871  
FXUS62 KJAX 221843  
AFDJAX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE JACKSONVILLE FL  
243 PM EDT SUN APR 22 2018  
   
NEAR TERM /THROUGH MONDAY/
 
 
BREEZY TO WINDY CONDITIONS WILL CONTINUE THROUGH TONIGHT,  
ESPECIALLY FOR COASTAL AREAS AS THE PRESSURE GRADIENT REMAINS  
TIGHT. SIGNIFICANT CLOUD COVER HAS SPREAD ACROSS THE REGION, WITH  
CEILINGS 3-6KFT. HIGH CLOUDS WERE ALSO STREAMING IN FROM THE WEST  
AHEAD OF THE UPPER LOW SITTING OVER ARKANSAS. A BAND OF LIGHT  
SHOWERS WAS MOVING NORTHWARD ACROSS SOUTHEAST GEORGIA NEAR THE  
ALTAMAHA RIVER, AND THIS IS THE WARM FRONT LIFTING NORTHWARD  
ACROSS THE AREA. DRY AIR IN THE LOW/MID LEVELS HAS KEPT A LID ON  
MOST CONVECTIVE ACTIVITY TODAY, AND ONLY ISOLATED TO WIDELY  
SCATTERED SHOWERS HAVE DEVELOPED THUS FAR. THE DRIER AIR IS  
FORECAST TO MOVE OUT THIS EVENING, WITH PRECIPITABLE WATER VALUES  
INCREASING TO 1.6-1.75 INCHES. ISOLATED STORMS DEVELOPED SOUTH OF  
THE REGION WHERE TEMPERATURES HAVE RISEN INTO THE LOWER 80S.  
OUTFLOW FROM THIS ACTIVITY WAS MOVING INTO THE SOUTHEAST PORTION  
OF THE REGION, AND SCATTERED TO NUMEROUS SHOWERS, AND POSSIBLE AN  
ISOLATED STORM IS EXPECTED ACROSS THIS REGION THIS AFTERNOON.  
ELSEWHERE, ISOLATED TO WIDELY SCATTERED SHOWERS ARE POSSIBLE.  
 
AN UPPER LEVEL LOW OVER ARKANSAS WILL ONLY SLOWLY MEANDER TO THE  
EAST OVER THE NEXT 24-HOURS. A SHORTWAVE ROTATING THROUGH THE  
SOUTHERN PORTION OF THE LOW WILL PUSH ACROSS THE PANHANDLE OF FL  
AND GEORGIA TONIGHT. AT THE SURFACE, AN AREA OF LOW PRESSURE  
OVER THE SOUTHEAST WILL BEGIN TO OCCLUDE, WITH THE SURFACE LOW  
RETROGRADING TO THE NORTHWEST OVER EASTERN ARKANSAS AND WESTERN  
TENNESSEE. AS THE SHORTWAVE PUSHES INTO THE AREA, A PREFRONTAL  
TROUGH WILL PUSH INTO SOUTHEAST GEORGIA AND THE SUWANEE VALLEY.  
THIS WILL BRING NUMEROUS TO WIDESPREAD SHOWERS AND EMBEDDED  
THUNDERSTORMS. SHOWERS AND EMBEDDED STORMS WERE BEGINNING TO  
DEVELOP TO THE WEST OF THE REGION, AND THESE SHOWERS AND STORMS  
WILL MOVE INTO THE WESTERN PORTION OF THE REGION TONIGHT. COASTAL  
CONVERGENCE IS ALSO FORECAST TO BRING SCATTERED TO NUMEROUS  
SHOWERS AND POSSIBLY A THUNDERSTORM FOR THE EAST COAST AS WELL  
AFTER MIDNIGHT, WITH LESSER ACTIVITY ACROSS THE REST OF INTERIOR  
NORTHEAST FLORIDA OVERNIGHT. RAINFALL AMOUNTS TONIGHT ARE  
FORECAST TO BE GENERALLY 0.5-1 INCH, WITH LOCALLY HIGHER AMOUNTS  
POSSIBLE.  
 
