FXUS62 KJAX 260839
AFDJAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
330 AM EST THU NOV 26 2009
...EARLY MORNING FOG FOLLOWED BY SUNNY SKIES TODAY AND COOL
CONDITIONS...
.SYNOPSIS...DEEP LAYER MOISTURE IS SHIFTING EWD PER WATER VAPOR
IMAGERY AND DRIER IN THE MID/UPPER LEVELS IS WORKING INTO THE
FORECAST AREA. LOW LEVEL MOISTURE STILL READILY APPARENT FROM MODEL
SOUNDINGS AND SATELLITE IMAGERY. SEVERAL OBS SHOWED DENSE FOG OVER
SE GA AND INTERIOR NE FL SO ISSUED A DENSE FOG ADVISORY WHICH IS IN
EFFECT THROUGH 9 AM. FOG WILL LIKELY SPREAD E AND SE. FOG MAY
IMPROVE SOMEWHAT AS 1 KFT WINDS INCREASE OUT OF THE NW.
LOW PRESSURE TROUGH IS WELL OFFSHORE OF THE SE U.S. COAST WITH NLY
WINDS OF 15-20 KT IN NE FL OFFSHORE WATERS. ALOFT...DEEP LAYER
TROUGH IS NOTED OVER THE MS VALLEY AREA SHIFTING SLOWLY EWD.
.SHORT TERM...
THANKSGIVING DAY. AREAS OF FOG...SOME OF IT DENSE...WILL CONTINUE
EARLY THIS MORNING. OTHERWISE MOSTLY SUNNY CONDS ARE EXPECTED. AS
THE MID/UPPER LEVEL TROUGH MOVES EWD HIGH PRESSURE BUILDS OVER THE
GULF COAST AND INTO OUR FORECAST AREA WITH NWLY WINDS AND COOLER AIR
FILTERING IN. MAX TEMPS OF MID 60S TO NEAR 70 EXPECTED.
TONIGHT...MID/UPPER LEVEL TROUGH AXIS PUSHES THROUGH THE AREA. CLEAR
SKIES AND NWLY WINDS STAYING UP ABOUT 5-15 MPH WILL KEEP COLD
ADVECTION ONGOING. MIN TEMPS MID 30S WELL INLAND AND AROUND 40
TOWARD THE COAST. WIND CHILLS MAY BRIEFLY DROP INTO LOWER 30S INLAND
LOCATIONS BY SUNRISE. FRI...CHILLY DAY ON TAP DESPITE FULL SUN.
LOCALLY GUSTY WINDS OF 20-25 MPH ARE POSSIBLE AND HIGHS EXPECTED IN
THE LOWER TO MID 60S. FRI NIGHT...SFC HIGH MOVES INTO THE WRN FL
PANHANDLE AND WINDS WILL BE LIGHTER. EXPECT TO SEE DRAINAGE TYPE
FLOW AND WEAK GRADIENT SUPPORTING WINDS AROUND 5 MPH. GUIDANCE LOWS
ARE CLOSE AND USED A BLEND OF PREVIOUS FORECAST AND 00Z GUIDANCE.
MINS AROUND MID 30S INLAND AND UPPER 30S/40 EXPECTED AT THIS TIME.
SOME LIGHT FROST FORMATION IS POSSIBLE BUT BL MIXING AND LIGHT WINDS
WILL HINDER DEVELOPMENT. IN ADDITION...MAY HAVE THIN HIGH CLOUDS
MOVE THROUGH ASSOCIATED WITH UPPER LEVEL SHORTWAVE. SAT...MOSTLY
SUNNY CONDS EXPECTED WITH LIGHT WINDS AND TEMPS REBOUNDING TO THE
MID TO UPPER 60S EXPECTED AS UPPER RIDGING DEVELOPS OVER THE
AREA.
.LONG TERM...SAT NIGHT-WED.
SAT NIGHT...ANOTHER COLD NIGHT IN STORE WITH SFC HIGH LIKELY PARKED
RIGHT OVER THE CWA. MAY SEE SOME LIGHT FROST FORMATION INLAND WITH
LOWS ADVERTISED IN THE MID 30S BUT UPPER 30S/LOWER 40S COAST.
SUN...WEAK HIGH PRESSURE RIDGE REMAINS OVER THE AREA AND INTO THE
WRN ATLC. FLOW JUST ABOVE THE SFC GRADUALLY TRANSITIONS TO MORE S
AND SW FLOW AS MID/UPPER TROUGHING AMPLIFIES OVER THE CENTRAL U.S.
