307
FXUS64 KMRX 251511
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
1111 AM EDT Tue Jun 25 2024

...New UPDATE...

.UPDATE...
Issued at 1101 AM EDT Tue Jun 25 2024

No changes were made to the forecast for this afternoon during
the morning update. Rain chances are near zero with a dry air mass
in place. With sunny skies and ideal mixing conditions, dew
points will likely get into the upper 50s briefly in many
locations.

&&

.SHORT TERM...
(Today and tonight)
Issued at 300 AM EDT Tue Jun 25 2024

Key Message

1. Hot and dry persists.

Discussion:

Rather benign weather pattern to start off. Light and variable winds
and extremely dry atmosphere are expected the next 24 hours.
Forecast soundings illustrate just how dry it is, however, some
meager moistening will occur overnight into Wednesday. PW values
generally increase approximately a half inch ahead of the next storm
system. Continue to practice heat safety.

&&

.LONG TERM...
(Wednesday through Monday)
Issued at 300 AM EDT Tue Jun 25 2024

Key Messages:

1. Decent rain chances in the forecast for Wednesday evening and
again on Sunday. Admittedly, doesn`t look like a slam dunk though.

2. Otherwise, continued hot and dry conditions in large part.

Discussion:

A shortwave trough will move eastward through the Great Lakes and
Ohio valley during the day Wednesday, eventually pushing a front
through our area late Wed evening into Wed night. Expect continued
warm temperatures during the day Wed as rainfall and significant
increases in cloud cover will hold off until after peak heating.
Speaking of rain, it`s kind of an interesting scenario with this
front. Guidance shows some sort of MCS activity on the
western/southern end of the front diving south from the midwest into
the lower Mississippi river valley while another organized batch of
convection follows the upper trough and associated H3 jet streak
eastward from the Ohio valley Wed afternoon and evening. Currently
have high PoPs in the forecast for Wed evening as the front moves
in, but this time period is within sight of some CAM guidance,
including all the members of the 00z SPC HREF and there`s a
suggestion by some that we could get left in a gap in rainfall.
While the front and convection will be moving into a hot and dry air
mass, it seems unlikely we`ll get no rain. Will keep PoPs as is, but
I could see a scenario where we have less coverage than perhaps the
high PoPs would suggest.

Thursday looks dry, with a slight cooldown and break from the
humidity as drier air moves in. That`s short lived however as
ridging builds in from the southwest by Friday morning, while low
pressure develops over the northern plains. With the surface high
and H85 ridge to our east, and the northern plains low developing,
southwest flow will send temperatures back into the low to mid 90s
for Friday into the weekend. The aforementioned northern plains low
will move east through the Great Lakes Friday into Saturday, pushing
another front our direction by Saturday night into Sunday. Stuck
generally close to NBM guidance for temperatures and rain chances
during this time, but cut back the dewpoints a significant amount as
the NBM guidance seems unreasonably high. This is another
interesting forecast period. NBM is forecasting dewpoints that are
essentially record values, along with widespread showers and
thunderstorms and afternoon highs in the low to mid 90s Sunday.
Something likely has to give here as it seems hard to imagine all
three of those occurring. Since we`ve been rather hot and dry of
late (less moisture to evaporate from the ground) chose to knock
down the dewpoints a bit and stay close to the NBM highs and PoPs.

&&

.AVIATION...
(12Z TAFS)
Issued at 700 AM EDT Tue Jun 25 2024

VFR conditions, with winds less than 5kt, are expected through
the period as the region remains beneath the influence of high
pressure.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             97  72  99  74 /   0   0  10  40
Knoxville McGhee Tyson Airport, TN  93  69  96  71 /   0   0  20  50
Oak Ridge, TN                       93  69  96  70 /   0   0  20  60
Tri Cities Airport, TN              90  65  94  69 /   0   0  30  60

&&

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

$$

SHORT TERM...
AVIATION...CD