Area Forecast Discussion

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Letterhead and timestamp

000 FXUS64 KMRX 210648 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 248 AM EDT Tue Apr 21 2026...New DISCUSSION...

KEY MESSAGES

Updated at 233 AM EDT Tue Apr 21 2026

- After a cool morning, a gradual warming trend is expected with dry conditions through much of the week.

- Showers and possibly a few storms are increasingly likely this weekend with Saturday having the best chances.

DISCUSSION

Issued at 233 AM EDT Tue Apr 21 2026

Currently, mid/upper troughing has pushed off into the Atlantic with surface high pressure to the northeast. This has led to another dry and seasonally cool morning with patchy frost in northeast Tennessee and southwest Virginia. Throughout the day, troughing will lift further east, leading to height rises and warmer temperatures than yesterday. Low RH's are expected again, but southerly flow will slightly increase moisture. On Wednesday, a very weak shortwave will pass to our northeast, bringing low-end rain chances close to southwest Virginia. However, our area is expected to remain dry with similarly mild temperatures.

By Thursday, a trough and deepening surface low will eject out of the Rockies leading to increasing ridging and southerly flow in the eastern U.S. Our area will remain dry during this time with most places rising into the 80s. The ridge becomes more suppressed on Friday, but continued southerly flow will lead to temperatures further into the 80s. On Saturday, a shortwave is expected to move into the region from the northwest with moisture having increased further. Showers and possibly some storms are increasingly likely across the area. Overall, winds aloft remain fairly light, but instability could maybe support some stronger storms as indicated by the CIPS Analogs. Hopefully, this provides some needed rainfall as the southern half of the area is anywhere from 4 to 8 inches below normal for the year so far. By Sunday, models differ on how much moisture will remain in the region, so rain chances are lessened.

AVIATION

(06Z TAFS) Issued at 151 AM EDT Tue Apr 21 2026

VFR and dry through the forecast period with light winds developing out of the SW later today. Clear skies at this time may lead to mid to high clouds during the day.

PRELIMINARY POINT TEMPS/POPS

Temperatures Chance of precipitation
Location Tonight Tomorrow Tomorrow night Next day Tonight Tomorrow Tomorrow night Next day
Chattanooga Airport, TN 81 ℉ 54 ℉ 83 ℉ 55 ℉ 0% 0% 0% 0%
Knoxville McGhee Tyson Airport, TN 77 ℉ 52 ℉ 80 ℉ 53 ℉ 0% 0% 0% 0%
Oak Ridge, TN 77 ℉ 50 ℉ 81 ℉ 53 ℉ 0% 0% 0% 0%
Tri Cities Airport, TN 72 ℉ 47 ℉ 77 ℉ 49 ℉ 0% 0% 0% 0%

MRX WATCHES / WARNINGS / ADVISORIES

NC...NONE. TN...NONE. VA...NONE.

DISCUSSION...BW AVIATION...KS