Newcomb, Tennessee Weather Forecast Discussion

997
FXUS64 KMRX 152029
AFDMRX
Area Forecast Discussion
National Weather Service Morristown TN
429 PM EDT Mon Sep 15 2025
...New UPDATE...
.UPDATE...
Issued at 425 PM EDT Mon Sep 15 2025
Added additional chances for rain given convection bubbling
outside, primarily in northeastern Tennessee into southwestern
Virginia. High resolution guidance is a little split on how long
convection will continue this evening, between the loss of
insolation as the sun goes down and a boost from slight orographic
influence as we`re on the west side of the upper low. Lightning
has been really isolated this afternoon thus far, helped by an
inversion around the 600 mb layer serving to cap off most of the
showers.
No significant weather expected, impacts will be limited to
isolated lightning and brief showers and downpours.
&&
.DISCUSSION...
Issued at 1246 PM EDT Mon Sep 15 2025
Key Messages:
1. Largely dry through the week, despite some isolated to scattered
storms being possible today and Tuesday.
2. Above normal temperatures continue, with highs in the upper 80s
to low 90s later this week.
Discussion:
An upper low will meander about over the eastern half of the
Carolinas today and tomorrow before shifting north to the mid-
Atlantic coastline and beyond for the latter half of the week.
Meanwhile a sharp/strong upper ridge will remain in place over the
Mississippi river valley through the midweek time frame, but then
shifts east towards the southern Appalachians as the aforementioned
upper low pushes off to the northeast.
What does this mean for us locally? Largely dry conditions are
expected, with some caveats I`ll mention momentarily, and
unfortunately warm temperatures for this time of year. Expect highs
during the mid to latter part of this week to be near 90 for much of
the central and southern parts of the TN valley, and even mid to
upper 80s in the lower elevations of the northern valley and our
Virginia counties as well. We won`t be setting any records, but
still, 4-7 degrees above normal in mid September is quite warm
compared to our early taste of cool fall weather recently.
Regarding rain chances, as mentioned most everywhere will be dry for
the next several days. However some isolated to scattered storms,
mostly over the TN mountains, could form this afternoon and again
tomorrow. The proximity of the upper low to our east, and associated
height falls aloft, combined with the warm temperatures will provide
enough instability to spark off some isolated to scattered
convection. Some of this activity could continue overnight as well
as embedded shortwaves rotate around the upper low and southward
across our forecast area. Again though, most places will remain dry
today and tomorrow. The widespread hot and dry conditions will round
out the work week as ridging builds in from the west.
Widespread rain chances may return this weekend but confidence is
quite low at the moment.
&&
.AVIATION...
(18Z TAFS)
Issued at 1246 PM EDT Mon Sep 15 2025
VFR flight categories are expected through the period. Some ISOLD
SHRA/TSRA could develop INVOF KTRI this afternoon and evening. Additional
ISOLD convection is expected across the region tomorrow as well.
However, confidence in any of this affecting terminals is quite
low so will leave out of the TAFs for now. Vsby restrictions
aren`t anticipated tonight either, and winds will be light through
the period.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             64  85  64  87 /  10  10   0   0
Knoxville McGhee Tyson Airport, TN  64  81  61  83 /  10  20   0   0
Oak Ridge, TN                       63  82  61  84 /  10  20   0   0
Tri Cities Airport, TN              58  76  57  79 /  10  20  10  10
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DISCUSSION...Wellington
AVIATION...CD

NWS MRX Office Area Forecast Discussion