253
FXUS64 KMRX 010135
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
935 PM EDT Sun Jun 30 2024

...New UPDATE, AVIATION...

.UPDATE...
Issued at 930 PM EDT Sun Jun 30 2024

Update to forecast with convection ending and the risk for more a
little lower as airmass has stabilized. Only a few more showers
and storms across the forecast area as cold front approaches from
the NW. The only existing showers across the northern plateau
moving south at this time. Airmass should begin to dry out late
tonight and with a light to moderate west to northwest wind not
expecting much fog will form. If any fog forms it will likely be
south and eastern parts of the forecast area ahead of cold front.
Updated hourly temperatures and dew points and lowered pops for
rest of the night.

&&

.SHORT TERM...
(This evening through Monday)
Issued at 307 PM EDT Sun Jun 30 2024

Key Messages:

1. Isolated to scattered showers and storms through this evening. A
few storms may become strong to severe.

2. Cooler and drier air moving in tonight.

3. Marvelous Monday!

Discussion:

Showers and storms across northern middle TN from this morning
advected quite a bit of debris clouds down across the central east
TN Valley. Thus far, the cloud cover has prohibited convection from
developing across the central valley. Most of today`s activity has
occurred across the southern Cumberland Plateau, southwest VA and
northeast TN. From now through sunset, scattered to widespread
showers and storms are expected across southwest VA and northeast
TN. Moderate instability and weak 0-6km shear are in place and
will allow for isolated strong to severe storm through this
evening. The main threat with any stronger storm will be damaging
straight line winds. Even though we have been dry, a localized
flood threat can`t be ruled out for any location that sees
repeated rounds of showers and storms.

Elsewhere, isolated showers and storms are still possible but
confidence is low, especially across the southern and central
east TN Valley. Based on the latest HRRR, these areas stay mostly
dry through this evening. This is quite unfortunate as many areas
needed the rain and after today we dry out again.

The cold front passes through tonight, brining cooler and drier air
into the region. The drier air and winds behind the front will
likely prevent any fog from developing. For Monday, expect sunny
skies, lower afternoon RH, and near normal to slightly below
normal temps.

&&

.LONG TERM...
(Monday night through next Sunday)
Issued at 307 PM EDT Sun Jun 30 2024

Key Messages:

1. Dry to mostly dry conditions through Wednesday, with increasing
chances of diurnal showers and storms Thursday into the weekend.

2. Hot conditions expected to continue through the extended.

Discussion:

The continued influence of upper level ridging & low-level flow
becoming more southwesterly will result in the return of slightly
above normal temperatures by Tuesday. A notable subsidence inversion
should inhibit shower & thunderstorm development Tuesday and for
most of us Wednesday as well. With increasing moisture Wednesday it
is not out of the question that isolated activity develops with
orographic influence, however, most should remain dry as NAMbufr
soundings(which is often most aggressive with instability) suggest
just a measly 500 J/kg or less.

The upper ridge flattens out due to shortwave energy translating
across the northern CONUS Thursday. With weakening influence of
subsidence aloft, increasing chances for diurnal showers and storms
are expected late week. This will also be paired with increasing
dewpoints and subsequently, increasing apparent temperature. Perhaps
a few locations across the southern valley flirt with heat advisory
criteria Thursday through Saturday, partially conditional on the
coverage and timing of showers of storms, but no widespread concerns
at this time.

A more notable shortwave will drive a surface boundary across the
region this weekend and bring more widespread chances of showers and
storms. Very minor relief of heat is possible but trends suggest
only by a few degrees as veering of the low-level winds to the
northwest post FROPA looks short-lived and rather weak.

&&

.AVIATION...
(00Z TAFS)
Issued at 930 PM EDT Sun Jun 30 2024

Earlier TAF issuance this evening included VCTS at TYS and CHA for
some storms in the vicinity first hour and kept prevailing showers
at TRI. Overall VFR conditions expected through the evening.
Early Monday MVFR conditions at TRI due to reduced visibility from
significant rainfall this afternoon and the potential for low
cloud ceilings forming late tonight. However winds will switch to
NW overnight into early Monday and this drying may end fog early
at TRI. VFR conditions expected Monday with NW winds locally gusty
at CHA not as confident for higher winds at TYS.


&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             71  89  70  91 /  10   0   0   0
Knoxville McGhee Tyson Airport, TN  67  85  64  91 /  20   0   0   0
Oak Ridge, TN                       65  84  64  90 /  20   0   0   0
Tri Cities Airport, TN              61  82  59  88 /  50   0   0   0

&&

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

$$

SHORT TERM...TD
LONG TERM....KRS
AVIATION...TD