-- Discussion containing changed information from previous version are highlighted. --
144
FXUS64 KMRX 210534
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
134 AM EDT Tue May 21 2024

...New AVIATION...

.UPDATE...
Issued at 846 PM EDT Mon May 20 2024

Only some minor tweaks made to the forecast for the rest of
tonight. Removed any mention of thunderstorms along the
plateau and mountains now that the sun is setting and CU field is
decreasing. Overnight we could see some patchy river valley fog,
but dew point depressions are generally larger than this time
yesterday, so am not anticipating any more widespread fog than
what we experienced this morning.

&&

.SHORT TERM...
(This evening through Tuesday)
Issued at 244 PM EDT Mon May 20 2024

Key Messages:

1. A few isolated showers and storms may linger until sunset, but
then dry through the night.

2. High pressure remains in control tomorrow, with slightly warmer
temperatures and mostly dry conditions. Except for isolated
afternoon showers and storms across the east TN mountains.

Discussion:

A few isolated showers and storms are ongoing at the current hour.
These are terrain driven and located across the Cumberland
Plateau, southwest NC, and the east TN mountains. An isolated
shower or storm may even pop up across the central east TN valley,
but very low chances. This activity comes to a screeching halt at
sunset as we lose our daytime heating and instability.

Calm and quiet conditions overnight with mild conditions as low
temps will be in the upper 50s to low 60s.

Tomorrow features a repeat of today with high pressure remaining in
control. Another round of terrain driven convection is possible
during the afternoon hours as we heat up, though most locations will
once again be dry. Slightly warmer temps tomorrow with highs ranging
from the low to mid 80s to near 90s.

&&

.LONG TERM...
(Tuesday night through next Monday)
Issued at 244 PM EDT Mon May 20 2024

.LONG TERM...

Key Messages:

1. Mostly dry through Wednesday, with daily chances for showers and
storms Thursday into early next week.

2. Temperatures will generally remain near to slightly above normal.

Discussion:

By Wednesday, broad upper troughing will expand across north-central
CONUS with ridging influence occurring locally. A deep surface low
will slide into the northern Great Lakes region, with an associated
boundary stretching from the Ohio River Valley southwestward into
the ArkLaTex region. Guidance continues to trend towards this
boundary losing its southeastern momentum throughout the mid-week.
As a result, Wednesday will remain mostly dry with the gradual
increase in chances for showers and storms delayed more so into
Thursday.

The front will then stall across the region as numerous shortwave
disturbances traverse mean flow aloft through the weekend. For this
reason, an unsettled pattern with daily chances for showers and
storms is expected into early next week. Most recent mean ensemble
guidance suggest that the probability of precipitation GTE 1"
Thursday through Monday is 70% or higher CWA wide. Additionally, GFS
soundings depict MLCAPE in excess of 1000 J/kg and mid-level lapse
rates approaching 7C/km at times during the weekend. While there is
no exact time or day that stands out at this moment, the potential
for a few stronger storms and flooding due to repeated rounds of
showers and storms cannot be totally ruled out, especially dependent
on the the potency of upper disturbances and their potential to lead
to any semi-organized convection. Give we are still 5+ days out,
will continue to utilize low probability wording in the HWO.
Temperatures will generally be near or slightly above normal,
however, some moderation higher or lower is possible depending on
timing and coverage of showers and storms.

&&

.AVIATION...
-- Changed Discussion --
(06Z TAFS)
Issued at 121 AM EDT Tue May 21 2024

VFR expected at CHA and TYS through the period. TRI is more
uncertain, dewpoint depressions at TRI have closed to 3 degrees,
and with continued radiational cooling should be near saturation
by 08z. Added a TEMPO to account for patchy fog at the terminal in
the early morning. Isolated shower or TS possible during the
afternoon in the wider region but no impacts to terminals
expected.
-- End Changed Discussion --

&&

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --
Chattanooga Airport, TN             89  65  89  68 /  10   0   0  10
Knoxville McGhee Tyson Airport, TN  86  65  86  67 /  10   0   0  10
Oak Ridge, TN                       86  64  86  66 /  10   0   0  10
Tri Cities Airport, TN              83  61  85  63 /  10  10  10  10
-- End Changed Discussion --

&&

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

$$

SHORT TERM...
LONG TERM....KRS
AVIATION...Wellington