422
FXUS63 KJKL 071040
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
640 AM EDT Mon Jul 7 2025

.KEY MESSAGES...

- Hot conditions will gradually moderate through the week as
  humidity increases.

- Increasing humidity through the coming week will be accompanied
  by a potential for showers/thunderstorms especially each
  afternoon and evening, lasting potentially all the way into
  next weekend.

&&

.UPDATE...
Issued at 1212 AM EDT MON JUL 7 2025

Added low-end PoPs for the remainder of the overnight through the
late morning given isolated shower activity developing over the
last hour. Would expect we will see occasional development
continue. No other significant changes otherwise.

UPDATE Issued at 1048 PM EDT SUN JUL 6 2025

Despite the loss of daytime heating, scattered to broken cloud
cover continues to develop over eastern and northeastern
Kentucky, with the GFS depicting a quasi-stationary disturbance in
the upper levels just upstream over central Kentucky and
Tennessee. With this disturbance remaining quasi-stationary
through the overnight before ejecting northeast during the day
Monday, clouds may continue to develop and bring higher Sky cover
than currently depicted in the grids, especially as the
environment above the decoupled stable surface layer remains
unstable. A stray shower or storm cannot be ruled out, either, so
the 5 percent PoPs currently look reasonable.

Despite the increased cloud cover, overnight lows were lowered a
few degrees in the valleys to account for persistence and COOP MOS
forecasts in addition to current cooling trends so far this
evening.

UPDATE Issued at 753 PM EDT SUN JUL 6 2025

Added low-end PoPs for the next hour near and just downstream of
where existing showers and isolated thunderstorms are occurring.
This activity should rapidly wane with the loss of daytime heating
through the 00z to 02z (8 to 10 PM) period, so have PoPs falling
back to near zero by 03z, if not sooner.

&&

.SHORT TERM...(This evening through Monday night)
Issued at 238 PM EDT SUN JUL 6 2025

Current satellite shows a cumulus field developing to the west with
even some shower activity near KSME and a more organized line of
showers and storms further to the west, just east of Louisville.

A short wave trough continues to move across the Upper Great Lakes
region this afternoon, with a trailing weak frontal passage coming
through Kentucky later this afternoon into the early evening. A low
chance of isolated showers are possible with this frontal passage (5-
20% chance), with temperatures near or in the lower 90s. Dew points
in the upper 60s to low 70s will lead to humid feeling conditions.
Abundant dry air in the mid levels may mitigate shower chances this
afternoon. Tonight, mostly clear conditions are expected with light
and variable winds. Some river valley fog may develop overnight
tonight. Temperatures will cool into the upper 60s to low 70s.

Monday marks the beginning of an active week of weather ahead. A
stronger cold front, still associated with the previously mentioned
Great Lakes system, will pass through Kentucky in the afternoon
bringing shower and thunderstorms chances to the area. In general,
rain amounts will be up to a tenth of an inch, however the most
persistent storms could lead to some areas approaching a quarter to
three tenths of an inch. Slightly cooler conditions are expected,
with temperatures in the upper 80s to low 90s. Humid feeling
conditions continue with dew points remaining in the low 70s across
Eastern Kentucky.

.LONG TERM...(Tuesday through Sunday)
Issued at 340 PM EDT SUN JUL 6 2025

The period is expected to begin with an upper level ridge centered
in the Atlantic north of Bermuda while another upper level ridge is
expected to be centered over the Southwest Conus toward the Northern
Rockies. In between an upper level trough should extend from Canada
across the upper MS Valley and western Great Lakes vicinity to the
mid MS Valley to Arklatex vicinity. At that point, an upper level
low and associated trough should be nearing BC to the west coast of
the Conus. At the surface, a wavy frontal zone is expected to be in
place from the Maritimes to the Northeast to mid Atlantic states to
just north of the OH River to IA to Central Plains while sfc high
pressure is expected to centered near the northeast TN/SW VA
vicinity as well as over the Central Great Lakes and Northern
Plains. Per 00Z LREF mean, PW should be a bit above normal for this
time of year between about 1.55 and 1.8 inches or roughly between
the 75th and 90th percentiles.

From Tuesday to Wednesday night, a shortwave trough at 500 mb is
expected to gradually shift across the Great Lakes and into the
Lower to Middle OH valley while the southern end of the 500 mb
troughing lingers from the Ozarks to the Arklatex region. To the
east and southeast of the Commonwealth, upper level ridging is
expected to remain in place over the western Atlantic and centered
near Bermuda. Meanwhile further west and southwest, upper level
ridging remains in place from the Southwest into the eastern Pacific
while the northern portion of the ridge moves across the Northern
Plains to the Upper MS Valley. The Upper level low initially nearing
BC to the west coast of the Conus will move into western Canada and
across the Northwest to Northern Rockies to Great Basin. At the
surface, a wave moving along the front in advance of the shortwave
approaching the OH Valley from the Central Conus should pass
northwest of eastern KY leading to the frontal zone shifting north
and northeast of the area near midweek, extending from the mid
Atlantic states to northern/northeast OH and then southwest north of
the OH river to the mid MS Valley and then into portions of the
Central to northern Plains. A weak ridge of sfc high pressure per
the consensus of guidance should persist from the Southeast/Gulf
into the Southern Appalachians.

