311  
FXUS62 KJAX 210810  
AFDJAX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE JACKSONVILLE FL  
310 AM EST TUE NOV 21 2017  
   
NEAR TERM (THROUGH TONIGHT)
 
 
A SHORT WAVE AND ASSOCIATED SURFACE LOW ACROSS THE SE GULF WILL MOVE  
INTO CNTL FL TONIGHT AND LIFT NE OFFSHORE BY LATE TONIGHT. RAIN WILL  
OVERSPREAD THE AREA FROM SOUTH TO NORTH TODAY WITH BULK OF ACTIVITY  
THIS AFTERNOON INTO THE EVENING. RAIN WILL TAPER OFF LATE TONIGHT AS  
THE SHORT WAVE LIFTS OUT OF THE AREA. WITH LOW PASSING TO THE SOUTH  
OF THE AREA...MODELS CONTINUE TO INDICATE A SHARP NW TO SE POP AND  
PCP GRADIENT WITH HIGHEST RAINFALL AMOUNTS (LOCALLY UP TO AN INCH  
POSSIBLE) MAINLY SOUTH OF THE I-10 CORRIDOR. MODEL SOUNDINGS ALSO  
CONTINUE TO INDICATE ENOUGH WEAK INSTABILITY FOR A FEW ELEVATED  
STORMS ACROSS THE SAME AREA. AS WINDS VEER TO THE EAST AND SOUTHEAST  
TODAY TEMPS WILL WARM INTO THE MID 70S MOST AREAS DESPITE CLOUD  
COVER. A COLD FRONT WILL DROP SOUTHEAST TOWARDS THE AREA BY LATE  
TONIGHT BEHIND THE DEPARTING LOW AND MOISTURE POOLING AHEAD OF THE  
FRONT MAY LEAD TO AREAS OF LATE NIGHT FOG WHICH IS STRONGLY  
SUGGESTED BY MOS AND SREF GUIDANCE.  
   
SHORT TERM /THROUGH WEDNESDAY NIGHT/
 
 
AS WEAK SHORTWAVE RIDGE SHIFTS EAST OF THE AREA WEDNESDAY MORNING...  
INCREASING LIFT AHEAD OF GULF OF MEXICO SHORTWAVE TROUGH WILL CAUSE  
INCREASING CLOUDINESS OVER EARLY MORNING FOG...WEAK WEAK ISENTROPIC  
LIFT RESULTING IN A MOSTLY CLOUDY DAY WITH SCATTERED LIGHT SHOWERS  
BREAKING OUT. WILL MAINTAIN ISOLATED T-STORMS DURING AFTERNOON GIVEN  
MODEL SUGGESTION OF 500-1000 J/KG CAPE...
BUT UNCERTAINTY AS TO HOW  
MUCH DESTABILIZATION IS REALIZED NORTH OF WARM FRONT IN CLOUDY  
CONDITIONS. CLOUDINESS AND SCATTERED SHOWERS WILL LIKELY KEEP HIGH  
TEMPS DOWN NORTH OF WARM FRONT ...FOLLOWING COOLER MET/ECS MOS  
GUIDANCE RATHER THAN WARMER MAV GUIDANCE FOR HIGH TEMPS...WOULDN'T  
SURPRISE ME IF TEMPS END UP A LITTLE LOWER THAN FORECAST...THOUGH  
ANY BREAKS IN CLOUDINESS ESPECIALLY SOUTHERN AREAS...WILL PUSH TEMPS  
UP TO FORECAST VALUES.  
 
WEDNESDAY NIGHT...LOW PRESSURE DEVELOPS OVER EASTERN GULF OF MEXICO  
WITH WARM FRONT EXTENDING EASTWARD OVER CTRL FL...CLOSE TO ECMWF  
SOLUTION...WHICH IS N OF NAM AND S OF GFS. ISENTROPIC LIFT NORTH OF  
WARM FRONT...IN RIGHT-REAR QUAD OF UPPER JET STREAK...SHOULD  
GENERATE NUMEROUS SHOWERS...POSSIBLY A FEW T-STORMS. MOST WIDESPREAD  
AND HEAVIEST RAINFALL LIKELY TO BE IN A BAND NORTH OVER NORTH-  
CENTRAL AND NORTHEAST FL INTO EXTREME SOUTHEAST GA.  
   
LONG TERM /THURSDAY THROUGH MONDAY/
 
 
FOLLOWING SOLUTIONS WITH SURFACE LOW MOVING SOUTH OF FORECAST  
AREA... WITH ISENTROPIC LIFT GRADUALLY SHIFTING EAST OF FORECAST AREA  
THURSDAY NIGHT AND FRIDAY. WENT WITH CONSENSUS GUIDANCE FOR HIGH  
TEMPS THURSDAY WITH LOW-MID 60S SE GA...MID-UPR 60S I-10  
CORRIDOR...UPR 60S-LWR 70S FURTHER SOUTH.  
 
LOW PRESSURE MOVES OFFSHORE OF E-CTRL FL AND LIFTS NE OFFSHORE OF GA  
AND CAROLINAS THRU SAT...WHILE WEAK HIGH PRESSURE BUILDS OVER OUR  
AREA FROM THE WEST. A STRONGER COLD FRONT MOVES THROUGH OVER THE  
WEEKEND. THE RESULT WILL BE BELOW NORMAL TEMPERATURES DURING THE  
FRIDAY-MONDAY PERIOD WITH DRY CONDITIONS.  
 

 
   
AVIATION
 
PREVAILING VFR CONDITIONS THROUGH THE MORNING BUT  
EXPECTING MVFR BY THIS AFTERNOON INTO THE EVENING AS RAIN  
OVERSPREADS THE AREA FROM SOUTH TO NORTH. A FEW ELEVATED STORMS  
POSSIBLE BUT CONFIDENCE NOT HIGH ENOUGH FOR MENTION IN CURRENT TAF  
PACKAGE.  
 

 
   
MARINE.
 
LOW PRESSURE WILL TRACK FROM THE EASTERN GULF OF MEXICO  
ACROSS CENTRAL FL...THEN NORTHEAST OVER THE OFFSHORE WATERS OF GA  
AND THE CAROLINAS THRU SATURDAY. WINDS WILL BE EASTERLY TO  
SOUTHEASTERLY TODAY...BECOME MORE NORTHEAST TO NORTH NORTHEAST WED-  
FRI AS THE LOW PASSES TO THE SOUTH OF THE AREA...THEN SHIFTS TO  
NORTHWESTERLY AS THE LOW LIFTS NORTHEAST OF THE AREA. DEPENDING ON  
HOW STRONG THE LOW IS AS IT PASSES...AND THE HIGH THAT BUILDS IN  
DURING THE WEEKEND...WINDS AND SEAS COULD APPROACH SMALL CRAFT  
ADVISORY CRITERIA AT TIMES.  
 
RIP CURRENTS: MODERATE RISK INTO WEDNESDAY DUE TO A PERSISTENT  
LONG PERIOD EASTERLY SWELL.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
AMG 73 54 69 51 / 30 30 20 60  
SSI 72 59 68 58 / 50 40 20 60  
JAX 74 57 71 57 / 50 40 30 70  
SGJ 74 61 72 60 / 60 50 40 60  
GNV 74 57 72 57 / 60 40 50 70  
OCF 74 58 75 59 / 60 40 40 50  
 

 
   
JAX WATCHES/WARNINGS/ADVISORIES
 
 
FL...NONE.  
GA...NONE.  
AM...NONE.  
 

 
 

 
 
PP/PW  
 
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