FXUS62 KJAX 220736
AFDJAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
235 AM EST TUE DEC 22 2009
...DRY WEATHER EXPECTED UNTIL CHRISTMAS EVE/DAY...
.SHORT TERM...TODAY THROUGH CHRISTMAS DAY...
TODAY...HIGH PRESSURE TO REMAIN IN CONTROL AS COLD START EXPECTED
THIS MORNING AS STUBBORN HIGH CLOUDS FINALLY PULL AWAY WITH FROST
ADVISORY AND FREEZE WARNINGS TO VERIFY NICELY. SKIES TO BECOME
MOSTLY SUNNY WITH MAX TEMPS INTO THE LOWER TO MID 60S WITH LIGHT AND
VARIABLE WINDS.
TONIGHT...HIGH PRESSURE SHIFTS NORTHEAST OF THE REGION AND SETS UP
LIGHT ONSHORE FLOW ALONG THE COAST...BUT CLEAR SKIES AND GOOD
RADIATIONAL COOLING CONDS WILL SET UP ANOTHER FROSTY NIGHT WITH MIN
TEMPS IN THE 30S INLAND AND 40S ALONG THE COAST. FROST ADVISORY WILL
LIKELY BE NEEDED ONCE AGAIN OVER INLAND AREAS AND WILL LET DAY SHIFT
RE-ISSUE WITH THE NEXT PACKAGE.
WEDNESDAY...ONSHORE FLOW TO INCREASE SLIGHTLY AS HIGH PRESSURE
REMAINS NORTH OF THE REGION...SLOW INCREASE IN MOISTURE WILL ALLOW
FOR A RETURN TO PARTLY CLOUDY SKIES. MAX TEMPS CONTINUE TO MODERATE
INTO THE MID/UPPER 60S WITH SOME LOWER 70S POSSIBLE ACRS NERN FL.
WEDNESDAY NIGHT...ONSHORE FLOW WILL BE DEEP ENOUGH FOR SOME POSSIBLE
ISOLD SHOWERS OFFSHORE WITH SOME SPRINKLES REACHING THE COAST AND
POPS INCREASE INTO THE SILENT 10% RANGE...WILL KEEP MOST OF THE LAND
AREAS WITH MENTION OF RAIN...BUT IT MAY NEED TO BE ADDED IF COASTAL
SHOWERS CAN DEVELOP IN SOME CONVERGENT BANDS...TOO EARLY TO JUMP ON
YET. MUCH WARMER OVERNIGHT LOWS IN THE UPPER 40S TO 50S.
CHRISTMAS EVE...LOW LEVEL FLOW SHIFTS TO THE SOUTHEAST AND THE TEMPS
WILL CONTINUE TO MODERATE INTO THE LOWER TO MID 70S BY THE AFTERNOON
WITH BREEZY E/SE WINDS. DEEPER MOISTURE INCREASING FROM THE WEST
AHEAD OF NEXT FRONTAL SYSTEM WILL INCREASE RAIN CHANCES INTO THE
20-30% RANGE ACRS THE REGION. STILL A CHALLENGE TO SEE WHETHER PCPN
TENDS TO BE MORE FROM THE ONSHORE FLOW OFF THE ATLC OR SOME OF THE
PRE-FRONTAL SHOWER ACTIVITY AHEAD OF NEXT FRONTAL SYSTEM. THE SFC TO
700 MB FLOW OUT OF THE SOUTHEAST TENDS TO BRING LESS COASTAL SHOWERS
AND MORE IN THE WAY OF JUST MILDER TEMPS AND BREEZY CONDS.
CHRISTMAS EVE NIGHT...NAM/GFS AND GFS ENSEMBLE IN GOOD AGREEMENT
THAT PRE-FRONTAL SURGE OF MOISTURE WILL MOVE INTO THE REGION WITH
SCTD TO NUMEROUS SHOWERS AND EMBEDDED ISOLD STRONG TSTMS OVERNIGHT
WITH GUSTY WINDS POSSIBLE. TEMPS WILL REMAIN MILD IN THE 50S TO
LOWER 60S IN SOUTHERLY FLOW. A SOLID TENTH TO QUARTER OF AN INCH
ACRS NERN FL AND QUARTER TO HALF AN INCH OF RAINFALL IS EXPECTED AND
SHOULD BE ENOUGH TO SUPPORT LIKELY POPS AT THIS TIME.
