Flash Flood Warning 8, NWS Morristown, TN

Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
1219 AM EST Sun Feb 16 2025

...New AVIATION...

.UPDATE...
Issued at 823 PM EST Sat Feb 15 2025

No significant changes were made to the forecast for tonight
during the evening update. Timing for the line of showers/storms
is on track. Strong southerly flow bringing higher dew points and
temps is currently over Middle Tennessee closer to the cold front.
This strong southerly flow will move into East Tennessee over the
next few hours. The line of storms ahead of the cold front is
still over Western Tennessee. This line is still expected to
weaken as it moves eastward into our area but a low damaging
wind/tornado threat still exists mainly in the western and
southernmost counties. Winds will be very gusty ahead of, during
and after this line. A Wind Advisory is in effect for the whole
region starting at midnight with gusts up to 45 mph possible.
Gusts up to 70 mph are possible in the East Tennessee Mountains
and foothills in locations prone to downslope winds.

Very concerned about the flooding threat tonight in Southwest
Virginia and the Upper Cumberland Plateau counties that got a lot
of rain already today. Parts of Southwest Virginia experienced
significant flooding this afternoon and evening as rain lingered
longer than expected along a stalling boundary. The rain overnight
will be fast moving but heavy downpours may dump about an inch of
rain possibly leading to more flooding late tonight into the
morning hours.

&&

.SHORT TERM...
(This evening through Sunday night)
Issued at 211 PM EST Sat Feb 15 2025

Key Messages:

1. Northern parts of the forecast area are primed for additional
flooding issues tonight as strong cold front moves through.

2. Severe weather concerns remain limited, but not zero.
Relatively speaking, highest risk is far southern plateau and TN
valley areas.

3. Non-diurnal temperature trend expected tomorrow, with strong
cold air advection and lingering precip turning to snow in higher
elevations.

Discussion:

An area of strong isentropic lift setup across the northern parts
of the forecast area overnight and earlier today, leading to
widespread moderate to heavy rainfall. This will continue to shift
north into the afternoon hours, leaving the area rain free before
a strong upper trough pushes a strong cold front through late
tonight. There are three main concerns for the short term period,
additional flooding, severe weather, and snow on the backside of
the system.

Flooding concerns:
Rainfall totals overnight and thus far today
have been in excess of 2" across areas close to the Kentucky,
Tennessee, and Virginia state lines. Radar estimates shows 2-3" of
rain have fallen in those areas, and we've received plenty of
reports of flooded roadways, creeks overflowing their banks, small
landslides, and so on. There's still some ongoing rainfall up
north, but the intensity has come down and it should lift north
out of that part of the CWA in the next couple of hours as forcing
pulls away. As such, I don't expect any worsening conditions
through the afternoon hours. However, with the cold front passage
tonight, an additional widespread 1" of rain is expected. The
latest flash flood guidance for our SW Virginia and far northern
TN counties is now basically 0.25" for 1hr, 3hr, and 6hr time
frames. That is to say it's effectively zero, and any additional
rainfall is going to go immediately to runoff and cause flooding
issues. Given there will be some embedded thunderstorm activity
with the incoming front, and the reports we've seen thus far
today, flash flooding is going to be a big concern tonight I
think. I went ahead and expanded the flood watch another row of
counties southward on the TN side, and also picked up Washington
county in Virginia.

