Johnson City, Tennessee 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

307
FXUS64 KMRX 242332
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
732 PM EDT Sun May 24 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 253 PM EDT Sun May 24 2026

- Numerous to widespread showers and storms are expected this
  afternoon. Isolated flooding and gusty winds are the primary
  concerns with the strongest activity.

- Daily chances of showers and storms exist each day through the
  forecast period.

- Conditions will also be humid with no relief in sight until
  possibly next weekend.

&&

.DISCUSSION...
Issued at 253 PM EDT Sun May 24 2026

H3 ridging is in place over the southeastern CONUS, with an upper
low having developed over the southern plains. This setup continues
to promote enhanced diffluence aloft among an airmass with highly
anomalous moisture availability. Latest mesoscale analysis suggest
PWAT values of 1.5 to 1.7 inches, which is well into the 90th
percentile per sounding climatology for KBNA. With an MCV expected
to work north/northeast this afternoon and evening, have decided to
introduce a short-fused Flash Flood Watch. Latest 12Z suite and
hourly runs of CAMs all generally have some variation of swaths of 2
to 4 inch rainfall totals... locations more so isolated and
variable. With 1hr FFGs ranging from 1.8 to as low as 1.2 inches,
and 3 hr FFGs largely 1.5-2.0 inches, isolated flash flooding will
be conditional on training areas of moderate to heavy precipitation.
Overall, the highest confidence of isolated flash flooding is for
areas south of I-40 and along and west of I-75. It is also possible
to see some locally gusty winds under the strongest convection.

Bulk of the rain gradually wanes southwest to northeast tonight,
with the potential for some breezy winds in the mountains as slight
enhancement to roughly 25-30kts is expected in the southerly H85
flow. Best chance for some lingering morning Memorial Day showers
will be in the far northeast. A vort max will promote development of
additional showers and storms Monday afternoon and evening as upper
diffluence and anomalous PWAT values remain in place. Some
additional isolated flooding issues may arise during this time as
well, but confidence is a little lower as the CAMs have not been in
the greatest agreement on how well activity holds together or how
great the coverage is. This is why the Flash Flood Watch was not
carried through tomorrow evening, allowing us to keep monitoring and
assessing new data as it comes through.

Overall, no significant change is expected in the synoptic pattern
as we head into the mid-week. Daily chances of showers and storms
will continue, and that may come with some flooding concerns
partially conditional on how exactly the previous days activity pans
out. There is also no standout threat for any strong to severe
storms, but with such anomalous PWAT content, heaviest downpours can
also lead to locally gusty winds due to precip loading.

Some models are hinting that a front could push to our south late in
the period, with drier air moving into our area sometime next
weekend. However, there is no consensus on this scenario for now
and the ensemble approach of the NBM shows showers and storms
again both days, albeit, PoPs trending a bit lower by Sunday.

&&

.AVIATION...
(00Z TAFS)
Issued at 725 PM EDT Sun May 24 2026

Showers and storms around to start, then a decrease in coverage
before coverage increases again by Monday afternoon. Will see
conditions lower in heavier showers/storms early, then more
widespread MVFR/IFR conditions are expected later tonight into
early Monday with the lowest cigs currently looking most likely
at CHA. Some improvement to VFR is likely for late in the period,
except in any storms. Winds will generally be light outside of any
storms.


&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             65  78  65  81 /  70  90  70  90
Knoxville McGhee Tyson Airport, TN  65  78  64  81 /  90  80  70  90
Oak Ridge, TN                       63  77  63  80 /  80  80  70  90
Tri Cities Airport, TN              61  77  61  81 /  80  80  80  90

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...Flood Watch until 2 AM EDT Monday for Cherokee-Clay.

TN...Flood Watch until 2 AM EDT /1 AM CDT/ Monday for Anderson-
     Bledsoe-Blount Smoky Mountains-Bradley-Campbell-Claiborne-
     Cocke Smoky Mountains-East Polk-Grainger-Hamblen-Hamilton-
     Hancock-Hawkins-Jefferson-Johnson-Knox-Loudon-Marion-McMinn-
     Meigs-Morgan-North Sevier-Northwest Blount-Northwest Carter-
     Northwest Cocke-Northwest Greene-Northwest Monroe-Rhea-
     Roane-Scott TN-Sequatchie-Sevier Smoky Mountains-Southeast
     Carter-Southeast Greene-Southeast Monroe-Sullivan-Unicoi-
     Union-Washington TN-West Polk.

VA...Flood Watch until 2 AM EDT Monday for Lee-Russell-Scott VA-
     Washington VA-Wise.

&&

$$

DISCUSSION...KRS
AVIATION...99