420
FXUS63 KJKL 300100 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
900 PM EDT Sun Jun 29 2025

.KEY MESSAGES...

- Hot and humid conditions will continue through Monday. Heat
  indices will peak in the 90s to around 100 degrees through
  Monday.

- Diurnal shower and thunderstorm chances continue through
  Tuesday.

- A cold front passage on Tuesday will bring temporary relief
  from the sustained heat and humidity.

- Daily high temperatures are favored return to the 90s from next
  Saturday onward.

&&

.UPDATE...
Issued at 900 PM EDT SUN JUN 29 2025

00Z sfc analysis shows a weak pressure pattern over eastern
Kentucky. This is allowing the diurnal cycle of instability to
dominate the convective development and weather. For the most
part, it has been quieter than the past several evenings. Expect
this to continue through midnight with minimal convection
afterwards. Currently temperatures are running in the upper 70s
to the lower 80s. Meanwhile, amid light south winds, dewpoints
are generally in the low to mid 70s. Have updated the forecast
mainly to add in the latest obs and trends for the T/Td/Sky grids
and also to fine tune the PoPs and late night valley fog through
the rest of the night. These minor adjustments have been sent to
the NDFD and web servers along with a freshening of the zones,
HWO, and SAFs.

&&

.SHORT TERM...(This evening through Monday night)
Issued at 406 PM EDT SUN JUN 29 2025

The last Sunday of June is going out on a seasonably hot and humid
note with widespread temperatures between 85 and 90F this
afternoon while dew points range in the upper 60s to lower 70s in
most locales. Convection so far has been minimal, confined to
some spotty activity over the Bluegrass and perhaps a few
sprinkles in the vicinity of Big Black Mountain. The surface
analysis shows little in the way of a defined pressure regime over
eastern Kentucky -- diurnal and topographic effects predominate.
Aloft, a shortwave trough extends from Minneapolis, MN southward
to the Mid-Mississippi Valley and appears to be supporting at
least scattered convection over central and western Kentucky.
Further upstream, a more substantial 500H trough extends southwest
from Lake Winnipeg to near Yellowstone National Park. A cold
front extends southward from this system`s surface reflection over
northwest Ontario across Iowa and then southwestward into
Colorado.

For the remainder of the daylight hours, still expect at least
scattered shower and thunderstorms (30-50 PoP) to develop across the
area with the best chances generally southwest of KY-15 due to a
combination of better topographical forcing and some weak upper
level support from the approaching shortwave trough. With relatively
weak instability and minimal shear, anticipate mainly garden variety
storms. The strongest storms could produce some brief wind gusts and
perhaps a very isolated instance of excessive rainfall.

For tonight, much of the time will be dry. However, with the
shortwave trough passing aloft, a few showers or thunderstorms
cannot be ruled out with better chances generally toward
and north of I-64. It will still be warm and muggy with lows
generally ranging from 65-71F. Fog formation is a good bet in the
favored river valleys and where rainfall occurs toward or after
sunset. On Monday, heights aloft will begin to fall as the cold
front and its parent 500H trough approach the Lower Ohio Valley.
Another disturbance skirting around the base of the trough
is likely to help spark additional convection during the day on
Monday. The primary concern with those storms remains the
possibility of isolated excessive rainfall as the swampy, humid air
mass lingers overhead. It will again be hot with high temperatures
from 85 to 90F at most locales.

On Monday night, shear will become strong enough for semi-organized
convection ahead of the cold front; yet instability will wane after
sunset. The NAMNEST hints at a possible QLCS diving southeast
ahead of the front and then eventually decaying as it nears the
I-64 corridor. This is a distinct possibility and could portend a
blustery but weakening squall line impacting portions of the
forecast area late Monday evening, especially toward the
Bluegrass; but, forecaster confidence in anything approaching
severe limits is very low at this time. Otherwise, Monday night
should be warm and a bit breezy with lows in the upper 60s to
lower 70s. Some temporary relief from the muggy weather is on the
way though -- the well-advertised cold front is expected to be on
our northwestern doorstep by sunrise Tuesday morning.

.LONG TERM...(Tuesday through Sunday)
Issued at 446 PM EDT SUN JUN 29 2025

The 29/12z model suite is in good agreement showing a surface cold
front on our northwestern doorstep Tuesday morning, just ahead of
a 500H trough axis. To the west, a seasonably strong ~591 dam
high is noted from Louisiana/Texas border west northwest into the
Four Corners Region.

Excellent model agreement buoys forecaster confidence that the
cold front will slide southeastward through the Coalfields on
Tuesday. Showers are likely ahead of the boundary. A faster
passage would limit the overall thunderstorm threat due to minimal
instability. However, a slower passage, which is favored by more
of the guidance, would allow for more destabilization, given
sufficient clearing. In the latter scenario, a stronger storm or
even a transient weak supercell structure is not outside the
realm of possibility as EBWD values approach 30 knots. Once the
front departs Tuesday night, the upper level high will gradually
propagate/expand eastward through the remainder of the week.
Disturbances riding around the high might be able to spark a very
isolated afternoon/evening shower or thunderstorm later in the
week but guidance has overall been trending drier with the
features such that PoPs are now below slight chance (15-24%)
levels through Saturday.

In sensible terms, look for one more muggy start to the day on
Tuesday before additional showers and possible thunderstorms
develop and generally move from northwest to southeast. There is a
greater chance for a few strong storms if the sun is able to
break through morning clouds and maximize destabilization. Drier
and slightly cooler air finally follows the front on Tuesday
night with widespread low temperatures in the lower to mid 60s
expected. Nighttime fog formation is likely, especially in the
river valleys. High temperatures return to mid 80s for most
locations on Wednesday but dew points in the lower to mid 60s
should keep the warmth at comfortable levels. However, the heat
and humidity will slowly creep back in as the weekend approaches --
high temperatures return to the lower/mid 90s by Saturday and
Sunday. Skies should be clear to partly cloudy as well, leading
to abundant sunshine for the Independence Day weekend across
eastern Kentucky. With that said, the return of higher humidity
levels will be attended by the slightest of shower and
thunderstorm chances as early as Thursday afternoon (though
presently below the mentionable 15% PoP level until Sunday
afternoon).

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 825 PM EDT SUN JUN 29 2025

While VFR conditions should generally prevail through the period,
briefly reduced flight categories are likely under any passing
shower or storm for the next few hours or during the afternoon on
Monday. Fog formation is favored again tonight in the typical
valleys. However, any fog impacts at the TAF sites is uncertain so
tempos have been employed from 08 to 12Z. Fog clears after
sunrise on Monday with renewed chances for storms by mid
afternoon. Winds will be variable, generally under 5 kts,
through the period, except potentially gusty and erratic near
thunderstorms.

&&

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

&&

$$

UPDATE...GREIF
SHORT TERM...GEERTSON
LONG TERM...GEERTSON
AVIATION...GEERTSON/GREIF