650  
FXUS64 KMRX 161141  
AFDMRX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MORRISTOWN TN  
741 AM EDT SAT OCT 16 2021  
   
AVIATION
 
 
12Z TAF DISCUSSION.  
 
RADAR INDICATES FRONT IS THROUGH CHA AND NEAR TYS NOW. WINDS  
SHIFTING TO NORTHWESTERLY WITH THE FROPA, AND PRECIP WILL CONTINUE  
TO BE USHERED EASTWARD OUT OF THE AREA THROUGH MORNING. SOME MVFR  
CONDITIONS TEMPORARILY OCCURRING WITH THE PRECIP, AND WITH LOW  
CLOUDS BEHIND THE FRONT. CONDITIONS WILL IMPROVE TO VFR FROM WEST  
TO EAST THROUGH THE DAY AS DRY AIR MOVES IN.  
 
GC  
 

 
   
SHORT TERM (TODAY AND TONIGHT)
 
 
FROPA WILL OCCUR THROUGH THE AREA THIS MORNING, USHERING OUR  
PRESENT BANDS OF SHOWERS EASTWARD. WE WILL OPEN THE PERIOD AT 12Z  
WITH THE BULK OF THE SHOWERS OVER THE EASTERN HALF OF THE CWA,  
AND BY THE AFTERNOON THERE WILL ONLY BE LINGERING SHOWERS NEAR THE  
SPINE OF THE EASTERN MOUNTAINS, AS SKIES CLEAR OVER THE VALLEY AND  
PLATEAU. WINDS WITH THE FROPA WILL BE A BIT BREEZY FROM THE WEST-  
NORTHWEST TODAY, SUSTAINED 10-20 MPH. CONDITIONS WILL BE  
NOTICEABLY COLDER AND DRIER TONIGHT IN COMPARISON TO OUR RECENT  
MUGGY WARMTH. EXPECTING ENOUGH WINDS TO PERSIST OVER THE  
MOUNTAINS TONIGHT SO AS TO MINIMIZE FROST OUTSIDE OF THE MOST  
SHELTERED SPOTS.  
 
GC  
   
LONG TERM (SUNDAY THROUGH FRIDAY)
 
 
KEY MESSAGES:  
 
1. DRY FOR MOST OF THE PERIOD WITH TEMPERATURES STARTING OUT BELOW  
NORMAL ON MONDAY MORNING, WARMING THROUGH THE WEEK.  
 
2. THE NEXT BEST CHANCE FOR CONVECTION IS ON THURSDAY NIGHT AND  
FRIDAY MORNING AS THE NEXT FROPA OCCURS FOR THE REGION.  
 
DISCUSSION:  
 
THE LONG TERM FCST PERIOD KICKS OFF ON SUNDAY MORNING AMIDST THE  
PASSAGE OF A LONGWAVE TROUGH AXIS OVER THE SOUTHERN APPALACHIANS  
FOSTERING DEEP NWLY FLOW (CAA), ALL WHILE FULL-LATITUDE RIDGING  
AMPLIFIES WESTWARD OVER THE ROCKIES/PLAINS. AT THE SURFACE,  
CONFLUENCE ALOFT ATOP THE SOUTHERN PLAINS WILL FAVOR A NEARLY 1025MB  
SFC RIDGE WHICH LOOKS TO EXTEND EAST THROUGH THE APPALACHIANS INTO  
THE EASTERN SEABOARD. AT FCST INITIALIZATION, CAA WILL PREVAIL WITH  
MODERATE WINDS (10-20MPH) AT THE HIGHER ELEVATIONS SLOWLY TAPERING  
AS PGFS LOOK TO RELAX THROUGH MORNING AMIDST BELOW NORMAL  
TEMPERATURES THROUGHOUT THE DAY. SUNDAY NIGHT'S WINDS SHOULD BE  
WEAKER AS THE UPPER RIDGE AXIS SHIFTS EAST ALLOWING THE SFC RIDGE TO  
CENTER ITSELF NEARLY OVERHEAD FOSTERING CLEAR SKIES AND GOOD  
RADIATIONAL COOLING CONDITIONS INTO MONDAY MORNING. WITH THAT, LOW  
TEMPERATURES IN THE 30S/40S ARE FAVORED, COOLEST ACROSS NORTHEAST TN  
AND SOUTHWEST VA WHERE EVEN SOME PATCHY FROST IS POSSIBLE BEFORE  
TEMPERATURES WARM NICELY FOR THE AFTERNOON HOURS AMIDST MOSTLY SUNNY  
CONDITIONS.  
 
MOVING ON INTO TUESDAY AND THROUGH THE REST OF THE WEEK, THE BRIEF  
OMEGA BLOCKING PATTERN LOOKS TO BREAK DOWN AS THE NORTHWESTERN CONUS  
CYCLONE ADVANCES THROUGH THE ROCKIES AND THE NORTHEAST UPPER LOW  
EJECTS INTO THE NORTH ATLANTIC, ALL ALLOWING THE H5 RIDGE AXIS TO  
TRANSITION ATOP THE APPALCHIANS ON TUESDAY/WEDNESDAY. TEMPERATURE  
TRENDS WILL BEGIN TO MODERATE DURING THIS TIMEFRAME AS THE SURFACE  
RIDGE SLIDES EAST OF THE MOUNTAINS ACROSS THE CAROLINAS, THUS  
EXPECTING NEARER NORMAL LEVELS BY MIDWEEK. AT THAT POINT THE FOCUS  
SHIFTS TO THE LATE WEEK ACTIVITY AS THE NORTHERN ROCKIES H5 CYCLONE  
ADVECTS EASTWARD OVER PLAINS INTO THE UPPER MIDWEST BY THURSDAY  
MORNING, WITH A SURFACE COLD FRONT EXTENDING FROM LAKE SUPERIOR LOW  
PRESSURE ALONG THE MS RIVER INTO THE MIDSOUTH REGION. OUT AHEAD,  
WARM ADVECTION WILL CONTINUE ACROSS THE TN VALLEY REGION AS THE  
EASTERN CONUS UPPER RIDGE AXIS DEAMPLIFIES. HEIGHTS WILL CONTINUE  
TO FALL EASTWARD AS THE UPPER LOW/TROUGH MOVES IN THURSDAY NIGHT  
INTO FRIDAY WITH A FROPA FAVORED OVERNIGHT INTO FRIDAY MORNING. AT  
THIS RANGE CONFIDENCE IN COVERAGE AND INTENSITY IS LOW, HOWEVER  
POSITIONING OF THE UPPER JET MAX SUGGEST AT LEAST SOME DIVERGENCE AS  
THE RIGHT ENTRANCE REGION PIVOTS OVERHEAD. THUS WILL CARRY CHANCE  
POPS THURSDAY NIGHT INTO FRIDAY MORNING, TAPERING SHARPLY POST FROPA  
INTO THE AFTERNOON HOURS AS CAA PREVAILS YET AGAIN.  
 
CDG  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
CHATTANOOGA AIRPORT, TN 66 46 67 45 71 / 10 0 0 0 0  
KNOXVILLE MCGHEE TYSON AIRPORT, TN 66 43 65 43 69 / 60 0 0 0 0  
OAK RIDGE, TN 65 43 65 43 69 / 10 0 0 0 0  
TRI CITIES AIRPORT, TN 66 39 61 39 66 / 70 0 0 0 0  
 

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

 
 

 
 
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