947  
FXUS64 KMRX 192353  
AFDMRX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MORRISTOWN TN  
753 PM EDT WED AUG 19 2026  
   
..NEW AVIATION  
 
   
KEY MESSAGES  
 
UPDATED AT 724 PM EDT WED AUG 19 2026  
 
- REMNANTS OF UPSTREAM STORMS MAY AFFECT THE AREA LATE TONIGHT AND  
THURSDAY MORNING, IF IT HOLDS TOGETHER.  
 
- ADDITIONAL ROUNDS OF SHOWERS/STORMS POSSIBLE THURSDAY AFTERNOON  
AND THURSDAY NIGHT/FRIDAY MORNING. THERE IS A MARGINAL RISK OF  
SEVERE STORMS IN SOUTHERN SECTIONS THURSDAY AFTERNOON.  
 
- MOSTLY DRY CONDITIONS WITH NEAR NORMAL TEMPERATURES THROUGH THE  
WEEKEND AND EARLY NEXT WEEK  
 
 
   
DISCUSSION  
 
ISSUED AT 126 PM EDT WED AUG 19 2026  
 
CONDITIONS APPEAR LESS FAVORABLE FOR FOG TONIGHT COMPARED TO LAST  
NIGHT, MAINLY DUE TO EXPECTED HIGH CLOUD COVER THAT WILL SPREAD IN  
FROM UPSTREAM CONVECTION, AS WELL AS LOWER DEWPOINTS OBSERVED THIS  
AFTERNOON COMPARED TO YESTERDAY.  
 
CONVECTION THAT IS EXPECTED TO DEVELOP ACROSS THE MID-MS VALLEY THIS  
EVENING WILL TRACK E-SE THROUGH TONIGHT. LATEST CAMS ARE IN GENERAL  
AGREEMENT THAT THIS ACTIVITY WILL SHOW A WEAKENING TREND AS IT  
CROSSES MIDDLE TN OVERNIGHT, AS INSTABILITY WILL BE LACKING.  
WHATEVER REMAINS OF THE MCS WILL LIKELY REACH OUR AREA AROUND 09Z.  
AS MENTIONED IN PREVIOUS FORECAST DISCUSSIONS, THIS EARLY TIMING  
WILL NOT BE FAVORABLE FOR ANY SEVERE THREAT.  
 
IN THE AFTERNOON, FORECAST SOUNDINGS SHOW PLENTY OF CAPE ABOVE A  
STABLE 850-700 MB LAYER WITH LITTLE IN THE WAY OF FORCING TO  
OVERCOME IT, AS THE MCV WILL BE EAST OF THE AREA BY THEN. A FEW  
CAMS HAVE SOME LATE AFTERNOON CONVECTION DEVELOPING, MAINLY IN THE  
SOUTHERN SECTIONS WHERE THE CAP IS WEAKER. SPC HAS ADDED THIS  
AREA TO A MARGINGAL RISK OF THE DAY 2 OUTLOOK. THIS SEEMS  
REASONABLE IF THE CAP CAN BE OVERCOME, AS THERE ARE GOOD LAPSE  
RATES ABOVE IT AS WELL AS ~30 KT OF EFFECTIVE SHEAR. BUT GIVEN THE  
DISPARITY OF CAMS SOLUTIONS RIGHT NOW, CONFIDENCE IS LOW.  
 
FORCING WILL INCREASE ON THURSDAY NIGHT AS A SHORTWAVE TROUGH  
AMPLIFIES TO OUR WEST AND PUSHES A SURFACE COLD FRONT TOWARD THE  
AREA. THE EXPECTED LATE NIGHT/EARLY MORNING TIMING OF THIS ACTIVITY  
AND THE ELEVATED NATURE OF ANY STORMS WILL MEAN THAT THE CHANCE OF  
SEVERE STORMS IS LOW. ALSO, CAMS ARE NOT IN GOOD AGREEMENT WITH  
COVERAGE OF SHOWERS/STORMS THIS PERIOD, WITH SOME KEEPING ACTIVITY  
WELL TO OUR SOUTH, SO FORECAST CONFIDENCE IS LOW.  
 
DRY CONDITIONS ARE EXPECTED ON SATURDAY AND SUNDAY DUE TO BUILDING  
SURFACE HIGH PRESSURE AND THE MIDLEVEL INFLUX OF DRIER AIR FROM THE  
NORTH. NEXT WEEK, THERE ARE SIGNS OF ANOTHER NORTHWEST FLOW PATTERN  
REMAINING ACROSS THE AREA INTO NEXT WEEK. WHILE NBM POPS ARE LOW, WE  
WILL HAVE TO KEEP AN EYE OUT FOR ANY UPSTREAM IMPULSES THAT MAY  
AFFECT OUR AREA NEXT WEEK. TEMPERATURES SHOULD BE NEAR NORMAL  
THROUGHOUT THIS TIME FRAME.  
 
 
   
AVIATION  
 
(00Z TAFS)  
ISSUED AT 724 PM EDT WED AUG 19 2026  
 
A BATCH OF SHOWERS OR RAIN WILL MOVE THROUGH THE REGION IN THE  
EARLY MORNING HOURS. MID CLOUDS LATE TONIGHT THROUGH THE EARLY  
MORNING HOURS WILL KEEP FOG DEVELOPMENT TO A MINIMUM IF ANY. EVEN  
WITH LIGHT SHOWERS MOVING THROUGH THIS MORNING, VFR CONDITIONS  
ARE EXPECTED. SHOWER/STORM CHANCES ARE LOW THIS AFTERNOON AND WILL  
INCREASE LATE IN THE EVENING JUST AFTER THIS TAF CYCLE ENDS.  
 
 
   
PRELIMINARY POINT TEMPS/POPS  
 
CHATTANOOGA AIRPORT, TN 73 94 73 92 / 20 30 50 60  
KNOXVILLE MCGHEE TYSON AIRPORT, TN 71 90 70 88 / 30 50 60 60  
OAK RIDGE, TN 70 89 69 88 / 40 50 60 60  
TRI CITIES AIRPORT, TN 67 85 66 84 / 10 40 50 50  
 
 
   
MRX WATCHES/WARNINGS/ADVISORIES  
 
NC...NONE.  
TN...NONE.  
VA...NONE.  
 
 
 
 
DISCUSSION...DGS  
AVIATION...MCD  
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