CAMS INDICATE THAT THE PREFRONTAL TROUGH ACTIVITY MAY WANE IN THE  
MORNING HOURS AS THE SHORTWAVE MOVES OFF TO THE EAST. THE AREA MAY  
SEE SOME HEATING DURING THE DAY, WITH TEMPERATURES RISING INTO THE  
UPPER 70S TO LOWER 80S. AN EAST COAST SEA BREEZE IS THEN FORECAST  
TO DEVELOP, WITH ACTIVITY DEVELOPING OR BECOMING REINVIGORATED FOR  
THE COASTAL COUNTIES IN THE MID AFTERNOON. CAPE VALUES IN THE  
1500-2500 J/KG RANGE SUPPORT STRONG STORMS DEVELOPING ALONG THE  
EAST COAST, WITH HAIL AND GUSTY WINDS THE MAIN THREATS. A DRY SLOT  
WILL PUSH INTO THE WESTERN PORTION OF THE REGION IN THE MID TO  
LATE AFTERNOON, AND SHOWERS AND STORMS WILL BEGIN TO END FROM WEST  
TO EAST. RAINFALL TOTALS 1-2 INCHES ARE EXPECTED ACROSS THE  
REGION, AND LOCALLY HEAVIER AMOUNTS ARE POSSIBLE.  
   
SHORT TERM /MONDAY NIGHT THROUGH THURSDAY/
 
 
A COLD FRONT EXTENDING FROM A LOW JUST TO THE NORTH WILL MOVE  
SOUTHEAST ACROSS THE REGION MONDAY NIGHT INTO TUESDAY MORNING WITH  
A CHANCE FOR SHOWERS AND STORMS. THE LOW MOVES UP THE EAST COAST  
ON TUESDAY, WITH AN ASSOCIATED TROUGH APPROACHING THE REGION FROM  
THE NORTHWEST IN THE AFTERNOON. BEST RAINFALL CHANCES ON TUESDAY  
WILL BE IN THE MORNING EAST WITH THE EXITING COLD FRONT.  
OTHERWISE, MOST OF THE DAY WILL BE DRY. THIS TROUGH WILL PASS  
THROUGH TUESDAY NIGHT WITH LIMITED MOISTURE.  
 
THE REGION WILL BE IN THE BASE OF A FAIRLY BROAD TROUGH EXTENDING  
SOUTH FROM THE NORTHEAST LOW WEDNESDAY INTO WEDNESDAY NIGHT,  
HOWEVER THERE IS LITTLE MOISTURE FORECAST FOR RAIN. NEAR NORMAL  
TEMPERATURES WILL BE EXPECTED WEDNESDAY.  
 
A QUICK MOVING WAVE IS EXPECTED TO MOVE EAST OVER THE REGION ON  
THURSDAY, WITH ENOUGH MOISTURE FOR SHOWERS AND POSSIBILITY OF  
STORMS. TEMPERATURES WILL TREND NEAR TO SLIGHTLY BELOW NORMAL ON  
THURSDAY, DUE TO THE EXPECTED CLOUD COVER.  
   
LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/
 
 
EXTENDED RANGE MODELS CONTINUE TO DIVERGE IN THIS PERIOD.  
REASONABLE AGREEMENT IN BRINGING A TROUGH IN THURSDAY NIGHT INTO  
FRIDAY. THE GFS PUSHES THIS FRONT THROUGH WITH HIGH PRESSURE  
BUILDING FROM THE WEST FOR THE WEEKEND. THE ECMWF ON THE OTHER  
HAND DEVELOPS A LOW IN THE GULF WHICH GETS CAUGHT IN THE FRONT,  
RESULTING IN A SLOWER PASSAGE, AND MUCH MORE MOISTURE INTO THE  
WEEKEND. THE ECMWF THEN PUSHES THIS SYSTEM TO THE EAST SATURDAY  
NIGHT WITH THE HIGH BUILDING FROM THE WEST SUNDAY. WILL TREND  
TOWARD ECMWF DEPICTION, BUT WITH LOWER PRECIPITATION CHANCES.  
 
TEMPERATURES WILL TREND NEAR TO SLIGHTLY BELOW NORMAL THIS PERIOD.  
 

