421
FXUS63 KJKL 142055
AFDJKL

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

.KEY MESSAGES...

- Areas of dense fog are possible tonight, especially in river
  valleys.

- 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...(Wednesday through Monday)
Issued at 440 PM EDT MON JUL 14 2025

The period is expected to begin with upper level ridging centered
in the Atlantic to the southeast of Bermuda and extending into
the Southeast to Arklatex regions. A shortwave trough per the
consensus of guidance moving around this ridging is expected to be
moving across the Lower OH Valley. A tropical wave/system should
be over the eastern Gulf at that point as well while upper level
ridging should extend into the southwest Conus at that time.
Further north, an upper level low is progged to be centered over
the eastern Hudson Bay vicinity with troughing south and
southwest into the Northern Plains/Upper MS Valley and into
portions of the Northern Rockies with multiple shortwaves likely
moving through this trough. At the surface, a frontal zone
is expected to be north of eastern KY from the mid Atlantic
states into the southern to western Great Lakes while another
frontal zone ahead of the upper low and troughing from Canada into
north central parts of the Conus should extend from the
Maritimes/Lower St Lawrence Valley across Quebec tot he Northern
Great Lakes to upper MS Valley to Central Plains and then into
portions of the western Conus. A sfc ridge of high pressure should
extend from the Southern Plains to the Atlantic.

Wednesday to Thursday night, upper level ridging is expected to
remain from the Atlantic into sections of the Southeast/northern
Gulf States tot he Arklatex vicinity while the tropical wave
likely moves west or west/northwest over the Gulf or near the Gulf
coast. A shortwave trough should track from the Lower to middle OH
Valley on Wednesday followed by some height rises over eastern KY
and the Southern Appalachians Wed night into early Thursday.
Neutral 500 mb height tendencies or slight rises generally follow
from Thursday afternoon into Thursday night. This will occur as
the 500 mb trough shifts east across the Northern Plains/Upper MS
Valley to the Great Lakes. An additional shortwave may also move
east from the western Conus to Central Conus in westerly flow and
near the Lower OH Valley late Thursday night. During this
timeframe, a ridge of sfc high pressure will extend form the
Atlantic into the Southern Appalachians/eastern KY while the
tropical wave/potential tropical system may near the Lower MS
Valley region. As the shortwave troughs pass by to the north and
northwest, the frontal zone initially north and northwest of the
OH Valley should gradually drop south and southeast across the
Great Lakes and approach the OH River by late Thursday night.
Convection will be possible during this time, generally peaking
each afternoon and evening. However, with some forcing from
passing shortwave troughs and the approach of the front,
convection cannot be ruled out at night. Fog, especially in the
valleys is anticipated for Wed night and Thu night and pending
the degree of clearing and where heavier rain falls each daytime
period could end up with greater areal extent or dense in some
areas. PW per the 00Z LREF mean is on the order of 1.7 to 1.9
inches with deterministic guidance nearer to 2 inches. Any
convection during this period could produce locally heavy rain
rates.

Friday to Saturday night, upper level ridging per the guidance
consensus should continue to extend from parts of the Atlantic
into the southeast Conus and perhaps develop over the Southern
Plains as well. The possible tropical system and its evolution
varies from model run to model run, though moisture form this
system should gradually move across sections of the Gulf coast
states. Further north, westerly flow aloft should remain from the
Rockies to the Central and Northern Plains to Great Lakes/OH
Valley to Northeast. Multiple shortwave troughs are progged to
move through the westerly flow during that time with guidance
having one crossing sections of the OH Valley and eastern KY on
Friday and another moving into the Great Lakes/Lower OH Valley
later Saturday into Saturday night. The frontal zone north of the
OH River early on Friday may tend to sag across the Northeast and
mid Atlantic states and middle OH Valley and into northern
sections of eastern KY Friday late Friday into Friday night before
returning north as low pressure treks from the Central Plains to
the Central Great Lakes. This westerly flow aloft from the
Rockies to eastern Conus will occur downstream of an upper trough
moving from BC into the Northwest Conus. Convection peaking in
coverage each afternoon and evening with the threat of locally
heavy rain as is typical of mid July is anticipated across eastern
KY Friday and Saturday with the potential for some convection at
night as well.

Sunday to Monday, uncertainty remains with the track and possible
remnants or moisture from the possible tropical system over the
Southeast Conus to end the weekend and begin next week. Otherwise,
generally higher heights and upper ridging should extend from the
Atlantic across much of the Southeastern Conus and Southern
Plains to Southwest. Shortwave troughs should continue moving east
across northern sections of the Conus and southern Canada during
this time. One may cross the Northern Plains/Upper MS Valley later
Sunday to Sunday night and reach the Great Lakes Monday while
another shortwave over the Great Lakes early on Sunday tracks to
the Northeast Conus Sunday to Sunday night. Associated sfc low
pressure in advance of this initial shortwave is expected to pass
well north of eastern KY with the trailing frontal zone sagging
south of the Great Lakes and approaches the Lower and Middle OH
Valley from Sunday to Sunday night though this front will likely
remain north of eastern KY through the period and perhaps lift
back north as the next system moves near the International border.
Convection, peaking in coverage each afternoon and evening is
anticipated to begin the new week as well and as in earlier
timeframe in the long term period, locally heavy rain will remain
a threat.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 203 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...JP
AVIATION...GINNICK