012
FXUS63 KJKL 141936
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
336 PM EDT Mon Jul 14 2025

.KEY MESSAGES...

- Warm/hot temperatures and high dew points will persist for the
  next week, resulting in sultry conditions.

- There will be a daily potential for showers/thunderstorms over
  the next week, especially in the afternoon/evening hours.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 336 PM EDT MON JUL 14 2025

Latest radar indicates scattered to numerous convective showers,
with embedded thunderstorms, progressing eastward across the CWA
at mid-afternoon. Temperatures range from the mid-80s where
sunshine has persisted longest, to the 70s in areas recently
impacted by convection. Upper-level analysis shows a weakening
shortwave trough over the Ohio Valley with a fairly weak ribbon of
500mb vorticity extending from stronger vorticity maxima over
Pennsylvania/New York down to another vorticity maximum over
Central Kentucky. CAPE profiles are skinny and relatively weak, in
the 500 to 1000 J/kg range, and shear is minimal. This is
limiting the strength of any convection. However, high PWATs (1.6
to 1.8 inches) and warm cloud layers over 10,000 feet suggest
efficient rainfall processes will continue to produce heavy,
albeit generally brief, downpours. Some ponding or minor poor
drainage/urban flooding cannot be ruled out with the most
persistent activity.

The 14/12Z model suite is generally in good agreement, showing
500mb heights rising slightly through at least the early overnight
hours as the dampening shortwave trough departs. This should
bring most, if not all, convection to an end, and favor subtle
surface pressure rises and clearing skies across the forecast
area. Given a very weak pressure gradient, clearing skies and
suppressed diurnal temperatures, combined with abundant low-level
moisture, fog is probable overnight. GFS LAMP guidance is
particularly bullish on dense fog thresholds (visibility  1/4
mile) being reached at multiple sites. River valley locations will
be most favored to experience dense fog, along with locations
that experience rainfall near or after sunset. Looking ahead to
Tuesday, another 500mb vorticity maximum ejects northeast out of
the Mid-Mississippi Valley, bringing subtle height falls and a
PWAT surge to around 2.0 inches. Additional convection is likely
to ignite ahead of this next disturbance and impact eastern
Kentucky on Tuesday afternoon/evening. Even with an increase in
instability (MLCAPE peaking between 1,000 and 2,000 J/kg), shear
will remain weak and the mid-levels moist. Thus, any severe
potential will be very low, though a few gusty strong storms
cannot be ruled out.

In more sensible terms, expect scattered to numerous showers with
isolated thunderstorms to progress eastward through the area this
afternoon before diminishing this evening. Tonight will be warm
and muggy, with temperatures falling into the upper 60s to lower
70s. Fog formation is likely and could become locally dense,
especially in river valleys. For Tuesday, fog will lift/dissipate
under morning sunshine, but that will give way to a robust cumulus
field and the threat of scattered showers and thunderstorms,
particularly by late in the day. It will be hotter and more humid,
with high temperatures reaching the upper 80s to lower 90s.
Partly cloudy skies and only a stray shower or storm are expected
Tuesday night. It will remain muggy with low temperatures in the
upper 60s to lower 70s. Fog formation is again favored overnight
where skies are able to at least partially clear.

.LONG TERM...(Tuesday night through Sunday)
Issued at 310 AM EDT JUL 14 2025

No major updates from the Sunday afternoon issuance of the long
term narrative which is below...

Any thunderstorm activity ongoing Tuesday evening is expected to
quickly weaken into the early overnight hours. Overnight low
temperatures cool down towards 70 degrees.

