A powerful upper jet and an approaching cold front help fuel strong synoptic winds that delivered high non-thunderstorm winds across East Tennessee, then a line of severe thunderstorms produced damaging straight line winds.
Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS MRX wrote it up.
A powerful upper jet and an approaching cold front help fuel strong synoptic winds that delivered high non-thunderstorm winds across East Tennessee, then a line of severe thunderstorms produced damaging straight line 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 Feb 27, 3:23 PM EST, 37 minutes earlier.
Area Forecast Discussion
National Weather Service Morristown TN
323 PM EST Tue Feb 27 2024
...New SHORT TERM, LONG TERM...
.SHORT TERM...
(This evening through Wednesday)
Issued at 322 PM EST Tue Feb 27 2024
Key Messages:
1. Strong winds will continue this evening through much of the day
on Wednesday, especially along the Tennessee mountains and adjacent
foothills.
2. A line of showers and embedded storms is expected to move through
the region late morning to early afternoon on Wednesday. Some storms
could be strong to severe with damaging wind gusts as the main
threat.
3. Temperatures will fall quickly by late afternoon Wednesday with a
changeover to light snow across the highest elevations.
This Evening/Tonight
Currently this afternoon, an upper jet in excess of 160 kts is
ejecting out of the Rockies with a deep surface low pressure system
centered over Illinois and Wisconsin. At the surface, a cold front
extends to its southwest. Throughout the evening, this jet will
strengthen even more to near 200 kts as it moves eastward. The low-
level jet, already in excess of 40 kts, will increase to over 50 kts
and in conjunction with a tightening MSLP gradient. As such, strong
winds and WAA will be the main focus this evening and overnight,
especially along the Tennessee mountains and foothills. While the
direction of the jet will not be ideal for mountain wave
enhancement, the overall strength of the jet is more than enough for
gusts from 50 to 70 mph. With the morning update, a Wind Advisory
was also extended to remaining areas with the strongest winds likely
being towards the early morning hours as the cold front approaches
the area. Regarding precipitation overnight, isolated light showers
are possible with weak isentropic lift.
Wednesday
By Wednesday morning, the associated cold front is expected to be
oriented through Middle Tennessee with the near 200 kt upper jet
along and just northwest of the Ohio River Valley. By this point,
the low-level jet will be exceeding 55 kts in portions of our area
and further north. While our placement in the upper jet will not be
completely ideal for divergence, the cold front will be the main
source of lift. The latest CAMs continue to suggest a convective
line quickly moving through the area from late morning to early
afternoon along the front. The wind profile from the surface to the
upper levels will be almost entirely veered with height an lesser
confidence in instability. High-res model soundings indicate about
100 to 200 J/kg of CAPE that is largely surface-based. Additionally,
mid-level lapse rates of 6 C/km or more are also indicated. Given
all of these factors, a marginal risk was extended across a good
portion of our area, mainly for damaging winds. This certainly is
warranted based on the sharp temperature gradient and very strong
low-level jet. The magnitude of low-level shear also suggests a non-
zero tornado risk, but the better overall setup for one to spin up
is to our north closer to the surface low. Additional messaging will
focus on the threat of isolated damaging wind gusts above those
synoptically-driven.
Behind the front, strong CAA from height falls and northwesterly
flow will lead to a quick drop in temperatures late in the afternoon
to the evening. Most of the precipitation will exit to the east by
the time locations below 4,000 feet ASL drop near or below freezing.
However, a changeover to light snow can be expected along the higher
terrain, driven almost solely by orographic means.
&&
.LONG TERM...
(Wednesday night through next Tuesday)
Issued at 322 PM EST Tue Feb 27 2024
Key Messages:
1. Much cooler Wednesday night and Thursday after the frontal
passage.
2. Next chance for rain Friday, temperatures begin to rebound back
to warm weather for the weekend.
3. Another system is possible early next week but uncertainty is
high.
Discussion:
Dry weather is expected Wednesday night and Thursday as high
pressure moves into the Ohio Valley. Some light snow will be
possible in the highest elevations of the East Tennessee mountains
Wednesday evening but little to no accumulation is expected. Temps
will be much cooler behind the cold front with lows in the 20s and
highs near 50. By Friday, a shortwave moving through the Midwest and
Ohio Valley will bring rain to the region through Saturday morning.
Instability will still be low on Friday with dew points peaking in
the 40s so thunderstorm potential will be very low.
Some low POPs, 10 to 25 percent, will persist through the weekend as
minor shortwaves appear to be embedded in the longwave ridge. High
pressure will be over the Eastern U.S. this weekend. Overall,
confidence is low on rain chances this weekend. Highs will be well
above normal Sat, Sun, Mon and Tues. Early next week another system
is expected but models are in disagreement on timing and strength of
the system, so uncertainty is high.
