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000
FXUS64 KMRX 181741
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
141 PM EDT Thu Apr 18 2024

...New AVIATION...

.UPDATE...
Issued at 1109 AM EDT Thu Apr 18 2024

Some tweaks were done to sky cover and temperature grids to better
match satellite and observations. Low clouds have stuck around in
some Plateau and southern valley locations, especially Jacksboro
arcing over to Chattanooga. The good news is the breakup of those
low clouds should accelerate over the next couple hours, leading
to more sunshine for the afternoon. No weather is expected this
afternoon.

&&

.SHORT TERM...
(Today and tonight)
Issued at 250 AM EDT Thu Apr 18 2024

Key Messages:

1. Another very warm day today with more sunshine expected

2. Shower and thunderstorm chances return late tonight into tomorrow.

Discussion:

Currently satellite imagery and surface observations show plenty
of low lying clouds and/or lowered visibilities across the region
early this morning. The cirrus clouds are slowly pulling out of the
area, and if some of the low level clouds begin to break up we could
see quickly developing fog, especially in locations that got heavy
rainfall from the storms on Wednesday. Places along and south of
Interstate 40 saw the most rainfall, and therefore have the best
chances to see the patchy fog early this morning.

Once the sun rises the mid level ridging, southerly winds at the
surface, and surface high pressure will combine to drive out the
clouds and bring in warmer temperatures. Expect highs to soar back
into the 80`s for much of the region, allowing for temperatures to
get within a handful of degrees of the daytime high records... but
as of right now don`t have any climate locations forecasted to
actually break a record today.

Records for April 18th: CHA  90/2002   TYS  90/1896   TRI  87/2002

Very late tonight and into Friday morning we may begin to see
showers and thunderstorms moving into the eastern Tennessee Valley
ahead of an incoming cold front. CAMs are still a bit up in the air
with the areal coverage of the storms, but are in fairly decent
agreement that we should see storms move onto the plateau and into
the valley before sunrise. The timing of them does not bode well for
strong to severe storms on the front end, but cannot completely rule
out seeing a brief strong storm early in the morning if the front
speeds up a bit overnight.

&&

.LONG TERM...
(Friday through Wednesday)
Issued at 250 AM EDT Thu Apr 18 2024

Key Messages:

1. Showers and thunderstorms return for Thursday night and Friday. A
few storms may be strong to severe with gusty winds and hail.

2. Turning much cooler this weekend, with some showers around
especially Sunday.

3. Mostly dry with a warming trend Monday and Tuesday.

Discussion:

The next system starts to move in Thursday night as a low moves into
the Ohio Valley with a weak shortwave aloft. The best chance for
showers and storms with this system will be Thursday night through
Friday. The boundary slows as it moves through the region bringing
showers and storms throughout the day on Friday. Instability may be
high enough to produce some strong storms with dew points in the
60s, mainly in the morning hours before this forecast period. CAM
guidance shows a line or cluster of showers and storms moving
through the region in the early morning hours Friday just before
this forecast period. Some clearing is likely by late morning or
early afternoon. CAM guidance has isolated to scattered showers and
storms developing Friday afternoon. If there is enough clearing,
instability will be high enough to bring a marginal threat for
severe storms Friday afternoon. CAM guidance looks pretty tame at
the moment though.

Saturday looks mostly dry after the frontal passage Friday night
with high pressure moving in from the west and nearly zonal flow
aloft. Temps will be closer to seasonal norms on Saturday with highs
in the upper 60s and lower 70s.

By Sunday, a weak Gulf Low moves into the Southeast bringing a warm
front over Georgia and Alabama. Showers will be possible across the
region on Sunday due to that boundary to the south. Thunder is
unlikely Sunday with dew points in the 40s. This system looks
progressive enough to dry us out by Sunday night or Monday. Temps
will be much cooler Sunday with highs in the upper 50s. Even with
cooler temps, it appears that precip in the higher elevations will
be liquid.

Monday and Tuesday will be dry with a warming trend. Rain chances
return on Wednesday with the next possible system.

&&

.AVIATION...
(18Z TAFS)
Issued at 136 PM EDT Thu Apr 18 2024

CHA skies are imminent to clear out, otherwise VFR conditions
will prevail until 12z in the morning. Overnight convection with
TSRA possible at CHA, rain at TYS, and rain at TRI by the
morning. Then all showers will end around or just after 14z, with
afternoon convection beginning to develop by the end of the
period. A MVFR cloud deck is likely to maintain after 12z for much
of the region through the end of the TAF period. Winds are
expected to be light, though gusty winds in any TS is possible.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             64  81  58  73 /  80  50  10  20
Knoxville McGhee Tyson Airport, TN  62  76  55  68 /  80  80  10  20
Oak Ridge, TN                       62  77  54  70 /  80  80  10  20
Tri Cities Airport, TN              57  73  53  66 /  50  80  20  20

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&

$$

SHORT TERM...Wellington
LONG TERM....McD
AVIATION...Wellington