Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN

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FXUS64 KMRX 130529
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
129 AM EDT Wed Mar 13 2024

...New AVIATION...

.UPDATE...
Issued at 1040 PM EDT Tue Mar 12 2024

Not many changes needed with dry weather continuing across the
forecast area. Sky forecast was adjusted a bit to account for the
mid to high clouds streaming across the area currently; mostly in
TN and NC. Noticed that RH and temp values today were a touch
off, so will keep that in mind with what will most likely be a
persistence forecast tomorrow. Although it looks like dew points
will be a bit higher for the afternoon with return flow setting up.

Other than that, the immediate hourly forecast was blended with
recent obs for a refreshed transition to overnight conditions.

KS

&&

.SHORT TERM...
(This evening through Wednesday)
Issued at 256 PM EDT Tue Mar 12 2024

.SHORT TERM...

Key Message:

Clear skies and low relative humidities expected the remainder of
the day.

Discussion:

Surface high pressure continues to sit over the region leading to
mostly clear skies with a few passing cirrus clouds from the west.
Temperatures have warmed up into the 60s across much of the eastern
Tennessee Valley, and dew point values have been a bit lower than
guidance previously suggested. The lower dew point values are pushing
relative humidity values into the mid 20th percentile, and it will
remain dry through the afternoon/evening hours. Mostly clear skies
and dry atmosphere will help drop temperatures down into the upper
30s or lower 40s overnight, but this is several degrees warmer than
last night and widespread frost looks much less likely overnight.
Quiet weather will continue into tomorrow with daytime highs
expected to be about 5 degrees warmer than today.

&&

.LONG TERM...
(Wednesday night through next Tuesday)
Issued at 256 PM EDT Tue Mar 12 2024

Key Messages:

1. Well above normal temperatures Thursday.

2. Chances for showers and a few thunderstorms increase Friday and
into Saturday.

3. Much cooler Monday and Tuesday with slight chance of rain and
snow higher elevations northeast part of the area.

Discussion:

For Thursday, as a cutoff low spins over the southwestern states
there will be upper level height rises occurring over the eastern
Tennessee Valley. This will allow for even more warming Thursday
afternoon with highs expected in the 70s to near 80, approaching 15
degrees above normal. Conditions should stay dry through Thursday
night. Increasing clouds and moisture with southwest flow ahead of
the upper low will keep lows very mild in the 50s.

On Thursday night into Friday, a frontal boundary will move from
northwest of the area and into the region slowly crossing Friday and
Friday night into Saturday. Rain chances increase during the day
Friday. Still looks like minimal instability late Thursday night,
Friday afternoon and overnight so isolated thunderstorms possible
during this timeframe. heavy rainfall a possibility Friday
decreasing Friday night with precipitable water values over 1 inch.

With any training of the convection some higher totals could occur.
Right now amounts look to be only about 0.50 to 1.00 early Friday
through Saturday morning. Will continue low probability wording in
HWO. The boundary stalls to the south later Saturday while to the
north an upper level trough begins to drop south out of Canada into
the Great Lakes and drops a front into the Ohio Valley Sunday and
approaching the forecast area Sunday. The front to the south will
also lift northward as low pressure moves up the front. The
combination of these two systems will increase rain chances again
late Saturday night in the south and then all areas Sunday. Only
light precipitation amounts expected. More significant rain will
stay to the south. This upper trough will then push the front to the
south. Some upper level energy rotating around the upper trough will
bring some light rain and snow across southwest Virginia and
northeast Tennessee Monday night and early Tuesday. Any snowfall
amounts will not be significant. The mild 60s temperatures Friday
into Sunday will be much lower Monday and Tuesday as the upper
troughing settles over the eastern third of the country. Highs will
be in the 40s to mid 50s each day. Lows will again drop below
freezing Monday night.

&&

.AVIATION...
(06Z TAFS)
Issued at 1238 AM EDT Wed Mar 13 2024

VFR conditions expected throughout the forecast for TRI, TYS, and
CHA. An area of broken clouds at 25kft is moving across TRI and
will lift northeast out of the area by 12Z. Scattered clouds at
4kft can also be expected at TRI this morning and possibly TYS.

Surface ridging is producing calm/light winds this morning. Winds
will increase out of the southwest up to 10 knots with daytime
mixing.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             73  48  79  59 /   0   0   0  40
Knoxville McGhee Tyson Airport, TN  71  45  78  57 /   0   0   0  30
Oak Ridge, TN                       71  44  77  56 /   0   0   0  40
Tri Cities Airport, TN              67  42  75  51 /   0   0   0  20

&&

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

$$

SHORT TERM...
LONG TERM....TD
AVIATION...DH


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