603
FXUS63 KJKL 240816
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
416 AM EDT Mon Jun 24 2024

.KEY MESSAGES...

- A fleeting sampling of drier and somewhat cooler air will be
  noticed today.

- Heat and humidity climbs Tuesday and Wednesday before another
  cold front arrives with a decent shot at thunderstorms
  Wednesday evening.

- The midweek cold front will be less impressive, with even hotter
  weather expected to make a comeback by Friday and Saturday.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 416 AM EDT MON JUN 24 2024

Cooler and drier air continues to slowly filter into eastern
Kentucky early this morning behind the passage of a cool front.
Rainfall varied widely from nothing to over an inch. Fog has formed
in many locations, especially in valleys, where rainfall occurred.
Temperatures presently range from the upper 60s in the cooler
northern valleys and in the lower to middle 70s elsewhere. At 730z,
a surface analysis suggests that the poorly defined cold front is
pressing southeast of the Hal Rogers Parkway/Highway 80 corridor. A
500H analysis shows a trough axis extends from the Ottawa Valley
down into the Mid-Ohio Valley/Central Appalachians. Further west, a
positively-tilted, upper-level ridge axis extends from an ~593
dam high centered over New Mexico, northeastward through the
Central Plains into Northern Ontario and is reflected at the
surface by high pressure extending from the Upper Midwest down
into the Mid-Mississippi Valley.

The 500H trough over our region will shift off to the east today
while the upstream ridge axis will drop southeastward and cross the
Ohio Valley late tonight. Precipitable water falling to between 0.6
and 0.8 inch and 850 mb temperatures falling to between 13 and 16C
will allow for a very comfortable late June afternoon. Heading
into tonight, the corresponding surface high crests over the
eastern Kentucky Coalfields around 3z tonight; with weak westerly
return flow commencing by early Tuesday morning and continuing
throughout the day tomorrow. This will buoy 850mb temperatures
back to around 20C by late in the day. The next trough will drop
into the Great Lakes late Tuesday evening/night, sending another
cold front toward eastern Kentucky early in the long-term.

In sensible terms, look for patchy low clouds and fog (especially
in southeastern valleys) this morning. After sunrise, the fog
should lift and the patchy low clouds will become an extensive
cumulus field. It will be cooler and less humid with highs in
lower to middle 80s. Mostly clear skies follow for tonight along
with fog forming in the favored valley locales and low
temperatures in the mid 50s cooler northern hollows to the mid
60s on the thermal belt ridgetops/slopes. Abundant sunshine and
hotter temperatures follow on Tuesday with highs in the upper 80s
and lower 90s. However, moderate dew points in the lower to middle
60s will prevent the heat from being to oppressive -- heat
indices generally peak in the upper 80s to lower 90s.

.LONG TERM...(Tuesday through Sunday)
Issued at 330 PM EDT SUN JUN 23 2024

The extended period will start off with an extensive ridge of high
pressure centered over the southwest CONUS and southern Plains.
The ridging will extend northward up the West Coast and into the
Pacific Northwest and into the western Gulf of Mexico on Tuesday.
A fast moving trough of low pressure will make its way east
through the Great Lakes and upper Ohio Valley, with a stronger
trough exiting extreme northern New England into the open
Atlantic. Weaker ridging will be in place across the Tennessee
Valley and Gulf Coast states to begin the period. The models were
in pretty good agreement with this starting set up and were
showing a general eastward progression of a cold front extended
southward from the northern trough and into the Ohio and Tennessee
Valleys Tuesday night and Wednesday. That will be the period where
we see our best rain chances in the extended, as the front moves
through and interacts with a northward surge of warm, moist air
off the Gulf of Mexico. A line of showers and storms is progged to
advance through the region from very late Tuesday night, through
the day on Wednesday, as the cold front moves through and then
slow greatly late Wednesday. In fact, the boundary may even stall
out near the VA border, and keeping scattered showers and storms
around the end of the day on Thursday for our southeastern
counties.

Once the first cold front moves away, another ridge of high
pressure will move in and bring another period of hot and muggy
weather to eastern Kentucky Thursday and Friday. We could see
highs on those days in the low to mid 90s. The ridge will bring
conditions favorable for modest ridge valley temperature
differences to the area Tuesday night, Thursday night, and Friday
night. Another area of low pressure will bring another round of
rain and storms to the area Saturday through Sunday. The primary
weather concerns in the extended will be how strong any storm we
see on Wednesday are able to become and the hot and muggy
conditions that will be returning on Friday and Saturday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 155 AM EDT MON JUN 24 2024

A cold front is dropping southeastward across the Eastern Kentucky
Coalfields early his morning as the last showers and thunderstorms
exit into Tennessee and Virginia. As the front departs and clears
away the deeper moisture, some patchy low clouds are likely to
linger overnight but are not anticipated to cause widespread sub-
VFR ceilings at this point.

Fog is also forecast to develop in valleys early this morning,
especially in southeast KY, but the extent of the fog is
uncertain. Moisture is present from earlier rainfall, but drier
air is also trying to advect into the area behind the front,
fighting the fog. Confidence in seeing at least minor visibility
restrictions was high enough to include 6SM BR at SYM, LOZ, and
SME terminals closer to sunrise. Sub-VFR visibility restrictions
are more likely at SJS and JKL. Fog will dissipate after sunrise
Monday morning and leave VFR conditions through the remainder of
the period.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...GEERTSON
LONG TERM...AR
AVIATION...GEERTSON