Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN

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526
FXUS64 KMRX 100628
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
228 AM EDT Thu Jul 10 2025

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

.SHORT TERM...
(Today and tonight)
Issued at 216 AM EDT Thu Jul 10 2025

Key Messages:

1. Near normal temperatures with additional afternoon showers and
thunderstorms. Main concern will be isolated flash flooding if any
stronger storms track over soils saturated from previous days
convection.

Discussion:

Lightning activity has largely come to an end with plenty of time
now passing since sunset & peak diurnal heating. A broad area of
showers continue for locations east of I-75 and north of I-40 but
this activity is anticipated to gradually diminish over the next few
hours. Expect there to be some patchy fog overnight into early
morning hours but there is low likelihood of widespread dense fog
due to expected mostly cloudy to overcast skies. HREF
probabilities of visibility 4 miles or less is 30% or lower with
some isolated areas along northern river valleys in the 40-50%
range. At this time do not believe any fog headline will be
necessary but will keep a close eye on observations as we trek
through the night. Main thing is to be cautious of localized dense
fog, especially near bodies of water or locations that observed
heavy rainfall this evening.

Shortwave troughing will remain in place over the southern
Appalachians today, though, it will gradually weaken as the main
vort lobe shifts east of the spine. Temperatures will trend to
seasonal norms. Additional afternoon and evening convection is
expected but the overall coverage should be less than what was
observed this past day with effective bulk shear diminishing to
10kts or less. Latest RAP model derived soundings depict MLCAPE
between 1500-2000 J/kg suggesting just general summertime
convection. PWAT values will remain between the 75th to 90th
percentile range with freezing levels around 14.5kft, thus, the
main focus will be on a continued threat for localized flash
flooding if any stronger storm tracks over vulnerable soils. Quiet
weather returns for the overnight.

&&

.LONG TERM...
(Friday through Wednesday)
Issued at 216 AM EDT Thu Jul 10 2025

Key Messages:

1. Drier weather expected Friday behind the shortwave.

2. Upper-level ridge brings hot weather this weekend into early next
week. Diurnal convective trends continue into next week.

3. Weak shortwave may bring more widespread scattered convection on
Monday afternoon and evening.

Discussion:

An upper ridge will begin to replace the shortwave troughing to end
the work week. Latest CAMs depict lesser coverage of diurnal
convection with increasing subsidence across the region. Most likely
locations to see additional showers and storms Friday will be across
higher terrain. The start of a slight warming trend can be noted
Friday as well. Much of the central and southern valley will see
temperatures returning to around 90 degrees.

Diurnal summertime convection and the slight warming trend will
persist as we head into the weekend. Heat indices in the 90s will be
widespread. Values will approach 100F across the southern valley,
potentially creeping into the central valley.  A more distinct
shortwave will translate across the Ohio Valley and Great Lakes
region late Sunday into Monday. This could lead to a greater
coverage of diurnal showers and storms Monday afternoon but no
strong signal for any organized severe potential stands out at this
time.

Impulses rotating through mean flow aloft could lead to varying
levels of convective coverage as we head into the mid-week, but for
now the main message remains the summertime pattern of hot &
humid conditions with daily chances of showers and storms
continues.


&&

.AVIATION...
(06Z TAFS)
Issued at 216 AM EDT Thu Jul 10 2025

Lingering showers mainly east of I-75 should continue to diminish
in coverage over the next few hours. A mid to low-level cloud
deck is expected to persist into the morning. To lesser
confidence, MVFR or lower vis/cigs could be possible for a brief
period due to a saturated boundary layer. HREF probabilities of
reduced flight categories are highest at TRI (40-60%), thus, a
tempo group has been included. Probs are closer to 30% for TYS so
no mention was included at this time. Additional isolated to
scattered convection expected this afternoon.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             89  71  91  72 /  70  20  40  10
Knoxville McGhee Tyson Airport, TN  87  70  90  71 /  70  20  30  10
Oak Ridge, TN                       87  70  89  70 /  70  10  30  10
Tri Cities Airport, TN              85  67  87  67 /  70  30  30  20

&&

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

$$

SHORT TERM...KRS
LONG TERM....KRS
AVIATION...KRS