Area Forecast Discussion Issued by NWS Knoxville/Tri Cities, TN
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FXUS64 KMRX 260300
AFDMRX
Area Forecast Discussion
National Weather Service Morristown TN
1100 PM EDT Mon Mar 25 2024
...New UPDATE...
.UPDATE...
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Issued at 1054 PM EDT Mon Mar 25 2024
High wind event is now underway tonight, with Cove Mountain
reporting a 76 mph wind gust at 10 PM and Camp Creek NOAA
reporting a peak wind gust of 66 mph also at 10 PM. Elsewhere
valley locations are gusting in the 20s and 30s, and Rockwood
Airport earlier reported a wind gust of 41 mph. Temperatures are
running a few degrees warm tonight thanks to the wind, so smoothed
the diurnal trend upwards a bit in response. Otherwise main
forecast and impacts are well on track. Regional radar shows rain
showers across Middle Tennessee, rain will move in later overnight
as saturation of the lower atmosphere improves.-- End Changed Discussion --
&&
.SHORT TERM...
(This evening through Tuesday)
Issued at 334 PM EDT Mon Mar 25 2024
1. Winds will further increase this afternoon and evening. A High
Wind Warning and Wind Advisory are in effect.
2. Rain arrives late tonight into Tuesday morning with mountain
wave wind gusts across the higher elevations and foothills of 80+
mph.
3. Along the line of rain showers, and a slight chance of embedded
thunderstorms, winds will be strong ahead of the cold front.
Discussion:
An approaching upper level trough and associated cold front is
expected to cross the area early Tuesday and into the afternoon.
Impacts though, will increase as we head into tonight. MinRH`s are
low in the teens and 20`s combined with wind gusts. An elevated
fire risk is still in effect and will be until tonight. The
pressure gradient across the mountains is expected to tighten
tonight with 70 KT or so SSE 850 flow. Strongest winds expected
overnight, with gusts near 80 mph possible over the higher
terrain of the Appalachians and adjacent foothills. Similar flow
will occur over the Cumberland Plateau, Southern Valley, and SW
North Carolina, thus a Wind Advisory is in effect for wind gusts
near 50 mph through Tuesday afternoon. Winds have already been
gusting in some locations near 25 mph.
The low-level flow and pressure gradient will weaken come Tuesday
afternoon. Flow will turn more southwesterly following the passage
of the front. A rain shadow is possible or lighter amounts on the
western side of the Appalachians and other downslope prone areas.
For example, by Wednesday night portions of NE Tennesee and
southwest Virginia will hardly reach a half inch of rain, while
portions of the southern valley and upslope areas of the
Cumberland Plateau may see totals around an inch or more. A slight
chance of thunderstorms is possible embedded within the line of
showers. Overnight temperatures will end up much warmer tonight
thanks in part to increasing cloud cover, strong winds, and
eventual rain showers.
&&
.LONG TERM...
(Tuesday night through next Monday)
Issued at 334 PM EDT Mon Mar 25 2024
Key Messages:
1. Rain will remain east of I-75 into Wednesday morning, and light
showers along the mountains into Thursday.
2. Temperatures drop into the 30s area wide Friday morning with
frost/freezing conditions possible.
Discussion:
By Tuesday night the front should be near Middle TN or the eastern
Tennessee Valley with rain showers present along and ahead of the
frontal boundary. Rain will slowly come to an end for most of the
area overnight Tuesday into Wednesday morning as the front
eventually moves east of the Appalachian Mountains. Light rain
showers could linger across the southern Appalachian Mountains into
Thursday as winds turn more northwesterly and some light moisture
remains present in the atmosphere... But any precipitation is
expected to come in the from of drizzle. We will see cooler
temperatures Wednesday night and Thursday with the colder northwest
air with highs about 5-10 degrees colder on Thursday vs Wednesday.
Friday morning will be the coldest temperatures in the forecast with
the cold northwest air and clear skies leading to effective
radiational cooling. As the surface high moves over the region the
winds will simultaneously really slack off and likely go calm
overnight. This will lead to the possibility of frost conditions for
much of the valley locations with temperatures dropping into the mid
to lower 30`s.
Temperatures will quickly rebound once the sun rises and plenty of
sunshine will be present as we head into the weekend. A pleasant
weekend looks to be in store with temperatures warming up into the
70s for Saturday and Sunday and the warm trend continues into
Monday with near 80 degrees along the TN/GA border and 70s in the
rest of the forecast area.
&&
.AVIATION...
(00Z TAFS)
Issued at 734 PM EDT Mon Mar 25 2024
Strong mountain wave wind event expected overnight, contributing
to LLWS at TYS and TRI overnight ending around 14z. CHA expected
to remain gusty, with winds increasing slightly overnight before
slackening with the arrival of the rain. Light and moderate
rainfall will move across East TN tomorrow between 14z to the end
of the period, bringing VIS restrictions to MVFR during the rain.
CIGs will gradually drop tonight, with CHA steadily deteriorating
to IFR or near IFR status by the end of the period, TYS and TRI
more resistant and may stay overcast just outside of restrictions.
&&
.PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 54 66 50 69 / 70 100 20 10
Knoxville McGhee Tyson Airport, TN 51 65 50 67 / 50 90 40 10
Oak Ridge, TN 51 64 49 69 / 50 100 30 10
Tri Cities Airport, TN 45 60 49 68 / 20 90 60 30-- End Changed Discussion --
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...Wind Advisory until 2 PM EDT Tuesday for Cherokee-Clay.
TN...Wind Advisory until 2 PM EDT /1 PM CDT/ Tuesday for Bledsoe-
Bradley-East Polk-Hamilton-Loudon-Marion-McMinn-Meigs-
Morgan-Northwest Monroe-Rhea-Roane-Scott TN-Sequatchie-West
Polk.
High Wind Warning until 2 PM EDT Tuesday for Blount Smoky
Mountains-Cocke Smoky Mountains-Johnson-Sevier Smoky
Mountains-Southeast Carter-Southeast Greene-Southeast
Monroe-Unicoi.
VA...NONE.
&&
$$
SHORT TERM...Wellington
AVIATION...Wellington