033  
FXUS64 KMRX 190542  
AFDMRX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MORRISTOWN TN  
1242 AM EST THU DEC 19 2024  
   
..NEW AVIATION  
 
   
UPDATE  
 
ISSUED AT 959 PM EST WED DEC 18 2024  
 
NO SIGNIFICANT CHANGES FOR THE EVENING UPDATE. MAINLY JUST MADE  
SOME ADJUSTMENTS TO THE NEXT 6HRS OR SO OF POPS TO COME IN LINE  
WITH CURRENT RADAR TRENDS, AS WELL AS WINDS TO ACCOUNT FOR CURRENT  
GUSTY NORTH WINDS. FOR THE LATTER, TRENDED HEAVILY TOWARDS THE  
LAST TWO RUNS OF THE HRRR WHICH SEEM TO BE HANDLING THE GUSTY  
CONDITIONS WELL. OTHERWISE, THAT'S ABOUT IT. RAIN HAS PRETTY MUCH  
CLEARED THE AREA TO THE EAST, ALTHOUGH THERE'S LIKELY STILL SOME  
SHOWERY CONDITIONS IN THE MOUNTAINS AS THE ONSET OF UPSLOPE FLOW  
IS COINCIDENT WITH PLENTY OF LOW LEVEL MOISTURE. THAT SHOULD ABATE  
WITHIN THE NEXT COUPLE OF HOURS THOUGH FOR DRY CONDITIONS THE  
REST OF THE NIGHT.  
 
 
   
SHORT TERM  
 
(THIS EVENING THROUGH THURSDAY)  
ISSUED AT 241 PM EST WED DEC 18 2024  
 
KEY MESSAGES:  
 
1. THUNDERSTORMS WILL CONTINUE TO WIND DOWN THIS EVENING WITH  
TIME, TURNING INTO SHOWERS. TRENDING DRIER AFTER SUNSET INTO  
TONIGHT.  
 
2. COLD FRONT PASSAGE TONIGHT WILL SEND DRIER AIR AND COOLER  
TEMPERATURES FOR THURSDAY. SUNSHINE WILL RETURN AS WELL.  
 
DISCUSSION:  
 
LEFT OVER THUNDERSTORMS FROM THE INITIAL LINE ARE ABOUT AT OUR  
EASTERN CWA BORDER AT THIS TIME. SPS OR LESS LEVEL WITH ISOLATED  
LIGHTNING. THINGS WILL CONTINUE TO TREND DOWNWARD AS FAR AS ANY  
SORT OF WIND THREAT OR THUNDERSTORM POTENTIAL. MOST OF THE SHOWERS  
OUT THERE DON'T HAVE ANY THUNDER WITH THEM. PEAK GUSTS ONLY  
RECORDED IN THE LOW TO MID 30'S MPH, ESPECIALLY AT CHA, TYS, AND  
SOUTHWEST VA. LOOKING AT HISTORICAL RAINFALL REPORTED SINCE THIS  
MORNING, THE HEAVIEST OF THE RAINFALL FELL WEST OF THE PLATEAU  
MAKING IT SEEM LIKE THE PLATEAU RUNG OUT MOST OF THE MOISTURE. AS  
MUCH AS OVER A HALF INCH MAXES WITH TODAY'S EVENT CURRENTLY, BUT  
OF COURSE THAT MIGHT NOT CAPTURE THE HEAVIEST SHOWER/STORM OVER AN  
AREA WITHOUT REPORTING EQUIPMENT.  
 
ANY THREAT FOR THUNDERSTORMS AND GUSTY WINDS WILL SOON END AND  
TURN MORE SHOWERY BEHIND THE SQUALL LINE THAT MOVED THROUGH  
EARLIER THIS AFTERNOON. RAINFALL EXPECTED TO END WEST TO EAST.  
TOWARDS 00Z AND AFTER, CHANCES FOR PRECIPITATION DROP OFF WITH THE  
GREATEST CHANCES LINGERING OVER THE MOUNTAINS. PATCHY FOG MAY BE  
POSSIBLE TONIGHT FOR ANYWHERE THAT MAY CLEAR OUT BEFORE SUNRISE.  
 
DRY AIR AND THUS COOLER TEMPERATURES, WILL FOLLOW THE DECREASING  
PRECIPITATION CHANCES TONIGHT AND INTO TOMORROW. 50S DEW POINTS  
TODAY WILL DROP TO THE 30S AND 40S FOR THURSDAY. LOW TEMPERATURES  
MAY RANGE IN THE 30S. WITH HIGH PRESSURE SHIFTING EAST FROM  
CENTRAL CANADA, CLOUDS WILL DISSIPATE INTO THURSDAY, PROVIDING DRY  
WEATHER AND HIGHS RANGING IN THE 40S TO 50S AFTER HIGHS THIS  
AFTERNOON NEARING 70 DEGREES.  
 
