741 FXUS64 KMRX 242347 AFDMRXArea Forecast Discussion National Weather Service Morristown TN 747 PM EDT Wed Sep 24 2025
...New AVIATION...
.KEY MESSAGES... Updated at 740 PM EDT Wed Sep 24 2025
- Periods of rain, and isolated thunderstorms, through Thursday. Flash flood risk will increase later today and Thursday as the ground continues to saturate. Small streams and poor drainage areas most at risk of seeing rapid rises.
- If thunderstorms occur today and tonight, a few strong to severe storms will be possible. Main risk is a low damaging wind threat. There is about a 5% chance of damaging winds within 25 miles of any location on this afternoon and evening, mainly west of Interstate 75 and south of Interstate 40.
- Friday and Saturday have shifted to a more rainy solution, but likely light precipitation. Low rain chances continue into next week as the upper-level low remains near the Southern Appalachians.
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.DISCUSSION... Issued at 1217 PM EDT Wed Sep 24 2025
Low pressure system is approaching the area with southwest flow aloft and synoptic ascent. Widespread scattered rain showers increase in coverage this evening and overnight tonight with a dry slot on Thursday afternoon as the front moves east. With PW values near 2.0 inches and saturated atmospheric profiles favoring warm rain processes, tropical-like heavy rain rates will be possible with localized flooding across flood prone locations this evening through Thursday morning. The severe threat continues to diminish with very limited instability this afternoon, although a low 5% risk of damaging winds continues across our far south and west corners of the forecast area near the southern plateau.
By Thursday afternoon, widespread precipitation will be east of the area with scattered diurnal showers expected later in the day as the upper-level low swings into the region. This upper-level low becomes cutoff on Friday and into Saturday with weak steering flow keeping it over the region. A mix of clouds and sun will be expected each day with mostly dry mornings and scattered rain showers during the afternoon hours. With high pressure building in early next week, a gradual drier trend is expected early to mid next week with rain chances shifting east of the area. Temperatures remain near normal.
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.AVIATION... (00Z TAFS) Issued at 740 PM EDT Wed Sep 24 2025
Precipitation is currently spreading E and NE from AL and GA. Appears lightning activity may remain confined around/near CHA tonight with any stronger storm. Rain and lower CIG will eventually reach TYS and TRI the next couple of hours. CIG will likely stay in the MVFR range for much of the TAF period. A cold front and upper trough will approach the terminals towards the end of the TAF period Thursday. There may be a break in heavier precipitation during the daylight morning hours, before the possible threat of PM storms arrive. PROB30 introduced to depict this chance.
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.PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 70 81 66 80 / 80 70 30 30 Knoxville McGhee Tyson Airport, TN 69 79 65 78 / 90 80 40 30 Oak Ridge, TN 68 78 64 78 / 90 70 30 30 Tri Cities Airport, TN 67 78 64 76 / 90 80 50 40
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.MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. &&
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DISCUSSION...99 AVIATION...KS
NWS MRX Office Area Forecast Discussion