 
   
AVIATION
 
 
MOSTLY CLOUDY TO CLOUDY SKIES WITH VFR CIGS ARE FORECAST TO  
CONTINUE THROUGH THE AFTERNOON HOURS. ISOLATED TO WIDELY SCATTERED  
LIGHT SHOWERS WERE DEVELOPING ACROSS THE REGION, AND THESE MAY  
IMPACT THE TAF SITES THIS AFTERNOON. AN ISOLATED THUNDERSTORM IS  
POSSIBLE ACROSS NORTH CENTRAL FLORIDA, MAINLY SOUTH OF THE TAF  
SITES THIS AFTERNOON. HI-RES MODELS INDICATE THAT SHOWERS WILL  
LIKELY DEVELOP AFTER MIDNIGHT FOR THE COASTAL TAF SITES, WITH  
ACTIVITY REMAINING MAINLY WEST OF KGNV OVERNIGHT. CEILINGS MAY  
BEGIN TO LOWER DUE TO SHOWERS OVERNIGHT. THERE IS A LOW CHANCE OF  
A THUNDERSTORM OVERNIGHT, BUT MUCH HIGHER CHANCES DURING THE DAY  
ON MONDAY. WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS ARE  
EXPECTED ON MONDAY. THE HEAVIEST ACTIVITY AT THE TAF SITES IS  
LIKELY TO BE FROM 14-22Z ON MONDAY. BREEZY EAST TO SOUTHEAST WINDS  
WILL PREVAIL, BECOMING SOUTHERLY ON MONDAY.  
 

 
   
MARINE
 
 
SCA CONDITIONS WILL CONTINUE FOR THE MARINE AREAS THROUGH MONDAY.  
EASTERLY WINDS 20-25 KNOTS WILL BECOME SOUTHEASTERLY TONIGHT AND  
MONDAY AHEAD OF FRONTAL BOUNDARY ACROSS THE SOUTHEAST. WINDS WILL  
THEN TURN SOUTHERLY AND DIMINISH TO 15-20 KNOTS MONDAY NIGHT. THE  
FRONTAL BOUNDARY WILL MOVE THROUGH THE REGION ON TUESDAY, WITH  
WINDS SHIFTING TO THE WEST. LIGHTER WINDS WILL THEN PREVAIL  
THROUGH THE MIDDLE OF THE WEEK.  
 
RIP CURRENTS: HIGH RISK OF RIP CURRENTS THIS AFTERNOON. MODERATE  
TO HIGH RISK OF RIP CURRENTS ON MONDAY.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
AMG 63 79 58 77 / 80 70 20 10  
SSI 65 77 63 75 / 80 100 20 10  
JAX 65 82 62 81 / 60 90 20 20  
SGJ 66 79 63 80 / 60 90 30 20  
GNV 65 83 62 80 / 40 50 30 20  
OCF 65 83 63 80 / 40 50 40 20  
 

 
   
JAX WATCHES/WARNINGS/ADVISORIES
 
 
FL...HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR COASTAL  
DUVAL-COASTAL NASSAU-FLAGLER-ST. JOHNS.  
 
GA...HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR COASTAL  
CAMDEN-COASTAL GLYNN.  
 
AM...SMALL CRAFT ADVISORY UNTIL 5 AM EDT TUESDAY FOR WATERS FROM  
ALTAMAHA SOUND GA TO FERNANDINA BEACH FL FROM 20 TO 60 NM-  
WATERS FROM FERNANDINA BEACH TO ST. AUGUSTINE FL FROM 20 TO  
60 NM-WATERS FROM ST. AUGUSTINE TO FLAGLER BEACH FL FROM 20  
TO 60 NM.  
 
SMALL CRAFT ADVISORY UNTIL 4 PM EDT MONDAY FOR COASTAL WATERS  
FROM ALTAMAHA SOUND TO FERNANDINA BEACH FL OUT 20 NM-  
COASTAL WATERS FROM FERNANDINA BEACH TO ST. AUGUSTINE FL  
OUT 20 NM-COASTAL WATERS FROM ST. AUGUSTINE TO FLAGLER  
BEACH FL OUT 20 NM.  
 

 
 

 
 
KENNEDY/23/SANDRIK  
 
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