880  
FXUS64 KMRX 132309  
AFDMRX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MORRISTOWN TN  
709 PM EDT WED AUG 13 2025  
   
..NEW AVIATION  
 
   
DISCUSSION  
 
ISSUED AT 133 PM EDT WED AUG 13 2025  
 
KEY MESSAGES:  
 
1. DECREASING RAIN CHANCES AND FLOODING THREAT THROUGH THE REST OF  
THE AFTERNOON AND EVENING.  
 
2. SCATTERED SHOWERS EXPECTED WITH AN UPPER TROUGH PASSAGE TOMORROW,  
MAINLY IN THE AFTERNOON.  
 
3. REDUCED COVERAGE OF DIURNAL SHOWER/THUNDERSTORM CHANCES THROUGH  
THE WEEKEND. ABOVE NORMAL TEMPERATURES AND MUGGY CONDITIONS RETURN  
OVER THE WEEKEND AND CONTINUE FOR THE FIRST HALF OF NEXT WEEK.  
 
DISCUSSION:  
 
A LOW PRESSURE SYSTEM OVER AL HAS BEEN PUMPING GULF MOISTURE INTO  
OUR AREA TODAY, PRODUCING HIGH PRECIPITABLE WATER CONTENT AND  
EFFICIENT RAINFALL RATES THAT HAVE LED TO FLOODING. RADAR TRENDS  
SHOW DECREASING OVERAGE AND INTENSITY OVER THE LAST FEW HOURS, BUT  
SOUTHERN SECTIONS WILL MAINTAIN A THREAT OF FLOODING THROUGH THE  
REST OF THE DAY. THE LOW WILL PROGRESS EASTWARD TONIGHT ACROSS GA  
AND SC, SHIFTING THE 850-500 MB FLOW TO A MORE WESTERLY DIRECTION  
TONIGHT. WITH THE REDUCTION OF DEEP MOISTURE AND LACK OF FORCING,  
MOST OF THE OVERNIGHT HOURS SHOULD BE DRY. HOWEVER, ABUNDANT LOW  
LEVEL MOISTURE IN PLACE WILL LIKELY RESULT IN FOG AND LOW CLOUDS  
AREA WIDE OVERNIGHT AND INTO TOMORROW MORNING. FOG COULD BE DENSE  
IN SOME LOCATIONS.  
 
A SHORTAVE TROUGH IS LOCATED FROM THE EASTERN GREAT LAKES TO THE  
OZARKS TODAY, AND WILL BE MOVING ACROSS OUR AREA TOMORROW. WE WILL  
STILL HAVE A GOOD AMOUNT OF MOISTURE THROUGH THE COLUMN, BUT PW  
VALUES DROP INTO THE 1.75-1.9 INCH RANGE, AND MLCAPE STAYS UNDER  
1000 J/KG FOR MOST OF THE AREA. FORCING WITH THE TROUGH SHOULD  
INITIATE CONVECTION IN THE LATE MORNING AND EARLY AFTERNOON, WITH  
THE TERRAIN AREAS BEING FAVORED FOR THE BEST COVERAGE. THE FLOODING  
THREAT WILL BE LESS TOMORROW GIVEN THE SLIGHTLY DRYING COLUMN AND  
STRONGER STEERING WINDS ALOFT, BUT SOME LOCALIZED FLOODING MAY BE  
POSSIBLE IN AREAS THAT HAD A LOT OF RAIN TODAY.  
 
A RIDGE OVER THE SOUTHWEST WILL MERGE WITH THE RIDGE OVER FL,  
LEADING TO A LARGE, AMPLIFIED RIDGE OVER THE TN/OH VALLEY REGIONS  
OVER THE WEEKEND. THIS WILL PROVIDE MOSTLY DRY CONDITIONS FOR OUR  
AREA, ASIDE FROM A FEW ISOLATED/SCATTERED DIURNAL SHOWERS AND STORMS  
IN THE HIGHER TERRAIN AREAS. TEMPERATURES WILL BE RISING ABOVE  
NORMAL, WITH HIGHS IN THE LOWER AND MID 90S BY SUNDAY. THIS WILL  
CONTINUE THROUGH THE FIRST HALF OF NEXT WEEK AS THE RIDGE REMAINS  
NEARLY STATIONARY OVER THE REGION.  
 
 
   
AVIATION  
 
(00Z TAFS)  
ISSUED AT 706 PM EDT WED AUG 13 2025  
 
VFR CONDITIONS WILL CONTINUE FOR MUCH OF THE EVENING WITH  
DETERIORATING CONDITIONS LATE TONIGHT INTO THE MORNING HOURS. IFR  
IS EXPECTED AT ALL OF THE SITES WITH PERIODS OF LIFR POSSIBLE,  
PRIMARILY DUE TO FOG. LIGHT SHOWERS ARE POSSIBLE AROUND THE  
TERMINALS, BUT MOST PLACES ARE LIKELY TO STAY DRY FOR THE NIGHT.  
GRADUAL IMPROVEMENTS TO VFR ARE EXPECTED LATE IN THE MORNING  
HEADING INTO THE AFTERNOON. ADDITIONAL SHOWERS AND STORMS ARE  
POSSIBLE AGAIN DURING THE AFTERNOON HOURS BUT WITH MORE LIMITED  
COVERAGE.  
 
 
   
PRELIMINARY POINT TEMPS/POPS  
 
CHATTANOOGA AIRPORT, TN 71 88 72 91 / 40 50 30 30  
KNOXVILLE MCGHEE TYSON AIRPORT, TN 71 87 70 91 / 40 50 20 20  
OAK RIDGE, TN 70 87 70 90 / 30 50 20 20  
TRI CITIES AIRPORT, TN 68 83 67 87 / 40 50 20 30  
 
 
   
MRX WATCHES/WARNINGS/ADVISORIES  
 
NC...NONE.  
TN...NONE.  
VA...NONE.  
 
 
 
 
DISCUSSION...DGS  
AVIATION...BW  
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