627  
FXUS62 KTAE 220153  
AFDTAE  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TALLAHASSEE FL  
953 PM EDT MON MAY 21 2018  
   
UPDATE
 
 
THE WEAK SURFACE LOW THAT BROUGHT ALL THE CONVECTION TO OUR AREA  
TODAY HAS MOVED WELL INLAND OVER SE AL THIS EVENING. LOCAL RADARS  
SHOW THAT THAT MOST OF THE RAIN HAS DIMINISHED OR MOVED NORTH OF  
OUR CWA LATE THIS EVENING. HOWEVER, AS WE SAW LAST NIGHT  
REGENERATION IS EXPECTED OVER NIGHT SO WILL LEAVE POPS AS IS  
TAPERED LIKELY WEST TO LOWER END CHANCE FAR EAST.  
 

 
   
PREV DISCUSSION [750 PM EDT]
 
 
   
NEAR TERM [THROUGH TONIGHT]
 
 
THE FEATURE TO WATCH THROUGH THE OVERNIGHT HOURS IS THE WEAK SURFACE  
LOW JUST SOUTHWEST OF PANAMA CITY. MODELS SHOW THIS FEATURE DRIFTING  
SLOWLY NORTHWARD THROUGH THE OVERNIGHT HOURS. DEEP TROPICAL MOISTURE  
IS IN PLACE ACROSS THE AREA WITH BANDS OF SHOWERS AND THUNDERSTORMS  
ON THE EASTERN SIDE. POCKETS OF HEAVY RAIN ARE THE MAIN THREAT  
THROUGH THE OVERNIGHT HOURS. IF ANY TRAINING OCCURS, THEN FLASH  
FLOODING ON A VERY LOCALIZED SCALE COULD OCCUR, SIMILAR TO WHAT WE  
SAW THIS MORNING IN SOUTHWEST WAKULLA COUNTY. HOWEVER, DUE TO THE  
UNCERTAINTY AND THE EXPECTED ISOLATED NATURE OF THE FLOODING SHOULD  
IT OCCUR, WE'VE OPTED NOT TO ISSUE A LARGE SCALE FLASH FLOOD WATCH  
FOR NOW. INSTEAD, A MENTION OF HEAVY RAINFALL WAS ADDED TO THE POINT  
AND CLICK FORECAST FOR THE WESTERN HALF OF THE AREA. OVERNIGHT LOWS  
WILL GENERALLY BE IN THE UPPER 60S TO LOWER 70S.  
 
   
SHORT TERM [TUESDAY THROUGH WEDNESDAY NIGHT]
 
 
AT THE START OF THE PERIOD, A WEAK SURFACE LOW PRESSURE AREA WILL  
BE MOVING INLAND ACROSS THE FLA PANHANDLE AND INTO SRN ALABAMA.  
THIS FEATURE IS EXPECTED TO CONTINUE TO BE A FOCUS FOR MORNING  
RAINFALL ACROSS THE WESTERN HALF OF THE REGION. SOME OF THIS RAIN  
COULD BE LOCALLY HEAVY. MODEL GUIDANCE WAS A LITTLE SPLIT ON POP  
CHANCES, BUT WITH A VERY MOIST TROPICAL AIRMASS IN PLACE AND SOME  
HEATING, AT LEAST 60-70 PERCENT POPS SEEM REASONABLE FOR TUESDAY  
AFTERNOON. WHILE LOCALLY HEAVY RAINFALL IS POSSIBLE, STORM MOTION  
SHOULD STILL BE FAST ENOUGH TO PREVENT ANY WIDESPREAD FLOOD  
CONCERNS.  
 
THE SURFACE LOW PRESSURE AREA DISSIPATES BY TUESDAY NIGHT BUT  
WITH SUFFICIENT MOISTURE IN PLACE, SHOWER AND THUNDERSTORM  
ACTIVITY SHOULD CONTINUE WELL INTO THE EVENING, BUT THEN TAPER OFF  
AFTER MIDNIGHT.  
 
