613  
FXUS62 KJAX 161832  
AFDJAX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE JACKSONVILLE FL  
132 PM EST WED JAN 16 2019  
   
..FROST ADVISORY INLAND TONIGHT
 
 
   
NEAR TERM...TONIGHT
 
 
COOL AND STABLE CONDITIONS TONIGHT AS SURFACE HIGH PRESSURE CENTERED  
ACROSS THE EASTERN GULF COAST STATES BUILDS ENE OVER THE LOCAL AREA.  
IDEAL RADIATIONAL COOLING CONDITIONS WITH DEW PTS NEAR FREEZING FAVOR  
FROST FORMATION FOR ALL INLAND AREAS, AND ISSUED A FROST ADVISORY.  
MINIMUM TEMPERATURES WILL NEAR FREEZING BRIEFLY ACROSS INLAND SE GA  
AND PORTIONS OF THE SUWANNEE RIVER VALLEY AND ALONG THE I-10 CORRIDOR,  
BUT DURATIONS NOT LONG ENOUGH TO SUPPORT A FREEZE WARNING. CLOSER  
TOWARD THE COAST, LOW TEMPERATURES WILL RANGE IN THE UPPER 30S TO  
NEAR 40.  
   
SHORT TERM...THU THROUGH SUN
 
 
WARMING TREND WITH INCREASING MOISTURE AND CLOUD COVER LATE THU  
INTO THU NIGH AS SURFACE RIDGE AXIS SHIFTS SOUTHWARD ACROSS THE FL  
PENINSULA AS A FRONT BEGINS TO STALL OVER SOUTHERN GA. WEAK MID  
LEVEL SHORT WAVE TROUGH ENERGY WILL OVERRIDE THIS LOW LEVEL TROUGH  
AXIS THU NIGHT INTO EARLY FRI WHICH COULD BRING SOME LIGHT  
SPRINKLES OR SHOWER ACROSS SE GA AFTER MIDNIGHT THU NIGHT THROUGH  
EARLY FRI MORNING WITH DRY CONDITIONS EXPECTED ACROSS NE FL AS THE  
SURFACE RIDGE AXIS HOLDS FIRM ACROSS THE PENINSULA. SW STEERING  
FLOW DEVELOPS INTO FRI NIGHT AS A FRONTAL SYSTEM DEVELOPS AND  
DEEPENS ACROSS THE CENTRAL CONUS. THE LINGERING SURFACE FRONT  
ACROSS SOUTH GA MORPHS INTO A WARM FRONT AHEAD OF THIS NEXT STORM  
SYSTEM, AS AS THE WARM FRONT LIFTS BACK NORTHWARD FRI NIGHT INTO  
EARLY SAT, ANOTHER ROUND OF SPRINKLES OR LIGHT SHOWERS COULD  
IMPACT OUR SE GA ZONES AND POTENTIALLY THE I-10 CORRIDOR SUWANNEE  
RIVER VALLEY COUNTIES. MUCH WARMER AND MOSTLY DRY CONDITIONS  
EXPECTED SAT AS DEEP LAYER SSW FLOW DEVELOPS WITH BREEZY WINDS  
GUSTING TO 15-25 MPH AT TIMES.  
 
SAT NIGHT FORECAST MODELS CONTINUED TO SUPPORT ELEVATED RAIN  
CHANCES ESPECIALLY 03-12Z SUNDAY AS PRE-FRONTAL RAINFALL  
OVERSPREADS THE AREA AS THE PARENT SURFACE LOW TRACKS NE ACROSS  
THE CAROLINAS. BOTH GFS20 AND ECMWF INDICATE 0.25-1" OF RAINFALL  
ACCUMULATION ACROSS THE LOCAL AREA WITH THE PASSAGE OF THIS FRONT,  
BUT VARY ON WHERE THE HIGHER AMOUNTS COULD FALL. WILL CONTINUE TO  
ADVERTISE ISOLATED THUNDERSTORM POTENTIAL AS THE LOCAL AREA WILL  
BE LOCATED WITH THE SYSTEMS WARM SECTOR WITH FAVORABLE DYNAMICAL  
SUPPORT INCLUDING 0-6 KM SHEAR OF 45-60 KTS AND DEEP LAYER  
MOISTURE IN PLACE, ALTHOUGH LOW LEVEL INSTABILITY WILL LACKING  
WITH SURFACE BASED CAPE OF ONLY 100-300 J/KG. THE MAIN CONVECTIVE  
CONCERNS AT THIS TIME WOULD BE STRONG WINDS IN DOWNDRAFTS WITH 850  
MB WINDS OF 40-50 KTS SAT NIGHT AND POTENTIALLY SOME ROTATING  
CELLS GIVEN VERY HIGH 0-1 KM HELICITY OF 200-400 M2/S2...BUT WITH  
LIMITED INSTABILITY MUCH OF THIS ENERGY WILL LIKELY NOT MIX DOWN  
TO THE SURFACE.  
 
