Johnson City, Tennessee 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

761
FXUS64 KMRX 111719 AAA
AFDMRX

Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
119 PM EDT Fri Apr 11 2025

...New AVIATION...

.UPDATE...
Issued at 930 AM EDT Fri Apr 11 2025

The only change for the morning update will be to remove fog, as
visibility across the area has lifted. Clouds will remain broken
to overcast through the day as a mid/upper level low now over the
TN/KY/VA border drifts east through the day. Moisture warpping
around this low will transition from the northern sections
southward through the day. Temperatures will remain cool, with
highs in the 50s to lower 60s south.

&&

.SHORT TERM...
(Today and tonight)
Issued at 305 AM EDT Fri Apr 11 2025

Key Messages:

1. Patchy dense fog this morning, primarily for south of I-40 and
near I-75.

2. Light rain showers continue today with isolated thunderstorms.

3. Cooler behind the cold front today and tonight. Frost possible
for the plateau and higher elevations into southwest VA Saturday
morning.

Discussion:

Conditions have rapidly cleared across the south within the past
hour or so, resulting in dense fog developing. Currently,
Chattanooga, Athens, and Cleveland are under a quarter mile of
visibility. Will issue an SPS for the morning hours to message the
possibility of dense fog elsewhere. This will primarily be for
everywhere EXCEPT the far northeastern part of the forecast area
currently under light showers and cloud cover. Be cautious
driving this morning, as we have not had a nearly moist and foggy
morning in quite some time.

The area is situated under an upper level trough and weak surface
low. The trough will slowly slide eastward with time today with
its axis over the Atlantic Coast by this time tomorrow. The weak
surface low will follow the same track. Northerly flow behind the
exit of the trough and low, will aid showers and possibly some
thunderstorms into the late afternoon and early evening today.
Best chances for greater than a quarter inch or so of rainfall
will be across the higher terrain and parts of the valley north of
I-40/81. Otherwise, it will be a mostly gloomy day with
temperatures in the 40s (higher elevations) and 50s. Some low 60s
possible for the southern valley where they may get more sun
poking through the clouds.

We dry pretty quickly than previously forecast tonight as high
pressure sags down from the NW and clouds begin to break further
away from the far eastern parts of the CWA. This paired with some
light winds or calm conditions overnight, and another cold night
on tap with lows in the 30s, frost will be possible especially
where the aforementioned area overlaps; almost everywhere except
the far southern valley, parts of the Southern Appalachians, and
parts of southwest VA. With that being said, the thinking of light
snowfall the past couple of days across the higher terrain
tonight will pretty much be null. There could still be a dusting
to a tenth somewhere across the highest peaks of the Smokies
though.

&&

.LONG TERM...
(Saturday through Thursday)
Issued at 305 AM EDT Fri Apr 11 2025

Key Messages:

1. Possible widespread frost Sunday morning with freeze across parts
of southwest Virginia, southwest North Carolina, and far east
Tennessee mountains.

2. Trending dry for the weekend with temperatures increasing into
the beginning of next week.

3. Cold front Monday night and Tuesday brings next chances of
showers.

4. Frost possible again Tuesday night and Wednesday night.

Discussion:

Temperature Rollercoaster is the main theme for the extended.

As usual for spring, a good deal of pattern change. Current deep
upper trough will move east of the southern Appalachians Saturday
with ridging building into the Tennessee valley and southern
Appalachians for this weekend.

Due to the surface ridging, good radiational cooling conditions are
expected Saturday night. Freeze is possible across the far east
Tennessee mountains, southwest Virginia, and southwest North
Carolina with a frost elsewhere.

For Sunday and Monday, developing upper ridge will produce mostly
dry conditions and warmer temperatures.

For Monday night, another deep upper trough becomes established over
the Great Lakes and eventually into the eastern United States for
Tuesday. A cold front will sweep southeast across the Tennessee
valley and southern Appalachians. NBM probabilities of a quarter
inch or more of QPF is low with this frontal passage. This is due to
limited Gulf moisture return and best dynamics from upper trough
well north of the region.

For Tuesday night and northern sections Wednesday night, surface
ridging and cooler airmass will produce area of frost.

For Thursday, another quick moving short-wave/jet streak in
northwest flow will move across the Tennessee valley into the
southern Appalachians. NBM CAPE ensembles show instability moving
back into the area with another round of convection. Confidence is
low on the development of this system but there is a potential of
strong to severe storms.

&&

.AVIATION...
(18Z TAFS)
Issued at 112 PM EDT Fri Apr 11 2025

Showers will be scattered to numerous around the area through the
evening. Prevailing VFR conditions are expected at all sites, but
a passing shower may bring brief MVFR conditions. TS cannot be
ruled out entirely but the chance is too low to mention. MVFR cigs
will persist overnight before gradually lifting/scattering
tomorrow morning as drier air builds in.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             63  41  63  37 /  50  20   0   0
Knoxville McGhee Tyson Airport, TN  58  38  59  35 /  70  20   0   0
Oak Ridge, TN                       59  36  61  35 /  60  10   0   0
Tri Cities Airport, TN              55  36  54  33 /  70  20   0   0

&&

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

$$

SHORT TERM...KS
LONG TERM....DH
AVIATION...DGS