959  
FXUS64 KMRX 211902  
AFDMRX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MORRISTOWN TN  
302 PM EDT THU MAY 21 2026  
   
..NEW DISCUSSION  
 
   
KEY MESSAGES  
 
UPDATED AT 238 PM EDT THU MAY 21 2026  
 
- MULTIPLE ROUNDS OF SHOWERS WITH SOME SCATTERED THUNDERSTORMS  
TODAY THROUGH SATURDAY. THE PRIMARY THREATS WITH STORMS EACH  
DAY WILL BE LIGHTNING, LOCALLY HEAVY RAINFALL, AND SOME GUSTY  
WINDS.  
 
- A WET WEATHER PATTERN PERSISTS THROUGH NEXT WEEK.  
 
 
   
DISCUSSION  
 
ISSUED AT 238 PM EDT THU MAY 21 2026  
 
SHOWERS THROUGH THE REST OF THE AFTERNOON AND EVENING WILL  
GENERALLY BE SCATTERED, WITH A DECREASING TREND EXPECTED AFTER  
SUNSET AS A SHORTWAVE TROUGH EXITS THE AREA. WE WILL STILL HAVE A  
SURFACE BOUNDARY LINGERING NEARBY, SO SOME LOW RAIN CHANCES WILL  
CONTINUE THROUGH THE NIGHT. VERY LITTLE LIGHTNING HAS BEEN  
OBSERVED SO FAR THIS AFTERNOON, LIKELY DUE TO THE OVERCAST CLOUD  
COVER AND WEAK LAPSE RATES ALOFT.  
 
MODELS ARE SHOWING A SHORTWAVE TROUGH LIFTING NE FROM LA/MS/AL  
TOMORROW MORNING, WHICH INCREASES LIFT ACROSS OUR AREA STARTING  
AROUND 12Z. A 850 MB JET NEAR 40 KT DEVELOPS DURING THE DAY, AND  
MLCAPE VALUES REACH NEAR 800 J/KG IN OUR SOUTHERN SECTIONS IN THE  
AFTERNOON. THIS MAY ALLOW FOR SOME STORMS TO PRODUCE GUSTY WINDS  
WITH STRONGER DOWNBURSTS, POTENTIALLY NEAR SEVERE LEVELS. SPC HAS  
INCLUDED OUR WESTERN HALF IN A MARGINAL RISK THE LATEST DAY 2  
SEVERE OUTLOOK, WITH WINDS BEING THE MAIN HAZARD. LOCALLY HEAVY  
RAIN MAY ALSO BE A THREAT GIVEN THE HIGH MOISTURE CONTENT THROUGH  
THE COLUMN. SATURDAY LOOKS PRETTY SIMILAR TO FRIDAY, WITH A  
SECOND SHORTWAVE TROUGH COMING OVER THE REGION IN THE AFTERNOON,  
LEADING TO OCCASIONAL SHOWERS AND SCATTERED THUNDERSTORMS THROUGH  
THE DAY.  
 
ANOTHER POTENTIAL WEATHER IMPACT ON FRIDAY AND SATURDAY IS GUSTY  
MOUNTAIN WAVE WINDS. A SURFACE CAD RIDGE EAST OF THE MOUNTAINS  
WILL DEVELOP, ENHANCING THE PRESSURE GRADIENT IN THE NC/TN BORDER  
MOUNTAINS AS A COUPLE LOW PRESSURE AREAS TRACK FROM WEST TN TO THE  
OH VALLEY. WINDS MAY APPROACH ADVISORY LEVELS IN WIND-PRONE  
LOCATIONS OF THE MOUNTAINS AND FOOTHILLS FRIDAY THROUGH SATURDAY.  
 
FOR SUNDAY THROUGH THURSDAY, A WET PATTERN WILL CONTINUE AS WE  
WILL MAINTAIN A DEEP S TO SW FLOW. TIMING OF SHOWERS AND STORMS  
WILL DEPEND ON DISTURBANCES IN THE FLOW AND SURFACE BOUNDARIES IN  
THE AREA, WHICH ARE DIFFICULT TO RESOLVE AT THIS TIME. HIGH POPS  
WITH LOW CHANCES OF THUNDERSTORMS APPEAR TO BE WARRANTED IN THIS  
PATTERN.  
 
 
   
AVIATION  
 
(18Z TAFS)  
ISSUED AT 128 PM EDT THU MAY 21 2026  
 
A COMPLEX WEATHER PATTERN THIS PERIOD WILL MEAN A LOW CONFIDENCE  
FORECAST. ROUNDS OF SHOWERS WILL PASS OVER THE TERMINALS THROUGH  
THIS EVENING, BRINGING MVFR TO IFR CONDITIONS AT TIMES. SHOWERS  
SHOULD GENERALLY DECREASE THROUGH THE NIGHT, WITH MVFR CIGS  
DEVELOPING LATE IN THE NIGHT. ADDITIONAL ROUNDS OF SHOWERS ARE  
POSSIBLE TOMORROW MORNING, ALTHOUGH DETAILS OF TIMING ARE HIGHLY  
UNCERTAIN AT THIS TIME.  
 
 
   
PRELIMINARY POINT TEMPS/POPS  
 
CHATTANOOGA AIRPORT, TN 64 78 64 80 / 80 90 90 90  
KNOXVILLE MCGHEE TYSON AIRPORT, TN 64 79 64 80 / 60 90 90 100  
OAK RIDGE, TN 62 78 62 79 / 70 90 90 90  
TRI CITIES AIRPORT, TN 61 77 60 78 / 60 80 90 100  
 
 
   
MRX WATCHES/WARNINGS/ADVISORIES  
 
NC...NONE.  
TN...NONE.  
VA...NONE.  
 
 
 
 
DISCUSSION...DGS  
AVIATION...DGS  
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