531
FXUS64 KMRX 061900
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
300 PM EDT Sat Jul 6 2024

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

.SHORT TERM...
(This evening through Sunday)
Issued at 251 PM EDT Sat Jul 6 2024

Key Messages:

1. Comfortable dewpoints and low temperatues in the 60s tonight.

2. Chance of showers tomorrow afternoon in the mountains and SW
NC.

Drier air has been building into the area through the day, and
along with boundary layer mixing, dewpoints have dropped into the
lower and mid 60s in many spots. A weak upslope flow is producing
some isolated light showers in the mountains. This NW flow will
shift around to N and E thorugh the night as the surface high over
West TN moves to the upper OH Valley region. With a broad trough
and jet streak to our NW, some scattered cloud cover may linger
overnight, but with the falling dewpoints, lows should be mainly
in the 60s overnight. Tomorrow, a SE low level flow will bring
moisture and instability back toward the area, mainly in SW NC
and the mountains, so we may see a little better coverage of
showers in that area during the afternoon. Valley locations should
stay dry with highs in the lower 90s in most spots.

&&

.LONG TERM...
(Sunday night through next Saturday)
Issued at 251 PM EDT Sat Jul 6 2024

Key Messages:

1. Heat indices of 100-105 degrees returns Monday and Tuesday as low-
level moisture pulls back into the area.

2. Next week looks convectively active. High rain chances return
later Monday and continue through the week.

3. Remains of BERYL with deep moisture may move into the Tennessee
valley Tuesday night through Thursday. Locally heavy rains and
localized flash flooding possible by late week but confidence of the
track for timing of heavy rainfall is still low.

Discussion:

For the extended forecast an upper trough continues over the middle
of the country with ridging aloft across the far southeastern part
of the southeast United States. As a result a southwest flow aloft
is in place over the eastern Tennessee Valley and Southern
Appalachians with low level moisture increasing by Monday. The main
weather story of the extended is the track of tropical system
BERYL`s moisture with the potential for deep tropical moisture from
the system mid to late in the week over the region which could lead
to a better threat of isolated flash flooding. Increasing chances
for showers and thunderstorms with highest coverage during the
afternoon and evening hours.

On Monday and Tuesday, a moist and unstable airmass will be over the
forecast area with increasing coverage of showers and thunderstorms
Temperatures will be warmest on these days too with highs in the
lower to mid 90s. Heat Index values will be highest Monday and will
be at heat advisory levels in the central and southern valley. On
Tuesday heat index values will be slightly lower.

Still looks like late Tuesday night through Thursday deep tropical
moisture from the remnants of BERYL may move across the Tennessee
Valley into the southern Appalachians. High PWs of 2.1 to 2.2 inches
along with a high Theta-e ridge axis over the area could set the
stage for locally heavy rainfall and flash flooding. The remnant
surface low that was Beryl is forecast to be over the Ohio and
Tennessee Valleys. Highs Wednesday and Thursday will be cooler with
more clouds and precipitation, only in the mid 80s to around 90.

Friday and again Saturday the surface low shifts northeast and its
deep sub-tropical moisture may move with it as upper ridging
strengthens across the southern Appalachians. Any leftover moisture
will still make it feel muggy and temperatures will again rise into
the lower 90s. There will still be high chances of showers and
storms only slightly less coverage.

&&

.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  71  95  75 /  10  10  10  20
Knoxville McGhee Tyson Airport, TN  90  69  93  73 /  10   0  20  20
Oak Ridge, TN                       90  68  93  72 /  10   0  10  10
Tri Cities Airport, TN              86  66  91  69 /  10  10  20  20

&&

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

$$

SHORT TERM...DGS
LONG TERM....TD
AVIATION...DGS