-- Discussion containing changed information from previous version are highlighted. --
962
FXUS64 KMRX 250518
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
118 AM EDT Tue Jun 25 2024

...New AVIATION...

.UPDATE...
Issued at 1030 PM EDT Mon Jun 24 2024

Super dry airmass tonight, 00z sounding from Nashville was at the
25th percentile for PWAT and low level water vapor imagery reveals
even drier air passing over East Tennessee, likely validating the
model depiction of 10th percentile PWAT air. Now that the sun has
set, temperatures are beginning to cool off, and we should finish
a few degrees below normal for this time of year, which is a rare
treat given the ongoing heat. Given the cool night ahead, there
are some activities I can imagine some of us doing before the Sun
returns tomorrow to heat the landscape back up again.

Great weather to go for a walk outside this evening or in the morning.
Beautiful clear skies in the dry post frontal air for stargazing.
Optimal conditions for early morning outdoor work before the heat
of the day returns by the afternoon. All in all good activities.

Forecast is for the most part on track, with only some blending to
match dewpoints to observations which had continued to run lower
than expected. That might indicate greater cooling than forecast,
but don`t want to be too hopeful on that.

&&

.SHORT TERM...
(This evening through Tuesday)
Issued at 218 PM EDT Mon Jun 24 2024

Key Messages:

1. Dry and hot conditions return for Tuesday.

Discussion:

An upper and surface ridging will build back into the Tennessee
valley and southern Appalachians. NAEFS shows PWS dropping to
around 2 deviations below normal with values of 0.6 to 0.8. These
values are also near the lowest 10 percentile. Definitely depicts
how dry the airmass will be for Tuesday morning.

The dry airmass will for large diurnal range of temperatures per
NBM guidance.

Overall, dry, mostly clear, and continued hot afternoon
conditions.

&&

.LONG TERM...
(Tuesday night through next Monday)
Issued at 218 PM EDT Mon Jun 24 2024

Key Messages:

1. Rain chances arrive on Wednesday into Thursday with a weak
frontal passage. Another front may bring showers and storms by the
weekend.

2. Above normal temperatures continue through the period with
slightly cooler temperatures expected Thursday before heating right
back up again Friday through Sunday.

Discussion:

Between the Bermuda High and the Four Corners High will be a 500 MB
trough that will encourage instability and a surface boundary for
Wed-Thur timeframe, aiding convective development.

The Four Corners High with will then stretch eastward, resuming a
drier weather pattern for late week, with precip limited mainly to
diurnal high terrain convection. But over the weekend, the high
pressure ridge will shift back westward again, opening another
northwesterly corridor for the impacts of another weather system
with a broad Saturday-to-Monday window of increased precip chances,
but peaking on Sunday. Given the heat during the period, tstms
should dot the convective areas during the extended period.

Speaking of heat, NBM dewpoints are progged to increase during the
Fri-Sun period, and GFS MOS supports that. Although I hedged the
dewpoints downward a bit this far out, afternoon heat indices during
Fri-Sun may top off between 100-105 degrees in portions of the
southern TN Valley, while running around 98-100 degrees in portions
of the northern Valley.

&&

.AVIATION...
-- Changed Discussion --
(06Z TAFS)
Issued at 117 AM EDT Tue Jun 25 2024

VFR conditions expected for the next 24 hours under the influence
of high pressure.
-- End Changed Discussion --

&&

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --
Chattanooga Airport, TN             96  72  98  73 /   0   0  20  40
Knoxville McGhee Tyson Airport, TN  92  69  95  71 /   0   0  20  50
Oak Ridge, TN                       92  69  95  70 /   0   0  30  50
Tri Cities Airport, TN              90  65  92  69 /   0   0  30  60
-- End Changed Discussion --

&&

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

$$