National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS64 KMRX 100729
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
329 AM EDT Wed Apr 10 2024

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

.SHORT TERM...
(Today and tonight)
Issued at 313 AM EDT Wed Apr 10 2024

Key Messages:

1. Increasing coverage of showers and thunderstorms tonight into
Thursday night. There is a chance of localized flooding and a
conditional chance of strong/severe storms Thursday.

2. Mountain wave induced strong winds possible in the mountains and
foothills tonight into Thursday afternoon. A High Wind Warning is
now in effect.

Discussion:

An active weather pattern for the next 36 or so hours. Currently,
upper air analysis and GOES WV imagery show a deepening shortwave
across the southern plains that is providing large scale ascent
across the western GoM, through the Arklatex and lower MS valley for
widespread showers and storms. Some of these showers are working
their way north into portions of central TN and northern AL. This
activity will slowly push into portions of the forecast area with
light rain showers expected early this morning. Soundings dry out
this afternoon which should lead to mostly dry conditions.
Temperatures will warm into the 70`s.

The upper shortwave will begin to eject into the MS Valley this
afternoon into Thursday promoting a surface low to deepen as it
moves NE into eastern AR by this evening and in the Ohio Valley by
Thursday afternoon. Very strong winds fields will overspread the
region tonight into Thursday associated with a ~90 knot upper jet
rounding the base of the shortwave. This will provide an
environment conducive for upward vertical motion and widespread
showers beginning tonight and continuing into Thursday. There
appears to be sufficient MUCAPE overnight for elevated
thunderstorms that could produce periods of heavy rainfall. The
big question comes Thursday with just how much advection can occur
ahead of the cold front. Many of the CAM`s suggest an influx of
higher theta-e air and subsequent boundary layer instability for
surface based convection. However, there is a lot of uncertainty
if this can happen. If storms can root into the boundary layer
than perhaps a strong to severe storm may be possible given strong
low to deep layer shear on the order of 30 kts at 0-1km, and
effective shear of 60+ kts. Localized flooding is also possible
especially with any training storms. WPC ERO has the area
highlighted with a low risk for flash flooding.

Finally, a mountain wave wind event certainly looks likely tonight
into Thursday. As mentioned previously, strong wind fields will
overspread the Tennessee Valley tonight and into Thursday. Wind
magnitudes at 850mb could approach 60+ kts in a climatologically
favored area for mountain waves. With a strong pressure gradient
along the mountains, and strong ducting modeled by the GFS and
NAM, confidence is high for mountain wave winds and did upgrade
the high wind watch to a warning for the mountain zones of East
Tennessee.

&&

.LONG TERM...
(Thursday through Tuesday)
Issued at 313 AM EDT Wed Apr 10 2024

Key Messages:

1. Showers and a few thunderstorms Thursday night into Friday,
especially north.

2. Gusty winds across the area Thursday night and especially Friday.

3. Mostly dry for the weekend into Tuesday, and it will become quite
warm.

Discussion:

There will be some lingering showers and perhaps a few thunderstorms
especially north/east behind the exiting cold front early Thursday
night, and with the powerful storm in no hurry to exit the eastern
Great Lakes Region we may see wrap around showers lingering all
night mainly northern half. Models show some upper level short wave
energy rotating around the upper low and brushing our northern and
central areas Friday with some additional showers and perhaps a few
rumbles of thunder.

The tight pressure gradient across the area will lead to gusty winds
Thursday night and Friday as well.  We may see wind advisory level
winds in the mountains Thursday night into Friday and it looks
borderline for wind advisory gusts even in the valleys mainly during
the day Friday. Will add this to the HWO.

For the latter periods, drier air will work in for the weekend as
the low pressure system finally pulls away to the northeast and high
pressure builds into our area. Much of the Saturday through Tuesday
time frame looks precipitation free, but some models brush the area
with weak short wave energy that brings a few showers/thunderstorms
mainly to northern portions of the area Sunday night into Monday. It
will also become quite warm, with high temperatures in most valley
locations reaching into the upper 70s and lower 80s for Sunday
through Tuesday.

&&

.AVIATION...
(06Z TAFS)
Issued at 1242 AM EDT Wed Apr 10 2024

Complex aviation forecast the next several hours. Low level
moisture is present across the area especially at TYS where LIFR
fog had been reported. The most recent trends suggest this will
continue to clear up over the next hour or so. Elsewhere
overnight VFR conditions will deteriorate to MVFR this morning
with increasing rain chances. VFR returns late this morning and
this afternoon at all sites. Additional chances of showers look to
return overnight. Light winds overnight will increase from the SW
between 10-15KT with gusts up to 24KT at times this afternoon.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             76  63  71  49 /  50 100  80  20
Knoxville McGhee Tyson Airport, TN  76  64  75  48 /  40  90  90  50
Oak Ridge, TN                       76  62  73  48 /  40  90  90  50
Tri Cities Airport, TN              73  61  76  48 /  70  80 100  70

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...High Wind Warning from 8 PM this evening to 4 PM EDT Thursday
     for Blount Smoky Mountains-Cocke Smoky Mountains-Sevier
     Smoky Mountains-Southeast Carter-Southeast Greene-Southeast
     Monroe-Unicoi.

VA...NONE.
&&

$$

SHORT TERM...Diegan
AVIATION...Diegan