304  
FXUS62 KJAX 250039  
AFDJAX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE JACKSONVILLE FL  
839 PM EDT THU SEP 24 2020  
   
UPDATE
 
 
WARM AND HUMID CONDITIONS WILL CONTINUE OVERNIGHT. AREAS OF  
STRATUS AND INLAND PATCHY FOG ARE EXPECTED BY MORNING. ISOLATED  
SHOWERS WILL AFFECT PARTS OF INTERIOR SE GA OVERNIGHT ALONG WITH  
A FEW SHOWERS POSSIBLE NEAR THE EAST COAST DUE TO SOUTHEAST WINDS  
PROVIDING COASTAL CONVERGENCE. LOWS TONIGHT WILL BE IN THE LOWER  
70S INLAND AND IN THE MID 70S NEAR THE COAST. AFTERNOON SHOWERS  
AND THUNDERSTORMS EXPECTED FRIDAY AFTERNOON WITH A FEW STRONG TO  
SEVERE STORMS POSSIBLE OVER SE GA.  
 

 
   
PREV DISCUSSION [730 PM EDT]
 
 
   
NEAR TERM [THROUGH TONIGHT]
 
 
LATE MORNING SURFACE ANALYSIS DEPICTED STRENGTHENING HIGH  
PRESSURE (1018 MILLIBARS) CENTERED BETWEEN CAPE HATTERAS AND  
BERMUDA. MEANWHILE, THE REMNANT LOW PRESSURE CENTER (1004  
MILLIBARS) THAT WAS ONCE TROPICAL STORM BETA WAS EXITING THE LOWER  
MISSISSIPPI VALLEY AND WAS PROGRESSING EAST-NORTHEASTWARD TOWARDS  
THE TENNESSEE VALLEY. ALOFT...DEEP-LAYERED RIDGING WAS CENTERED  
OVER THE BAHAMAS. OTHERWISE, A SHORTWAVE TROUGH THAT IS WEAKENING  
OVER THE OHIO VALLEY WILL BE RE-INVIGORATED BY A MORE POTENT  
UPSTREAM SHORTWAVE THAT IS DIVING SOUTHEASTWARD ACROSS THE UPPER  
MIDWEST. GOES-EAST DERIVED TOTAL PRECIPITABLE WATER VAPOR IMAGERY  
DEPICTS A GRADUALLY MOISTENING AIR MASS OVER OUR REGION, WITH  
PWATS STILL BELOW 1.5 INCHES AREA-WIDE. A RIBBON OF DEEP TROPICAL  
MOISTURE IS ADVECTING NORTHWARD FROM THE GULF OF MEXICO INTO THE  
FL PANHANDLE, WHERE PWATS ARE SURGING TO ABOVE 2 INCHES.  
 
ISOLATED SHOWERS WILL BE POSSIBLE THROUGH THE AFTERNOON HOURS  
TODAY ALONG THE I-95 CORRIDOR ALONG AN INLAND MOVING ATLANTIC SEA  
BREEZE BOUNDARY. A FEW SHOWERS WILL ALSO BE POSSIBLE NEAR THE  
ALTAMAHA RIVER AS DEEPER MOISTURE ADVECTS NORTHEASTWARD FROM THE  
GULF OF MEXICO AND THE FL PANHANDLE. OTHERWISE, BREEZY ONSHORE  
WINDS WILL DEVELOP AT COASTAL LOCATIONS BY NOON AS OUR LOCAL  
PRESSURE GRADIENT CONTINUES TO TIGHTEN. WARM AIR ADVECTION WILL  
BOOST HIGHS INTO THE UPPER 80S AT MOST INLAND LOCATIONS, WITH LOW  
TO MID 80S EXPECTED AT COASTAL LOCATIONS. MUCH WARMER LOWS ARE  
EXPECTED TONIGHT AS A LOW LEVEL VEERING WIND PROFILE ADVECTS DEEP  
TROPICAL MOISTURE ACROSS THE REST OF OUR REGION OVERNIGHT. A FEW  
SHOWERS WILL REMAIN POSSIBLE ACROSS INLAND PORTIONS OF SOUTHEAST  
GA OVERNIGHT, WITH COASTAL CONVERGENCE STRENGTHENING AND  
DEVELOPING A FEW SHOWERS TOWARDS SUNRISE FOR LOCATIONS ALONG  
COASTAL PORTIONS OF ST. JOHNS AND FLAGLER COUNTIES. LOWS TONIGHT  
WILL RANGE FROM THE LOWER 70S INLAND TO THE MID 70S AT COASTAL  
LOCATIONS.  
 
