036
FXUS64 KMRX 131904
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
304 PM EDT Thu Jun 13 2024

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(This evening through Friday)
Issued at 254 PM EDT Thu Jun 13 2024

Key Messages:

1. Hotter weather tomorrow. Very low chance at a shower or
thunderstorm.

Discussion:

Summer weather to continue. Scattered cu fields of variable
thickness exist across the wider region, with more consistent
coverage over the mountains. Only question this afternoon is if any
shower or thunderstorm can fire. The HRRR has a midlevel inversion
around 3km, whereas the NAM has a slightly more favorable profile
that would allow for convection. 12z HREF paints a consistent
showing for a thunderstorm or two over the mountains. It`s not
impossible for a brief storm over the Plateau, but it`s not
expected.

The upper level ridge dominating our weather is currently anchored
over the southern Plains, and will slowly move east with time. The
588dm line will move over the Chattanooga metro tomorrow. This
corresponds to roughly the 90th percentile for 500 mb heights off
the Nashville sounding climatology. Accordingly thanks to the
building heights, tomorrow will be slightly warmer than today was,
with some locations in the southern valley entering the low 90s. GFS
and HRRR have some convection riding the ridge axis tomorrow coming
from the midwest but collapsing before entering this area. HREF
brings a slight 20% chance for additional northwest flow storms
tomorrow afternoon. No significant weather is expected.

&&

.LONG TERM...
(Friday night through next Thursday)
Issued at 254 PM EDT Thu Jun 13 2024

Key Messages:

1. Above normal temperatures through the period, and right now the
hottest days look like Sunday and perhaps Monday.

2. Mostly dry overall, but a few spots especially over the higher
terrain will see a shower or thunderstorm with the highest coverage
potential expected to occur Monday.

Discussion:

We start the period with an upper ridge centered to our west, and a
large area of surface high pressure extending into our area from the
northwest.  The upper ridge will build east and will set up
residence over the eastern U.S. where it will remain for the
remainder of the period. Meanwhile, the surface high will slide east
and will continue to extend into our area but will be centered off
the the East Coast by early in the week. In this pattern, we will
see mostly dry conditions as organized convection will be unlikely
under the upper ridge.  However, there may be some mainly isolated
and diurnally driven convection especially over the higher terrain.
Most model solutions show a bit more moisture available on Monday,
so the coverage is expected to tick higher Monday afternoon and
there may be isolated showers or storms even over valley locations.

Temperatures will run above normal for the entire period, with the
heat likely peaking Sunday and possibly again Monday as the
combination of higher dew points and well above normal temperatures
are expected to result in heat index values reaching to around 100
across portions of the central and southern valley. The flow will
turn more easterly for the latter periods as the highest heights
shift to the northeast, which should result in slightly lower
temperatures, although highs will still be significantly above
normal for Tuesday through Thursday.

&&

.AVIATION...
(18Z TAFS)
Issued at 132 PM EDT Thu Jun 13 2024

VFR and dry expected through the TAF period. Cumulus clouds this
afternoon with a very low chance of an isolated shower or TS along
elevated ridges and mountains. Overnight clear skies and calm
winds expected. Tomorrow similar daytime weather as today expected
under the ridge of high pressure.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             69  94  72  93 /   0  10   0   0
Knoxville McGhee Tyson Airport, TN  66  91  69  90 /   0  10  10   0
Oak Ridge, TN                       66  91  68  90 /   0  10   0   0
Tri Cities Airport, TN              63  86  65  86 /   0  20  10   0

&&

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

$$

SHORT TERM...Wellington
AVIATION...Wellington