JKL issues Area Forecast Discussion (AFD) at Aug 22, 4:38 PM EDT566
FXUS63 KJKL 222038
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
438 PM EDT Fri Aug 22 2025
.KEY MESSAGES...
- A cold front will bring a potential for showers and
thunderstorms this weekend, with the greatest probability in
southeast Kentucky.
- A cool and dry air mass more typical of late September or early
October will arrive by Monday and persist through the new work
week.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 343 PM EDT FRI AUG 22 2025
Fog and low clouds were slow to break up again today, but the
process was faster than yesterday. This allowed for more heating,
which has managed to fuel some shower and thunderstorm development
near the VA border. Will look for the precip to die out with loss
of heating/instability this evening.
Pattern changes then begin, leading to significant change in the
long term. A significant upper low along the Manitoba/Ontario
borer will slowly move east tonight through Saturday night, with
an associated trough expanding/deepening over the eastern CONUS.
As minor geopotential height falls begin by Saturday morning for
our area, would not completely rule out isolated precip again by
dawn, but the probability looks to low for inclusion in the
forecast at this point. As heating/destabilization occur on
Saturday with more height falls, will expected more development of
convective precip. The deepest moisture will be present over our
southeast counties, which will probably allow for the easiest
development and greatest coverage there. Activity is expected to
decline on Saturday night, but possibly at a slower pace due to
support from the amplifying upper level trough.
.LONG TERM...(Sunday through Friday)
Issued at 435 PM EDT FRI AUG 22 2025
The long-term period opens Sunday morning with a deep trough
dropping across the Eastern CONUS, associated with a nearly
vertically stacked ~550 dam low over James Bay. A surface cold
front extends southward from the low across the Eastern Great
Lakes and then southwestward along the western foothills of the
Central/Southern Appalachians. Behind this cold front, cool and
dry air is flooding southeastward from the Canadian prairies.
The cold front is progged to slowly drop southeast across the JKL
forecast area on Sunday. Locations near the Virginia-Kentucky
border will see the best opportunity for modest destabilization
prior to the fronts arrival. This will have a direct bearing on
overall rain chances. The highest PoPs, 50 to 60 percent, are
adjacent to Virginia but diminish to around 15 percent in the I-64
corridor. Once the boundary clears Eastern Kentucky, the cool and
dry Canadian air mass will flood in on a northwesterly breeze
during the evening, though it may relax a bit in deeper valleys
overnight. Dew points on Monday could drop into the 40s for most
locales by the afternoon while 850 mb temperatures settle to
between 10-11C. The chilly air will be maintained throughout the
day; in fact, a weak secondary cold frontal passage is possible on
Tuesday as a shortwave passes through the lingering troughing
aloft. Given the already dry air in place (PWATs of 0.5 to 0.75
inches), no rainfall is anticipated. However, LREF mean 850 mb
temperatures are forecast to sink further to between 8 and 10C. If
realized, these values would support daily maximum surface
temperatures of only 69 to 74 degrees below 1,500 feet ASL, and
even chillier temperatures over the higher terrain. This would be
10+ degrees below normal for the day. Shortwave ridging builds in
on Wednesday before heights start to fall again on Thursday-Friday
as additional vorticity energy rides through the lingering
troughing aloft. At the surface, this will be reflected by a high
pressure building and then later cresting over the Ohio Valley
late Wednesday. With the high center in close proximity, Wednesday
night may support the coldest temperatures we have seen since the
beginning of June. COOP MOS from the sheltered northern valleys
(e.g. West Liberty and Sandy Hook) suggests mid 40s as a real
possibility, though upper 40s to lower 50s are more likely at most
locations. The surface high will slowly shift off to the east
later in the week, allowing moisture and warmer temperatures to
filter back into the Commonwealth on a southerly flow.
In sensible terms, look for scattered to locally numerous showers
and thunderstorms on Sunday, with the best chances toward the
Virginia-Kentucky border and the lowest chances toward the I-64
corridor. It will still be warm with high temperatures expected to
be in the lower to mid 80s. A dry and cool stretch of weather
then ensues from Sunday night through the remainder of the new
work week with daytime highs mostly in the 70s and nighttime lows
in the mid 40s to mid 50s. The coolest time period appears to be
Tuesday through Thursday morning when nighttime temperatures for
many will drop to around 50 or lower while day highs will struggle
to surpass 75F in all but the warmest spots. Fog formation is
likely in the favored river valleys on most nights.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
ISSUED AT 218 PM EDT FRI AUG 22 2025
Conditions were wide ranging at the start of the period, with an
area of mainly MVFR and IFR ceilings extending east/west through
the middle of the forecast area and affecting KJKL and KPBX. To
the north and south, conditions were mostly VFR. More improvement
is forecast this afternoon, with the low clouds continuing to
lift and break up, allowing a return of mostly VFR conditions
area wide. However, the sun and heating which has occurred in some
locations is leading to shower/thunderstorm development near the
VA border, with associated localized sub=VFR conditions. The
precip will die out this evening.
Valley fog development is expected late tonight, growing in
breadth and depth and bringing localized IFR or worse conditions.
All TAF sites have a potential for impacts to varying extents.
The fog will dissipate on Saturday morning, with conditions
eventually reverting to VFR again area wide.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...HAL
LONG TERM...GEERTSON
AVIATION...HAL
Source:
JKL issues Area Forecast Discussion (AFD) at Aug 22, 4:38 PM EDT---------------
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