Severe Weather:
The latest high resolution CAM guidance shows the cold front not
making it into eastern TN until the 08z-10z time frame tonight.
Looking at some HREF joint probabilities of surface based CAPE in
excess of 250 J/kg and CINH values in the 0 to -50 range, there is
essentially zero chance of those values aligning over any part of
our CWA tonight. Trends in the convective outlook (yesterday's Day
2, and today's Day 1 updates) also tell the tale, which is
continued reduction in Slight and Marginal risk areas across our
CWA and thus a decreasing risk of severe storms. The greatest risk
area, relatively speaking, would remain the far southern
Cumberland plateau region and perhaps into the far southern TN
valley in the vicinity of Chattanooga. But, all things considered
I believe the risk of severe storms will be west of our CWA in
middle TN, southward into northern Alabama. That being said,
if...and this is a big IF at the moment...there is some surface
based instability present, both wind and tornado hazards would be
on the table. There should be a robust squall line shifting east
from middle TN into our CWA tonight. It seems like it will be
weakening and sub-severe, but if there is some instability still
present the shear parameter space will be extremely strong so
damaging winds and tornadoes would be on the table. Again though,
it seems like instability will not be present and that it should
be sub-severe (aside from the additional flooding threat) as it
moves through.

Winter Weather:
Strong cold advection behind the front should mean temperatures
holding steady tomorrow or possibly falling through the day. I
wouldn't be surprised to see the Sunday calendar day highs be
right after midnight tonight because of that. Models show H85
temps dropping into the -6 to -8 range by midday, with northwest
flow showers lingering well into the overnight hours. I'm not
highly confident on the accumulations here as I'm not confident in
how long the NW flow showers will persist and the low level
saturated layer is not particularly deep. Assuming they last well
into the overnight hours Sunday night, I could see Mt. LeConte
getting maybe 3-4", with some 1-2" totals elsewhere down to maybe
3,500 ft in elevation. Given the uncertainty on the totals, would
prefer to hold off on headlines for the time being.

&&

.LONG TERM...
(Monday through next Saturday)
Issued at 211 PM EST Sat Feb 15 2025

Key Messages:

1. Continued cold conditions.

2. More winter weather, possibly widespread even in lower
elevations, possible on Wednesday.

Discussion:

The main focus of the long term is going to be the potential for
widespread winter weather on Wednesday. Will tailor the discussion
to that but need to at least talk about the continued cold weather
we're expected. The front tonight into Sunday will usher in an
extended period of more winter like temperatures as opposed to the
early Spring we've seen of late. A steady supply of continental
polar air will spill out of Canada through the week, being
reinforced on Wednesday behind the system that will bring winter
weather to us. Temperatures will be around or slightly below
normal through midweek, then 5 to 15 degrees below normal to
finish out the work week with a risk of single digit lows Thursday
night into Friday morning. Zonal upper flow behind the departing
trough tomorrow will remain in place through Wednesday with the
next disturbance ejecting ENE out of Texas Tuesday night into
Wednesday morning. Associated surface low looks to track along the
I-20 corridor across the Gulf coast states to our south, which
would place us favorably on the cold side of the system with
respect to winter ptypes. But we're going to be battling an
increasing sun angle as this system moves through during the
daytime hours, as well as some potential downslope warming with
SELY H85 flow and the potential for warm nose intrusion. It's far,
far too early to be discussing snowfall totals here, but suffice
it to say that if this track continues, some measurable daytime
snowfall will be on the table for much of the forecast area on
Wednesday. That's especially true for northern areas and the
northern plateau, further removed from any warm nose that may
occur. Conversely, any northward adjustment in the track would
mean less snow chances. For now, we'll continue to monitor as the
details come into better view.

&&

.AVIATION...
(06Z TAFS)
Issued at 1216 AM EST Sun Feb 16 2025

A line of showers and thunderstorms will move across the area
overnight, mainly between 08Z and 12Z. Light surface winds in
current obs plus strong winds aloft will create LLWS for the first
few hours of the TAF. The showers/storms will produce at least
MVFR vis/cigs with IFR in heavier showers. TS should be mainly in
CHA and TYS. Behind the line, MVFR cigs and gusty winds from the
W-SW will prevail through the day.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             57  26  46  28 /  20   0   0   0
Knoxville McGhee Tyson Airport, TN  57  24  42  26 /  60   0   0   0
Oak Ridge, TN                       57  24  43  26 /  50   0   0   0
Tri Cities Airport, TN              56  23  40  24 /  90  20   0   0

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...Wind Advisory until noon EST today for Cherokee-Clay.

