516
FXUS64 KMRX 272324
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
724 PM EDT Thu Mar 27 2025

...New AVIATION...

.SHORT TERM...
(This evening through Friday)
Issued at 238 PM EDT Thu Mar 27 2025

Key Messages:

1. Enhanced fire conditions through this evening and possibly
again for Friday.  Low afternoon relative humidity will continue
today and again Friday. Relative Humidity in the mid 20s to lower
30s. Winds will be west to southwesterly between 5 to 15 mph with
gusts to 20 mph for Friday afternoon.

2. Unseasonably warm with high temperatures around 10 degrees
above normal.

Discussion:

For tonight, surface and upper ridge will produce dry conditions.
Plenty of high and mid level clouds at times overnight. Ensemble
soundings show a sharp inversion up to 3kft. This will allow for
great variability of temperatures from the sheltered valley to the
ridge tops for the lows.

A ridge of high pressure will remain across the southern
Appalachians producing mostly dry conditions and unseasonably warm
temperatures. Highs will be around 10 degrees above normal.

The warm temperatures and dry conditions with the surface ridging
will produce another possibly enhanced fire danger day for Friday.
Relative Humidity in the mid 20s to lower 30s. Winds will be
southwesterly between 5 to 15 mph with gusts to 20 mph for Friday
afternoon.

&&

.LONG TERM...
(Friday night through next Thursday)
Issued at 238 PM EDT Thu Mar 27 2025

Key Messages:

1. A dynamic system will affect much of the eastern United States
Sunday into Monday with the best chances for storms in our area
being Monday morning. Some storms could be strong to severe with the
main threat in our area being damaging winds.

2. Strong winds are also likely in the mountains associated with
this system.

3. Drier and cooler conditions arrive by Tuesday with another system
likely to impact the eastern U.S. by Wednesday to Thursday. A lot is
uncertain about this system, but it could be similarly dynamic and
impactful.

Friday Night through Monday

At the start of the period, ridging will be in place aloft with a
weak shortwave located to our west. Bermuda high pressure will also
be located well to our east. This initial setup will lead to a dry
and mild start to the period. On Saturday, this shortwave will
approach the area, leading to some low-end rain chances. The main
focus of the extended period will be the development of the next
system as a deeper, negatively tilted shortwave ejects out of the
Rockies. Cyclogenesis is expected to produce a surface low of 995mb
to 1,000mb that will progress towards the Mississippi River Valley
and Lake Michigan on Sunday.

Ahead of this system, varying indications of upper divergence will
promote additional chances for showers and a few storms earlier in
the day on Monday. However, the main focus will be when the cold
front approaches the region. At the time of this update, there are
still discrepancies in the timing of this system and its associated
cold front. A broad warm sector is expected to be in place across
much of the eastern U.S. with a line of robust convection
approaching from the west ahead of the cold front. The overall
consensus is for the front to arrive by Monday afternoon, meaning
the most likely time for convection in our area currently looks to
be early on Monday. Based on this timing, the better instability and
overall severe chances will be to our west. The current wind
profiles suggest more impressive winds in the upper-levels with
850mb winds generally around 40 to 45 kts. This is also reflected by
better deep-layer shear in comparison to the lower levels. This
continues to highlight damaging winds as the main threat with less
confidence for tornadoes. More limited instability and warmer air in
the lower levels could also inhibit chances for hail. The question
will be if the timing of this front speeds up or slows down further.
If everything speeds up, the greater threat would be from everything
approaching overnight on Sunday. But if a slower trend continues,
there may be ample time on Monday for further destabilization. The
850mb winds and increasing MSLP gradient will also create strong
winds in the mountains ahead of the front, but the setup is
certainly not as ideal as some systems we`ve already seen.

Tuesday through Thursday

Monday night into Tuesday morning, the front associated with this
dynamic system is expected to be east of the area with deepening
upper troughing. Cooler and drier air will arrive ahead of
approaching high pressure. By Wednesday to Thursday, there are
increasing indications another trough and potentially dynamic system
impacting the eastern U.S. This was previously indicated by the
ECMWF, but now other deterministic models and many ensembles are
showing this. Based on the GEFS, there is well over 500 miles of
spread for where this system could track. Regardless, this system
will be worth keeping an eye on with increasing potential for more
showers and storms.

&&

.AVIATION...
(00Z TAFS)
Issued at 711 PM EDT Thu Mar 27 2025

High clouds will continue through tomorrow, possibly with some
clearing overnight. Southerly winds will become more southwesterly
tomorrow with some gusts possible mainly near TRI and TYS.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             50  79  57  79 /   0  10   0  10
Knoxville McGhee Tyson Airport, TN  46  78  56  79 /   0  10   0  20
Oak Ridge, TN                       46  77  55  77 /   0  10   0  20
Tri Cities Airport, TN              41  77  53  78 /   0  10   0  10

&&

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

$$

SHORT TERM...DH
AVIATION...McD