678
FXUS64 KMRX 171831
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
231 PM EDT THU SEP 17 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 136 PM EDT THU SEP 17 2026
- WELL ABOVE NORMAL TEMPERATURES TO PERSIST THROUGH EARLY NEXT WEEK.
SLIGHT COOLING TOWARDS THE END OF THE FORECAST PERIOD MID-WEEK.
- INCREASING RAIN CHANCES FOR THE HIGHER TERRAIN THIS WEEKEND INTO
NEXT WEEK WITH THE VALLEY LEAST LIKELY TO SEE RAIN, SIMILAR TO A
TYPICAL SUMMER PATTERN.
DISCUSSION
ISSUED AT 239 AM EDT THU SEP 17 2026
AN APPROXIMATE 600 DAM UPPER HIGH CENTERED NEARLY OVERHEAD EARLIER,
HAS BEGUN IT'S JOURNEY OF WEAKENING AND CYCLING BACK WEST TODAY.
RECORD HEAT FOR MID SEPTEMBER WILL CONTINUE THOUGH. AT THE SURFACE,
HIGH PRESSURE OVER THE E AND NE, WILL ALSO WEAKEN, LEAVING OUR AREA
MORE SUSCEPTIBLE TO JUST ENOUGH INSTABILITY FOR DIURNAL SHOWER
DEVELOPMENT. ISOLATED TO SCATTERED SHOWERS/STORM WILL BE POSSIBLE
FOR THE SOUTHERN APPALACHIANS, NE TENNESSEE, AND SW VIRGINIA THIS
AFTERNOON AND EVENING. TOMORROW MAY INTRODUCE SOME ISOLATED TO
SCATTERED DEVELOPMENT FOR PARTS OF THE CENTRAL AND NORTHERN VALLEY.
SUMMER-LIKE PRECIPITATION CHANCES FOR THE AFTERNOON AND EVENING WILL
PERSIST INTO NEXT WEEK WITH POSSIBLE EXPANSION IN COVERAGE SOME DAYS.
LOWER TO MID WITH SOME UPPER 90S, ARE FORECAST THROUGH THE WEEKEND,
BEFORE A SLIGHT TURN DOWNWARD TOWARDS THE END OF THE FORECAST PERIOD
OR AS WE APPROACH THE MIDDLE OF NEXT WEEK. UPPER 90S TO LOW 100S
HEAT INDICES WILL BE POSSIBLE FROM THE SOUTHERN VALLEY UP THROUGH
THE CENTRAL VALLEY. THE HIGHEST HEAT INDICES MAY PEAK TOMORROW.
THOUGH MOST OF THE AREA WON'T REACH HEAT ADVISORY CRITERIA, THAT
DOESN'T MEAN TO LET YOUR GUARD DOWN WHEN IT COMES TO BEING OUTDOORS,
STAYING COOL, AND HYDRATED. OUR DAYTIME HIGHS YESTERDAY (BEFORE
CLIMATE OFFICIALLY RUNS AFTER THIS DISCUSSION), TIED THE DAILY
RECORD AT TRI-CITIES. THAT MAKES CHATTANOOGA'S STREAK OF 90 AND
ABOVE AT 44 DAYS AND COUNTING, WITH NO BREAK IN SIGHT.
AVIATION
(18Z TAFS)
ISSUED AT 136 PM EDT THU SEP 17 2026
A FEW POPCORN SHOWERS ON RADAR NOW AND A FEW MORE THIS AFTERNOON
EXPECTED, BUT NOT EXPECTING TERMINAL IMPACTS. VFR CONDITIONS
SHOULD GENERALLY REIGN SUPREME THROUGH THE PERIOD WITH THE
EXCEPTION OF ANOTHER BOUT OF FOG AT TRI-CITIES TOMORROW MORNING.
INCLUDED A TEMPO FOR IFR FOG DURING THE MOST LIKELY TIMEFRAME. VFR
BY OR SHORTLY AFTER 12Z, AS IS TYPICAL.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 73 98 72 97 / 10 10 10 20
KNOXVILLE MCGHEE TYSON AIRPORT, TN 72 95 70 93 / 10 20 10 20
OAK RIDGE, TN 71 95 70 93 / 10 30 10 20
TRI CITIES AIRPORT, TN 68 89 67 88 / 20 50 10 30
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...KS
AVIATION...99
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