893 
FXUS62 KJAX 170936
AFDJAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
436 AM EST SUN FEB 17 2013

...HARD FREEZE TONIGHT WITH LOW WIND CHILLS...
...FREEZE SUNDAY NIGHT/MONDAY MORNING...

.CURRENTLY...COLD AIR PRES DOME WAS CENTERED OVER SRN MS VALLEY WITH 
COLD NWLY FLOW OVER THE AREA. TEMPS ARE SLOWLY FALLING THROUGH THE 
30S AND UPPER 20S WITH SOME A FEW 40S NEAR THE COAST AT THIS TIME. 
DEEP LAYER TROUGH IS POSITIONED JUST E OF THE FORECAST AREA AND WILL 
CONTINUE TO PUSH EWD THROUGH THE MORNING. WINDS ARE FINALLY SUBSIDING 
BUT 5-10 MPH FLOW STILL OCCURRING WHICH MAY CONTINUE TO VERY SLOWLY 
WEAKEN. ADVY FOR WIND CHILL MAY JUST MEET THE MINIMUM WIND CRITERIA 
OF 10 MPH SO WILL KEEP IN PLACE THIS MORNING. HARD FREEZE WARNING 
REMAINS IN EFFECT BUT WITHIN ~10 MILES OF THE COAST PROBABLY WON'T 
MEET HARD FREEZE CRITERIA DUE TO WINDS STAYING FROM 
OFFSHORE/DRAINAGE FLOW. 

.SHORT TERM...
TODAY...AFTER FREEZING TEMPS IN THE MORNING HIGHS ONLY TO REACH THE 
LOWER AND MID 50S UNDER SUNNY SKIES. NWLY WINDS AROUND 5-15 MPH WILL 
MAKE IT FEEL IN THE LOWER TO MID 40S THOUGH. TONIGHT...THE HIGH PRES 
CENTER WILL MOVE TO THE FL PANHANDLE IN THE EVENING THEN TO EXTREME 
NE FL AND SE GA LATE. MEAN 1000-850 MB WINDS DROP TO NEAR 0 TO 8 MPH. 
THIS SHOULD ENABLE A RAPID FALL IN TEMPS THIS EVENING/TONIGHT. GIVEN 
THE CONFIDENCE IN A LONG DURATION FREEZE AND TEMPS DROPPING TO THE 
LOWER AND MID 20S OVER A MAJORITY OF THE AREA HAVE PREFERRED TO GO 
WITH A HARD FREEZE WARNING ATTM. EXCEPTIONS TO THESE COLDER TEMPS 
WILL BE LOCATIONS IN AND NEAR THE ST JOHNS RIVER AND NEAR THE COAST 
WHERE WINDS WILL STAY A BIT MORE MIXED WITH MINS AROUND 30-33. 

MONDAY...HEIGHTS RISE AND SFC HIGH PRES PROGRESSES EWD INTO THE ATLC 
ALLOWING FOR E TO SE FLOW AND RATHER FAST MODIFICATION TO THE 
AIRMASS. HIGHS IN THE 60S EXPECTED WITH GRADUAL INCREASING MOISTURE 
AROUND 4 KFT AND ABOVE 25 KFT. MON NIGHT...LIKELY TO SEE QUICK 
FALL IN TEMPS AGAIN MON EVENING WITH LOWS IN THE 40S TO NEAR 50. 
WELL INLAND...NORMALLY COLDER LOCALES WILL DROP TO UPPER 30S. NEXT 
COLD FRONT AND ASSOCD BAND OF CONVECTION IS FCST BY NAM AND GFS TO 
PUSH EWD TO WRN PARTS OF GA BY 12Z TUE SO ANY SIGNIFICANT PRECIP 
WILL STAY W OF THE AREA DURING THIS TIME FRAME. FOG POTENTIAL 
UNCERTAIN AND FOR THIS REASON WILL NOT MENTION IN FCST ATTM. 

