944  
FXUS64 KMRX 212332  
AFDMRX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MORRISTOWN TN  
732 PM EDT TUE APR 21 2026  
   
..NEW AVIATION
 
 
   
KEY MESSAGES
 
 
UPDATED AT 730 PM EDT TUE APR 21 2026  
 
- UNSEASONABLY WARM AND DRY CONDITIONS WILL CONTINUE THROUGH  
FRIDAY. HIGHS WILL BE AROUND 10 DEGREES ABOVE NORMAL. LOW  
AFTERNOON RELATIVE HUMIDITY EACH DAY WITH 20S AND 30S EXPECTED.  
 
- INCREASING MOISTURE AND INSTABILITY THIS WEEKEND WITH LIKELY  
CHANCES OF SHOWERS AND POSSIBLY STORMS, ESPECIALLY SATURDAY.  
 
- ANOTHER ROUND OF STORMS ANTICIPATED FOR MONDAY AND TUESDAY. THERE  
IS A THREAT FOR STRONG TO SEVERE STORMS.  
 

 
   
DISCUSSION
 
 
ISSUED AT 230 PM EDT TUE APR 21 2026  
 
FOR TONIGHT AND WEDNESDAY, A SHORT-WAVE WILL MOVE ACROSS THE UPPER  
OHIO VALLEY INTO THE CENTRAL APPALACHIANS. THIS WAVE WILL PRODUCE AN  
AREA OF SHOWERS AND THUNDERSTORMS THAT WILL APPROACH SOUTHWEST  
VIRGINIA TOWARD WEDNESDAY MORNING. AT THIS TIME, THE DYNAMICS AND  
MOISTURE WILL STAY NORTH OF THE REGION WITH SURFACE RIDGING, SO DRY  
CONDITIONS ARE ANTICIPATED. LOW AFTERNOON RELATIVE HUMIDITY WILL  
WITH VALUES IN THE 20S.  
 
FOR THURSDAY AND FRIDAY, UPPER RIDGE BUILDS OVER THE AREA PRODUCING  
MOSTLY DRY AND UNSEASONABLY WARM CONDITIONS. HIGHS WILL BE AROUND 10  
DEGREES ABOVE NORMAL. LOW AFTERNOON RELATIVE HUMIDITY WILL CONTINUE  
WITH VALUES IN THE 20S/30S.  
 
FOR FRIDAY NIGHT THROUGH SATURDAY, A NORTHERN STREAM (GREAT  
LAKES/OHIO VALLEY) AND SOUTHERN STREAM WAVES (CENTRAL GULF COAST  
STATES) PRODUCE AN AREA OF SHOWERS AND POSSIBLY A THUNDERSTORM.  
SINCE LIMITED PHASING IS EXPECTED WITH THESE WAVES, AND INSTABILITY  
AND DYNAMICS ARE LIMITED, CONFIDENCE IS LOW ON QPF AMOUNTS.  
CURRENTLY EXPECTING FROM 0.25 TO 0.50 INCH BUT ENSEMBLE  
PROBABILITIES SUGGEST LESSER AMOUNTS.  
 
ANOTHER SYSTEM MOVES INTO THE TENNESSEE VALLEY AND SOUTHERN  
APPALACHIANS EARLY NEXT WEEK. THE SHORT-WAVE AND JET DYNAMICS WILL  
THIS WAVE IS STRONGER AND TAPS INTO GULF MOISTURE. JOINT ENSEMBLE  
PROBABILITY OF CAPE/SHEAR SUGGEST A GREAT THREAT OF STRONG TO SEVERE  
STORMS POSSIBLE. WILL NEED TO WATCH THE EVOLUTION OF THIS SYSTEM  
CLOSE AS WE MOVE INTO THE WEEKEND FOR POSSIBLE MESSAGING OF SEVERE  
STORMS. CIPS ANALOG ALSO SUGGEST THE POTENTIAL OF SEVERE STORMS.  
 

 
   
AVIATION
 
 
(00Z TAFS)  
ISSUED AT 730 PM EDT TUE APR 21 2026  
 
VFR AND DRY TAFS TO CONTINUE. WEAK WIND SHEAR OVERNIGHT AT KTRI AS  
WINDS ALOFT BRIEFLY STRENGTHEN. TOMORROW'S DAYTIME WINDS WILL BE  
STRONGER IN THE NORTH, WITH GUSTS TO 20 KNOTS AT KTRI, A FEW GUSTS  
AT KTYS, AND LIGHTER WINDS AT KCHA.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
CHATTANOOGA AIRPORT, TN 53 83 54 84 / 0 0 0 0  
KNOXVILLE MCGHEE TYSON AIRPORT, TN 51 81 54 82 / 0 0 0 10  
OAK RIDGE, TN 50 82 52 83 / 0 0 0 10  
TRI CITIES AIRPORT, TN 44 78 49 79 / 0 0 0 10  
 

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

 
 

 
 
DISCUSSION...DH  
AVIATION...WELLINGTON  
 
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