744
FXUS64 KMRX 210657
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
257 AM EDT Sat Sep 21 2024

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(Today and tonight)
Issued at 254 AM EDT Sat Sep 21 2024

Key Messages:

1. A few location may see a shower this afternoon mainly north, but
most locations will be dry for the short term period.

2. Temperatures will be above normal again.


We remain on the eastern side of the upper ridge that is centered to
our southwest. Some very weak short wave energy dropping southeast
along the periphery of the ridge may be enough to bring isolated
showers mainly to northern portions of the area this afternoon into
early evening. A rumble or two of thunder cannot be ruled out, but
convective energy looks quite limited so will just carry the
isolated showers in the forecast for now. Most areas will be dry
today and tonight, with high temperatures today again around 5 to 10
degrees above seasonal normals and low temperatures above normal as
well.

&&

.LONG TERM...
(Sunday through Friday)
Issued at 254 AM EDT Sat Sep 21 2024

Key Messages:

1. Hot weather to gradually subside into the work week.

2. A low chance exists for an isolated thunderstorm Sunday
afternoon, higher chances for unsettled weather exist Monday through
Wednesday, mainly across northern TN into VA.

3. Considerable uncertainty exists over precipitation chances late
week.

Discussion:

Expecting mostly dry conditions on Sunday as hot temperatures peak
thanks to the influence of a high pressure ridge to our south. The
GFS, HRRR, and high res FV3 all depict attempts at showers or a
thunderstorm on Sunday afternoon, especially over higher terrain of
the Plateau, so bumped up PoPs in areal coverage in response. Monday
and Tuesday a shortwave to our north helps bring light rain
primarily across our northern counties bordering Kentucky into
Virginia. Ensemble probabilities greater than a tenth of an inch QPF
during this timeframe are not great south of Knoxville.

Heading into Wednesday, a significant trough is expected to dive
down into the heart of the country and will be a major influence on
our weather through the remainder of the week. However there remains
considerable uncertainty over how the overall pattern evolves, with
major changes in guidance from even 24 hours ago. Left PoPs alone
for the latter half of the week with no clear indication of where
major weather features will evolve in that timeframe.

&&

.AVIATION...
(06Z TAFS)
Issued at 1254 AM EDT Sat Sep 21 2024

Biggest concern is possible fog development especially TRI.
Conditions look less favorable for dense fog than last night
although dense fog is still possible. For now will include MVFR
vsby with a tempo IFR vsby group for fog at TRI toward sunrise.
There may be a shower around at TRI this afternoon/early evening,
but probability looks too low to include for now. Other than the
aforementioned fog, will have a VFR forecast all sites for the
period. Winds will generally be light.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             94  69  94  70 /  10  10  10   0
Knoxville McGhee Tyson Airport, TN  90  67  92  68 /  10  10  10  10
Oak Ridge, TN                       90  67  91  67 /  10  10  20  10
Tri Cities Airport, TN              86  62  87  63 /  20  10   0  10

&&

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

$$

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