ON WEDNESDAY, THERE DOESN'T APPEAR TO BE ANY LARGE SCALE TRIGGER  
FOR SHOWER AND THUNDERSTORM ACTIVITY, SO STORMS ARE EXPECTED TO BE  
MORE DIURNAL IN NATURE. STORMS SHOULD BEGIN DEVELOPING BY LATE  
MORNING AND CONTINUE THROUGH THE AFTERNOON HOURS. WENT ABOUT 10-20  
PERCENT HIGHER THAN GUIDANCE FOR AN AFTERNOON POP FORECAST AROUND 70  
PERCENT MOST AREAS, WHICH IS MORE TYPICAL FOR A SUMMERTIME SOUTHERLY  
FLOW REGIME.  
 
TEMPERATURES THROUGH THE SHORT TERM PERIOD WILL BE BELOW NORMAL  
DURING THE DAYTIME HOURS DUE TO ALL THE CONVECTIVE ACTIVITY BUT  
ABOVE NORMAL OVERNIGHT, POSSIBLY IN THE LOW 70S FOR A FEW PLACES.  
 
   
LONG TERM [THURSDAY THROUGH MONDAY]
 
 
THE LATEST MODEL RUNS CONTINUE TO INDICATE A LOW AND UPPER-LEVEL LOW  
DEVELOPING IN THE GULF ON THURSDAY. THERE IS CONSIDERABLE  
DISAGREEMENT ON TRACK AND INTENSITY BETWEEN MODELS AT THIS TIME. THE  
12Z EURO HAS THE LOW MOVING NORTH FROM THE YUCATAN TOWARDS LOUISIANA  
AND MISSISSIPPI. THE 12Z GFS, ON THE OTHER HAND, SHOWS THE LOW  
MOVING NORTHEAST AND TURNING FURTHER NORTH ALONG THE WESTERN COAST  
OF FLORIDA. DESPITE THE CURRENT LACK OF CONSENSUS, THE LATEST  
RUNS OF BOTH HAVE SHIFTED TOWARDS MORE AGREEMENT IN COMPARISON TO  
PREVIOUS RUNS. BASED ON THIS GUIDANCE, A SUB-TROPICAL OR TROPICAL  
SYSTEM AFFECTING THE CWA IS CERTAINLY POSSIBLE IN THE LONG TERM  
PERIOD. REGARDLESS OF HOW THE SYSTEM DEVELOPS, HIGHER POPS CAN BE  
EXPECTED. HIGH TEMPERATURES WILL STAY IN THE 80S THROUGHOUT THE  
PERIOD AND LOWS WILL REMAIN STEADY AROUND THE UPPER 60S AND LOWER  
70S.  
 
   
AVIATION [THROUGH 00Z WEDNESDAY]
 
 
ALTHOUGH SHOWERS AND THUNDERSTORMS HAVE DIMINISHED SOMEWHAT ACROSS  
THE REGION THIS EVENING, WE WILL BE LOOKING FOR POSSIBLE  
REGENERATION OVERNIGHT. EITHER WAY, WITH ABUNDANT MOISTURE IN  
PLACE EXPECT WIDESPREAD IFR CIGS WITH AT LEAST PERIODS OF LIGHT  
RAIN OR SHOWERS. MVFR CONDITIONS SHOULD PREVAIL FROM JUST AFTER  
DAYBREAK TO MID MORNING BEFORE VFR CONDITIONS RETURN IN THE  
AFTERNOON ALONG WITH A BETTER CHANCE FOR ADDITIONAL SHOWERS AND  
VFR TUESDAY MORNING BUT ANOTHER ROUND OF SHOWERS AND  
THUNDERSTORMS.  
 
   
MARINE
 
 
DESPITE A STORMY WEATHER PATTERN THROUGH THE WEEK, WINDS AND SEAS  
SHOULD BE FAIRLY LOW OUTSIDE OF THUNDERSTORMS GIVEN THE WEAK  
PRESSURE PATTERN. AN INCREASE IN WINDS AND SEAS IS EXPECTED BY  
FRIDAY AS A TROPICAL DISTURBANCE MOVES INTO THE SOUTHERN GULF OF  
MEXICO. ADVISORY CONDITIONS ARE POSSIBLE ACROSS THE MARINE AREA  
THEREAFTER.  
 
   
FIRE WEATHER
 
 
WITH AMPLE MOISTURE AND LIGHT WINDS ACROSS OUR AREA THERE ARE NO  
FIRE WEATHER CONCERNS THROUGH THE NEXT SEVERAL DAYS.  
 