 
   
LONG TERM  
 
(THURSDAY NIGHT THROUGH NEXT WEDNESDAY)  
ISSUED AT 241 PM EST WED DEC 18 2024  
 
KEY MESSAGES:  
 
1. TURNING COLDER FOR THURSDAY THROUGH THE WEEKEND.  
 
2. SCATTERED RAIN AND SNOW EXPECTED FRIDAY AFTERNOON AND NIGHT.  
ACCUMULATING SNOWFALL EXPECTED IN THE MOUNTAINS WITH 1 TO 3 INCHES  
ABOVE 2500 FEET.  
 
3. DRY SUNDAY THROUGH TUESDAY, WITH A GRADUAL WARMING TREND FOR  
MONDAY AND TUESDAY.  
 
4. MILD CONDITIONS AND RAIN CHANCES ARRIVE BY CHRISTMAS.  
 
DISCUSSION:  
 
A QUICK MOVING SHORTWAVE TROUGH AND CLIPPER LOW PRESSURE SYSTEM WILL  
DIVE SOUTHEAST ACROSS THE OHIO VALLEY AND CENTRAL APPALACHIANS ON  
FRIDAY WITH NORTHWEST FLOW BEHIND THE FRONT. THIS WILL PRODUCE  
OROGRAPHIC LIFT AND CONTINUED PRECIPITATION ACROSS THE HIGHER  
ELEVATIONS OF OUR FORECAST AREA FRIDAY AFTERNOON THROUGH SATURDAY  
MORNING. ACCUMULATING SNOW IS EXPECTED ACROSS THE MOUNTAINS WITH A  
MIX OF RAIN AND SNOW ACROSS LOWER TERRAIN WITH NO IMPACTS FOR VALLEY  
LOCATIONS. OVERALL, 1 TO 3 INCHES OF SNOW WILL BE POSSIBLE ACROSS  
THE HIGHER ELEVATIONS OF THE MOUNTAINS WITH LOCALLY HIGHER AMOUNTS.  
IF THIS FORECAST TREND CONTINUES, A WINTER WEATHER ADVISORY WILL  
LIKELY BE NEEDED IN SUBSEQUENT FORECAST UPDATES.  
 
FLURRIES TAPER OFF ON SATURDAY WITH CLEARING SKY CONDITIONS. AS  
RIDGING BUILDS IN, UPPER-LEVEL HEIGHTS RISE TO ABOVE NORMAL LEVELS  
EARLY NEXT WEEK WITH GRADUAL WARMING CONDITIONS. DRY WEATHER  
CONTINUES THROUGH EARLY NEXT WEEK.  
 
SOUTHERLY FLOW AND INCREASING MOISTURE AHEAD OF A LOW PRESSURE  
SYSTEM TO OUR WEST WILL RESULT IN GRADUALLY INCREASING RAIN CHANCES  
BY THE MIDDLE OF NEXT WEEK. AT THIS TIME, PROBABILITIES ARE  
INCREASING FOR CLOUDY, AND POTENTIALLY WET, CONDITIONS ON CHRISTMAS.  
 
 
   
AVIATION  
 
(06Z TAFS)  
ISSUED AT 1238 AM EST THU DEC 19 2024  
 
DRY, WITH WINDS CONTINUING TO LESSEN GRADUALLY THROUGH THE PERIOD.  
MVFR CIGS SHOULD SCATTER OUT BETWEEN 16Z AND 20Z. PATCHY FOG IS  
POSSIBLE BETWEEN NOW AND 14Z BUT IMPACTS TO TERMINALS IS TOO  
UNCERTAIN TO INCLUDE IN TAFS.  
 
 
   
PRELIMINARY POINT TEMPS/POPS  
 
CHATTANOOGA AIRPORT, TN 54 35 50 32 / 0 0 0 0  
KNOXVILLE MCGHEE TYSON AIRPORT, TN 50 35 47 30 / 0 0 20 10  
OAK RIDGE, TN 50 33 46 30 / 0 0 20 10  
TRI CITIES AIRPORT, TN 48 35 44 28 / 0 0 50 50  
 
 
   
MRX WATCHES/WARNINGS/ADVISORIES  
 
NC...NONE.  
TN...NONE.  
VA...NONE.  
 
 
 
 
SHORT TERM...CD  
LONG TERM....JB  
AVIATION...WELLINGTON  
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