122
FXUS64 KMRX 061710 AAA
AFDMRX

Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
110 PM EDT Sat Jul 6 2024

...New AVIATION...

.UPDATE...
Issued at 1021 AM EDT Sat Jul 6 2024

A diffuse cold front appears to be moving through the area this
morning, or perhaps just south, best identified by a dewpoint
gradient from lower/mid 70s dewpoints in the NC border counties
and northern GA, to mid/upper 60s dewpoints in the Plateau, Middle
TN, and eastern KY. These lower dewpoints will continue to spread
into the area this afternoon with a northerly wind. A weak upslope
flow and higher dewpoints in the mountains may result in a few
isolated showers developing near the TN/NC border and our SW NC
counties. 12Z BNA sounding shows a capping inversion at 800-700 mb
that will suppress convection elsewhere. The update will make a
few changes to PoP/Wx and temp/dewpoint grids, but nothing major.

&&

.SHORT TERM...
(Today and tonight)
Issued at 253 AM EDT Sat Jul 6 2024

Key Messages:

1. Patchy fog this morning will dissipate shortly after sunrise.

2. Low chances for showers and storms today will be confined to
near the East Tennessee Mountains and North Carolina counties.

Discussion:

In the upper levels, a broad trough remains over the Great Plains
and the Midwest. At the surface, a cold front will move through
the region early this morning, weak high pressure will move in
behind it. Patchy fog has developed this morning. Fog will
dissipate shortly after sunrise if not sooner as the front moves
through. Although, the much lower dew points are still in Western
and Central Kentucky. Highs today will be mainly in the upper 80s
and lower 90s but humidity will be lower with those lower dew
points en route. Most locations will be sunny today and showers
and storms will be confined to near the East Tennessee Mountains
and North Carolina counties. Even there, rain chances are low
since northwesterly 850mb flow will be weak around 5 to 10 kt.
The tonight period will be dry and pleasant.

&&

.LONG TERM...
(Sunday through Friday)
Issued at 253 AM EDT Sat Jul 6 2024

Key Messages:

1. Mostly dry conditions continue into Sunday.

2. Heat indices of 100-105 degrees returns for early next week as
low-level moisture pulls back into the area.

3. First half of next week looks fairly active, so confidence is a
little higher for better afternoon thunderstorm coverage each day.

4. Remains of BERYL with deep moisture may move into the Tennessee
valley for mid to late week. Locally heavy rains and localized flash
flooding possible but confidence on track of best convection low.

Discussion:

Dayshift discussion nailed things down quite well and essentially
will replicate what was stated. For much of the extended, upper
trough over the mid-section of the nation with ridging far southeast
United States. This pattern will keep southwest flow aloft over the
region for the extended with increasing moisture (PWs) by early next
week. One of the main weather stories will be the track of BERYL
moisture with the potential of deep tropical moisture by mid to late
week over the region which would lead to better threat of isolated
flash flooding. As was stated, convection is possible anytime but
diurnally greatest coverage in the afternoon and evening hours.

For Sunday, the Theta-e ridge is initially east of the spine of the
Appalachians but pulls into the far east Tennessee mountains and
southwest North Carolina in the afternoon and evening.

For Monday and Tuesday, the moist and unstable Theta-e ridge axis
pulls far westward into much of the area with increasing coverage of
storms especially afternoon/evening.

For late Tuesday night through Thursday, deep tropical moisture from
the remnants of BERYL may move across the Tennessee valley into the
southern Appalachians. Anomously high PWs of 2.1 to 2.2 inches along
with high Theta-e ridge axis over the area will set the stage for
increasing threat of flash flooding.

For Friday, deep sub-tropical moisture will remain but upper ridging
will strengthen across the southern Appalachians. Overall, hot and
muggy conditions with continued diurnal convection. Coverage of
storms will likely be less due to the higher heights.

&&

.AVIATION...
(18Z TAFS)
Issued at 109 PM EDT Sat Jul 6 2024

VFR conditions are forecast at all sites through this period. A
potential exception may be TRI, where fog cannot be ruled out.
Since dewpoints are expected to fall this afternoon as dry air
moves in, fog potential seems too low at this time to mention any
in the TAF.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             93  73  96  74 /  10  10  10  20
Knoxville McGhee Tyson Airport, TN  92  70  94  73 /  10   0  20  20
Oak Ridge, TN                       92  69  94  72 /  10   0  10  10
Tri Cities Airport, TN              88  66  92  70 /  10  10  20  10

&&

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

$$

SHORT TERM...DGS
LONG TERM....DH
AVIATION...DGS