FXUS62 KJAX 250804
AFDJAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
255 AM EST FRI DEC 25 2009

.SHORT TERM (CHRISTMAS-SUN)...INTENSE LOW ACROSS MISSOURI RACES NE 
THIS MORNING BEFORE BECOMING OCCLUDED TODAY. PRE-FRONTAL SQUALL LINE 
ACROSS THE EASTERN FL PANHANDLE WILL MOVE EAST...TO ACROSS THE 
SUWANNEE VALLEY REGION INTO INLAND SE GA BY 12Z AND THE REMAINDER OF 
THE AREA BETWEEN 15Z-18Z. HAVE LEANED TOWARDS THE NAM WHICH APPEARS 
TO HAVE THE BEST HANDLE ON THE TIMING OF THE SQUALL LINE. THE NAM 
ALSO DEVELOPS A SECONDARY AREA OF PCP...OUT AHEAD OF THE 
LINE...ACROSS NE FL BETWEEN 09Z-12Z. THE STRONG JET DYNAMICS AND 
HIGH HELICITIES IN PLACE FOR SEVERE WX. THE LACKING INGREDIENT IS 
SURFACE BASED INSTABILITY WHICH IS TOTALLY LACKING RIGHT NOW. MODELS 
(ESP NAM) INDICATE THERE MAY BE JUST ENOUGH INSTABILITY (EHI OF 1 TO 
1.5) FOR POSSIBLY A FEW LOW TOPPED SEVERE STORMS WITH DAMAGING WIND 
POTENTIAL OR EVEN ISOLATED TORNADOES GIVEN THE HIGH 0-1 KM 
HELICITIES. BUT THAT WILL DEPEND ON THE DESTABILIZATION. SPC DOES 
HAVE OUR AREA UNDER A SLIGHT RISK OF SEVERE WX TODAY. 

IMPROVING CONDITIONS WILL TRAIL FRONTAL PASSAGE WITH MUCH 
COOLER AND DRIER CONDITIONS IN STORE FOR THE WEEKEND....WITH 
AFTERNOON HIGHS IN THE UPPER 50S TO LOWER 60S. AT THIS TIME...A 
FREEZE IS NOT EXPECTED BUT PATCHES/AREAS OF FROST ARE EXPECTED ALONG 
THE INTERSTATE 75 AND U.S HIGHWAY 441 CORRIDORS. 

A DISTURBANCE MOVING IN FROM THE GULF WILL BRING A SLIGHT CHANCE
OF RAIN FOR SUNDAY.
  
.LONG TERM (MON-THU)...A NEARLY ZONAL PATTERN ALOFT WILL SEND SERIES 
OF HIGH PRESSURE SYSTEMS EASTWARD MONDAY-WEDNESDAY. HIGH 
TEMPERATURES WILL BE ON AVERAGE 3-5 DEGREES BELOW NORMAL WITH 
MINIMUM TEMPERATURES 5-10 DEGREES BELOW NORMAL. DRY CONDITIONS ARE 
FORECAST EACH DAY. NEXT CHANCE FOR RAIN IS EXPECTED NEW YEARS EVE
AS LOW PRESSURE IS FORECAST TO TRACK ACROSS THE FL PENINSULA.

&&

.AVIATION...VFR CONDITIONS NOTED AT THE TAF SITES AT THIS MOMENT BUT 
INCREASING ISENTROPIC UPGLIDE AHEAD OF THE FRONT IS EVENTUALLY 
EXPECTED TO PRODUCE MVFR CIGS BY 12Z TODAY. MAINLY LOOKING AT THE 
09Z-18Z TIME FRAME FOR MVFR WITH CONDITIONS IMPROVING AS THE FRONT 
PUSHES RAPIDLY EWD BY LATE AFTERNOON WITH DRIER AIR FILTERING IN.
COULD BE SOME BRIEF IFR CONDITIONS IN SHOWERS NEAR THE FRONT BUT 
GENERALLY MVFR FORECAST AT THIS TIME. GUSTS TO NEAR 35 KT POSSIBLE 
IN THE SHOWERS. IN ADDITION...LLWS IS A CONCERN THROUGH EARLY MORNING 
AS GUIDANCE AND VWP PROFILES INDICATE SLY WINDS AT 1500-2000 FT NEAR 
40-50 KT. OTHERWISE....VFR EXPECTED AT ALL SITES BY 21Z TODAY.

&&

.MARINE...WINDS AND SEAS AT THE SCA CRITERIA ATTM. SURPRISINGLY BUOY 
41008 IS ALSO REPORTING 8 FT SEAS WITH 41012 AT 9 FT...SLIGHTLY 
ABOVE GUIDANCE. WINDS ARE EXPECTED TO PEAK FROM NOW THROUGH EARLY 
AFTERNOON THEN DECREASE AS THE LLVL JET AHEAD NE OF THE AREA. 
CURRENT GALE WARNING LOOKS ON TRACK WITH 41012 (S OF GALE AREA) HAS 
REPORTED GUSTS OF 31-33 KT. ONLY SLIGHT CHANGES TO HAZARDS TO EXTEND 
SCA FURTHER INTO SAT AM FOR THE OFFSHORE WATERS. HIGH PRESSURE 
BUILDS INTO THE REGION SAT NIGHT AND SUN WITH LIGHTER WINDS. 
HOWEVER...A A REINFORCEMENT OF COLD AIR EXPECTED LATE SUNDAY NIGHT 
RAMPING UP NWLY WINDS AND SEAS AGAIN...LIKELY INTO SCA CRITERIA 
THROUGH EARLY TUE.

&&

.FIRE WX...DRIER AIR FILTERS IN LATE TODAY WITH MAIN PUNCH OF DRIER 
AIR FOR TONIGHT AND SAT. NEW GUIDANCE SUGGESTS ABOUT 3 HRS OF 
CRITICAL RH VALUES ON SAT AFTERNOON OVER THE SUWANEE VALLEY 
AREA...BUT RELATIVELY SHORT DURATIONS/WINDS LESS THAN 15 MPH AND 
EXPECTATION OF COLD ADVECTION PATTERN SUGGESTS WAITING ANOTHER MODEL 
RUN BEFORE ISSUANCE OF A FIRE WEATHER WATCH. 

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  68  36  57  33 /  70  10  10  10 
SSI  70  43  57  40 /  80  10  10  10 
JAX  72  41  59  38 /  70  10  10  10 
SGJ  73  47  59  43 /  70  10  10  10 
GNV  73  40  57  38 /  70  10  10  20 
OCF  74  42  60  39 /  70  10  10  20 

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 10 AM EST SATURDAY FOR FERNANDINA 
     BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM OFFSHORE-ST 
     AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM OFFSHORE.

     SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST 
     SATURDAY FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH FL 20 NM 
     TO 60 NM OFFSHORE.

     GALE WARNING UNTIL 11 AM EST THIS MORNING FOR ALTAMAHA SOUND GA 
     TO FERNANDINA BEACH FL 20 NM TO 60 NM OFFSHORE.

     SMALL CRAFT ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR ALTAMAHA 
     SOUND GA TO FERNANDINA BEACH FL OUT 20 NM-FERNANDINA BEACH 
     TO ST AUGUSTINE FL OUT 20 NM-ST AUGUSTINE TO FLAGLER BEACH 
     FL OUT 20 NM.

&&

$$

PP/ARS