513  
FXUS64 KMRX 200748  
AFDMRX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MORRISTOWN TN  
348 AM EDT THU MAR 20 2025  
   
..NEW SHORT TERM, LONG TERM
 
 
   
SHORT TERM
 
 
(TODAY AND TONIGHT)  
ISSUED AT 336 AM EDT THU MAR 20 2025  
 
KEY MESSAGES:  
 
1. LIGHT RAIN MOVES ACROSS THE AREA THIS MORNING, WITH LINGERING  
LIGHT RAIN/DRIZZLE AND COOLER TEMPERATURES THIS AFTERNOON.  
 
2. RAIN WILL TRANSITION TO SNOW SHOWERS FOR THE EAST TENNESSEE  
MOUNTAINS AND HIGHER ELEVATIONS OF SOUTHWEST VIRGINIA LATE THIS  
AFTERNOON INTO THURSDAY NIGHT. LIGHT ACCUMULATIONS ARE EXPECTED.  
SEE WINTER WEATHER ADVISORY OR SPECIAL WEATHER STATEMENT FOR  
ADDITIONAL DETAILS.  
 
DISCUSSION:  
 
A DECAYING LINE OF SHOWERS IS CURRENTLY PROGRESSING FROM THE  
CUMBERLAND PLATEAU INTO THE EAST TENNESSEE VALLEY AHEAD OF AN  
EASTWARD PROPAGATING COLD FRONT. LATEST SPC MESOANALYSIS AND  
SOUNDINGS FROM HI-RESOLUTION GUIDANCE SUGGEST MUCAPE IS LESS THAN  
100 J/KG, IF NOT ZERO, WITH NO SURFACE BASED INSTABILITY. AS A  
RESULT, THERE IS A VERY LOW CHANCE OF A RUMBLE OF THUNDER OR TWO AS  
THIS ACTIVITY TRACKS EASTWARD INTO THE MORNING HOURS AND WORDING HAS  
BEEN REMOVED FROM THE FORECAST. ANY MODERATE INTENSITY RAINFALL  
COULD LEAD TO SOME GUSTS OF 20-30MPH WITH A STRONG H85 JET NEAR  
50KTS ALOFT. THIS LOW-LEVEL JET WILL CONTINUE TO PRODUCE STRONG  
GUSTY WINDS IN THE MOUNTAINS AND ADJACENT FOOTHILLS OVER THE NEXT  
FEW HOURS. NO CHANGE TO THE REMAINING WIND ADVISORY PRODUCTS ARE  
NEEDED.  
 
FLOW WILL GRADUALLY VEER NORTHWESTERLY BEHIND THE COLD FRONT INTO  
THE AFTERNOON HOURS. WRAP AROUND MOISTURE WILL LINGER LIGHT  
RAIN/DRIZZLE FOR MUCH OF THE CUMBERLAND PLATEAU AND CENTRAL VALLEYS  
NORTHWARD. DEPTH OF SATURATION WILL BE LIMITED TO AROUND NO GREATER  
THAN 800MB WHICH GENERALLY RANGES FROM -10 TO -12 DEGREES CELSIUS.  
AS THE H85 NWLY JET AMPLIFIES TO NEAR 35KTS LATE THIS AFTERNOON AND  
INTO THE OVERNIGHT, OROGRAPHIC LIFT WILL PROMOTE A TRANSITION TO  
SNOW SHOWERS IN FAVORED NWFS LOCATIONS. CURRENT FORECAST IS FOR 1-3  
INCHES 2.5KFT AND HIGHER, WITH ISOLATED HIGHER TOTALS POSSIBLE  
ACROSS 5KFT AND ABOVE. TEMPERATURES WILL TREND MUCH COOLER DO TO  
THE STRONG CAA, AND WE HAVE LIKELY ALREADY SEEN OUR HIGH  
TEMPERATURES AROUND OR SHORTLY AFTER MIDNIGHT THIS MORNING.  
WIDESPREAD TEMPERATURES AT OR A FEW DEGREES BELOW FREEZING ARE  
EXPECTED TONIGHT.  
 

 
   
LONG TERM
 
 
(FRIDAY THROUGH WEDNESDAY)  
ISSUED AT 336 AM EDT THU MAR 20 2025  
 
1. DRY AND MILDER CONDITIONS ARE EXPECTED FRIDAY AND SATURDAY.  
 
2. A SYSTEM WILL BRING CHANCES FOR WIDESPREAD SHOWERS AND EVEN SOME  
THUNDERSTORMS SUNDAY EVENING THROUGH MONDAY MORNING. STRONGER AND  
MORE ORGANIZED STORMS CURRENTLY LOOK TO STAY TO OUR WEST.  
 
3. DRIER AND COOLER CONDITIONS ARRIVE BY TUESDAY WITH ANOTHER WEAK  
SYSTEM BRINGING A RETURN OF RAIN CHANCES BY WEDNESDAY.  
 
