A weak boundary progressed across Tennessee and further into Alabama and Georgia during the mid day and evening hours. Weak but supportive shear combined with instability helped power a mesoscale convective system that brushed Marion and Hamilton counties as the complex exited Tennessee, leading to a couple instances of damaging winds.
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The episode as NWS MRX wrote it up.
A weak boundary progressed across Tennessee and further into Alabama and Georgia during the mid day and evening hours. Weak but supportive shear combined with instability helped power a mesoscale convective system that brushed Marion and Hamilton counties as the complex exited Tennessee, leading to a couple instances of damaging winds.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Morristown, TN wrote its last area forecast discussion before the first event at May 25, 1:39 PM CST, 2 hours 16 minutes earlier.
Area Forecast Discussion National Weather Service Morristown TN 339 PM EDT Sun May 25 2025 ...New SHORT TERM, LONG TERM... .SHORT TERM... (This evening through Tuesday night) Issued at 207 PM EDT Sun May 25 2025 Key Messages: 1. Isolated to scattered showers and storms through Monday. 2. Monday night through Tuesday night, showers and storms will be more widespread as the surface boundary moves closer to the region. Discussion: In the upper levels, flow is more zonal today with a weak ridge building into the Midwest and Southeast. By Monday, a ridge builds into the Ohio River Valley and the Southeast. Tuesday and Tuesday night a closed low will be over the Upper Midwest bringing a trough down into the Tennessee Valley. At the surface, high pressure over Canada is extending down into the Ohio Valley. A weak surface low will move from East Texas to the Tennessee Valley by Tuesday. A weak boundary is currently over Middle Tennessee dipping southward into Northwest Georgia. A line of showers and thunderstorms will move through the region this evening. CAMs show the possibilty of a few strong to severe storms near Chattanooga this evening. Some strong storms are currently moving through Middle Tennessee. Forecast soundings show CAPE around 1000 J/kg and effective shear around 35-40 knots near Chattanooga. By Monday, the surface boundary moves into Central or Northern Alabama and Georgia. Showers and thunderstorms will be isolated to scattered again Monday. Confidence is fairly low on timing and coverage. NBM guidance has been overdoing rain chances and CAMs have been better. Confidence in widespread coverage will increase Monday night through Tuesday night as the dynamics line up better with the trough moving in and weak surface low bringing a boundary into the region. Forecast rain totals are lowest in Northeast Tennessee and Southwest Virginia around 1 to 1.5 inches through Tuesday night. Forecast rain totals are highest south of I-40, closer to the boundary, at 2 to 3 inches through Tuesday night. Luckily, we have had several days of dry weather but still flooding may become an issue by Tuesday at the earliest. && .LONG TERM... (Monday night through next Sunday) Issued at 207 PM EDT Sun May 25 2025 Key Messages: 1. Showers and storms will continue through the end of the week with the best coverage expected to be on Wednesday and Thursday. Some storms could produce small hail due to falling freezing levels. 2. Temperatures will be slightly below normal, especially by next weekend. Discussion: At the start of the period, a negatively-tilted trough and surface low will be to our northwest with embedded shortwaves over our area. With sufficient moisture still in place, chances for showers and storms will continue as in previous days. The environment will be modestly unstable with around 500 J/kg of MLCAPE and fairly uni- directional flow, keeping severe chances limited. On Thursday, an upper-level shortwave will move through the region with a deepening closed low noted across the Great Plains. A surface front will also approach the area from the northwest. During this time, low-level flow will become more southerly and advect better moisture into the area, evidenced by PWATs exceeding 1.4 inches. The overall thermodynamic environment will be comparable but with decreasing freezing levels due to height falls. The repeated rainfall could also lead to isolated flooding. This may provide better chances of small hail within storms. Heading towards Friday, it is unclear if the aforementioned front will have passed through the area or not, which will impact temperatures and overall rain chances. By Saturday, it is likely that this front will have passed to the south and east, leading to decreased rain chances and continued mild temperatures. && .AVIATION... (18Z TAFS) Issued at 131 PM EDT Sun May 25 2025 Showers and possibly some thunder is expected this evening mainly near CHA. Rain chances are lower for TYS and TRI but they will likely see some sprinkles and possibly some showers but confidence is low on timing and coverage near TYS and TRI. MVFR CIGs are likely late tonight and tomorrow morning. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 64 80 64 74 / 70 70 80 80 Knoxville McGhee Tyson Airport, TN 60 78 62 75 / 70 60 80 90 Oak Ridge, TN 59 78 62 74 / 70 50 80 90 Tri Cities Airport, TN 56 73 57 68 / 60 40 60 80 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && SHORT TERM...McD LONG TERM....BW AVIATION...McD
Hazardous Weather Outlook National Weather Service Morristown TN 350 PM EDT Sun May 25 2025 NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002- 005-006-008-262000- Cherokee-Clay-Scott TN-Campbell-Claiborne-Hancock-Hawkins- Sullivan-Johnson-Morgan-Anderson-Union-Grainger-Hamblen- Northwest Cocke-Cocke Smoky Mountains-Northwest Greene- Southeast Greene-Washington TN-Unicoi-Northwest Carter- Southeast Carter-Roane-Loudon-Knox-Jefferson-Northwest Blount- Blount Smoky Mountains-North Sevier-Sevier Smoky Mountains- Sequatchie-Bledsoe-Rhea-Meigs-McMinn-Northwest Monroe- Southeast Monroe-Marion-Hamilton-Bradley-West Polk-East Polk-Lee- Wise-Scott VA-Russell-Washington VA- 350 PM EDT Sun May 25 2025 /250 PM CDT Sun May 25 2025/ This Hazardous Weather Outlook is for portions of southwest North Carolina...east Tennessee and southwest Virginia. .DAY ONE...This Afternoon and Tonight There is a marginal risk for severe storms this evening, mainly south of I-40. If strong storms in Middle Tennessee are able to hold together the main threat will be damaging straight line winds. .DAYS TWO THROUGH SEVEN...Monday through Saturday By Tuesday, the risk for flooding issues will increase with 2 to 3 inches possible south of I-40 by Tuesday night with more rain expected later in the week. The risk for severe storms will be low but nonzero. .SPOTTER INFORMATION STATEMENT... Spotter activation is not needed at this time.
The Northeast Alabama radar (KHTX), 44 km away, was scanning. The volume nearest the first event began at 21:56 UTC.
2 thunderstorm wind. Local standard time, as filed.
Widespread trees and powerlines were blown down by severe thunderstorm wind gusts.
Large tree blown down by severe thunderstorm wind gusts.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Tennessee in 2025Every state in 2025This day in weather historyWarnings in Tennessee, May 2025
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1263160, 1263161.