TEMPS CONTINUE A WARMING TREND. MON THRU TUE...MID/UPPER TROUGH DIGS
OVER THE ERN U.S. DRAGGING A SFC COLD FRONT INTO OUR AREA LATE MON
NIGHT. THE FRONT APPEARS TO STALL IN NRN FL TUE AS A CLOSED
MID/UPPER LEVEL LOW OVER NRN MEXICO TRANSLATES EWD PROMOTING SFC LOW
PRES DEVELOPMENT IN THE CENTRAL GOMEX. GFS AND ECMWF ARE IN FAIRLY
GOOD AGREEMENT WITH THIS SCENARIO. THE APPROACH OF SRN STREAM ENERGY
AND THE Q-STATIONARY FRONTAL BOUNDARY MAY PRODUCE SOME HEAVY
RAINFALL OVER PORTIONS OF THE AREA. WE CONTINUE TO ADVERTISE ONLY
30-40% POPS MON NIGHT THROUGH WED NIGHT DUE TO UNCERTAINTY ISSUES
WITH TIMING AND MODEL INCONSISTENCIES FROM RUN TO RUN. MODELS ARE IN
AGREEMENT THAT SFC LOW DOES TRACK ACROSS THE SE U.S AND MOVES NE OF
THE AREA BY LATE WED NIGHT. TEMPS WILL BE TRICKY DUE TO PSN OF THE
FRONT AND HAVE NOT DEVIATED MUCH FROM PREVIOUS FORECASTS. POTENTIAL
FOR SOME STRONG THUNDERSTORMS ON MON NIGHT WITH FROPA AND AGAIN TUE
NIGHT AND WED BASED ON LATEST GFS GUIDANCE SHOWING MODERATE TO
STRONG SFC LOW MOVING ACROSS THE SE CONUS.
&&
.AVIATION...YET ANOTHER CHALLENGING FORECAST ON TAP WITH LOW CLOUDS
AND FOG BECOMING PREVALENT ON THE BACK SIDE OF DEPARTING LOW. MOST
OF THIS ACTIVITY IS ASSOCIATED WITH A LOW LEVEL MOISTURE AXIS WHICH
SHOULD ROTATE THROUGH THE AREA FOR THE REMAINDER OF THE OVERNIGHT
HOURS. THEREFORE..EXPECT A DETERIORATING TREND FOR THE EAST COAST
TERMINALS WITH IFR CONDITIONS LOOKING LIKELY THROUGH 12Z. WILL MAKE
SOME ADJUSTMENTS TO CURRENT SET OF TAFS TO ACCOUNT FOR THIS.
OTHERWISE...CONDITIONS SHOULD IMPROVE BY 14Z WITH VFR FOR THE
REMAINDER OF THE TAF CYCLE.
&&
.MARINE...MODELS IN VERY GOOD AGREEMENT INITIALLY WITH HIGH
PRESSURE BUILDING OVER THE SOUTHERN PLAINS AND INTO THE NORTHERN
GULF LATER TONIGHT. THIS HIGH ALONG WITH DEPARTING FRONTAL BOUNDARY
WILL INCREASE THE GRADIENT SUFFICIENTLY TO ALLOW FOR SCA FOR THE
OFFSHORE FROM THIS EVENING THROUGH LATE FRIDAY NIGHT. WILL BE A
CLOSE CALL FOR THE NEARSHORE PORTION...BUT FOR NOW WILL CAP WINDS
AT 15 TO 20 KNOTS AND ONLY ADVERTISE SCEC CONDITIONS. STRONG GUSTS
POSSIBLE AS WINDS MIX DOWN WHICH MAY TIP THE SCALES IN UPGRADING
TO SCA WITH SUBSEQUENT FORECASTS.
MODELS DIVERGE FOR THE NEXT SYSTEM WITH THE GFS MAKING SIGNIFICANT
RUN TO RUN CHANGES. LOOKS AS THOUGH THE LATEST ECMWF COMING IN IS
AT LEAST CLOSER TO THE LATEST GFS ADDING EXTRA ALBEIT STILL LOW
CONFIDENCE. WILL LEAN MORE TOWARD THE ECMWF IN A MORE NORTHERLY
POSITION FOR THE FRONTAL BOUNDARY UNTIL NEXT STRONG SYSTEM LIFTS
FRONT WELL NORTH OF THE AREA. STRONG SOUTHERLY FLOW LOOKS TO KEEP
WATERS IN LONG TERM SCA CONDITIONS FOR THE MIDDLE OF NEXT WEEK.
&&
.FIRE WEATHER...JUST ABOUT AS MARGINAL AS YOU CAN GET FOR FRIDAY
WITH 30 TO 35 % RH AND WINDS AROUND 15 MPH. SINCE WE ONLY NEED AN
HOUR TO VERIFY...HAVE ISSUED A WATCH BASED ON MIXING POTENTIALLY
PRODUCING WINDS IN EXCESS OF 20 MPH ACCORDING TO THE BOSTON
TECHNIQUE. COULD VERY WELL BE A SITUATION WHERE THE EAST COAST
VERIFIES EASIER BASED ON RIVER INFLUENCES INCREASING WIND SPEEDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 65 37 61 34 / 0 0 0 0
SSI 67 42 60 41 / 0 0 0 0
JAX 69 39 63 36 / 0 0 0 0
SGJ 69 43 62 41 / 0 0 0 0
GNV 68 38 62 35 / 0 0 0 0
OCF 69 39 63 35 / 0 0 0 0
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR COLUMBIA-
HAMILTON-SUWANNEE.
FIRE WEATHER WATCH FRIDAY AFTERNOON FOR ALACHUA-BAKER-BRADFORD-
CLAY-COLUMBIA-DUVAL-GILCHRIST-HAMILTON-MARION-NASSAU-PUTNAM-
ST JOHNS-SUWANNEE-UNION.
GA...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR APPLING-
ATKINSON-BACON-BRANTLEY-CHARLTON-CLINCH-COFFEE-ECHOLS-JEFF
DAVIS-PIERCE-WARE-WAYNE.
AM...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 6 PM EST FRIDAY
FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH FL 20 NM TO 60 NM
OFFSHORE-FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM
OFFSHORE-ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM
OFFSHORE.
&&
$$
SHASHY/DEESE
