-- Discussion containing changed information from previous version are highlighted. --
962
FXUS64 KMRX 210516
AFDMRX

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

...New AVIATION...

.UPDATE...
Issued at 926 PM EDT Fri Sep 20 2024

Temperatures are falling a little faster than forecast, so hourly
temp/dewpoint grids will need an update. Other than that, the
forecast looks in good shape. Fog is not expected to be as dense
or widespread as last night as afternoon dewpoints were lower
today compared to yesterday. Still, some valleys and rivers/lakes
could see some fog, mainly in northern sections.

&&

.SHORT TERM...
(This evening through Saturday)
Issued at 305 PM EDT Fri Sep 20 2024

If you love today then you will like tomorrow. Daytime temps will
be about the same, maybe slightly more humid. Patchy morning fog
for the northeast third, and during the afternoon there may be
isolated showers over VA and the northern mountains. Otherwise,
lots of similarities with today because our controlling ridge of
high pressure will remain in place, allowing only the weakest
shortwave on its northern perimeter to bring those isolated
showers tomorrow afternoon.

&&

.LONG TERM...
(Saturday night through next Friday)
Issued at 305 PM EDT Fri Sep 20 2024

Key Messages:

1. Hot and mostly dry through the weekend. Max temps around 10
degrees above normal

2. Above normal temperatures remain through Tuesday, but with
increasing chances of precipitation.

Mostly dry conditions in place through Sunday as we will be under
the influence of high pressure just to our south. Temperatures will
be around 10 degrees above normal on Sunday, with Heat Indices in
the mid to upper 90s across the central and southern TN Valley.

By Monday the ridge begins to flatten as a shortwave moves into the
Missouri River Valley. Due to decreasing heights, and weak
divergence from the upper jet, POPs will increase on Monday. POPs
will be diurnally driven. On Tuesday, the ridge axis shifts to our
east as the aforementioned shortwave swings up into the Great Lakes.
A slightly stronger 300mb jet is overhead on Tuesday, resulting in
slightly higher POPs than Monday.

Wednesday and beyond, the forecast becomes much more uncertain.
Models generally show a long wave trough diving down into the
central U.S. and moving east. However, the evolution and placement of
this feature is in high disagreement. Will leave slight chance and
chance NBM POPs alone as of now.

&&

.AVIATION...
-- Changed Discussion --
(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.
-- End Changed Discussion --

&&

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --
Chattanooga Airport, TN             94  69  94  70 /  10  10  10   0
Knoxville McGhee Tyson Airport, TN  91  67  92  68 /  10  10  10   0
Oak Ridge, TN                       91  66  92  67 /  10  10  10  10
Tri Cities Airport, TN              86  62  87  63 /  20  10  10  10
-- End Changed Discussion --

&&

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

$$

SHORT TERM...DGS
AVIATION...