TN...Wind Advisory until noon EST /11 AM CST/ today for Anderson-
     Bledsoe-Bradley-Campbell-Claiborne-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.

     Flood Watch until noon EST /11 AM CST/ today for Anderson-
     Bledsoe-Campbell-Claiborne-Grainger-Hancock-Hawkins-Marion-
     Morgan-Scott TN-Sequatchie-Sullivan-Union.

     High Wind Warning until noon EST today for Blount Smoky
     Mountains-Cocke Smoky Mountains-East Polk-Johnson-Sevier
     Smoky Mountains-Southeast Carter-Southeast Greene-Southeast
     Monroe-Unicoi.

VA...Wind Advisory until noon EST today for Lee-Russell-Scott VA-
     Washington VA-Wise.

     Flood Watch until noon EST today for Lee-Russell-Scott VA-
     Washington VA-Wise.

&&

SHORT TERM...CD
LONG TERM....CD
AVIATION...DGS

Hazardous Weather Outlook
National Weather Service Morristown TN
400 PM EST Sat Feb 15 2025

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-162100-
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-
400 PM EST Sat Feb 15 2025 /300 PM CST Sat Feb 15 2025/

This Hazardous Weather Outlook is for portions of southwest North
Carolina...east Tennessee and southwest Virginia.

.DAY ONE...This Afternoon and Tonight

Significant flooding possible through tonight as another round of
heavy rain is expected with a strong cold front moving through.
Generally speaking, southwest Virginia and areas near the
Tennessee, Kentucky, and Virginia border have seen 2-3" of rain or
more today. These same areas should see an additional 1" of rain
tonight, with locally heavier amounts. As a result, additional
widespread flooding issues are expected to develop tonight.

Mountain wave high winds are likely across the Tennessee
mountains and adjacent foothills, where wind gusts up to 70 mph
are possible. In addition, strong wind gusts are expected across
the entire area from midnight tonight until noon Sunday, with
gusts up to 45 mph. This could cause downed trees and power
outages due to saturated grounds.

Southern portions of East Tennessee, including the Chattanooga
area, are highlighted in a Slight Risk for severe thunderstorms
Saturday night. Damaging winds will be the main threat from
thunderstorms.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Significant flooding through Sunday morning is possible with heavy
rainfall. A Flood Watch is in effect until noon Sunday. Strong
wind gusts are expected across the entire area until noon Sunday,
with gusts up to 45 mph in the advisory area and 70 mph in the
east Tennessee mountains and foothills. This could cause downed
trees and power outages due to saturated grounds.

A developing system along the Gulf coast Tuesday night will
spread moisture north into the Tennessee Valley through Wednesday
night. With a colder airmass in place some light snow is expected
across lower elevations and more significant snowfall across the
higher elevations.

.SPOTTER INFORMATION STATEMENT...

Detailed reports of flooding, severe thunderstorm damage and non
thunderstorm high wind damage this weekend will be appreciated.

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Preliminary Local Storm Report
National Weather Service Morristown TN
315 AM EST Sun Feb 16 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0215 AM     Tstm Wnd Dmg     5 NNW Orme              35.08N 85.84W
02/16/2025                   Marion             TN   911 Call Center

            Tree(s) down along S Pittsburg Mountain Rd.
            Location approximated.

&&

Preliminary Local Storm Report
National Weather Service Morristown TN
319 AM EST Sun Feb 16 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0240 AM     Tstm Wnd Dmg     5 SSE Powells Crossroad 35.12N 85.44W
02/16/2025                   Marion             TN   911 Call Center

            Tree(s) down. Location approximate.

&&

Special Weather Statement
National Weather Service Morristown TN
326 AM EST Sun Feb 16 2025

NCZ060-TNZ085>087-100>102-160915-
Cherokee NC-West Polk TN-Northwest Monroe TN-East Polk TN-
Southeast Monroe TN-Bradley TN-McMinn TN-
326 AM EST Sun Feb 16 2025

...A STRONG THUNDERSTORM WILL IMPACT CHEROKEE...EASTERN BRADLEY...
POLK...SOUTHERN MCMINN AND SOUTHWESTERN MONROE COUNTIES THROUGH 415
AM EST...

