-- Discussion containing changed information from previous version are highlighted. --
919
FXUS64 KMRX 200722
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
322 AM EDT Thu Jun 20 2024

...New SHORT TERM, LONG TERM...

.SHORT TERM...
-- Changed Discussion --
(Today and tonight)
Issued at 258 AM EDT Thu Jun 20 2024

Key Messages:

1. Patchy fog early this morning mainly near area waterways.

2. Hot and dry conditions continue with strong ridging in place.

Discussion:

Early this morning, patchy fog has developed mainly near area
waterways. Fog will dissipate soon after sunrise.

Also, thicker ci/cs over far southwest Virginia, northeast
Tennessee, and southwest North Carolina will move out this
morning. Overall, mostly clear sky but do expect scattered cloud
cover development over the orographic areas this afternoon.

NAFES anomalies continues to depict a strong upper ridge across
the mid-Atlantic states into the Tennessee valley and Appalachians.
Dry airmass with model soundings depicting PWs in the bottom
quartile with a subsidence inversion around the 700mb layer.

Surface ridging into the southern Appalachians with weak pressure
gradients will produce light winds.

For tonight, dry airmass remains with mostly clear sky.
-- End Changed Discussion --

&&

.LONG TERM...
-- Changed Discussion --
(Friday through Wednesday)
Issued at 258 AM EDT Thu Jun 20 2024

Key Messages:

1. Above average temperatures continue with strong ridging in place.

2. Diurnal convection probabilities increasing Sunday into early
next week.

Discussion:

Anomalously strong ridging continues across the Eastern CONUS Friday
through the weekend with 500mb heights of 594 to 596 dam across the
Tennessee and Ohio Valleys. NAEFS anomalies show this near the max
of climatology. The 850mb ridge also remains across the Ohio Valley
with weak easterly flow resulting in subsidence and limited moisture
transport across the region on Friday and Saturday. This will keep
LFC heights higher with limited probabilities for diurnal convection
on Friday and Saturday.

The upper ridge retrogrades and flattens across the Ohio Valley on
Sunday as a shortwave trough and associated surface frontal features
moves eastward across the Great Lakes and Ohio Valley. The 850mb
ridge shifts east with southerly flow resulting in increasing
moisture beginning Sunday. This increased moisture and lower upper
heights will increase instability with higher probabilities for
diurnal convection into early next week. While timing of
thunderstorms outside of diurnal convective trends is still
uncertain, northwesterly upper level flow and the general synoptic
pattern will bear watching with potential MCS/MCV thunderstorm
complexes riding the periphery of the ridge.
-- End Changed Discussion --

&&

.AVIATION...
(06Z TAFS)
Issued at 128 AM EDT Thu Jun 20 2024

VFR conditions expected at all TAF sites through the forecast
period. There is a probability of fog development at TRI but
confidence is too low to include.

Surface ridging and weak pressure gradient will produce light
winds as well.

&&

.PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN             93  72  95  73 /   0   0   0   0
Knoxville McGhee Tyson Airport, TN  91  70  93  72 /   0   0  10   0
Oak Ridge, TN                       91  70  93  72 /   0   0  10   0
Tri Cities Airport, TN              90  64  92  68 /   0   0  10   0
-- End Changed Discussion --

&&

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

$$

SHORT TERM...DH
LONG TERM....JB
AVIATION...DH