FRIDAY THROUGH SUNDAY  
 
AT THE START OF THE PERIOD, THE RECENT SYSTEM THAT IS AFFECTING THE  
AREA WILL BE WELL OFF TO THE EAST WITH UPPER-LEVEL RIDGING BUILDING  
IN. SURFACE HIGH PRESSURE WILL ALSO BE EXPANDING INTO THE AREA FROM  
THE GULF. ALL OF THE MOISTURE ASSOCIATED WITH THIS SYSTEM WILL HAVE  
PULLED OUT OF THE AREA WITH SUBSIDENCE AND HEIGHT RISES SUPPORTING  
WARMER AND DRIER CONDITIONS. LOW RHS CAN BE EXPECTED AGAIN ON  
FRIDAY, LIKELY DROPPING BELOW 30 PERCENT. HOWEVER, LOW-LEVEL WINDS  
AND THE MSLP GRADIENT SUGGEST FAIRLY LIGHT WINDS OVERALL. FRIDAY  
NIGHT INTO SATURDAY, ANOTHER SHORTWAVE WILL PROGRESS WELL TO OUR  
NORTH WITH LIMITED MOISTURE KEEPING THE AREA DRY. INCREASED CLOUD  
COVER MAY LIMIT THE DROP IN RHS, BUT WINDS WILL LIKELY BE STRONGER  
WITH 850MB FLOW OVER 20 KTS AND A TIGHTER MSLP GRADIENT.  
 
SATURDAY NIGHT INTO SUNDAY, ANOTHER SYSTEM WILL DEVELOP ACROSS THE  
NORTHERN PLAINS AND PROGRESS EASTWARD. SOME RAIN CHANCES START TO  
ARRIVE IN WESTERN AREAS ON SUNDAY, BUT THE MAIN TREND DURING THE DAY  
WILL BE BROAD SOUTHERLY FLOW AND FURTHER WARMING.  
 
SUNDAY NIGHT THROUGH WEDNESDAY  
 
SUNDAY NIGHT INTO MONDAY MORNING, THIS SYSTEM IS EXPECTED TO  
PROGRESS INTO THE UPPER GREAT LAKES REGION WITH A NEAR 995MB LOW  
PRESSURE CENTER. THIS TIMEFRAME WILL ALSO BE WHEN WIDESPREAD RAIN IS  
EXPECTED AHEAD OF ITS ASSOCIATED FRONT. BASED ON THE LATEST MODEL  
GUIDANCE, A LINE OF SHOWERS AND STORMS IS LIKELY TO BE ONGOING TO  
OUR WEST AND ARRIVING IN OUR AREA OVERNIGHT. SOME ELEVATED  
INSTABILITY IS INDICATED IN WESTERN PORTIONS OF THE AREA WITH  
MINIMAL INSTABILITY IN THE LOWER-LEVELS. THIS TIMEFRAME WILL BE  
WORTH WATCHING, BUT THE BETTER CHANCES FOR ANY ORGANIZED CONVECTION  
STILL LOOK TO BE WELL WEST OF THE AREA. BEHIND THIS SYSTEM, DEEP  
UPPER TROUGHING AND CAA WILL BRING TEMPERATURES BACK BELOW NORMAL.  
HIGH PRESSURE WILL LIKELY KEEP THE REGION DRY BY TUESDAY. SOME  
MODELS INDICATE ANOTHER WEEK SYSTEM MID-WEEK THAT WILL BRING SOME  
ADDITIONAL RAIN CHANCES, MAYBE EVEN MIXED PRECIPITATION IN THE  
MOUNTAINS.  
 

 
   
AVIATION
 
 
(06Z TAFS)  
ISSUED AT 142 AM EDT THU MAR 20 2025  
 
A WEAKENING LINE OF SHOWERS HAS MOVED ONTO THE CUMBERLAND PLATEAU  
AND WILL GRADUALLY TRANSITION EASTWARD OVERNIGHT. INCREASING LOW-  
LEVEL CLOUDS WITH A LOW CHANCE OF MVFR CIGS ARE EXPECTED WITH THIS  
ACTIVITY. BASED OFF UPSTREAM OBSERVATIONS HAVE CURRENTLY OPTED TO  
NOT INCLUDE MVFR MENTION AT THIS TIME. WRAP AROUND MOISTURE WILL  
REINFORCE LOW-LEVEL CLOUDS THURSDAY AFTERNOON WITH LIGHT  
PRECIPITATION POSSIBLE AT TYS/TRI IN THE AFTERNOON AND EVENING  
HOURS. AGAIN, SOME PERIODS OF MVFR CIGS ARE POSSIBLE AT THESE TWO  
SITES AND HAS BEEN INCLUDED WITHIN PROB30S. WINDS WILL REMAIN  
BREEZY FROM THE SOUTHWEST OVERNIGHT BUT GRADUALLY VEER WESTERLY  
INTO MID-DAY, CONTINUING TO VEER TO THE NORTHWEST BY THE EVENING.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
CHATTANOOGA AIRPORT, TN 51 33 62 40 / 20 0 0 0  
KNOXVILLE MCGHEE TYSON AIRPORT, TN 53 30 58 40 / 30 10 0 0  
OAK RIDGE, TN 51 29 57 38 / 30 10 0 0  
TRI CITIES AIRPORT, TN 55 28 54 36 / 50 50 0 0  
 

 
   
MRX WATCHES/WARNINGS/ADVISORIES
 
 
NC...NONE.  
TN...WIND ADVISORY UNTIL 8 AM EDT THIS MORNING FOR BLOUNT SMOKY  
MOUNTAINS-COCKE SMOKY MOUNTAINS-EAST POLK-JOHNSON-SEVIER  
SMOKY MOUNTAINS-SOUTHEAST CARTER-SOUTHEAST GREENE-SOUTHEAST  
MONROE-UNICOI.  
 
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 4 AM EDT  
FRIDAY FOR BLOUNT SMOKY MOUNTAINS-COCKE SMOKY MOUNTAINS-  
SEVIER SMOKY MOUNTAINS.  
 
VA...NONE.  

 
 

 
 
SHORT TERM...KRS  
LONG TERM....BW  
AVIATION...KRS  
 
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