439
FXUS64 KMRX 201917
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
317 PM EDT THU AUG 20 2026
..NEW DISCUSSION
KEY MESSAGES
UPDATED AT 310 PM EDT THU AUG 20 2026
- ANOTHER ROUND OF SHOWERS/STORMS LATE THIS AFTERNOON AND
EVENING. MAIN THREAT IS DAMAGING WIND GUSTS AND SMALL HAIL.
- MOSTLY DRY CONDITIONS WITH NEAR NORMAL TEMPERATURES THROUGH THE
WEEKEND AND EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 310 PM EDT THU AUG 20 2026
THIS MORNING'S CONVECTIVE DEBRIS ASSOCIATED WITH LAST NIGHT'S
THUNDERSTORM COMPLEX HAS MOSTLY CLEARED OUT AS OF THIS AFTERNOON.
TEMPERATURES HAVE REBOUNDED INTO THE MID TO UPPER 80S WITH A FEW
LOCATIONS IN THE 90S ACROSS SE TN. THE COMBINATION OF HEAT AND
HUMIDITY HAS ALLOWED FOR MODERATE INSTABILITY TO BUILD BACK INTO THE
TENNESSEE VALLEY AREA. HI-RES GUIDANCE HAS NARROWED IN ON
THUNDERSTORMS DEVELOPING LATE AFTERNOON AND EARLY EVENING TO OUR
WEST IN MIDDLE TN. STORMS AND SHOWERS SHOULD TRACK EAST THROUGH THE
SOUTHERN VALLEY AREA THIS EVENING BEFORE TURNING MORE NORTHEASTERLY
OVERNIGHT. A FEW STORMS COULD BE STRONG TO SEVERE MAINLY POSING A
THREAT FOR DAMAGING WIND GUSTS THIS EVENING. FORECAST SOUNDINGS
HIGHLIGHT 2000 J/KG MLCAPE AND 25 KNOTS OF SHEAR. THE CLASSIC
INVERTED V SHAPE/HIGH LCLS IS COUPLED WITH 1000-1200 DCAPE
SUPPORTING OUR CONCERN FOR DAMAGING WIND POTENTIAL. SPC DAY 1
OUTLOOK HAS INCLUDED A SLIVER OF SLIGHT RISK (2 OF 5) FOR OUR FAR SW
CWA IN SE TN AROUND CHATTANOOGA. FLOW ALOFT SHOULD PROMOTE STORM
PROGRESSION TO THE EAST, BUT DEPENDING ON HOW OUTFLOWS EVOLVE, THERE
COULD BE SOME ACTIVITY THAT DRIFTS NORTH LATE EVENING/TONIGHT. THIS
SHOULD LIMIT THE POTENTIAL OF FLASH FLOODING, BUT WE CANNOT RULE OUT
ISOLATED IMPACTS FROM LOCALLY HEAVY RAIN.
FRIDAY WILL FEATURE TEMPERATURES NEAR NORMAL WITH THE POTENTIAL FOR
ISOLATED SHOWERS AND STORMS, PRIMARILY ALONG OUR TERRAIN. THE CHANCE
OF SEVERE THUNDERSTORMS ON FRIDAY IS LOW, BUT ISOLATED
WINDS/DOWNBURST CANNOT BE RULED OUT. DRY CONDITIONS ARE EXPECTED ON
SATURDAY AND SUNDAY AS A SFC HIGH PRESSURE BUILDS INTO THE REGION
AND USHERS IN DRIER AIR FROM THE NORTH. OUR STRETCH OF MOSTLY DRY
WEATHER CONTINUES THROUGH THE START OF NEXT WEEK, BUT NORTHWESTERLY
FLOW ALOFT WILL PROVIDE A PARADE FOR WEAK SHORTWAVES FOR MID-WEEK,
SO POPS ARE GENERALLY 20-40 PERCENT RANGE NEXT WEDNESDAY AND
THURSDAY.
AVIATION
(18Z TAFS)
ISSUED AT 118 PM EDT THU AUG 20 2026
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOP MAINLY ALONG AND
SOUTH OF I-40 AFTER 23Z. IFR/LIFR CONDITIONS IN ANY THUNDERSTORMS.
THUNDERSTORMS WILL PUSH SOUTH OF THE AREA BY 05Z BUT A FEW
SHOWERS WILL LINGER OVERNIGHT. MVFR CIGS WILL DEVELOP FOR KTYS
OVERNIGHT AND LINGER THROUGH MUCH OF THE MORNING BEFORE VFR
RETURNS. VARIABLE WINDS UNDER 5 KNOTS.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 73 93 70 93 / 80 20 0 0
KNOXVILLE MCGHEE TYSON AIRPORT, TN 70 89 69 89 / 80 20 20 0
OAK RIDGE, TN 70 89 67 89 / 80 30 10 0
TRI CITIES AIRPORT, TN 67 85 65 84 / 60 50 30 10
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...BH
AVIATION...MUELLER
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page