917  
FXUS62 KTAE 152349  
AFDTAE  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TALLAHASSEE FL  
649 PM EST FRI DEC 15 2017  
   
NEAR TERM [THROUGH TONIGHT]
 
 
LOCAL RADAR IMAGERY SHOWS PATCHY LIGHT DRIZZLE ACROSS THE  
NORTHWESTERN HALF OF OUR CWA THIS EVENING AND MODEL ANALYSIS SHOWS  
MODERATE ISENTROPIC ASCENT ALONG THE 300-305K SURFACE WILL ALLOW  
THIS PATCHY DRIZZLE TO CONTINUE THROUGH AROUND 2 AM, BUT TAPERING  
OFF THROUGH THE EVENING AS THE FORCING SHIFTS EASTWARD. OTHERWISE,  
EXPECT A CLOUDY NIGHT WITH LOW TEMPERATURES IN THE 30S NORTH OF A  
LINE FROM DE FUNIAK SPRINGS, FL TO FITZGERALD, GA AND LOWS IN THE  
LOW TO MID 40S SOUTH OF THAT LINE.  
 

 
   
PREV DISCUSSION [621 PM EST]
 
 
   
SHORT TERM [SATURDAY THROUGH SUNDAY NIGHT]
 
 
ON SATURDAY, ZONAL FLOW ALOFT WILL AMPLIFY INTO DEEP LAYER  
RIDGING, WITH NO RAIN FORECAST AND MID/HIGH CLOUDS GRADUALLY  
DISSIPATING. SUNDAY, WHILE RIDGING WILL PREVAIL OVER THE IMMEDIATE  
TRI-STATE REGION, A SHORTWAVE MOVING THROUGH THE MISSISSIPPI  
VALLEY WILL RESULT IN INCREASED RAIN CHANCES FROM THE CENTRAL GULF  
COAST THROUGH THE TENNESSEE VALLEY. THOUGH THE SHORTWAVE WILL  
QUICKLY LIFT NORTHEAST AND THE ASSOCIATED COLD FRONT WON'T QUITE  
REACH OUR AREA BY SUNDAY NIGHT, IT WILL OPEN UP A STRONG LOW-LEVEL  
WAA REGIME AS THE SURFACE RIDGE SLIDES EASTWARD, WITH ISENTROPIC  
ASCENT FOCUSED PRIMARILY IN THE 295-305K WINDOW. THUS, SHOWER AND  
ISOLATED THUNDERSTORM CHANCES WILL INCREASE DRAMATICALLY OVERNIGHT  
SUNDAY, ESPECIALLY ALONG AND WEST OF A LINE FROM ALBANY THROUGH  
PANAMA CITY. AFTER SATURDAY, TEMPERATURES BOTH DAY AND NIGHT WILL  
LIKELY BE 10+ DEGREES ABOVE NORMAL.  
 
   
LONG TERM [MONDAY THROUGH FRIDAY]
 
 
THE UNSTABLE WAA REGIME UNDER LOW AMPLITUDE RIDGING WILL CONTINUE  
THROUGH TUESDAY WHEN A SHORTWAVE IS FORECAST TO MOVE THROUGH THE  
SOUTHEAST AND POSSIBLY CLEAR OUT THE WET PATTERN BY WEDNESDAY  
AFTERNOON. HOWEVER, THERE REMAINS DISAGREEMENT AS TO JUST HOW  
FAST THIS IS GOING TO HAPPEN, WITH THE ECMWF BEING THE SLOWER  
SOLUTION AND NOT REALLY PUSHING THE SHORTWAVE THROUGH UNTIL  
THURSDAY AFTERNOON. FURTHER, THE GFS AND THE ECMWF ARE IN DECENT  
AGREEMENT TIMING ANOTHER LATE WEEK COLD FRONT INTO THE REGION. SO,  
WITH THE SLOWER ECWMF SOLUTION REGARDING THE INITIAL WAVE, THE  
ENTIRE EXTENDED PERIOD REMAINS WET WHILE THE GFS GIVES US A COUPLE  
DRY DAYS TO END THE WEEK. FWIW, THE CANADIAN FAVORS THE MORE  
PROGRESSIVE GFS AND SO THE FORECAST CLOSER REFLECTS THE GFS THOUGH  
HOLDS SLIGHT CHANCE POPS THROUGH THE PERIOD. EITHER WAY, EXPECT  
TWO FRONTAL SYSTEMS NEXT WEEK WITH THEIR EXACT TIMING STILL A BIT  
UNCERTAIN. HIGHS AND LOWS WILL GENERALLY BE ABOVE AVERAGE,  
ESPECIALLY IN THE ECMWF SOLUTION.  
 