TUESDAY...THE NAM SEEMS TOO SLOW WITH THE FRONTAL PROGRESSION WHILE 
GFS AND ECMWF ARE SIMILAR MOVING THE FRONT INTO SE GA IN THE AFTN. 
FRONT WILL PUSH INTO NE FL BY THE LATE AFTN AND EVENING. FOR NOW 
CHANCE POPS ARE FCST NW OF A LINE FROM DUVAL COUNTY TO ALACHUA 
COUNTY...WITH SLIGHT CHANCES ELSEWHERE. CONVECTIVE INSTABILITY TOO 
WEAK FOR TSTMS. BREEZY SWLY FLOW WILL HELP PUSH HIGHS TO NEAR 70 N 
TO MID/UPPER 70S S. TUE NIGHT...COLD FRONT WILL MOVE THROUGH NE FL 
OVERNIGHT AND S OF THE AREA BY WED MORNING AS HIGH PRES BUILDS IN 
FROM THE NW. POPS AND CLOUDS WILL DECREASE FROM N TO S OVERNIGHT. 
TEMPS FCST TO COOL OFF TO UPPER 30S N TO LOWER 50S ACROSS EXTREME S. 

.LONG TERM...WED-SAT. 
A PROGRESSIVE PATTERN CONTINUES WED AND THU WITH SFC HIGH PRES N OF 
THE AREA MOVING EWD WHILE ANOTHER POTENT SHORTWAVE TROUGH AND ASSOCD 
SFC FRONT OVER THE CENTRAL PLAINS MOVES ENEWD. THIS WILL RESULT IN 
VEERED FLOW AND ANOTHER WARMUP. MEAN LAYER 1000-500 MB FLOW IS SWLY 
OVER THE SE STATES AND PARENT LOW FROM THE SHORTWAVE TROUGH MOVES 
INTO THE WRN GREAT LAKES FRI AND SAT. THIS WILL ACT TO SLOW THE 
APPROACHING COLD FRONT WITH A SWATH OF MOISTURE AHEAD OF THE SYSTEM 
INCREASING OUR POPS TO 20-40% RANGE FRI AND SAT WITH THE HIGHEST 
CHANCES OVER SE GA WHERE BETTER FORCING/DEEPER MOISTURE WILL BE 
LOCATED. WILL GO WITH SLIGHT CHANCE OF TSTMS FRI NIGHT INTO SAT OVER 
PARTS OF SE GA WHERE DEWPOINTS IN THE 60S AND ADEQUATE INSTABILITY 
WILL BE AVAILABLE. COOL TEMPS ON WED NEAR CLIMO BUT TEMPS WILL 
MODERATE THE REST OF THE WEEK BECOMING 5-10 DEG ABOVE NORMAL DUE TO 
PREVAILING S TO SWLY FLOW. 

&&

.AVIATION...
VFR CONDITIONS WILL CONTINUE AT ALL TERMINALS THE NEXT 24 HOURS.

&&

.MARINE...
STRONG WINDS OFFSHORE WILL BEGIN TO SUBSIDE BY MID MORNING. IN
THE MEANTIME...FREQUENT GUSTS TO GALE FORCE WILL CONTINUE OVER THE
OFFSHORE ZONES. THE GALE WARNING IS IN EFFECT UNTIL 15Z AND A
SMALL CRAFT ADVISORY IS IN EFFECT FOR THE OFFSHORE ZONES FROM 15Z
TO 21Z TO ALLOW TIME FOR WINDS/SEAS TO RAMP DOWN. FOR THE NEARSHORE
ZONES...SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED TO END BY
LATE MORNING. HIGH PRESSURE WILL QUICKLY BUILD IN FROM THE WEST
THIS AFTERNOON WITH RATHER BENIGN CONDITIONS TONIGHT AND TOMORROW.
WINDS WILL TURN TO THE SOUTH AND INCREASE MONDAY NIGHT INTO
TUESDAY AHEAD OF THE NEXT FRONTAL SYSTEM...AND A BRIEF PERIOD OF
SMALL CRAFT ADVISORY CONDITIONS WILL BE POSSIBLE ON TUESDAY.

