773  
FXUS64 KMRX 161122  
AFDMRX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MORRISTOWN TN  
622 AM EST MON DEC 16 2024  
   
..NEW AVIATION
 
 
   
SHORT TERM
 
 
(TODAY AND TONIGHT)  
ISSUED AT 312 AM EST MON DEC 16 2024  
 
KEY MESSAGES:  
 
1. PATCHES OF LIGHT RAIN/DRIZZLE WITH FOG AND LOW CLOUDS TO START,  
THEN SOME IMPROVEMENT DURING THE DAY.  
 
2. ANOTHER ROUND OF LIGHT RAIN TONIGHT.  
 
DISCUSSION:  
 
WE START THE PERIOD WITH LOW LEVEL MOISTURE LINGERING AND PATCHES OF  
LIGHT RAIN/DRIZZLE ALONG WITH FOG AND LOW CLOUDS ACROSS THE AREA. NO  
MAJOR DRYING TODAY BUT WE WILL SEE SOME IMPROVEMENT WITH  
PRECIPITATION GRADUALLY ENDING, AND BREAKS IN THE CLOUDS ARE LIKELY  
TO DEVELOP THIS AFTERNOON OVER PORTIONS OF THE NORTHERN AND CENTRAL  
VALLEYS.  
 
A WEAK COLD FRONT APPROACHING FROM THE NORTHWEST WILL PUSH INTO OUR  
AREA TONIGHT. FORCING WITH THIS FEATURE IS NOT STRONG, BUT WE WILL  
SEE ANOTHER ROUND OF MOSTLY LIGHT RAIN OVERNIGHT TONIGHT.  
 
IT WILL REMAIN MILD FOR THE SHORT TERM PERIOD, WITH ABOVE NORMAL  
TEMPERATURES CONTINUING.  
 

 
   
LONG TERM
 
 
(TUESDAY THROUGH SUNDAY)  
ISSUED AT 312 AM EST MON DEC 16 2024  
 
KEY MESSAGES:  
 
1. ACTIVE WEATHER PATTERN CONTINUES WITH ANOTHER ROUND OF BENEFICIAL  
RAINFALL CULMINATING IN WIDESPREAD SHOWERS ON WEDNESDAY.  
 
2. ABOVE NORMAL TEMPERATURES THROUGH THE FIRST HALF OF THE WEEK WILL  
TRANSITION TO COLDER WEATHER LATE NEXT WEEK AND CONTINUE INTO THE  
WEEKEND.  
 
DISCUSSION:  
 
NOT MUCH HAS CHANGED WITH THIS FORECAST PACKAGE, THOUGH THE  
PROBABILITIES FOR A HALF INCH OF RAINFALL HAVE DECREASED ON THE  
WEDNESDAY FROPA EVENT, DRIVEN BY THE GFS AND ITS ENSEMBLE BRINGING  
IN A LINE OF SHOWERS THAT DECAYS QUICKER. STILL A BIT OF CAPE  
PRESENT, SO ADVERTISING A VERY LOW, BUT NONZERO, CHANCE OF THUNDER.  
REGARDLESS, A COOLER AIRMASS WILL BEGIN TO MOVE IN AFTER FRONTAL  
PASSAGE, AND DAYTIME TEMPERATURES ON THURSDAY WILL BE A STEP DOWN  
FROM WEDNESDAY'S. TOWARDS THE END OF THE WEEK INTO THE WEEKEND THE  
TWO EMBEDDED SHORTWAVES IN THE LARGER TROUGH SYSTEM ARE STILL ON  
TRACK TO BRING COLD AIR INTO THE TENNESSEE VALLEY. SOME LIGHT SNOW  
POTENTIAL EXISTS FOR THE HIGHER ELEVATIONS IN NORTHEAST TN AND  
SOUTHWEST VIRGINIA FRIDAY NIGHT AS A WEAK SHORTWAVE PUSHES THROUGH  
IN THE LARGER REGIME CHANGE. NORTHERLY FLOW ON THE BACKSIDE IS NOT  
TOO STRONG, BUT AN APPROACHING JET STREAK MAY PROVIDE ENOUGH BROAD  
LIFT TO FORCE LIGHT SNOW SHOWERS. OTHER THAN THAT THE WEEKEND LOOKS  
DRY FOR MOST OF THE AREA, DRY AND DECEMBER COLD THAT IS. SUNDAY  
LOOKS TO BE THE WORST DAY TEMPERATURE WISE, WITH SOME ENSEMBLE  
GUIDANCE CLUSTERING AROUND A COLDER SOLUTION THAN CURRENTLY  
FORECAST, SO THERE'S A CHANCE TRI-CITIES AND NORTH DON'T GET ABOVE  
FREEZING.  
 

 
   
AVIATION
 
 
(12Z TAFS)  
ISSUED AT 535 AM EST MON DEC 16 2024  
 
WILL SEE MAINLY IFR OR LOWER CONDITIONS WITH LOW CLOUDS/FOG AND  
A FEW PATCHES OF LIGHT RAIN/DRIZZLE TO START AT CHA AND TYS,  
WHILE TRI IS MORE LIKELY TO START WITH IFR/MVFR CONDITIONS.  
TYS AND TRI WILL LIKELY SEE CONDITIONS IMPROVE TO VFR BY EARLY  
AFTERNOON WHILE CHA WILL BE SLOWER TO IMPROVE BUT SHOULD MAKE IT  
TO AT LEAST MVFR, THEN ALL SITES WILL SEE CONDITIONS DETERIORATE  
AGAIN AS ANOTHER ROUND OF LIGHT RAIN BEGINS TO MOVE TONIGHT.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
CHATTANOOGA AIRPORT, TN 60 55 64 56 / 20 90 40 50  
KNOXVILLE MCGHEE TYSON AIRPORT, TN 63 54 62 54 / 40 90 30 60  
OAK RIDGE, TN 60 52 61 53 / 50 90 30 60  
TRI CITIES AIRPORT, TN 61 50 60 50 / 40 90 20 40  
 

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

 
 

 
 
SHORT TERM...  
LONG TERM....WELLINGTON  
AVIATION...  
 
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