   
HYDROLOGY
 
 
EARLY THIS MORNING, A NARROW BAND OF HEAVY RAINFALL TRAINED OVER  
COASTAL WAKULLA COUNTY NEAR SOPCHOPPY AND PRODUCED AN ESTIMATED  
8-11 INCHES OF RAINFALL IN A 6 HOUR TIME PERIOD. THIS RESULTED IN  
SIGNIFICANT RISES ON THE SOPCHOPPY RIVER. BECAUSE THE BULK OF THE  
HEAVIEST RAINFALL (AND ASSOCIATED RIVER RISES) OCCURRED BELOW THE  
GAUGE SITE, AN AREAL FLOOD WARNING WAS ISSUED FOR SOPCHOPPY AND  
WILL REMAIN IN EFFECT FOR THIS AREA THROUGH THE OVERNIGHT HOURS.  
 
RAINFALL ELSEWHERE WAS GENERALLY IN THE 1-2 INCH RANGE OVERNIGHT  
WITH SOME ISOLATED HEAVIER TOTALS. AS A RESULT, WE'RE BEGINNING TO  
OVERCOME THE RECENT DRY CONDITIONS AND FLOODING IS BECOMING MORE  
OF A CONCERN.  
 
OVER THE NEXT COUPLE OF DAYS, MODEL GUIDANCE SUGGESTS AN INCREASED  
POTENTIAL FOR FLOODING ACROSS SOUTHEAST ALABAMA AND THE FLORIDA  
PANHANDLE ALONG THE BACKSIDE OF A DEPARTING AREA OF LOW PRESSURE,  
MUCH AS OCCURRED THIS MORNING IN SOPCHOPPY. SINCE THE THREAT IS  
LOCALIZED, A FLOOD WATCH WON'T BE ISSUED AT THIS TIME. HOWEVER  
THERE IS POTENTIAL FOR STORMS TO PRODUCE A QUICK 2-5 INCHES OF  
RAIN WITH ISOLATED HEAVIER TOTALS IN SOME AREAS OVERNIGHT THROUGH  
TUESDAY.  
 
LONGER TERM, THE WET PATTERN IS EXPECTED TO CONTINUE INTO NEXT  
WEEK. WHILE IT IS TOO EARLY TO SPECULATE ON RAINFALL AMOUNTS, THE  
PERSISTENT WET PATTERN SUGGESTS THAT THE FLOOD RISK WILL CONTINUE  
TO INCREASE THROUGH THE WEEK.  
 
MOST OF THE RIVERS HAVE NOW MOVED WELL OFF BASE FLOWS AND BY THE  
END OF THE WEEK, SOME OF THE LARGER-STEM RIVERS WILL NEED TO BE  
MONITORED FOR THE POTENTIAL FOR MINOR FLOODING DEPENDING ON WHERE  
THE HEAVIEST RAIN SETS UP FOR THIS WEEKEND.  
 
   
SPOTTER INFORMATION STATEMENT
 
 
SPOTTER ACTIVATION IS NOT REQUESTED. HOWEVER, SPOTTERS ARE ALWAYS  
ENCOURAGED TO SAFELY REPORT SIGNIFICANT WEATHER CONDITIONS WHEN THEY  
OCCUR BY CALLING THE OFFICE OR TWEETING US @NWSTALLAHASSEE.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
TALLAHASSEE 70 85 68 85 70 / 50 60 50 70 50  
PANAMA CITY 73 82 71 83 73 / 70 70 50 60 40  
DOTHAN 69 83 68 85 70 / 70 80 60 70 50  
ALBANY 70 85 68 86 70 / 50 70 50 70 50  
VALDOSTA 69 85 66 85 69 / 40 60 40 70 40  
CROSS CITY 69 85 67 86 70 / 50 60 40 60 40  
APALACHICOLA 73 82 72 82 73 / 60 50 40 50 40  
 

 
   
TAE WATCHES/WARNINGS/ADVISORIES
 
 
FL...HIGH RIP CURRENT RISK UNTIL 2 AM EDT TUESDAY FOR COASTAL  
FRANKLIN.  
 
GA...NONE.  
AL...NONE.  
GM...NONE.  

 
 

 
 
UPDATE...BARRY  
NEAR TERM...DVD  
SHORT TERM...GODSEY  
LONG TERM...SKEEN/GODSEY  
AVIATION...BARRY  
MARINE...GODSEY  
FIRE WEATHER...BARRY  
HYDROLOGY...GODSEY  
 
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