272
FXUS64 KMRX 200531
AFDMRX

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

...New AVIATION...

.UPDATE...
Issued at 917 PM EDT Wed Jun 19 2024

Quiet evening across the area and the forecast is on track. Minor
adjustments to hourly temps and dewpoints to match up with latest
obs but otherwise no changes.

&&

.SHORT TERM...
(This evening through Thursday)
Issued at 238 PM EDT Wed Jun 19 2024

Key Messages:

1. Hot and dry conditions continue with strong ridging in place
tonight and Thursday.

Discussion:

At mid afternoon today the forecast area remains under the
influence of a large upper level ridge centered over New Jersey.
It extends southwest across the southern Appalachians and
Tennessee Valley. Also high level cloudiness has spread northeast
from Tropical Storm Alberto into the Tennessee Valley which has
kept temperatures down across the central and southern valley
parts of the forecast area. Dew points are lower today, mostly
lower to mid 60s with the dry air and subsidence under the ridge.
At mid afternoon temperatures were in the mid to upper 80s. Tonight
cloudiness should thin out based on model guidance and drop to the
lower to mid 60s, upper 60s south. Thursday Tropical Storm Alberto
moves into Mexico. Thursday is forecast to be slightly warmer with
less high cloud cover and still lower dewpoints.

&&

.LONG TERM...
(Thursday night through next Wednesday)
Issued at 238 PM EDT Wed Jun 19 2024

Key Messages:

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

2. Rain chances increasing Sunday into early next week as the ridge
weakens.

Discussion:

A large high pressure ridge will continue to dominate the weather
pattern through the end of this week. At the surface, a Bermuda high
will extend west across the southern Appalachians and Tennessee
Valley. Aloft, a large ridge centered off the Mid-Atlantic coast
today will gradually retrograde toward the SW, and end up in the
lower MS/southern Plains region by Sunday. Anomalously high 500
mb heights will bring subsidence to the area Friday and Saturday,
leading to above normal temperatures and dry, stable conditions.
Some isolated, short-lived showers and storms may be possible in
the higher terrain each afternoon.

The ridge loosens its grip on the area by Sunday as a broad trough
develops across the Great Lakes and OH Valley. The jet streak takes
a more southward position, pushing a cold front into the OH Valley
region on Sunday. This should bring more low level moisture, and
thus better potential for afternoon convection to develop Sunday
afternoon. PoPs in the chance range continue into Monday with the
trough/front passage. Behind the trough on Tuesday, we get into a NW
flow pattern with a large ridge over the Plains, with the potential
for upstream MCSs to bring precip to the area. The details of this
are too uncertain this far out, so no changes will be made to NBM.

&&

.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...
Chattanooga Airport, TN             92  70  95  72 /   0   0   0   0
Knoxville McGhee Tyson Airport, TN  92  68  93  70 /   0   0  10   0
Oak Ridge, TN                       92  68  93  70 /   0   0  10   0
Tri Cities Airport, TN              90  63  92  66 /   0   0  10   0

&&

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

$$

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