RIP CURRENTS: LOW RISK.

&&

.FIRE WEATHER...
AN EXTREMELY DRY AIRMASS WILL BE OVER THE AREA TODAY. DEWPOINTS
WILL APPROACH ZERO DEGREES IN SOME LOCATIONS. RELATIVE HUMIDITIES
WILL BE BELOW CRITICAL THRESHOLDS FOR MOST OF THE DAY WITH MINIMUM
VALUES IN THE 15 TO 20 PERCENT RANGE THIS AFTERNOON. DESPITE THE
EXTREMELY LOW RH VALUES...WINDS WILL NOT REACH RED FLAG CRITERIA.
WE WILL HOWEVER ISSUE A FIRE DANGER STATEMENT FOR THE EASTERN
PORTIONS OF NORTHEAST FLORIDA TO ACCOUNT FOR A BRIEF PERIOD LATER
THIS MORNING WHERE CRITICALLY LOW RELATIVE HUMIDITIES WILL
COMBINE WITH 20 FT WIND GUSTS IN EXCESS OF 15 MPH. RELATIVE
HUMIDITIES WILL BE VERY LOW AGAIN ON MONDAY BUT WINDS WILL REMAIN
LESS THAN 15 MPH AND ERC VALUES WILL REMAIN LOW...THUS RED FLAG
CRITERIA IS NOT EXPECTED.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  51  24  63  40 /   0   0  10  20 
SSI  50  32  56  48 /   0   0  10  10 
JAX  51  25  61  42 /   0   0  10  10 
SGJ  50  32  60  51 /   0   0  10  10 
GNV  53  23  65  42 /   0   0   0  10 
OCF  54  24  66  45 /   0   0  10  10 

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...HARD FREEZE WARNING UNTIL 9 AM EST THIS MORNING FOR ALACHUA-
     BAKER-BRADFORD-CLAY-COLUMBIA-DUVAL-FLAGLER-GILCHRIST-
     HAMILTON-MARION-NASSAU-PUTNAM-ST JOHNS-SUWANNEE-UNION.

     HARD FREEZE WARNING FROM 10 PM THIS EVENING TO 9 AM EST MONDAY 
     FOR ALACHUA-BAKER-BRADFORD-COLUMBIA-GILCHRIST-HAMILTON-
     SUWANNEE-UNION.

     HARD FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EST MONDAY FOR 
     CLAY-DUVAL-FLAGLER-MARION-NASSAU-PUTNAM-ST JOHNS.

     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR CLAY-DUVAL-
     FLAGLER-NASSAU-PUTNAM-ST JOHNS.

GA...HARD FREEZE WARNING UNTIL 9 AM EST THIS MORNING FOR APPLING-
     ATKINSON-BACON-BRANTLEY-CHARLTON-CLINCH-COASTAL CAMDEN-
     COASTAL GLYNN-COFFEE-ECHOLS-INLAND CAMDEN-INLAND GLYNN-JEFF 
     DAVIS-PIERCE-WARE-WAYNE.

     HARD FREEZE WARNING FROM 10 PM THIS EVENING TO 9 AM EST MONDAY 
     FOR APPLING-ATKINSON-BACON-BRANTLEY-CHARLTON-CLINCH-COFFEE-
     ECHOLS-JEFF DAVIS-PIERCE-WARE-WAYNE.

     HARD FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EST MONDAY FOR 
     COASTAL CAMDEN-COASTAL GLYNN-INLAND CAMDEN-INLAND GLYNN.

AM...GALE WARNING UNTIL 10 AM EST THIS MORNING 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.

     SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING 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.

&&

$$

SHASHY/SHULER/