&&
.AVIATION...
(18Z TAFS)
Issued at 1212 PM EST Tue Feb 27 2024
The main aviation impact for the day will be strong winds at and
just above the surface that will continue to increase through the
afternoon hours. Gusts in excess of 25 kts have already been
confirmed at TYS. The expectation is for these winds to continue
at the surface into the evening hours with some decrease after
dark. During this time, values around 2,000 feet AGL will be in
excess of 40 kts with even higher winds just above this level.
While the consistency is a bit uncertain, LLWS was introduced into
the TAFs with better confidence existing at CHA and TRI where
surface winds may be lighter. Still, this will be a fairly notable
impact to monitor overnight. Regarding reduction in the flight
category, this is most likely to occur at CHA overnight into the
morning with inclusion in the TAF. By late morning, surface winds
are expected to become strong again with gusts in excess of 30 kts
likely, followed by showers and isolated thunderstorms.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 64 68 31 53 / 20 80 0 0
Knoxville McGhee Tyson Airport, TN 63 66 29 50 / 20 90 0 0
Oak Ridge, TN 62 66 28 51 / 20 90 0 0
Tri Cities Airport, TN 57 66 25 48 / 20 80 10 0
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...Wind Advisory until 1 PM EST Wednesday for Cherokee-Clay.
TN...Wind Advisory until 1 PM EST /noon CST/ Wednesday for Anderson-
Bledsoe-Bradley-Campbell-Claiborne-East Polk-Grainger-
Hamblen-Hamilton-Hancock-Hawkins-Jefferson-Knox-Loudon-
Marion-McMinn-Meigs-Morgan-North Sevier-Northwest Blount-
Northwest Carter-Northwest Cocke-Northwest Greene-Northwest
Monroe-Rhea-Roane-Scott TN-Sequatchie-Sullivan-Union-
Washington TN-West Polk.
Wind Advisory until 7 PM EST Wednesday for Johnson-Southeast
Carter-Southeast Greene-Southeast Monroe-Unicoi.
High Wind Warning until 7 PM EST Wednesday for Blount Smoky
Mountains-Cocke Smoky Mountains-Sevier Smoky Mountains.
VA...Wind Advisory until 1 PM EST Wednesday for Lee-Russell-Scott VA-
Washington VA-Wise.
&&
SHORT TERM...BW
LONG TERM....McD
AVIATION...BWHazardous Weather Outlook National Weather Service Morristown TN 325 PM EST Tue Feb 27 2024 NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002- 005-006-008-282030- 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- 325 PM EST Tue Feb 27 2024 /225 PM CST Tue Feb 27 2024/ This Hazardous Weather Outlook is for portions of southwest North Carolina...east Tennessee and southwest Virginia. .DAY ONE...This Afternoon and Tonight Strong winds are expected in the east Tennessee mountains and adjacent foothills today and tonight. Also expect to see some windy conditions across the remainder of the area. A Wind Advisory has been extended to include the remaining areas. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Strong winds will continue into Wednesday as a sharp cold front pushes across the area. Winds ahead of the front will be strong area wide but especially in the terrain. A line of showers and storms will also progress along the frontal boundary, some of which could be strong to severe. Isolated damaging wind gusts are the main concern. Winds will then gradually subside into the evening after the front swings through. .SPOTTER INFORMATION STATEMENT... Spotter activation is not needed at this time.
The Knoxville radar (KMRX), 44 km away, was scanning. The volume nearest the first event began at 17:04 UTC.
6 thunderstorm wind, 3 high wind. Local standard time, as filed.
The Cove Mountain wind tower recorded several high wind gusts, beginning with a 62 mph wind gust then ending the following morning with a peak gust of 71 mph.
A private weather station near Max Patch Mountain recorded a 62 mph non-thunderstorm wind gust.
A public weather station recorded a 63 mph non-thunderstorm wind gust southeast of Citico, Tennessee.
Numerous trees and powerlines were blown down by powerful severe thunderstorm wind gusts across the county.
Several trees and three power poles were blown down by severe thunderstorm wind gusts at the intersection of McGee Boulevard and Rock Springs Road.
The ASOS weather station KTYS measured a 65 knot thunderstorm wind gust.
A personal weather station recorded a thunderstorm wind gust of 62 mph.
A personal weather station recorded a severe thunderstorm wind gust of 58 knots. The thunderstorm winds broke and bent structural posts along a fence.
Multiple trees were blown down by powerful thunderstorm wind gusts in Seymour.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Tennessee in 2024Every state in 2024This day in weather historyWarnings in Tennessee, February 2024
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: 1163020, 1163021, 1163027, 1163028, 1163033, 1163031, 1163029, 1163032, 1163030.