267  
FXUS64 KMRX 202355 AAA  
AFDMRX  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE MORRISTOWN TN  
755 PM EDT SUN SEP 20 2026  
   
..NEW AVIATION  
 
   
KEY MESSAGES  
 
UPDATED AT 746 PM EDT SUN SEP 20 2026  
 
- WELL ABOVE NORMAL TEMPERATURES TO PERSIST INTO EARLY THIS WEEK. BUT  
RELIEF IS ON THE WAY, WITH A PATTERN CHANGE EXPECTED MID-WEEK  
AND MUCH COOLER TEMPERATURES TO FOLLOW.  
 
- EXPECT ISOLATED TO SCATTERED SHOWERS TODAY, WITH INCREASING  
COVERAGE MONDAY THROUGH WEDNESDAY.  
 
- A FEW STRONG TO SEVERE STORM WITH DAMAGING WINDS COULD OCCUR  
TODAY AND MONDAY, WITH DAMAGING WINDS BEING THE PRIMARY THREAT.  
LOCALIZED FLOODING WILL BE POSSIBLE EACH DAY THROUGH WEDNESDAY  
AS WELL.  
 
 
   
DISCUSSION  
 
ISSUED AT 133 PM EDT SUN SEP 20 2026  
 
CURRENTLY ANOTHER HOT DAY WITH HIGHS ONCE AGAIN EXPECTED TO TOP OUT  
IN THE UPPER 80'S TO LOWER 90'S ACROSS THE EASTERN TENNESSEE VALLEY.  
WHILE THERE ARE A FEW SHOWERS OUT THERE AS OF EARLY THIS AFTERNOON  
THE COVERAGE AND INTENSITY SHOULD BOTH BE LOWER THAN WHAT WE  
EXPERIENCED YESTERDAY WITH WEAKER SYNOPTIC FORCING AND LOWER PWAT  
VALUES ACROSS THE REGION. SIMILAR CONDITIONS EXPECTED TOMORROW AND  
TUESDAY WITH MORE HOT DAYS EXPECTED. WE'LL SEE MORE AFTERNOON  
SHOWERS AND THUNDERSTORMS ONCE AGAIN... FORECAST SOUNDINGS SUGGEST  
MORE INSTABILITY ON MONDAY AND TUESDAY LEADING TO MORE VIGOROUS  
AFTERNOON CONVECTION. WE COULD SEE A FEW SEVERE THUNDERSTORMS WITH  
DAMAGING STRAIGHT LINE WINDS POSSIBLE IN THE STRONGEST STORMS. WITH  
THE MULTIPLE DAYS OF STORMS AND VERY LITTLE MOVEMENT IN THE MEAN  
FLOW INDICATES THE STORMS COULD SIT OVER THE SAME AREA FOR A WHILE  
LEADING TO ISOLATED FLOODING.  
 
BY THE MIDDLE OF THE WEEK WE WILL FINALLY SEE A LARGE SCALE PATTERN  
CHANGE AND USHER IN THE FIRST INKLINGS OF FALL. RIDGE BUILDS IN OVER  
CANADA AND A TROUGH SETS UP CLOSER TO HOME THAT WILL SLOWLY MEANDER  
IT'S WAY THROUGH THE EASTERN HALF O THE UNITED STATES FOR THE REST  
OF THE WEEK AND INTO THE WEEKEND. THIS WILL MUCH COOLER TEMPERATURES  
STARTING WEDNESDAY AND BY THURSDAY THROUGH THE WEEKEND WE SHOULD SEE  
HIGHS TOPPING OUT ONLY IN THE 70'S FOR EVERY EXCEPT SOUTHEAST TN  
WHERE THEY MAY SQUEAK ACROSS THE 80 DEGREE MARK. THIS PATTERN WILL  
ALSO BE FAIRLY DRY WITH A MORE CANADIAN AIRMASS MOVING IN.  
 
LOOKS LIKE WE'LL FINALLY GET TO OPEN THE WINDOWS THIS WEEKEND!  
 
 
   
AVIATION  
 
(00Z TAFS)  
ISSUED AT 746 PM EDT SUN SEP 20 2026  
 
MAIN CONCERNS FOR THE 00Z TAF CYCLE ARE FOG POTENTIAL AGAIN  
TONIGHT AND HOW MUCH, IF AT ALL, TERMINALS WILL BE AFFECTED BY  
SHRA/TSRA TOMORROW. REGARDING THE FOG, GUIDANCE IS NOT  
ENTHUSIASTIC ABOUT IT BY ANY STRETCH FOR THE OVERNIGHT HOURS.  
STILL THE PATTERN SUGGESTS THE POTENTIAL IS THERE. DIDN'T GO QUITE  
AS AGGRESSIVE WITH IT TONIGHT, OPTING FOR PREVAILING MVFR VSBY AND  
A TEMPO 1SM TO HEDGE FOR POTENTIALLY LOWER VISIBILITY AND  
CEILINGS, BETWEEN 09Z AND 14Z. OTHERWISE, GREATER CONVECTIVE  
COVERAGE IS EXPECTED TOMORROW. THE BETTER UPPER SUPPORT FOR STORMS  
WILL BE IN THE NORTH SO PROB30 GROUPS AT KTYS AND KTRI FOR SHRA  
AT THE TAIL END OF THE PERIOD SHOULD SUFFICE FOR NOW.  
 
 
   
PRELIMINARY POINT TEMPS/POPS  
 
CHATTANOOGA AIRPORT, TN 95 72 95 71 / 20 10 40 40  
KNOXVILLE MCGHEE TYSON AIRPORT, TN 93 71 92 69 / 10 10 40 40  
OAK RIDGE, TN 92 70 91 68 / 20 10 50 50  
TRI CITIES AIRPORT, TN 87 66 88 65 / 20 10 40 60  
 
 
   
MRX WATCHES/WARNINGS/ADVISORIES  
 
NC...NONE.  
TN...NONE.  
VA...NONE.  
 
 
 
 
DISCUSSION...99  
AVIATION...CD  
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