961
FXUS64 KMRX 141721
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
121 PM EDT Sat Jun 14 2025

...New AVIATION...

.UPDATE...
Issued at 1144 AM EDT Sat Jun 14 2025

Upper trough over the mid-Mississippi valley will continue to move
slowly east northeast. Waves rotating around the low will continue
to focus convection. One such was is moving across the Plateau
with an area of scattered showers and thunderstorms. Another focus
will be the terrain features.

Airmass ahead of this wave is relatively drier. PWs over much of
east Tennessee is between 1.3 and 1.5 inch. The drier mid-level
air is producing DCAPEs of 800-1000. MLCAPES will increase to
around 1500 (possibly 2000 J/Kg). Similar to yesterday, isolated
strong to possibly severe storms are expected. As the wave moves
across the region PWs will increase with heavy rainfall again
possible with localized runoff issues.

Overall, current forecast looks good.

&&

.SHORT TERM...
(Today and tonight)
Issued at 258 AM EDT Sat Jun 14 2025

Key Messages:

1. Scattered storms are expected again this afternoon and evening
with strong winds and isolated flooding possible.

2. Warm and humid conditions are expected again with temperatures
rising well into the 80s.

Discussion: both from development in our area and progression from
the west Currently early this morning, a shortwave is centered just
to our west with a weak surface low along the western Ohio River
Valley. Somewhat drier air is in place over the region with better
moisture and areas of convection ongoing to our west. Throughout the
day, these features will shift eastward, bringing better moisture
into the region. This will support scattered to numerous showers and
storms due to development in our area and arrival from the west.

Overall, the environment will be comparable to yesterday with
fairly uni-directional flow, MLCAPE up to around 1,500 J/kg, and
limited mid-level lapse rates. Some sources do indicate better
DCAPE values of 800 to 1,000 J/kg or more, but this would depend
on how late the timing is and any morning activity. Just like
yesterday, this will present the potential for isolated stronger
storms producing high winds. While many places saw quick, heavy
downpours yesterday, most places measured less than an inch of
total rainfall. Isolated flooding still remains possible. Activity
will decrease overnight with another chance for patchy fog in
places that saw rain.

&&

.LONG TERM...
(Sunday through Friday)
Issued at 258 AM EDT Sat Jun 14 2025

Key Messages:

1. Unsettled and active weather continues.

2. A few strong storms are possible, mainly each afternoon with
peak heating. Gusty winds and heavy rainfall are the main
concerns.

3. With above normal moisture available, several inches of rain will
likely occur in some locations over the period. Isolated flash
flooding is possible in areas that see repeated or prolonged periods
of heavy rainfall.

Discussion:

There really isn`t any change in this long term forecast issuance.
An unsettled pattern will continue through at least Thursday, with
multiple upper level short waves moving across the region in a
moisture rich environment. The greatest coverage of showers and
storms is still most likely to be during the afternoon and early
evening hours, coinciding with peak heating. The risk for organized
severe weather still looks low during the period, as shear is
expected to be weak. As the previous discussion mentioned, models do
hint at the possibility of drier air beginning to move in for
Friday, which would lower the chances for convection by the end of
the period. However, this ultimately depends on where the center of
high pressure sets up across the country, so stay tuned.

Hazards and Impacts:

Hazards and impacts are unchanged. A few strong storms will be
possible any given day during the afternoon and early evening hours.
An isolated severe storm is possible at some point in the next 7
day. However, most storms are expected to remain below severe
strength. Any stronger storms that do occur will be capable of
producing strong and gusty winds and locally heavy rainfall.
Isolated flash flooding continues to be a concern. Both GEFS and
ECMWF ensemble mean PW values still show a range of 1.5 to 1.75
inches through the period. These values are above normal,
generally falling in the 75th to 90th percentile based on BNA
sounding climo for this time of year. A few locations may see in
excess of 3 or even 4 inches of rainfall through the long term
period, while most locations will see less due to the unorganized
and scattered nature of the convection. While narrowing down the
areas that will see the higher precipitation amounts is not
possible this far out, everyone should be alert for the threat of
flooding especially in areas that receive multiple or prolonged
rounds of heavy rainfall.

&&

.AVIATION...
(18Z TAFS)
Issued at 116 PM EDT Sat Jun 14 2025

Scattered showers and thunderstorms will gradually move east
across the forecast area through the afternoon into at least 06z
particularly across northeast Tennessee. Low ceilings at times can
be expected at times as well as visibility when the showers/storms
drift over airfields. Rain chances diminish around midnight with
some scattered activity possible overnight near KTRI and possibly
KTYS. Low confidence on exact locations/timing of precip.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             70  86  70  87 /  70  80  30  80
Knoxville McGhee Tyson Airport, TN  69  84  69  85 /  70  90  40  70
Oak Ridge, TN                       69  83  69  85 /  70  90  40  70
Tri Cities Airport, TN              66  81  67  83 /  70  90  50  80

&&

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

$$

SHORT TERM...DH
AVIATION...