RAINFALL CLEARS QUICKLY SUN MORNING, WITH DRIER NW FLOW TRAILING  
THE 850 MB TROUGH PASSING FILTERING MUCH COLDER AIR SOUTHWARD SUN  
NIGHT. LATEST FORECAST MODEL CONSENSUS INDICATED AN ADVECTIVE  
LIGHT FREEZE INLAND SUN NIGHT WITH WIND CHILLS IN THE MID 20S MON  
MORNING AS WINDS REMAIN ELEVATED NEAR 10 MPH. COULD REACH WIND  
CHILL ADVISORY CRITERIA FOR PARTS OF NE FL IN ADDITION TO LIGHT  
FREEZE INLAND.  
   
LONG TERM...MON THROUGH WED
 
 
DRY AND COLD MON AS SURFACE HIGH BUILDS NORTH OF THE REGION WITH  
BELOW NORMAL HIGHS ONLY IN THE 50S FOR MOST LOCATIONS. AS THE  
SURFACE RIDGE BEGINS TO BUILDS OVER THE MID-ATLANTIC REGION,  
ONSHORE FLOW BEGINS TO DEVELOP INTO MON NIGHT BRINGING MODERATING  
TEMPERATURES INTO TUE. A COASTAL TROUGH BEGINS TO DEVELOP OVER THE  
LOCAL ATLANTIC WATERS TUE INTO TUE NIGHT WITH A CHANCE OF COASTAL  
SHOWERS AS TEMPERATURES CONTINUE TO WARM BACK TOWARD CLIMO  
VALUES. MODELS DIVERGE WITH THE TIMING AND STRUCTURE OF THE NEXT  
STORM SYSTEM AS IT APPROACHES FROM THE WEST MID-WEEK, SO FOR NOW  
WILL TREND WITH LOW CHANCES OF RAINFALL WED.  
 

 
   
AVIATION.../18Z TAF PERIOD/
 
 
PREVAILING VFR CONDITIONS EXPECTED THIS 18Z TAF PERIOD.  
 

 
   
MARINE
 
 
HIGH PRESSURE WILL BUILD EAST OVER THE LOCAL WATERS TONIGHT  
THROUGH THURSDAY. HIGH PRESSURE WILL SHIFT SOUTH OVER CENTRAL  
FLORIDA FRIDAY AS A WEAKENING FRONT STALLS ACROSS SOUTHERN  
GEORGIA. A STRONGER COLD FRONT WILL MOVE ACROSS THE REGION LATE  
SATURDAY THROUGH EARLY SUNDAY, WITH ADVISORY CONDITIONS EXPECTED  
OVER AT LEAST THE OUTER WATERS BY SAT NIGHT. ADVISORY CONDITIONS  
FOR ALL WATERS SUN-SUN NIGHT DUE TO STRONG POST-FRONTAL NW WINDS.  
HIGH PRESSURE BUILDS NORTH OF THE WATERS MONDAY WITH WINDS VEERING  
MORE NNE AND DECREASING IN MAGNITUDE TO EXERCISE CAUTION LEVELS.  
 
RIP CURRENTS: MODERATE RISK THROUGH THU.  
 

 
   
FIRE WEATHER
 
 
LOW DAYTIME DISPERSION THU DUE TO SUBSIDENCE INVERSION CREATING  
LIGHT WINDS.  
 

 
   
HYDROLOGY
 
 
MINOR FLOODING CONTINUED ACROSS PARTS OF SE GA INCLUDING WITHIN  
THE ALTAMAHA AND SATILLA RIVER BASINS. MODERATE TO MINOR FLOODING  
CONTINUED ACROSS PARTS OF NE FL INCLUDING WITHIN THE SUWANNEE AND  
SANTA FE RIVER BASINS.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
AMG 33 64 46 66 / 0 0 10 10  
SSI 40 61 48 64 / 0 0 10 10  
JAX 35 65 45 69 / 0 0 10 10  
SGJ 41 64 47 69 / 0 0 10 0  
GNV 34 67 42 71 / 0 0 10 10  
OCF 35 68 41 72 / 0 0 10 10  
 

 
   
JAX WATCHES/WARNINGS/ADVISORIES
 
 
FL...FROST ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR ALACHUA-BAKER-  
BRADFORD-CLAY-COLUMBIA-GILCHRIST-HAMILTON-INLAND DUVAL-  
INLAND FLAGLER-INLAND NASSAU-INLAND ST. JOHNS-MARION-PUTNAM-  
SUWANNEE-UNION.  
 
GA...FROST ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR APPLING-  
ATKINSON-BACON-BRANTLEY-CHARLTON-CLINCH-COFFEE-ECHOLS-  
INLAND CAMDEN-INLAND GLYNN-JEFF DAVIS-PIERCE-WARE-WAYNE.  
 
AM...NONE.  

 
 

 
 
ENYEDI/23  
 
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