PW during the Tuesday to Wednesday night timeframe should generally
remain a bit elevated for this time of year in the 1.6 to 1.8 inch
range or no higher than the 75th to 90th percentile range. With the
slowly approaching shortwave trough and ample moisture in place,
convection cannot be ruled out at any point from Tuesday to
Wednesday night, though coverage and intensity should peak during
each diurnal cycle. 00Z LREF mean bulk shear is generally only on
the order of 10 to 15 KT so convection may be pulse in nature as
well and a lower end threat for gusty winds pending degree of
instability is anticipated for Tuesday and perhaps Wednesday per
experimental probabilistic guidance. Thunderstorms will likely
produce brief heavy rainfall, but the past several days have been
dry across eastern KY and only spotty rainfall is anticipated in the
short term. For any high water problems to develop, a location would
need to receive multiple rounds of heavy ran. High temperatures
should be nearer to normal for this time of year for Tuesday and
Wednesday.

Thursday to Friday night, the shortwave trough that is expected to
move across portions of Ontario and the Great Lakes as well as the
Lower to Mid OH Valley regions should move northeast and dampen
early in the long term period while another shortwave is progged to
approach the Lower OH Valley and Commonwealth from the Mid MS Valley
on Thursday gradually crossing the region through Friday and Friday
night. Upper ridging is expected to remain in place over the
Atlantic centered near or northeast of Bermuda while another upper
level ridge should remain centered from the Southwest Conus to parts
of the eastern Pacific. Further west and northwest, an upper level
low and associated upper level troughing should move from western
parts of Canada and the Northwest Conus and Northern Rockies to near
the Manitoba/Ontario border to upper MS Valley and portions of the
Northern to Central Plains per the consensus of guidance. At the
surface, a ridge of high pressure should remain in place from the
Gulf and Southeast into the Southern Appalachians while a frontal
zone remains north and northeast of eastern KY from the mid Atlantic
states to north of the OH River to south of the Great Lakes, though
by Friday to Friday night should lift further north into the Great
Lakes. This should occur as a sfc low associated with the shortwave
trough approaching from the west nears the Great Lakes while a cold
front trailing to the Southern Plains. A warm and rather moist
airmass will remain in the warm sector though shear should continue
to be limited with 00Z LREF mean bulk shear on the order of 10 to
15KT so convection may continue to be pulse type/typical of this
time of year. Convection cannot be completely ruled out at any point
with the shortwave trough gradually moving across the OH and TN
Valley region though coverage should generally peak each afternoon
and evening. Highs should average near normal to a few degrees below
normal

Saturday to Sunday, guidance varies with the handling of the upper
level low as it moves east or northeast over Canada with the
trailing shortwave trough moving into the Great Lakes while
confidence is greater that upper level ridging will remain centered
over the Southwest Conus to parts of the eastern Pacific and in the
Atlantic. Some of the guidance has a more southern shortwave nearing
the Lower OH Valley from the central Conus to end the period. Sfc
low pressure should track north of eastern KY during this period
while the trailing cold front should approach the Lower OH Valley
next weekend though it may not pass south of eastern KY. A general
diurnal peak in convection is anticipated next weekend as well
though. 00Z LREF mean and 12Z GFS MUCAPE is the highest of the
next 7 days on Saturday afternoon and evening, but shear should
continue to be limited. Some, but not all, AI EC based forecasts
have a bit higher convective chances for Saturday as does the
experimental GEFS based severe probabilties and trends for that
timeframe will be monitored as the week progresses for the
potential for strong storms. Highs should remain near normal.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 638 AM EDT MON JUL 7 2025

VFR conditions are expected through the period. Showers and
thunderstorms will be possible later this afternoon, with PROB30
and/or VCTS beginning in the TAFs around 17Z-18Z, with the
highest likelihood of terminal impacts at KSYM. Any stronger
storms could lower flight categories to MVFR.

River valley fog may develop after 06Z tonight, lasting through
13z Monday morning, with brief reductions possible. However,
continued to keep these out of the TAFs given the lower
confidence.

Light and variable winds will continue this morning before
increasing by 18Z as a cold front approaches the area, with gusts
of 15-20 kts possible. This will only persist a few hours, with
winds diminishing by the evening.

&&

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

&&

$$

UPDATE...CMC
SHORT TERM...GINNICK
LONG TERM...JP
AVIATION...WFO SGF