For the rest of the long term forecast period, the guidance suite
collectively resolves a stagnant weather pattern over the eastern
half of the country. A broad anticyclone is forecast to remain
parked over the Southeastern states, whereas zonal flow will move
through the Upper Midwest and into the Great Lakes. The Ohio River
Valley will be situated between the two, and our sensible weather
will accordingly be driven by characteristics of both.
Southwesterly flow in the lower levels of the atmosphere will
persistently advect a warm, moist airmass into the Commonwealth,
keeping temperatures and humidity high. This will lead to above-
normal PWATs and increasingly oppressive heat indices on Wednesday
and Thursday. Expect afternoon highs in the low 90s on both days
and peak heat indices in the upper 90s in the deepest valleys and
urban corridors. These warm/humid conditions will combine with
some shortwave impulses moving through the broader zonal flow to
enhance precipitation chances across the area on Wednesday and
Thursday. Thunderstorms will be possible, but they are likely to
remain pulse-like in nature. Weak winds aloft and dry air in the
column will mitigate deep-layer shear and thus the potential for
highly-organized convection. This is particularly true for
southern KY, which will be closer to the center of the
southeastern ridging.

Thus, the greatest sensible weather impacts over the area next
week will likely come from the cumulative nature of the heat and
the repetitive nature of the precipitation chances. Rain chances
will peak every day in the afternoon/evening hours, and the
heaviest showers could provide some localized relief from the hot
apparent temperatures. However, overnight lows near 70 degrees
will provide limited nocturnal relief. The NWS HeatRisk tool has
been picking up on the potential for heat-related health impacts
across Eastern Kentucky in the Wednesday-Thursday time frame.
Likewise, WPC has outlined the forecast area in Marginal (Level
1/4) Excessive Rainfall Outlook on both Thursday and Friday. The
potential for localized flash flooding will be highest in areas
that see multiple rounds of heavy rain multiple days in a row next
week, as soils in those places will progressively be able to
absorb less moisture.

Guidance suggests that the SE ridge may flatten late next week
and allow a weak frontal boundary to slide into the forecast area.
This could yield slightly cooler afternoon highs in the 80s, but
a lack of deep upper level support means that said front is likely
to stall out. This will keep diurnally-peaking rain chances in
the forecast for next weekend, and we will closely monitor the
potential for any potential excessive rainfall-related impacts as
the mesoscale details of the forecast become clearer by mid-week.

In short, expect an active summertime weather pattern to persist
across Eastern Kentucky this week. Confidence is high that Eastern
Kentucky will experience seasonably warm/humid conditions and
daily diurnal peaks in shower/storm chances throughout the next
week. Only minor adjustments were made to the NBM-populated long
term forecast grids, as it is capturing the general pattern well.
Confidence in the magnitude of overnight ridge-valley temperature
splits is low due to the potential for lingering clouds from
diurnal convection. Likewise, nocturnal fog may form in locations
with wet grounds beyond the typical river valleys. With that being
said, grid edits were limited to minor reductions in valley low
temperatures, minor increases in ridgetop low temperatures, and
the addition of valley fog in the weather grids.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 2:03 PM EDT MON JUL 14 2025

Showers and storms have already started to develop, mainly west of
I-75 and continue to move east. Convection chances remain 18-23Z
with Prob30 in each TAF site. Convection could bring brief
decreased categories to terminals, but coverage should remain
generally ISO to SCT in nature. Lastly, winds are forecast to be
light and variable. Convective activity decreases during the
evening hours with terminals VFR through 04Z. There is a fairly
robust signal for some areas of BR/FG development tonight.

LIFR conditions have been added to sites KJKL, KSME, with the
potential of LIFR at KSYM. KSYM seems to be the trickiest
forecast with the site largely dependent on if a cloud deck
develops like the NAM suggests, or if the site clears out after
00Z like the GFS suggests. A wind shift to the southeast at this
location also works against seeing those lower fog visibilities,
due to surrounding terrain restrictions. Decided to go a middle of
the road approach and keep IFR in there. Visibilities and
ceilings improve around 12Z at each site.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SHORT TERM...GEERTSON
LONG TERM...MARCUS/ILN
AVIATION...GINNICK