775  
FXUS64 KMRX 180551  
AFDMRX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MORRISTOWN TN  
151 AM EDT TUE AUG 18 2026  
   
..NEW DISCUSSION, AVIATION
 
 
   
KEY MESSAGES
 
 
UPDATED AT 144 AM EDT TUE AUG 18 2026  
 
- REGULAR WARM TO HOT AUGUST TEMPERATURES TO CONTINUE, WITH ON AND  
OFF RAIN AND THUNDERSTORM CHANCES RETURNING THURSDAY AND  
CONTINUING INTO THE WEEKEND.  
 

 
   
DISCUSSION
 
 
ISSUED AT 144 AM EDT TUE AUG 18 2026  
 
WE WILL SEE SOME MINOR RELIEF NEXT TWO DAYS, WITH A RETURN TO  
TYPICAL SUMMERTIME TEMPERATURES AND A DROP IN THE OVERALL PWAT FOR  
THE ATMOSPHERE. PWATS DROP DOWN TO 1.2" OR SO, WHICH IS JUST ABOVE  
THE 25TH PERCENTILE FOR AUGUST, A TIME OF YEAR IN WHICH WE'RE AT THE  
CLIMATOLOGICAL MAXIMUM FOR VERTICAL WATER CONTENT. SINCE THE UPPER  
HEIGHTS ARE OTHERWISE FAIRLY FLAT, WE ONLY RETURN TO NEAR OR  
SLIGHTLY ABOVE TYPICAL HIGHS FOR AUGUST, SO NOT SURE HOW MUCH  
JUMPING FOR JOY OUR ANTI-HUMIDITY CABAL WILL BE DOING THIS WEEK. WE  
WILL ALSO LIKELY REMAIN DRY THE NEXT TWO DAYS, WITH SURFACE RIDGING  
OVERHEAD AND NO OBVIOUS DISCERNIBLE SOURCE OF FORCING TO GET US  
STORM DEVELOPMENT.  
 
UNFORTUNATELY WE GET ANOTHER SHORTWAVE TO ARRIVE ON THURSDAY, WHICH  
HAS THE SIDE EFFECT OF RE-INTRODUCING MORE RAIN AND STORM CHANCES TO  
OUR REGION, WITH HIGHER CHANCES IN THE NORTH. 30 TO 40 KNOTS OF  
SHEAR EXIST THURSDAY INTO THURSDAY NIGHT, GFS AND LONG RANGE RRFS  
BOTH DEPICT A DYING STORM CLUSTER EARLY ON THURSDAY TO OUR WEST,  
THEN A LULL LIKELY FROM CLOUD DEBRIS, THEN POTENTIAL FOR SCATTERED  
PM AND LATE NIGHT THUNDERSTORMS. WHETHER OR NOT THAT SCENARIO COMES  
TO FRUITION IS AN UNKNOWN. CAPE IS A BIT OF A QUESTION, THOUGH  
DEPENDING ON HOW THE MORNING GOES WE MAY REALIZE MORE CAPE THAN THE  
LOW-BIASED GFS DEPICTS. SHEAR PROFILES ARE MORE FAVORABLE FOR STRONG  
WINDS. SOMETHING TO WATCH, ANYWAYS. SCATTERED RAIN AND STORMS THEN  
WILL LIKELY REMAIN IN THE FORECAST INTO THE WEEKEND, AS A SERIES OF  
SHORTWAVES OCCUR BEFORE A LARGE TROUGH DIGS INTO THE GREAT LAKES AND  
THEN THE NORTHEASTERN US SUNDAY INTO MONDAY.  
 

 
   
AVIATION
 
 
(06Z TAFS)  
ISSUED AT 144 AM EDT TUE AUG 18 2026  
 
THE THREAT FOR PRECIP/LIGHTNING FROM EARLIER IS WELL OVER. LOW  
CIG AND VSBY POSSIBLE THROUGH THE EARLY MORNING HOURS, WITH THE  
WORST CONDITIONS MOST LIKELY AT TRI. CHA MAY WALK THE LINE OF VFR  
AND MVFR. ONCE CIG BREAK AND LIFT LATER ON THIS MORNING, VFR WILL  
DOMINATE WITH DRY WEATHER ANTICIPATED UNDER STRENGTHENING SURFACE  
HIGH PRESSURE.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
CHATTANOOGA AIRPORT, TN 93 69 95 74 / 0 0 0 20  
KNOXVILLE MCGHEE TYSON AIRPORT, TN 89 68 92 71 / 10 0 0 10  
OAK RIDGE, TN 89 66 91 71 / 0 0 0 20  
TRI CITIES AIRPORT, TN 85 64 88 67 / 10 0 0 10  
 

 
   
MRX WATCHES/WARNINGS/ADVISORIES
 
 
NC...NONE.  
TN...NONE.  
VA...NONE.  

 
 

 
 
DISCUSSION...WELLINGTON  
AVIATION...KS  
 
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