688
FXUS64 KMRX 200050
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
850 PM EDT Sun May 19 2024

...New UPDATE...

.UPDATE...
Issued at 845 PM EDT Sun May 19 2024

Isolated showers this evening have pretty much ended across the
eastern Tennessee Valley. After a warm day in the lower to mid
80s temperatures were starting to fall back into the 70s. A few
showers and storms were over the mountains earlier. These showers
have ended or were dissipating fast. Skies should now be mostly
clear and continue overnight. Some patchy fog should form
especially northeast half of the area. Lows tonight will be
in the comfortable mid 50s to lower 60s. Updated zone forecast has
been sent.

.SHORT TERM...
(This evening through Monday)
Issued at 305 PM EDT Sun May 19 2024
Key Messages:

1. A few isolated showers and storms through late evening but most
locations will be dry.

2. Patchy fog tonight.

3. Beautiful, dry, and warm tomorrow.

Discussion:

Upper trough continues to slowly push east and out of the area.
However, a few isolated showers and storms can be expected through
late evening. This activity will mainly be focused along the east TN
mountains and southwest NC but an isolated shower or storm is also
possible across the Cumberland Plateau and east TN valley.

Patchy fog likely tonight for some areas. Best chances will be
across northeast TN, southwest VA, and southwest NC.

Tomorrow will be a dry and sun-filled day. High temps will be a few
degrees above normal as high pressure strengthens across the area.

&&

.LONG TERM...
(Monday night through next Sunday)
Issued at 305 PM EDT Sun May 19 2024

Key Messages:

1.Drier and warmer through Wednesday, with only isolated
thunderstorm potential generally in the higher elevations.

2. Unsettled pattern with multiple rounds of showers and storms
possible Thursday through the weekend.

Discussion:

Influence from surface high pressure and upper level ridging will
allow for mostly dry conditions to persist across the forecast area
as we head into the middle of the work week. Surface heating may be
strong enough to allow for a isolated showers and storms mainly
across higher elevations of the East Tennessee mountains, Tuesday
afternoon. The recent suite of NAM model runs have followed trends
of global ensemble members in that Wednesday will remain mostly dry
as the aforementioned ridging really slows southward progression of
an approaching frontal boundary.

Frontal forcing will increase early Thursday as ridging shifts
eastward due to weak disturbances traversing the flow aloft. This
frontal forcing along with increasing moisture transport(PWAT values
~ 1.5") will be sufficient for the return of widespread
precipitation chances. However, ensemble guidance suggest the
greater chances for 24-hr precipitation GTE 0.1" will be along and
north of I-40 in closer proximity to the stalling front.

The chance of showers and storms will really persist through the
remainder of the long term from this point onwards. A more prominent
shortwave will swing atop the region Friday and may pose concern for
more efficient rainfall rates. The lingering boundary and
additional, but weaker disturbances, hold onto daily chances for
precipitation through the weekend. At this time there is not any
particular part portion of the unsettled weather that brings too
much concern but as is anytime there are repeated chances for rain,
localized flooding could occur for locations that see numerous
rounds of any strong convection. GEFS ensemble mean suggest a 20-40%
chance of total accumulation of 2 inches or greater through the
weekend. Temperatures through the long term will generally bounce
around near to above normal depending on the coverage of
clouds/precipitation for any given day.

&&

.AVIATION...
(00Z TAFS)
Issued at 700 PM EDT Sun May 19 2024

VFR conditions expected at CHA and TYS through the period. TRI
will be VFR except some IFR to MVFR conditions with fog late
tonight through early Monday morning. After 12 to 13Z Fog should
lift at TRI with VFR conditions resuming.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             63  86  64  88 /   0  10   0   0
Knoxville McGhee Tyson Airport, TN  60  84  63  85 /   0  10   0  10
Oak Ridge, TN                       60  85  63  86 /   0  10   0  10
Tri Cities Airport, TN              57  82  59  83 /   0  10   0  20

&&

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

$$

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