   
AVIATION [THROUGH 00Z SUNDAY]
 
 
EXPECT A BROKEN TO OVERCAST UPPER LEVEL CLOUD DECK WITH SURFACE  
WINDS VEERING TO THE NORTH THEN NORTHEAST THROUGH THE PERIOD AS  
A LOW LEVEL RIDGE OF HIGH PRESSURE SHIFTS EASTWARD. LOW TO MID  
LEVEL ISENTROPIC ASCENT ACROSS 305K SURFACE IS ALLOWING PATCHY  
DRIZZLE ACROSS THE REGION THIS EVENING, WHICH MAY CONTINUE ON AND  
OFF THROUGH AROUND 06Z, BUT IS NOT EXPECTED TO REDUCE VSBYS AT  
THIS TIME.  
 
   
MARINE
 
 
WINDS WILL GENERALLY BE IN THE 10 TO 15 KNOT RANGE THROUGH THE  
WEEKEND WITH SLIGHTLY ELEVATED SEAS (ESPECIALLY OFFSHORE).  
CONDITIONS WILL CALM A BIT TO START NEXT WEEK BEFORE BECOMING A  
BIT MORE UNSETTLED BY MID-WEEK DEPENDING ON THE TIMING OF A COLD  
FRONT. SHOWERS AND THUNDERSTORM CHANCES INCREASE SUNDAY NIGHT  
THROUGH MUCH OF NEXT WEEK.  
 
   
FIRE WEATHER
 
 
MUCH DRIER AIR WILL BE IN PLACE TOMORROW AND RELATIVE HUMIDITY  
VALUES WILL DIP INTO THE LOW 30S. TRANSPORT WINDS WILL BE LOW,  
WHICH WILL MEAN NO RED FLAG CONDITIONS, BUT WILL ALSO MEAN LOW  
DISPERSIONS IN THE SOUTHEAST BIG BEND.  
 
   
HYDROLOGY
 
 
RAIN IS NOT EXPECTED THROUGH SUNDAY. STARTING SUNDAY NIGHT WE'LL  
TRANSITION TO A WETTER PATTERN WITH THE POTENTIAL FOR WIDESPREAD  
AVERAGE RAIN AMOUNTS FROM 1-3" THROUGH NEXT WEEK. THESE AMOUNTS  
WILL BE MOST COMMON ALONG AND WEST OF A LINE FROM ALBANY THROUGH  
PANAMA CITY, WITH ISOLATED HIGHER AMOUNTS POSSIBLE. AT THIS TIME,  
THE FORECAST RAIN AMOUNTS ARE NOT EXPECTED TO CAUSE ANY FLOODING  
CONCERNS.  
 
   
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 42 63 44 73 59 / 10 0 10 10 20  
PANAMA CITY 42 61 50 70 64 / 10 0 10 20 40  
DOTHAN 34 58 40 69 60 / 10 0 0 20 50  
ALBANY 34 58 39 68 58 / 10 0 0 10 40  
VALDOSTA 41 61 42 72 57 / 10 0 0 0 20  
CROSS CITY 45 67 46 75 60 / 10 0 0 0 10  
APALACHICOLA 45 62 52 70 65 / 10 0 10 20 30  
 

 
   
TAE WATCHES/WARNINGS/ADVISORIES
 
 
FL...HIGH RIP CURRENT RISK UNTIL 4 AM EST /3 AM CST/ SATURDAY FOR  
COASTAL GULF.  
 
GA...NONE.  
AL...NONE.  
GM...NONE.  

 
 

 
 
NEAR TERM...NGUYEN  
SHORT TERM...HARRIGAN  
LONG TERM...HARRIGAN  
AVIATION...NGUYEN  
MARINE...HARRIGAN  
FIRE WEATHER...NGUYEN  
HYDROLOGY...HARRIGAN  
 
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