118
FXUS64 KMRX 281727 AAA
AFDMRX

Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
1227 PM EST Fri Feb 28 2025

...New AVIATION...

.UPDATE...
Issued at 1026 AM EST Fri Feb 28 2025

The main weather concern today will be low RH and winds, creating
concerning fire weather conditions. A Fire Danger Statement has
been issued and will continue, but some adjustments will be made
to min RH and dewpoints/temperatures this afternoon. Looking at
the 12Z soundings from OHX and RNK, dewpoints at the top of the
bounary layer are in the teens. While surface dewpoints probably
won`t drop that low, there will be a significant drop in dewpoints
with boundary layer mixing this afternoon. Dewpoint grids were
updated with the NBM 5th percentile. Forecast temperatures were
also raised slightly this afternoon based on current obs being
warmer than forecast. This will put min RH values in the 15-20%
range for some locations in the southern TN Valley and SW NC. The
wind forecast will remain unchanged, with sustained SW winds 10-15
mph with gusts of 20-30 mph.

&&

.SHORT TERM...
(Today and tonight)
Issued at 310 AM EST Fri Feb 28 2025

Key Messages:

1. Fire Danger Statement in effect this afternoon and evening for
all of our Tennessee counties and southwest North Carolina.

2. Dry and mild today with mostly clear skies and gusty winds.

Discussion:

First and foremost, a Fire Danger Statement is in effect for the
afternoon and evening for all of eastern Tennessee, and southwest
North Carolina due to expected low relative humidities, paired
with gusty winds, and dry surface conditions. Please see the SPS
for more details.

We will go from northwesterly low level flow this morning to more
westerly by Saturday morning as longwave troughing to our north
sinks a bit more southward. At the surface though, southwest winds
will be on the incline for later today, as a deepening and rather
strong clipper low moves closer to the the Great Lakes region
from Canada and high pressure is squeezed to our south. This will
explain the funneling and enhanced gusty wind effect that is
forecast everywhere this afternoon and evening. Wind gusts will
near 20 to 25 mph for many valley locale and general lower
elevation spots, while the higher terrain can experience wind
gusts closer to 30 and upwards of 35 mph. This, paired with a dry
air mass and minimum RH`s expected to drop into the 20s or lower,
is why a Fire Danger Statement is in effect.

Otherwise, today will kick-start a very nice weekend ahead with
just above normal temperatures and mostly sunny/clear skies. For
tonight, winds will gradually decrease for lower elevations, but
will remain elevated over the higher terrain as the strong low
responsible for the windy conditions today, moves to northern New
England by early Saturday. Some increasing cloud cover from
upslope flow expected for the Allegheny`s, and of course winds,
will keep low temperatures on the mild side tonight.

&&

.LONG TERM...
(Saturday through Thursday)
Issued at 310 AM EST Fri Feb 28 2025

Key Messages:

1. Cold front passage on Saturday will bring cooler temperatures
Sunday into Monday morning. Stray shower not out of the question,
but expect dry conditions with this moisture starved front.

2. Wind gusts up to 35 mph possible in the higher terrain Saturday.

3. We`re monitoring the chances for severe storms Tuesday night into
Wednesday with strong cold front passage. Strong winds will
accompany this system, especially in the East Tennessee mountains
and foothills.

Discussion:

A cold front will move through the area on Saturday, likely doing so
during the morning hours. Moisture will be hard to come by with this
system so the forecast shows dry conditions (as do most guidance
sources) for Saturday, but I wouldn`t be surprised if a stray shower
or two develops over southwest Virginia or the northern Tennessee
mountains. Continue to believe that winds will be gusty on Sat,
especially in the mountains where some gusts into the upper 30 mph
range could occur. A brief cool down is expected on Sunday behind
the front, with 20s expected Sat night as high pressure builds in
and highs only in the 40s to around 50 on Sunday.

Attention then turns to the system that will eject out of the
southern plains on Tuesday. A substantial severe weather outbreak
appears possible over the Arklamiss region Tue afternoon and
evening. Further east across our CWA the risk is less clear. SPC has
highlighted middle and part of East Tennessee for potential severe
weather with this system. The shear with this system will be quite
impressive, but the question is whether we will have any instability
to accompany the shear. If so, this could prove to be a significant
event for our area. Right now it doesn`t look like instability will
be very high due in part to limited quality dew point advection, but
shear will be more than enough to support severe storms. At bare
minimum it currently appears like we`ll see a decaying squall line
moving into the forecast area Tuesday night into Wednesday morning
for widespread chances of showers and thunderstorms. For now We`ll
continue to monitor trends with this system.

Southerly winds will be gusty with the system next week, especially
in the East Tennessee Mountains and foothills due to downslope wind
enhancement. Gusts up to 60 mph seem likely in downslope prone
areas, especially Tuesday night.

&&

.AVIATION...
(18Z TAFS)
Issued at 1226 PM EST Fri Feb 28 2025

Wind gusts to around 20 kt are expected to develop in the next
hour or two at TYS. TRI could also see some gusts in the 15-20 kt
range. Winds will drop under 10 kt around sunset, then increase
again tomorrow morning. Gusts of 20-25 kt are expected at all
sites tomorrow, mainly from the west.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             67  46  61  29 /   0   0   0   0
Knoxville McGhee Tyson Airport, TN  63  43  58  25 /   0   0   0   0
Oak Ridge, TN                       63  43  56  25 /   0   0   0   0
Tri Cities Airport, TN              59  41  54  22 /   0   0  10  10

&&

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

$$

SHORT TERM...DGS
LONG TERM....CD
AVIATION...DGS