREASES IN ASSOCD WITH MID LEVEL SHORTWAVE ENERGY. MAX TEMPS AGAIN
NEAR CLIMATOLOGY IN THE 60S MOST LOCATIONS.

FRIDAY NIGHT THROUGH SATURDAY NIGHT...THE EXTENDED DRY WEATHER
PERIOD COMES TO A CLOSE AS SFC LOW CONTINUES TO DEVELOP OVER THE
NORTHERN GULF OF MEX AND TRAVEL EASTWARD TOWARDS THE FL PENINSULA.
LOW LEVEL MOISTURE WILL PUSH INTO THE AREA AHEAD OF THIS SYSTEM
INCREASING PRECIP CHANCES FRIDAY NIGHT INTO SATURDAY WITH THE
HIGHEST CHANCES...AROUND 40 TO 50 PERCENT...DURING THE AFTERNOON
SATURDAY ACROSS SE GA CLOSEST TO THE MID LEVEL IMPULSE PASSING TO
THE NORTH OVER CENTRAL GA. LOWER PRECIP CHANCES EXPECTED OVER NE
FL WITH LESS UPPER LEVEL SUPPORT. MINIMUM TEMPS WILL MODERATE
FRIDAY AND SATURDAY NIGHTS INTO THE UPPER 40S AND 50S WITH
INCREASED CLOUD COVER. MAX TEMPS SATURDAY WILL REMAIN NEAR NORMAL
ACROSS SE GA IN THE LOW/MID 60S WITH NE FL WARMING INTO THE UPPER
60S TO LOW 70S WITH A FEW MORE BREAKS IN THE CLOUDS.


.LONG TERM...
SUNDAY THROUGH WEDNESDAY....LONG TERM MODELS IN DECENT AGREEMENT
ON THE TIMING OF FOLLOWING SHORTWAVE AS IT RUNS UP OVER A FRONTAL
BOUNDARY WHICH HAS BECOME MOSTLY STATIONARY OVER THE AREA SUNDAY INTO
MONDAY. RAIN CHANCES WILL INCREASE FROM SUNDAY NIGHT INTO MONDAY
WITH LIKELY CHANCES ON MONDAY AS DEEP SOUTHWESTERLY FLOW LIFTS
RELATIVELY WARM AIRMASS OVER COOLER AIR. COVERAGE OF PRECIP SHOULD
DECREASE MONDAY NIGHT AS SFC LOW MOVES OFF TO THE NORTHEAST UP THE
ATLANTIC COAST BUT WILL INCREASE ONCE AGAIN ON TUESDAY AS UPPER
TROUGH DEEPENS OVER THE GREAT LAKES REGION WITH SFC LOW AND
ASSOCIATED COLD FRONT PULLING MOISTURE UP OVER THE AREA AS THE
BOUNDARY APPROACHES THE REGION. THUNDERSTORMS WILL BE POSSIBLE TUESDAY
INTO EARLY WEDNESDAY WITH UPPER TROUGH CONTINUING TO DEEPEN AND
BECOME NEGATIVELY TILTED AND SFC COLD FRONT PASSES THROUGH. CURRENT WPC
QPF FORECASTS SHOWING RAINFALL TOTALS SUNDAY THROUGH WEDNESDAY UP
TO 3 INCHES WITH HIGH LEVELS OF AVAILABLE MOISTURE AND PERSISTENT FORCING
MECHANISMS. CONDITIONS WILL BEGIN TO IMPROVE ON WEDNESDAY AS COLD
FRONT PUSHES THROUGH AND DRIER AIRMASS FILTERS IN BEHIND. MILD
TEMPERATURES EXPECTED EACH AFTERNOON SUNDAY THROUGH TUESDAY IN THE
60S AND LOW 70S BEFORE COLD AIR ADVECTION INITIATES ON WEDNESDAY
AND TEMPS BEGIN TO DECREASE. MIN TEMPS WILL FOLLOW SUIT IN THE
UPPER 40S AND 50S ACROSS MUCH OF THE AREA EACH NIGHT UNTIL
WEDNESDAY NIGHT WHEN COLDER TEMPS ARE EXPECTED.

&&

.AVIATION...VFR BUT BRIEF VSBY REDUCTIONS POSSIBLE AT VQQ.
OCNL CIGS AOA 20 KFT THROUGH 06Z FRI. LIGHT NW TO W WINDS...THOUGH A
WEAK SEA BREEZE WILL BE POSSIBLE AT SSI AFTER 20Z.

&&

.MARINE...BENIGN CONDITIONS CONTINUE THROUGH FRIDAY WITH FAIRLY
LIGHT NLY WINDS AND LOW SEA HEIGHTS. NELY FLOW LIGHT ON FRIDAY AND
SHIFTS TO MORE SLY ON SAT. A WEAK AREA OF LOW PRESSURE AND
ASSOCIATED COLD FRONT WILL MOVE EASTWARD AND STALL ACROSS THE WATERS
SUNDAY AND MONDAY MAKING FOR UNSETTLED WEATHER WITH A GOOD CHANCE OF
RAIN. ANOTHER STRONGER COLD FRONT WILL APPROACH FROM THE W BY
TUESDAY. STILL CAN`T TOTALLY DISCOUNT A CHANCE OF SEA FOG EARLY SAT
MORNING AND/OR SAT EVENING AS DEWPOINTS INCREASE AS FLOW TURNS TO NE
AND SE BUT POTENTIAL SEEMS TOO LOW TO INCLUDE ATTM.

RIP CURRENTS: LOW RISK EXPECTED THROUGH FRIDAY.


&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  63  38  64  49 /   0   0  10  30
SSI  61  44  62  52 /   0   0  10  20
JAX  64  41  66  51 /   0   0  10  10
SGJ  64  46  65  55 /   0   0  10  10
GNV  66  40  68  51 /   0   0  10  10
OCF  67  40  70  52 /   0   0  10  10

&&

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

$$

GUILLET/SHASHY/





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