Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS64 KMRX 242344
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
744 PM EDT Sun Mar 24 2024

...New AVIATION...

.SHORT TERM...
(This evening through Monday)
Issued at 230 PM EDT Sun Mar 24 2024

Key Messages:

1. Dry for the short term period.

2. Winds will become strong and gusty in some of the mountains and
foothills of the E TN mountains tonight and Monday.

3. Low RH values expected Monday afternoon, and this will combine
with the strengthening winds to elevate fire weather concerns
especially to the lee of the mountains.

Discussion:

We start the period with surface high pressure centered to our
northeast and a low pressure system over the western Plains. This
low pressure system will track slowly east across the central Plains
during the short term period. Out ahead of this system, a low level
southeasterly jet will strengthen over our area. While moisture will
be slow to move in and the short term period will be rain free, the
set up looks favorable for mountain wave wind enhancement to occur
in the usual higher elevation and foothill areas starting tonight
and continuing through the short term period. Right now it looks
like we will see gusts to around 50 mph at times later tonight into
Monday in the usual areas, and the winds may begin to strengthen
further late Monday afternoon. Will issue a wind advisory starting
at midnight tonight in the E TN mountains, with a high wind watch
beginning late in the day.

In addition to the wind, RH values will get quite low Monday
afternoon with many areas dipping into the 20s. This will increase
the fire weather danger especially in the areas that see gusty winds
on the leeward side of the mountains.  After coordinating with TN
state forestry, no fire weather watch will be issued at this time
given the recent rain and rapid greenup that is occurring. However,
later shifts will continue to monitor and at least a fire danger
statement may be issued closer to the time of the winds/low RH
combo.  For now will headline these conditions in the FWF.

&&

.LONG TERM...
(Monday night through next Sunday)
Issued at 230 PM EDT Sun Mar 24 2024

Key Messages:

1. Mountain wave wind event expected to strengthen Monday into Tuesday

2. Showers and isolated thunderstorms are expected off and on
Tuesday through Tuesday night with shower coverage decreasing on
Wednesday.

3. Near freeing temperatures possible Friday morning.

Discussion:

By Monday night the incoming frontal boundary will be moving near
the Mississippi river as the Tennesee Valley will likely remain well
north of the warm front, waiting for the occluded frontal boundary
to move in. Along and ahead of this system a very strong LLJ will
bring impactful weather to start the work week. Biggest impact will
likely be breezy conditions Monday night through Tuesday as core of
the jet looks to increase above 70 knots in northern TN and central
KY. This jet being out of the south to southeast will induce a very
strong mountain wave effect for multiple days, peaking in strength
late Monday into early Tuesday. Orientation of the jet, strength of
the jet, and inversion in the lower levels all point towards a
strong wind event. Based on latest high resolution guidance am
expecting multiple reports of 60+ mph winds and cannot rule out
seeing gusts over 80 mph in some locations. With this in mind will
issue a High Wind Watch for the southern Appalachian Mountains and
foothills Monday afternoon through Tuesday afternoon. Elsewhere
expect conditions to be breezy in the valley, and especially along
the Cumberland Plateau, with winds possibly gusting over 45 mph on
Monday into Tuesday. Further down in the valley it wont be nearly as
strong, but still expect fairly stout winds most of the day on
Monday into Tuesday, especially along ridge tops and higher
elevations.

Besides the wind the other impact will be widespread showers Tuesday
morning into Wednesday morning as the front sweeps through. Cannot
completely rule out seeing a few rumbles of thunder (with the
highest chances occurring across southeast TN) but expect most people
will just see light to moderate rainfall. Most places will see less
than an inch of rain over 24-36 hour event, but some places south of
Interstate 40 could see storm totals over an inch.

Once the front finally sweeps through we`ll see broad troughing into
Thursday with near freezing tempos Friday morning under clear skies
and calm winds. Friday morning could see frost develop especially
along and north of Interstate 40 for a few hours before sunrise.

Strong ridging and surface high pressure will quickly warm things up
to end the work week and the upcoming weekend is shaping to up to be
fairly pleasant with mostly sunny skies and temperatures in the 70s

&&

.AVIATION...
(00Z TAFS)
Issued at 740 PM EDT Sun Mar 24 2024

VFR through the TAF period for all sites with scattered to broken
high clouds aloft, still think LLWS will be borderline at CHA.
Winds are expected to be light overnight, winds will increase
again at CHA at daybreak and remain gusty through the remainder of
the period. Otherwise a strengthening mountain wind event will
contribute to southeasterly flow at TYS and TRI.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             45  62  52  62 /   0   0  60  90
Knoxville McGhee Tyson Airport, TN  40  67  50  63 /   0   0  30  90
Oak Ridge, TN                       40  66  49  63 /   0   0  40  90
Tri Cities Airport, TN              37  65  45  61 /   0   0  10  80

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...Wind Advisory from 1 AM to 5 PM EDT Monday for Blount Smoky
     Mountains-Cocke Smoky Mountains-Johnson-Sevier Smoky
     Mountains-Southeast Carter-Southeast Greene-Southeast
     Monroe-Unicoi.

     High Wind Watch from Monday afternoon through Tuesday afternoon
     for Blount Smoky Mountains-Cocke Smoky Mountains-Johnson-
     Sevier Smoky Mountains-Southeast Carter-Southeast Greene-
     Southeast Monroe-Unicoi.

VA...NONE.
&&

$$

SHORT TERM...
AVIATION...Wellington


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.