Johnson City, Tennessee 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

995
FXUS64 KMRX 150547
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
1247 AM EST Fri Nov 15 2024

...New AVIATION...

.UPDATE...
Issued at 945 PM EST Thu Nov 14 2024

Going forecast seems to be in good shape this evening. We do have
some breaks in the low clouds across the area as clouds associated
with the front depart to the east and post-frontal low clouds are
moving in from the northwest. Expect all of this to fill in over
the next few hours, enough for overcast skies in most all
locations through the night. As such, don`t think that fog is
going to be an issue, so that part of the forecast is in good
shape. Overnight lows also seem to be on track as well due to the
expected cloud cover and impacts on radiational cooling.
Otherwise, there`s still some sparse, light returns on radar in
the Tri-Cities area and points northward into our Virginia
counties. The slight chance PoPs in those areas through 06z covers
this well I think and don`t see a need to extend them out beyond
that.

&&

.SHORT TERM...
(This evening through Friday)
Issued at 241 PM EST Thu Nov 14 2024

Key Messages:

1. Drizzle and to gradually come to an end tonight, with some
drizzle potentially hanging on late overnight across portions of
northeastern Tennessee into southwest Virginia.

Discussion:

Well. Today has been pretty dreary, a good day for night shifters
looking to sleep. The good news is the mountain wave wind event is
done, with observations dropping back to much calmer values.
The bummer news is there`s still plenty of stratus out grasping
the area in a gray gloom and that will continue to be the case.
Some holes in the clouds down towards Georgia. We`re
transitioning to the backside of the upper trough, with weak
northwest flow advecting cool 850 temperatures around and over us
through the short term. Heavy cloud cover over much of the area
will persist through the period, with fairly stable temperatures.
Radar still shows some light returns over the northeastern half of
the area, these will produce negligible amounts of rainfall if
any. Drizzle is a possibility tonight across portions of
northeastern Tennessee into Virginia with saturated low levels
underneath the drier upper levels, but only included a low PoP for
that. Otherwise the area will be damp, even without the drizzle.
Some patchy fog possible by morning.

&&

.LONG TERM...
(Friday night through next Thursday)
Issued at 241 PM EST Thu Nov 14 2024

Key Messages:

1. Dry weather is expected this weekend through Monday.

2. Chances for rain will increase for Tuesday into Thursday.

3. Much colder air likely to begin moving in by the end of the
period.

Discussion:

We start the period under a large upper level ridge with broad
surface high pressure in place over the region. This upper ridge and
surface high will control our weather through the weekend into
Monday while gradually shifting east and southeast. It will be dry
with a warming trend through Monday.  High temperatures Saturday
will be near to slightly above normal Saturday, but will be well
above normal by Sunday and Monday.

Confidence in the details for the latter periods suffers as the
model data shows significant spread, but there is general agreement
that more unsettled weather will be arriving with chances for rain
in the Tuesday through Thursday time frame. An upper low will lift
northeast out of the southwestern CONUS tracking across the Plains
into the western Great Lakes Region by Tuesday, then additional
energy will drop in behind it carving out a deeper trough or closed
upper low to our west by the Wednesday/Thursday time frame. The
evolution of this trough and how far east it progresses by the end
of the period is where there is high variability in the model data,
and uncertainty for this part of the forecast is high. However,
while the details are uncertain, chances for rain will be higher for
the Tuesday through Thursday time frame, and a cold front will
likely move through sometime around Wednesday with colder, possibly
very much colder, air pushing in by the end of the long term period
as the upper trough progresses east toward/over our area.

&&

.AVIATION...
(06Z TAFS)
Issued at 1243 AM EST Fri Nov 15 2024

A bit of a tricky aviation forecast. Most guidance suggests that
all sites will go MVFR soon. However, northwesterly downsloping
winds will continue off of the Cumberland Plateau through the
night. This could keep CHA and TYS VFR longer than anticipated. So
confidence is low at CHA and TYS overnight. Higher confidence at
TRI where northwesterly downslope winds don`t affect them like
CHA and TYS. VFR conditions anticipated tomorrow afternoon.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             62  44  66  43 /   0   0   0   0
Knoxville McGhee Tyson Airport, TN  59  43  63  40 /   0   0   0   0
Oak Ridge, TN                       59  42  63  39 /   0   0   0   0
Tri Cities Airport, TN              57  40  60  35 /   0  10   0   0

&&

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

$$

SHORT TERM...CD
AVIATION...