-- Discussion containing changed information from previous version are highlighted. --
811
FXUS64 KMRX 130235
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
1035 PM EDT Sun May 12 2024

...New UPDATE...

.UPDATE...
-- Changed Discussion --
Issued at 1027 PM EDT Sun May 12 2024

Forecast remains in good standing for the overnight, with just
minor upward adjustments made to sky cover as upper-level clouds
advect atop the forecast area.
-- End Changed Discussion --

&&

.SHORT TERM...
(This evening through Monday)
Issued at 245 PM EDT Sun May 12 2024

Key Messages:

1. Quiet weather for the rest of this afternoon and overnight.

2. Increasing clouds and rain showers Monday as a system
approaches from the west.

Discussion:

The overnight period will be quiet with ridging and high pressure
over the region. High clouds begin to increase overnight as a
trough moves into the Mississippi Valley. Any fog development will
be limited to near bodies of water.

On Monday, isolated to scattered showers are expected starting in
the late morning or early afternoon hours. Shower activity will
be light and spotty with the trough and surface system remaining
well to the west through Monday afternoon. The CAMs agree that
activity will be light and spotty tomorrow. Thunder potential is
low with a fairly dry air mass in place. Highs will be in the 70s
again tomorrow.

&&

.LONG TERM...
(Monday night through next Sunday)
Issued at 245 PM EDT Sun May 12 2024

Key Message:

1. Showers and thunderstorms continue through Wednesday

2. After a brief break another round of storms expected as we head
into the weekend.

Discussion:

By Monday night we`ll likely start to see the more widespread
showers and thunderstorms moving through ahead of the incoming low
being driven by a slowly progressing trough as it moves through the
Ohio and Tennessee Valleys. We`ll definitely have several breaks
between rounds of showers and thunderstorms... But with the
prefrontal activity, storms along the front, and being positioned
near the base of the trough, we`re going to be seeing several wet
and overcast days for the first half of the work week. With the
slower moving nature of this system, the cloudy skies, and only
being positioned in a favorable jet region for a brief period on
Tuesday the synoptic features of this system aren`t lining up to see
widespread severe thunderstorms. So at this time the primary threat
continues to be heavy downpours and eventually ponding/flooding by
the middle of the week for places that are underneath multiple
rounds of heavy showers. In addition with the more saturated soils
we could see some downed trees under storm enhanced wind gusts.

We`ll get a brief respite from cloud coverage and precipitation
chances for Wednesday night through Friday morning. During this
break we`ll see temperature climb back to near seasonal normals by
Thursday.

As we head into the weekend models are in good agreement that
another system will move thorugh the eastern half of the U.S. but
that`s about all they can agree on at this time. Still lots of
deterministic model variances, and lower probabilistic chances lead
to a decrease in forecast confidence for Friday and beyond. This next
system does look to have stronger forcing and better lower level
thermodynamics to possibly support stronger thunderstorms. So this
system will be worth keeping an eye on, especially with the
possibility to impact Friday night and/or Saturday outdoor
activities.

&&

.AVIATION...
(00Z TAFS)
Issued at 730 PM EDT Sun May 12 2024

Increasing high clouds are expected tonight, with rain chances
increasing at CHA and TYS late tomorrow morning and into the
afternoon. Expect BKN/OVC low-mid level VFR clouds to become more
predominant with rain as well. Non-zero rain chances exist in the
afternoon at TRI, however, potential for downslope drying across
far northeast Tennessee leads to lower confidence so no mention
has been included at this time. CHA has the greatest likelihood to
see potential reduced vis or cigs with strongest showers.
Lightning is not expected at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             58  72  63  77 /   0  60  80  90
Knoxville McGhee Tyson Airport, TN  54  76  61  75 /   0  40  70  90
Oak Ridge, TN                       54  75  61  74 /   0  40  60  90
Tri Cities Airport, TN              49  76  57  74 /   0  20  60  80

&&

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

$$

SHORT TERM...McD
AVIATION...KRS