Area Forecast Discussion Issued by NWS Knoxville/Tri Cities, TN
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000
FXUS64 KMRX 141702
AFDMRX
Area Forecast Discussion
National Weather Service Morristown TN
102 PM EDT Thu Mar 14 2024
...New AVIATION...
.SHORT TERM...
(Today and tonight)
Issued at 242 AM EDT Thu Mar 14 2024
Key Messages:
1. Low afternoon relative humidity for much of southwest Virginia
and northeast Tennessee today.
2. Unseasonably warm today with highs some 15 to 20 degrees above
normal.
2. A line of showers and embedded thunderstorms will move across
the area Friday morning. Strong storms are possible across the
Plateau and southeast Tennessee. Some of these storms may be
strong producing high winds causing down trees and power lines.
3. Localized heavy rainfall possible across the Plateau and
southeast Tennessee. Isolated flooding problems possible.
Discussion:
For today, upper ridging and increasing warm southerly flow into
the Tennessee valley and southern Appalachians will produce mostly
sunny sky and unseasonably warm conditions. Highs today will be
just below record highs but some 15 to 20 degrees above normal.
Definitely will feel more summer-like this afternoon.
Here are the record highs for today...
Date Chattanooga Knoxville Tri-Cities Oak Ridge
03-14 83(2012) 85(1990) 82(1990) 84(1990)
For southwest Virginia and northeast Tennessee, another day of low
afternoon relative humidity is expected.
For tonight, conditions will remain mostly clear until midnight
then a strong upper jet across the Ohio into the Tennessee valleys
will produce broad divergence aloft. The right entrance region
will enhance the front-genetic forcing with an approaching front.
Also, in response to the upper jet dynamics, an increasing low-
level jet toward Friday morning with 850mb southwest winds of
35-40 knots. The low-level jet will produce isentropic lift toward
daybreak.
For friday, the strong frontal-genetic forcing along with elevated
CAPE of 250-750 J/Kg will produce a solid line of showers and
embedded thunderstorms area-wide. The strongest of the storms will
move across the Plateau and southeast Tennessee between 6 and 10
am. This line may produce localized high winds causing isolated
down trees and power lines.
NAEFS shows high PWs around the 95th percentile with 850mb
moisture transport around 1 standard deviation above normal. End
result will be localized heavy rainfall mainly across the Plateau
and southeast Tennessee. Due to the relatively fast speed of the
showers/storms, only isolated flooding is possible.
Winds Friday, will be breezy area-wide by afternoon with windy
conditions across the higher terrain.
&&
.LONG TERM...
(Friday through Wednesday)
Issued at 242 AM EDT Thu Mar 14 2024
Key Messages:
1. Showers/storms gradually taper off Friday night, with conditions
mostly dry through the remainder of the extended forecast period.
2. Hard Freeze growing increasingly likely for much of the area
Tuesday morning. This would be accompanied by wind chills in the the
teens for portions of SW Virginia, the Cumberland Plateau, NE
Tennessee Valley, and the E TN mountains.
Discussion:
By Friday night the main frontal forcing and impactful weather will
have shifted southeast of the area, though some lingering light
showers and perhaps an isolated rumble of thunder will be possible
overnight. Saturday continues to trend dry. Shortwave energy then
sharpens upper level troughing into Sunday, sending a reinforcing
cold front through the region. This quick moving front looks
moisture starved and slight chance PoPs have been limited to higher
elevations of the East Tennessee mountains. Perhaps portions of NE
TN see some drizzle, but the main impacts will be increased clouds
and much cooler air filtering in post-fropa.
By Monday night, low temperatures are expected to be below freezing
area wide. Light northwesterly winds will result in windchill values
in the teens for portions of NE TN, SW VA, and the Cumberland
Plateau. Wind chills in higher elevations of the East Tennessee
mountains may fall into the single digits. The cold blast will be
short-lived however. Height rises will lead to a gradual warming
trend through the remainder of the work week. Conditions will also
remain mostly dry through this time. GEFS and ECMWF ensemble mean
suggest a vort lobe rounding the base of the trough Monday night
could bring light snow flurries to higher elevations of SW VA and
the E TN mountains but probability of snowfall GTE 1 inch is less
than 20% at this time. NBM has left mentionable PoPs out of the
forecast and see no reason to deviate from this at this time.
&&
.AVIATION...
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(18Z TAFS)
Issued at 1259 PM EDT Thu Mar 14 2024
Mostly clear skies with occasional wind gusts expected the rest
of the daytime hours today. Late tonight and into tomorrow morning
a line of showers and thunderstorms will quickly blast through
the region. Have put in PROB30 during the most likely time period
of heaviest showers/storms, but will hold off on the details until
later TAF issuances. Expect lower ceilings to remain in place
tomorrow after the initial round of storms.-- End Changed Discussion --
&&
.PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 60 70 53 70 / 50 80 60 0
Knoxville McGhee Tyson Airport, TN 60 68 50 66 / 50 70 30 0
Oak Ridge, TN 59 68 50 67 / 60 70 30 0
Tri Cities Airport, TN 53 66 48 64 / 40 80 50 0-- End Changed Discussion --
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...
LONG TERM....KRS
AVIATION...