529  
FXUS64 KMRX 212316  
AFDMRX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MORRISTOWN TN  
616 PM EST SUN DEC 21 2025  
   
..NEW AVIATION  
 
   
KEY MESSAGES  
 
UPDATED AT 1243 PM EST SUN DEC 21 2025  
 
- DRY CONDITIONS WILL CONTINUE TODAY AND TOMORROW WITH RH'S  
FALLING WELL INTO THE 20S AND EVEN UPPER TEENS.  
 
- CHANCES FOR LIGHT RAIN ARRIVE BY TUESDAY.  
 
- DRY AND VERY MILD CONDITIONS ARE EXPECTED HEADING INTO CHRISTMAS  
DAY WITH HIGHS WELL INTO THE 60S TO LOW 70S IN THE SOUTH. RAIN  
CHANCES RETURN AGAIN FRIDAY INTO SATURDAY.  
 
 
   
DISCUSSION  
 
ISSUED AT 1243 PM EST SUN DEC 21 2025  
 
CURRENTLY, TROUGHING IS CENTERED OVER THE EASTERN U.S. WITH HIGH  
PRESSURE OVER ILLINOIS. THIS SETUP HAS PUT THE REGION IN A  
NORTHEASTERLY FLOW PATTERN WITH CONTINUED DRY AIR, WITH PERSISTENT  
CLOUD COVER LIKELY TO DISSIPATE THIS AFTERNOON. RH VALUES HAVE  
ALREADY FALLEN IN SOME SPOTS WITH MANY LIKELY TO SEE VALUES DEEP  
INTO THE 20S AND EVEN UPPER TEENS FOR SOME. ON MONDAY, TROUGHING  
WILL LIFT TOWARDS THE NORTHEAST WITH HIGH PRESSURE SHIFTING JUST TO  
OUR EAST. THE CLOSER PROXIMITY WILL LEAD TO A WEAKER MSLP GRADIENT  
AND LIGHTER WINDS BUT DRY AND WARMER CONDITIONS. MONDAY NIGHT INTO  
TUESDAY, A WEAK SYSTEM WILL PROGRESS INTO THE GREAT LAKES WITH  
INCREASING MOISTURE AND SOUTHWESTERLY 850MB FLOW STRENGTHENING TO 40  
KTS OR GREATER. WHILE THE SETUP IS NOT IDEAL FOR MOUNTAIN WAVES,  
STRONG WINDS CAN BE EXPECTED AT HIGH ELEVATIONS. THIS WILL ALSO  
BRING A RETURN OF CHANCES FOR LIGHT RAIN WITH TEMPERATURES NEAR AND  
BELOW 850MB WARM ENOUGH FOR NO FROZEN PRECIPITATION. RAIN CHANCES  
WILL DECREASE BY CHRISTMAS EVE AS MOISTURE LIFTS NORTH AND WEST OF  
THE REGION.  
 
FOR CHRISTMAS DAY, BROAD RIDGING AND HIGH PRESSURE TO OUR SOUTH AND  
EAST WILL SUPPORT DRY AND UNSEASONABLY MILD CONDITIONS WITH MOST  
PLACES RISING WELL INTO THE 60S. ANOTHER SYSTEM WILL ALSO DEVELOP TO  
OUR NORTHWEST AND TRACK TOWARDS THE GREAT LAKES, STRENGTHENING  
SOUTHERLY FLOW. FRIDAY INTO THE WEEKEND, THE FRONT ASSOCIATED WITH  
THIS SYSTEM WILL APPROACH FROM THE NORTHWEST, BRINGING ANOTHER  
RETURN OF CHANCES FOR LIGHT RAIN. TEMPERATURES WILL REMAIN WARM  
ENOUGH FOR LIQUID PRECIPITATION BUT STILL LACKING INSTABILITY FOR  
CONVECTION.  
 
 
   
AVIATION  
 
(00Z TAFS)  
ISSUED AT 522 PM EST SUN DEC 21 2025  
 
VFR CONDITIONS ARE EXPECTED FOR THE PERIOD ALL SITES. LIGHT WINDS  
WILL BECOME SOUTH AND SOUTHWEST AT CHA AND TYS LATE IN THE PERIOD  
BUT STILL GENERALLY LESS THAN 10 KTS.  
 
 
   
PRELIMINARY POINT TEMPS/POPS  
 
CHATTANOOGA AIRPORT, TN 34 58 48 66 / 0 0 10 10  
KNOXVILLE MCGHEE TYSON AIRPORT, TN 29 56 43 61 / 0 0 20 20  
OAK RIDGE, TN 30 55 43 59 / 0 0 20 20  
TRI CITIES AIRPORT, TN 24 55 37 55 / 0 0 20 20  
 
 
   
MRX WATCHES/WARNINGS/ADVISORIES  
 
NC...NONE.  
TN...NONE.  
VA...NONE.  
 
 
 
 
DISCUSSION...BW  
AVIATION...99  
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