National Weather Service Weather Forecast Office

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

000
FXUS64 KMRX 231708
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
108 PM EDT Tue Apr 23 2024

...New AVIATION...

.UPDATE...
Issued at 828 AM EDT Tue Apr 23 2024

No significant changes were made to the forecast for today. Today
will be dry, breezy and warmer. Southwesterly winds will gust up
to 25 mph this afternoon in the Tennessee Valley. With a dry air
mass in place and clear skies bringing good mixing conditions,
relative humidity values may get into the 20 percent range this
afternoon despite WAA. The good news is that fuel moisture levels
are likely high enough to keep fire danger limited.

&&

.SHORT TERM...
(Today and tonight)
Issued at 256 AM EDT Tue Apr 23 2024

Key Messages:

1. Frost Advisory remains in effect until 9AM ET. See product for
additional details.

2. Dry and breezy this afternoon.

3. Increasing chances of rain overnight into the first half of
Wednesday. Only light rain is expected before becoming mostly dry
for Wednesday afternoon/evening.

Discussion:

A surface cold front has led to scattered radar returns across
portions of the midwest and into the Great Lakes region. This has
resulted in some minor high clouds advecting across the area.
Additionally, most recent surface observations have a wide range of
dewpoints from lower 40s to upper 20s, along with a few places
holding onto a light(3-5kt) wind. A Frost Advisory remains in effect
until 9AM EDT as patchy frost is possible, primarily in sheltered
valleys where there is a lower likelihood of aforementioned light
winds/clouds weakening favorable radiational cooling.

Tuesday afternoon will be dry as high pressure remains in control
ahead of the aforementioned approaching surface boundary. A
tightening pressure gradient and favorable mixing will result in
low relative humidities and breezy southwest winds throughout the
afternoon hours. Have continued to headline this in the FWF.

An upper level shortwave will drive the cold front into the region
overnight Tuesday, with rather light precipitation of a tenth of an
inch or less expected for most. Locally higher totals will be
possible within the East Tennessee mountains where orographic lift
helps squeeze out as much moisture as possible. The best chances
for rain exist in the northern half of the area during this
Tuesday night through early Wednesday timeframe. Rain chances
gradually come to an end around mid-day Wednesday, as most places
should remain dry for the afternoon and evening.

&&

.LONG TERM...
(Wednesday through Monday)
Issued at 256 AM EDT Tue Apr 23 2024

Key Messages:

1. Overall, mostly dry extended forecast into the weekend.

2. A warm-up with temperatures becoming above normal with breezy
conditions late week and into the weekend.

3. A chance of showers and thunderstorms return early next week.

Discussion:

Overall, the extended will be dominated by upper and surface ridging
into the southern Appalachians and southeast United States. Ridging
will block upper forcing well west and northwest of the area and
limit deep moisture and instability return into the southern
Appalachians. Best chance of showers and increased
moisture/instability return early next week.

For Wednesday night through Thursday night, building upper ridge and
surface ridging across the southern Appalachians into southeast
United States will produce dry and warm conditions.

For Friday, an upper jet moves northeast across the mid-section of
the nation strengthening the low-level jet over the western Ohio and
Tennessee valleys. The deterministic models, especially the GFS,
suggests an area of isentropic forced scattered showers will lift
north over the area. However, the ensemble probabilities from the
NBM depict meager chances (10 to 30 percent) at most.  This seems
reasonable given the continued surface ridging into the
southeast/eastern Gulf coast states limited moisture return.

For Saturday and Sunday, ridging surface and aloft builds into the
southern Appalachians producing unseasonably warm and dry
conditions. There may be a few showers develop across the higher
elevations due to orographic lift but overall dry. Temperatures will
be some 5 to 10 degrees above normal.

For Monday, another jet moves from the mid-section of the nation
into the Great Lakes/Ohio valley. In response, a frontal boundary
moves into the Tennessee valley. NBM ensemble probabilities are more
aggressive with chances of measurable rainfall as well as higher
SBCAPE. Chance of showers and thunderstorms will return for early
next week.

&&

.AVIATION...
(18Z TAFS)
Issued at 102 PM EDT Tue Apr 23 2024

Southwesterly winds will be breezy this afternoon with gusts up to
20 to 25 knots likely. A weak cold front will approach the region
tonight bringing low clouds late tonight and into the morning
hours. CIGs may go MVFR briefly in the morning hours, otherwise
VFR conditions will prevail. Light rain will also be possible
especially near TRI. By mid to late morning the cold front will
move through and clouds/rain will move out of the region.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             54  76  50  77 /  10  10   0  10
Knoxville McGhee Tyson Airport, TN  55  72  47  75 /  30  30   0  10
Oak Ridge, TN                       54  74  47  76 /  40  30   0  10
Tri Cities Airport, TN              50  68  42  71 /  40  40   0   0

&&

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

$$

SHORT TERM...KRS
LONG TERM....DH
AVIATION...McD