640
FXUS64 KMRX 312359 AAA
AFDMRX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MORRISTOWN TN
759 PM EDT FRI JUL 31 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 753 PM EDT FRI JUL 31 2026
- ONE LAST DRY DAY TODAY WITH SEASONABLE TEMPERATURES AND
RELATIVELY COMFORTABLE HUMIDITY.
- A LOW CHANCE FOR A FEW STRONG STORMS TOMORROW AFTERNOON INTO THE
LATER HOURS OF THE NIGHT. DAMAGING WINDS THE MAIN THREAT WITH
LOCALIZED FLOODING ALSO POSSIBLE. A TORNADO ALSO CANNOT BE RULED
OUT, ESPECIALLY NEAR THE PLATEAU.
- THE WET PATTERN THAT BEGINS TOMORROW WILL PERSIST INTO NEXT
WEEK. TEMPERATURES WARM UP TOWARDS NEXT WEEKEND.
DISCUSSION
ISSUED AT 215 PM EDT FRI JUL 31 2026
ONE LAST DRY DAY TODAY WITH A BIT OF AN INCREASE IN HUMIDITY
UNDER SHORTWAVE RIDGING ALOFT AND SURFACE HIGH PRESSURE SITUATED
OVER THE APPALACHIANS. A FAIRLY STOUT CLOSED UPPER LOW WILL ARRIVE
FROM THE NORTHERN PLAINS TOMORROW VERTICALLY STACKED ABOVE A
SURFACE LOW. AROUND SUNDAY, THE TROUGH AXIS AND CUT OFF LOW
SEEMINGLY PARKS RIGHT OVER US, FOR THE MOST PART. THERE'S STILL
SOME UNCERTAINTY ABOUT HOW THIS WILL PLAY OUT BECAUSE OF MODEL
DISCREPANCIES. IT'S NOT UNTIL WEDNESDAY THAT THE NEXT TROUGH ROLLS
IN AND ABSORBS THE AFOREMENTIONED LOW. THEREAFTER UNTIL THE END
OF THE FORECAST PERIOD, WEAK STEERING DEVELOPS, AND DAILY CHANCES
OF SHOWERS AND STORMS CONTINUE WITH TEMPERATURES PUSHING ABOVE 90
AGAIN. PRECIPITATION CHANCES LATER IN THE WEEK WILL BE BEST OVER
THE HIGHER TERRAIN.
TOMORROW WILL PRESENT A CHANCE OF STRONG TO POSSIBLY A SEVERE
STORM, AS WELL AS ISOLATED FLOODING. THERE WILL BE A COUPLE OF
ROUNDS OF STORMS TOMORROW WITH THE FIRST BETWEEN 7 AM AND 3 PM ET
AND 4 PM UNTIL POSSIBLY AFTER MIDNIGHT FOR THE SECOND. NULL
SURFACE INSTABILITY AMID A LOW LEVEL INVERSION, WILL PREVENT THE
EARLY DAY ROUND FROM GETTING STRONG. THERE MAY BE SOME
THUNDERSTORMS, BUT IT'LL BE MOSTLY RAIN. THE AREA WITH THE
GREATEST THREAT OF STRONGER STORMS WILL BE THE PLATEAU/WEST OF
I-40, WHERE SPC HAS THE AREA UNDER A SLIGHT RISK. A SLIM MARGINAL
AREA TO THE EAST OF THAT AND THEN NO SEVERE FOR MUCH OF NORTHEAST
TN AND SOUTHWEST VA. THIS MAKES SENSE AS SOUTHERLY FLOW OVER THE
TERRAIN IS TRYING TO PULL WHAT WE'D TYPICALLY SEE IN WINTER;
DOWNSLOPING ERADICATING PRECIPITATION OR JUST KEEPING IT AT BAY.
THE STRONGEST WINDS OVER THE HIGHER TERRAIN WILL BE LATER IN THE
DAY TOMORROW, BUT QUICKLY DROPPING OFF INTO THE OVERNIGHT HOURS,
SO NOT LIKE HOW TRUE WINTER MOUNTAIN WAVE EVENTS BEHAVE. SOUTHERLY
FLOW DEVELOPS IN THE AFTERNOON AND TURNS OUT OF THE SW CLOSE TO
MIDNIGHT AND AFTER, WHICH IS WHY THE DOWNSLOPING SHOULDN'T
PERSIST OVERNIGHT.
THE STRONG TO SEVERE THREAT FOR LATER TOMORROW WILL SURELY NEED
MONITORED WITH CAPE PUSHING 2000 J/KG, DEEP LAYER SHEAR AROUND 35
KT, PWATS NEARING 2 INCHES, AND DCAPE OVER 700. TORNADIC ACTIVITY
ALSO CANNOT BE RULED OUT WHEN SURFACE WINDS WILL BE AT THEIR MOST
"SOUTHERLY". 18Z HRRR FORECAST SOUNDINGS AROUND THE PLATEAU AREA
DEPICT SOUTHERLY OR SLIGHTLY BACKED WINDS AT THE SURFACE,
INCREASED SRH, 0-1 SHEAR OVER 20 KT, AND 3CAPE AROUND 70 OR
HIGHER. THIS THREAT WILL ONLY BE LIMITED TO WESTERN PARTS OF THE
FORECAST AREA (PLATEAU), AS THE ENTIRETY OF THREATS IS FORECAST
TO DROP OFF AS IT MOVES EAST, POSSIBLY BEING CHOKED OFF BY THE
DOWNSLOPE FLOW. MAINLY, DAMAGING WIND GUSTS WILL BE THE CONCERN
WITH POSSIBLE FLOODING TOMORROW.
AVIATION
(00Z TAFS)
ISSUED AT 753 PM EDT FRI JUL 31 2026
STORMS OVER MIDDLE TENNESSEE DOWN INTO WESTERN ALABAMA ARE
FORECAST TO DIE OFF QUICKLY IN THE NEXT FEW HOURS, WITH OUTFLOW
BOUNDARIES FIRING UP EARLY MORNING CONVECTION INVOF KCHA BETWEEN
10Z-12Z TOMORROW MORNING BEFORE MOVING NE TOWARDS KTYS. UNCERTAINTY
IS MUCH HIGHER AT KTRI DUE TO THE LIKELIHOOD OF DOWNSLOPE FLOW
WORKING AGAINST SHOWER ACTIVITY AS IT MOVES NORTHEAST. ANOTHER
ROUND OF CONVECTION APPEARS LIKELY TOMORROW AFTERNOON BUT IT WOULD
LIKELY BE WITHIN THE LAST FEW HOURS OF THE TAF PERIOD SO WILL
LEAVE THAT OUT FOR NOW. AS FOR FLIGHT CATEGORIES, MOSTLY VFR IS
EXPECTED BUT DO HAVE SOME MVFR CONDITIONS WITH THE TSRA IN THE
PROB30 GROUPS. WINDS SHOULD GENERALLY BE 10KT OR LESS, ALTHOUGH
THERE'S SOME INDICATION OF SOME GUSTS AT KCHA.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 71 86 71 86 / 20 80 80 40
KNOXVILLE MCGHEE TYSON AIRPORT, TN 69 87 72 86 / 0 70 80 60
OAK RIDGE, TN 68 85 70 85 / 0 80 90 60
TRI CITIES AIRPORT, TN 64 86 69 84 / 0 30 60 80
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...KS
AVIATION...CD
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