Johnson City, Tennessee 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

475
FXUS64 KMRX 160135 AAA
AFDMRX

Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
935 PM EDT Tue Apr 15 2025

...New UPDATE...

.UPDATE...
Issued at 932 PM EDT Tue Apr 15 2025

No changes are needed to the forecast this evening. With sunset
and building high pressure, winds have dropped off in the last few
hours, and that trend will continue overnight. The lighter winds
tomorrow will be good news for fire weather interests, although
afternoon RH values will drop quite low again, in the 20-30%
range.


&&

.SHORT TERM...
(This evening through Wednesday)
Issued at 241 PM EDT Tue Apr 15 2025

Key Messages:

1. Breezy conditions the rest of the day today.

2. Gusty winds and low relative humidity values will lead to
dangerous fire weather conditions for areas that did not receive
rainfall overnight.

.SHORT TERM...

Currently very gusty winds across the southern Appalachian region as
deep mixing of the atmosphere is occurring under the clear and sunny
skies. This is allowing the strong winds of the mid/low level jets
to mix down to the surface. Sustained winds are hovering in the 10-
20 mph range, but gusts are causing winds to jump up an extra 10-20
mph above that. These strong winds, generally out of the west to
northwest are also brining in lower dew point values and in response
the relative humidity across the region this afternoon have really
dropped quickly. Many locations north of Interstate 40 received at
least some rainfall overnight, but areas to the south of Interstate
40 remained mostly dry. With the combination of low relative
humidities, gusty winds, and lack of rainfall we`ve issued a Fire
Danger Statement for southeast Tennessee and far southwest North
Carolina until 00z when the jet exits the region and the strongest
winds begin to decouple.

Overnight winds should calm down in all areas except for the highest
elevations of the Southern Appalachians which could still see some
elevated gusts as the jet slowly exits the region. Under the clear
skies, overnight lows will drop about 10 degrees cooler than what we
experienced this morning. Sunny skies expected again tomorrow, and
winds will eventually tick back up, especially across northeast TN
and southwest VA, but not expected to be nearly as gusty as what
we`re experiencing today.

&&

.LONG TERM...
(Wednesday night through next Tuesday)
Issued at 241 PM EDT Tue Apr 15 2025

.LONG TERM... (Wednesday night through Tuesday)...

Key Messages:

1. Dry late this week with low rain chances over the weekend.

2. Warming trend through the weekend as ridging sets up across the
Southeast.

3. Potential system early next week as shortwave amplifies troughing
across the Mississippi Valley, but height falls across the Southeast
U.S. are more uncertain.

Discussion:

Surface high pressure and a clear sky Wednesday night will result in
conditions favorable to patchy frost, especially in sheltered
valleys of southwest North Carolina, northeast Tennessee, and
southwest Virginia.

High pressure slides eastward with southwest flow increasing on
Thursday. Heights increase as ridging builds across the Tennessee
Valley and Southern Appalachians with mostly clear conditions and a
warming trend into the weekend.

Considerable uncertainty exists for our expected weather this
weekend, especially on Sunday. A shortwave will amplify upper
troughing across the Great Plains with a surface front located near
the Mississippi Valley. The question is how quickly, and how far
eastward, this front will move. Most guidance is indicative of this
trough flattening the ridge with the surface cold front moving
across our region sometime between Sunday afternoon and Tuesday
morning. Depending on the timing and exact placement of this front,
there will be opportunities for severe weather across the Tennessee
Valley; however, higher probabilities exist to our west, and
uncertainty is high. Precipitation probabilities remain slight
chance/chance through the weekend into early next week because of
this uncertainty. We`ll likely be dry for most of the weekend with
higher probabilities for rain directly ahead of the cold front.

If this cold front does not stall out and makes it through the area,
we`d likely see a brief cool down with additional chances of frost
across the region. However, it must be emphasized that uncertainty
is high, and it`s not certain the cold front ever makes it through
our area if ridging remains strong across the Southeast CONUS.

&&

.AVIATION...
(00Z TAFS)
Issued at 726 PM EDT Tue Apr 15 2025

VFR conditions are forecast through this period. Winds this
evening will diminish in a few hours to under 10 kt sustained.
Winds tomorrow afternoon will be lighter, but may have some gusts
around 20-25 kt at TRI.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             43  70  44  76 /   0   0   0   0
Knoxville McGhee Tyson Airport, TN  41  66  42  71 /   0   0   0   0
Oak Ridge, TN                       40  67  42  72 /   0   0   0   0
Tri Cities Airport, TN              39  61  36  70 /   0   0   0   0

&&

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

$$

SHORT TERM...DGS
AVIATION...DGS