   
SHORT TERM [FRIDAY THROUGH SATURDAY NIGHT]
 
 
COLD FRONT TRAILING FROM THE REMNANTS OF BETA WILL MOVE THROUGH  
THE AREA FRIDAY, EXITING FRIDAY NIGHT. PWATS WILL CONTINUE TO RISE  
AHEAD OF THIS SYSTEM, WITH 1.8-2.2 INCHES ON TAP FOR STORMS TO  
PRODUCE ISOLATED HEAVY RAINFALL. WE'RE TRANSITIONING INTO THE TIME  
OF YEAR WHEN WE'RE STARTING TO GET STRONGER WINDS ALOFT AGAIN AND  
WITH ABOUT 30 KTS 0-6 KM SHEAR IN PLACE FRIDAY ALONG WITH AROUND  
1500 J/KG MLCAPE, WE COULD SEE A FEW STORMS PRODUCING DAMAGING  
WIND GUSTS TO AROUND 30-50 MPH. ON SATURDAY, HIGH PRESSURE WILL  
BUILD OVER THE SOUTHEAST IN THE WAKE OF THE FRONT, BUT WITH  
SOUTHWESTERLY FLOW FROM THE GULF, WARM TEMPERATURES, AND JUST  
ENOUGH MOISTURE, COULD SEE SCATTERED SHOWERS WITH EMBEDDED  
THUNDERSTORMS SATURDAY AFTERNOON.  
 
   
LONG TERM [SUNDAY THROUGH THURSDAY]
 
 
A PARADE OF (MOSTLY DRY) COLD FRONTS WILL CONTINUE, BRINGING  
DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS SUNDAY THROUGH  
TUESDAY. A MUCH DRIER, COLDER AIRMASS WILL BUILD OVER THE AREA  
TUESDAY INTO TUESDAY NIGHT, HOWEVER, SO THINGS WILL DRY OUT MID-  
WEEK. TEMPERATURES WILL COOL DOWN THROUGH THE WEEK, STARTING NEAR  
90 ON SUNDAY AND RETURNING BACK TO THE UPPER 70S-LOW 80S BY  
THURSDAY. OVERNIGHT LOWS WILL DROP THROUGH THE WEEK AS WELL,  
STARTING AROUND 70 ON SUNDAY NIGHT AND FALLING INTO THE MID 50S-  
LOW 60S THURSDAY NIGHT.  
 
   
AVIATION
 
[THROUGH 00Z SATURDAY]  
VFR CONDITIONS WILL PREVAIL FOR MOST OF TONIGHT. LATE NIGHT MVFR  
OR IFR CONDITIONS DUE TO FOG/LOW CLOUDS ARE POSSIBLE 08Z-12Z  
INLAND...MAINLY AT GNV AND VQQ. SCATTERED SHOWERS AND THUNDERSTORMS  
ARE EXPECTED ON FRIDAY...MORE LIKELY AFTER 17Z.  
 
   
MARINE
 
 
WAVES WILL CONTINUE TO SLOWLY FALL BELOW 7 FT THROUGH THE EVENING  
HOURS, WHILE SOUTHEAST WINDS AROUND 15 TO 20 KNOTS PREVAIL  
TONIGHT AND INTO FRIDAY AHEAD OF OUR NEXT COLD FRONT. A MORE  
ACTIVE PATTERN FOR SHOWERS AND THUNDERSTORMS IS SETTING UP AS A  
SERIES OF COLD FRONTS ROLL ACROSS THE COASTAL WATERS THE NEXT FEW  
DAYS, WITH THE STRONGEST FRONT ON TUESDAY. CHANCE TO SLIGHT CHANCE  
FOR SHOWERS AND THUNDERSTORMS ANTICIPATED THROUGH TUESDAY.  
 
RIP CURRENTS: HIGH RISK OF RIP CURRENTS AT ALL AREA BEACHES  
TODAY THROUGH FRIDAY, THEN RISK SHOULD DECREASE OVER THE WEEKEND.  
 
   
HYDROLOGY
 
 
ELEVATED WATER LEVELS WILL CONTINUE TO GRADUALLY LOWER THROUGH  
THE ST. JOHNS RIVER BASIN. TIDAL GAUGE AT BUFFALO BLUFF PEAKED IN  
MINOR FLOOD AT 1.64 FT AROUND 11 AM THIS MORNING AND IS TRENDING  
DOWN. MINOR FLOODING AROUND 1-1.5 FT MHHW WILL REMAIN POSSIBLE,  
MOSTLY IN PUTNAM AND FLAGLER COUNTY THROUGH FRIDAY WITH NUISANCE  
FLOODING OF LESS THAN A FOOT POSSIBLE FURTHER NORTH.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
AMG 71 88 71 88 70 / 20 70 40 20 0  
SSI 75 85 74 85 73 / 20 50 30 30 10  
JAX 72 90 72 89 73 / 10 50 40 30 0  
SGJ 75 88 74 88 73 / 20 50 40 30 10  
GNV 72 91 72 90 71 / 10 60 30 40 0  
OCF 72 91 72 90 73 / 10 60 30 40 0  
 

 
   
JAX WATCHES/WARNINGS/ADVISORIES
 
 
FL...HIGH RIP CURRENT RISK THROUGH FRIDAY EVENING FOR COASTAL DUVAL-  
COASTAL FLAGLER-COASTAL NASSAU-COASTAL ST. JOHNS.  
 
COASTAL FLOOD ADVISORY UNTIL 11 PM EDT FRIDAY FOR INLAND FLAGLER-  
PUTNAM.  
 
GA...HIGH RIP CURRENT RISK THROUGH FRIDAY EVENING FOR COASTAL CAMDEN-  
COASTAL GLYNN.  
 
AM...NONE.  

 
 
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