At 326 AM EST, Doppler radar was tracking a strong thunderstorm over
East Cleveland, or near Cleveland, moving east at 60 mph.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Cleveland, Murphy, Benton, Ducktown, Etowah, Charleston, East
Cleveland, Wildwood Lake, South Cleveland, and Calhoun.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

A Tornado Watch remains in effect until 900 AM EST for east
Tennessee.

&&

LAT...LON 3499 8492 3533 8485 3534 8408 3500 8399
      3499 8402
TIME...MOT...LOC 0826Z 270DEG 53KT 3513 8483

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

BW

Special Weather Statement
National Weather Service Morristown TN
347 AM EST Sun Feb 16 2025

TNZ013-014-036>038-067>071-073-VAZ001-160930-
Anderson TN-Jefferson TN-Claiborne TN-Roane TN-Union TN-Loudon TN-
Campbell TN-Grainger TN-Knox TN-North Sevier TN-NW Blount TN-Lee VA-
347 AM EST Sun Feb 16 2025

...STRONG THUNDERSTORMS WILL IMPACT NORTHEASTERN LOUDON...
CLAIBORNE...ANDERSON...KNOX...NORTHWESTERN BLOUNT...NORTHWESTERN
JEFFERSON...CAMPBELL...NORTHWESTERN SEVIER...NORTHEASTERN ROANE...
UNION...WESTERN GRAINGER AND SOUTHWESTERN LEE COUNTIES THROUGH 430 AM
EST...

At 347 AM EST, Doppler radar was tracking strong thunderstorms along
a line extending from near Zion Hill to 9 miles northwest of Oliver
Springs to 6 miles south of Wartburg to near Fairview. Movement was
east at 60 mph.

HAZARD...Wind gusts up to 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Knoxville, Oak Ridge, Sevierville, Clinton, Lenoir City, Alcoa, La
Follette, Kingston, Maynardville, and Rutledge.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3666 8346 3626 8350 3619 8354 3585 8362
      3581 8445 3600 8443 3605 8434 3610 8440
      3617 8438 3659 8413 3658 8369 3662 8365
      3667 8352
TIME...MOT...LOC 0847Z 257DEG 51KT 3654 8418 3615 8442 3601 8454 3582
8453

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

BW

Special Weather Statement
National Weather Service Morristown TN
349 AM EST Sun Feb 16 2025

TNZ067>069-071>073-085>087-160930-
Blount Smoky Mountains TN-Northwest Monroe TN-Roane TN-Loudon TN-
Knox TN-Southeast Monroe TN-North Sevier TN-NW Blount TN-McMinn TN-
349 AM EST Sun Feb 16 2025

...STRONG THUNDERSTORMS WILL IMPACT LOUDON...SOUTHERN KNOX...
NORTHEASTERN MCMINN...BLOUNT...MONROE...NORTHWESTERN SEVIER AND EAST
CENTRAL ROANE COUNTIES THROUGH 430 AM EST...

At 348 AM EST, Doppler radar was tracking strong thunderstorms along
a line extending from 6 miles southwest of Oak Ridge to near
Sweetwater to near Athens. Movement was east at 55 mph.

HAZARD...Wind gusts up to 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Knoxville, Oak Ridge, Maryville, Sevierville, Athens, Lenoir City,
Alcoa, Sweetwater, Loudon, and Madisonville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3536 8470 3563 8447 3590 8441 3599 8356
      3569 8363 3568 8366 3562 8366 3557 8371
      3552 8388 3547 8392 3545 8397 3541 8402
      3537 8401 3534 8403 3533 8403
TIME...MOT...LOC 0848Z 251DEG 49KT 3589 8436 3565 8441 3539 8464

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

BW