378
FXUS63 KJKL 200000
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
800 PM EDT Tue Aug 19 2025

.KEY MESSAGES...

- Showers and thunderstorms will be possible at times through
  Sunday, with the greatest probability associated with cold
  fronts forecast to move through on Wednesday and during the
  weekend.

- A cold front moving through Wednesday will bring a modest drop
  in temperatures, followed by a much more noticeable cool-down
  behind another cold front passing during the weekend.

&&

.UPDATE...
Issued at 800 PM EDT TUE AUG 19 2025

PoPs, T, Td, and Sky cover grids have been updated to reflect the
latest hourly observations this evening and high-resolution model
trends heading into the overnight hours. Very isolated weak
convection could bubble up over the Cumberland Mountains over the
next hour or two. Otherwise, we will be monitoring diminishing
convection as it slowly drifts southeast toward our CWA through
the overnight.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 433 PM EDT TUE AUG 19 2025

A weak mid/upper level trough moving east largely over the Great
Lakes and New England will brush our area as it passes by. It will
be enough to support passage of a weak cold front here. The
approaching trough and cold front are spawning thunderstorms to
our northwest late today in southern IL, southern In, western OH,
and adjacent portions of KY. The precipitation will develop
further southeast with time, but once heating is lost and
instability wanes it should be on an overall decline tonight as it
tries to make it into the JKL forecast area. Redevelopment is
expected after more heating/destabilization occurs on Wednesday,
particularly where the front will be latest to pass in south
central and southeast KY. This will end as the front departs and
instability again fades on Wednesday night. Only a modest change
in air mass is expected with the cold front.

.LONG TERM...(Thursday through Tuesday)
Issued at 433 PM EDT TUE AUG 19 2025

The period is expected to begin with an upper level ridge
centered near the Four Corners region and extending into the Central
Plains to Great Lakes. Erin is expected to be east of the NC coast
as the period begins while upper troughing is expected to linger
from the Central Appalachians to the western Gulf. Further
northwest, meanwhile, an upper level low is expected to be in place
near the Alberta and Saskatchewan border with an associated trough
south into the Northern Rockies. At the surface, the boundary that
will have crossed the area on Wednesday is expected to have become
diffuse over the Appalachians while a ridge of sfc high pressure
should extend from Ontario to the mid to Upper MS Valley. Further
west, a sfc low pressure system preceding troughing moving across
western Canada should be centered near the Saskatchewan and Alberta
border with a cold front trailing into the Dakotas to parts of the
Great Basin/western Conus.

Thursday to Friday night, the axis of upper troughing should shift
gradually to the south and southeast from the mid Atlantic states to
the Southern Appalachians to TX and the northwestern Gulf.
Meanwhile, Erin should track between Bermuda and the mid Atlantic
and Northeast Conus. Upper troughing should continue east across
Canada and the Northern Plains to Quebec to the western Great Lakes
and Upper MS Valley to the Mid MS Valley, downstream of the upper
ridging into the western Conus that continues to be progged to build
into sections of the Great Basin to Pacific Northwest. An associated
sfc low should track toward northern Ontario and near Hudson and
James Bay with the trailing cold front reaching the Upper MS Valley
to Central Plains. Despite some 500 mb height rises by Thursday
night into Friday, an inverted trough may develop from the Gulf
States/TN Valley and into the Commonwealth. Near and east of this
feature, especially nearer to the VA and TN borders, convection will
remain possible, mainly on Thursday afternoon and Friday afternoon.
Upper height rises should lead to generally lesser coverage of
convection on Friday particularly in the more northern and western
locations and it is possible that guidance and the current forecast
could end up with pops that are too high. Fog should affect some
valleys each morning and could be dense in spots with that most
probable for Thursday morning where any heavier rain falls on
Wednesday. Otherwise, Temperatures are expected to be near if not a
few degrees below normal and near normal for Friday.

Saturday to Saturday night, upper troughing south of an upper low in
Ontario is expected to evolve from Ontario across the Great Lakes to
the OH Valley and parts of the Southeast downstream of upper ridging
over the western Conus to Southern Plains. As this trough begins to
take shape, a shortwave is expected to rotate around the upper low
to the western Great Lakes and portions of the mid to upper mS
valley. The sfc low in Canada should gradually move to Quebec/James
Bay with the trailing cold front reaching Quebec to the eastern Great
Lakes to OH Valley to Southern Plains by late Saturday night. As the
front approaches and mid level heights begin to fall, scattered
convection is possible generally peaking Saturday afternoon, though
chances linger through Saturday night.

Sunday to Tuesday, the axis of upper troughing should move to Quebec
to the OH valley to Southeast downstream of ridging over the western
Conus through Monday with upper troughing remaining from eastern
Canada to the Northeast and mid Atlantic states. The surface cold
front meanwhile should cross the area Sunday, with sfc high pressure
building into the Lower OH Valley and SOuthern Appalachians from the
Plains and Central Conus to begin the new week. Chances for
convection will linger near and in advance of the front Sunday, with
drier and colder weather to follow. The high building in behind the
front is expected to usher in colder air with below normal
temperatures forecast through at least the middle of next week.
Recent long range guidance and CPC outlooks carry the colder and
drier trend though much of next week.n colder air with below
normal temperatures forecast through at least the middle of next
week. Recent long range guidance and CPC outlooks carry the colder
and drier trend though much of next week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
ISSUED AT 800 PM EDT TUE AUG 19 2025

VFR conditions should persist until late tonight at most
locations. Valley fog is forecast to develop overnight, but
impacts at TAF sites are likely to be limited due to another day
of drying and lower crossover temperatures. SME seems most
favored TAF site for fog impacts, but confidence is relatively low
even there. Otherwise, a cold front will bring a possibility of a
few showers/thunderstorms tonight and Wednesday as it approaches
and moves through from northwest to southeast. The most likely
locations for these would be in south central and southeast KY
on Wednesday. The precip could result in localized IFR or worse
conditions.

&&

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

&&

$$

UPDATE...GEERTSON
SHORT TERM...HAL
LONG TERM...JP
AVIATION...GEERTSON/HAL