CHRISTMAS DAY...TIMING OF FRONTAL PASSAGE STILL IN QUESTION AND
EXPECT AT LEAST SCTD SHOWERS AND ISOLD TSTMS POSSIBLE IN THE MORNING
WITH DECREASING RAIN CHANCES IN THE AFTERNOON. SFC TO 700MB FLOW AND
MILD OVERNIGHT TEMPS WILL ALLOW FOR MAX TEMPS INTO THE LOWER/MID 70S
BUT WILL COOL QUICKLY AFTER FRONTAL PASSAGE LATER IN THE DAY.
.LONG TERM...SATURDAY THROUGH MONDAY...
SATURDAY/SUNDAY...WAVE IMPULSE ALONG TRAILING SECONDARY FRONT MAY BE
ENOUGH TO KICK OFF ISOLD SHOWER ACTIVITY...MAINLY ACRS NERN FL WHICH
SHOULD CLEAR THE REGION BY SUNDAY NIGHT. MAX TEMPS WILL BE MUCH
COOLER IN THE UPPER 50S/LOWER 60S.
MONDAY...MUCH COLDER AIR TO POUR INTO REGION SUNDAY NIGHT WITH LIGHT
FREEZE CONDS POSSIBLE EARLY MONDAY MORNING AND AGAIN EARLY TUESDAY
MORNING WITH CLEAR SKIES. MAX TEMPS TO HOLD IN THE UPPER 50S/LOWER
60S.
&&
.AVIATION...VFR CONDITIONS EXPECTED.
&&
.MARINE...NO HEADLINES THROUGH WEDNESDAY. SCA CONDITIONS POSSIBLE BY
WEDNESDAY NIGHT AS GRADIENT TIGHTENS WITH APPROACH OF FRONTAL
SYSTEM.
&&
.FIRE WEATHER...WARMER AFTERNOON TEMPERATURES AND DRY AIR MASS IN
PLACE THIS AFTERNOON WILL ALLOW HUMIDITIES TO DROP BELOW 35 PERCENT
OVER THE INLAND AREAS OF NORTHEAST FLORIDA FOR DURATIONS OF 4 TO 6
HOURS. A RED FLAG HAS BEEN ISSUED FOR THIS AREA. LIGHT WINDS WILL
RESULT IN LOW DISPERSION TODAY. DISPERSION VALUES INCREASE WEDNESDAY
AS TRANSPORT WINDS INCREASE.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 62 34 64 44 / 0 0 0 10
SSI 60 46 63 55 / 0 0 0 10
JAX 63 37 67 50 / 0 0 0 10
SGJ 63 46 68 56 / 0 0 0 10
GNV 64 36 71 49 / 0 0 0 10
OCF 64 37 72 51 / 0 0 0 10
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...FROST ADVISORY UNTIL 9 AM EST THIS MORNING FOR ALACHUA-BAKER-
BRADFORD-CLAY-DUVAL-MARION-NASSAU-PUTNAM-UNION.
RED FLAG WARNING FROM NOON TODAY TO 5 PM EST THIS AFTERNOON FOR
ALACHUA-BAKER-BRADFORD-COLUMBIA-GILCHRIST-HAMILTON-MARION-
PUTNAM-SUWANNEE-UNION.
FREEZE WARNING UNTIL 9 AM EST THIS MORNING FOR COLUMBIA-
GILCHRIST-HAMILTON-SUWANNEE.
GA...FROST ADVISORY UNTIL 9 AM EST THIS MORNING FOR APPLING-BACON-
BRANTLEY-CHARLTON-COASTAL CAMDEN-COASTAL GLYNN-COFFEE-
INLAND CAMDEN-INLAND GLYNN-JEFF DAVIS-PIERCE-WARE-WAYNE.
FREEZE WARNING UNTIL 9 AM EST THIS MORNING FOR ATKINSON-CLINCH-
ECHOLS.
AM...NONE.
&&
$$
HESS/PETERSON
