536
FXUS64 KMRX 141332
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
932 AM EDT Sat Sep 14 2024

...New UPDATE...

.UPDATE...
Issued at 929 AM EDT Sat Sep 14 2024

Update this morning to tweak temp/dewpoint values heading into
the afternoon. Rain still trying to transit northward out of
Alabama, but expect the vast majority of the precipitation to stay
west of the Cumberland Plateau. Southern TN and southwest NC
continue to have the best chances at precipitation with the most
widespread rain expected in the afternoon. However it won`t be a
drought busting rain, and the majority of people near I-40 and
northward will remain dry and sunny today.

&&

.SHORT TERM...
(Today and tonight)
Issued at 337 AM EDT Sat Sep 14 2024

Key Messages:

1. Some showers possible mainly in the south, but overall largely
expect dry conditions for the forecast area today.

2. Another warm day, with temperatures 2-4 degrees above normal.

Discussion:

The short term will feature a rex block across the eastern CONUS as
an upper low (remnants of what was once Francine) spins away over
the MS/AL region, beneath a large scale ridge centered over the
Great Lakes area. With little to no movement in either feature, our
forecast area will be locked beneath southeasterly upper flow and
the influence of surface high pressure to our north. Most all
guidance continues to show that a persistent band of convection will
remain situated from middle/western Tennessee, south southeast into
Alabama through the short term period, with only occasional and
sporadic convective development further northeast during the
afternoon hours later today. PoPs reflect this, showing mostly dry
conditions across the forecast area, save an expansion of rain
chances to roughly the I-40 corridor and west of the I-75 corridor
in the northern plateau area for a few hours this afternoon. The one
caveat to this will be the far southern plateau and TN valley (think
Marion county over to Bradley county perhaps) which will remain
close enough to that aforementioned band of convection through the
day to warrant keeping some rain chances in the forecast. Otherwise,
expect to see mostly dry conditions across the board as we remain in
southeasterly flow across the Appalachians, which favors warm and
drying conditions.

Speaking of warming, southeasterly downslope flow, high temperatures
will be warm again today. Expect to see highs 2-4 degrees above
normal this afternoon, generally in the mid to upper 80s, with the
warmest locations being in the central valley around the Knoxville
metro. Not near any records, but fairly impressive nonetheless given
the duration of this persistent downslope flow pattern which is in
its third day or so now.

&&

.LONG TERM...
(Sunday through Friday)
Issued at 337 AM EDT Sat Sep 14 2024

Key Messages:

1. Gusty winds over the higher terrain of the E TN mountains
Sunday.

2. Most areas are expected to see little rainfall for the
extended period, but there is low confidence in the details.

Discussion:

The long term period will depend on the evolution of the remnants of
Francine and new development off of the SE coast. Gusty winds will
continue over the higher terrain of the Appalachians through late
Sunday as SEly 25-30 kt flow crosses the mountains. Although some
gusts may reach Wind Advisory criteria, for the most part, most
areas should remain sub advisory level.

As expected with uncertainty surrounding tropical development,
rainfall amounts have changed in the past 24 hours since the last
early morning forecast issuance. Precip chances across the south of
our forecast area through late Monday will shift to far NE Tennessee
and SW Virginia when Francine further dissipates while sinking
southward and the new development aims for the Carolina coast. SE
coast unsettled weather looks to continue beyond the "landfall" of
the Carolina low, which further increases the spread of what to
expect towards the end of the period. TN valley high temperatures
appear will remain in the 80s much of the week with humid conditions.

&&

.AVIATION...
(12Z TAFS)
Issued at 713 AM EDT Sat Sep 14 2024

VFR conditions should prevail at all sites through the 12z TAF
period. Do believe some ISOLD SHRA will pop up across the region
this afternoon, but much of our area should remain in the dry.
KCHA would be the site most likely to see some rain given the
proximity to rain bands with the remnants of Francine, but
confidence in occurrence and timing is low enough to not include
it for now.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             81  68  85  65 /  60  30  30  20
Knoxville McGhee Tyson Airport, TN  88  66  88  64 /  10  10  10  20
Oak Ridge, TN                       87  66  86  64 /  20  10  10  10
Tri Cities Airport, TN              82  62  82  59 /  10   0  10  20

&&

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

$$

SHORT TERM...
LONG TERM....KS
AVIATION...CD