837
FXUS63 KJKL 110747
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
347 AM EDT Tue Jun 11 2024

.KEY MESSAGES...

- Slightly cooler than normal and pleasant weather will hold
  through mid-week.

- Hot weather arrives late this week, with highs in low to mid 90s
  with heat indices approaching 100 degrees beginning Sunday and
  persisting into Monday.

&&

.UPDATE...
Issued at 135 AM EDT TUE JUN 11 2024

Low clouds in the southeast part of the area continue to slowly
clear off. Mainly made adjustments for this process and also to
fine tune the fog threat in the river valleys into dawn. The
latest obs and trends for the T/Td grids were also included with
this update. These tweaks have been sent to the NDFD and web
servers.

UPDATE Issued at 1026 PM EDT MON JUN 10 2024

Sky/cloud cover continues to be the trickiest part of the
overnight forecast, with some areas of clear skies and others
overcast. Models suggest areas east of I-75 and near/along the
Hal Rogers Parkway have the highest probability of sustained cloud
cover. Sky grids use a blend of CONShort, HRRR, and NBM to reflect
this thinking. The forecast is on track otherwise, with hourly
observations blended into the gridded forecast.

UPDATE Issued at 730 PM EDT MON JUN 10 2024

Quite the difficult cloud cover forecast tonight as a large area
of stratus clouds sits over the Ohio River Valley poised to move
southeast into the area. The problem is that models don`t seem to
be resolving this area of clouds. Blended in the HRRR with the
previous Sky grid forecast through tonight, which results in
increased cloud cover at times.

Otherwise, the forecast is on track with little in the way of any
significant changes.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 326 PM EDT MON JUN 10 2024

The afternoon surface analysis shows a cold front is in the
process of pushing across eastern Kentucky this afternoon. We are
seeing NW flow at JKL likely indicating the passage of the front.
This front will lead to some wind gusts of 15-20 mph at times this
afternoon under decent mixing from the front. The other issue has
been more cloud cover and this has limited some locations form
achieving the afternoon high particularly in somewhat higher
terrain areas given the cold air advection. Overall lowered
afternoon highs in some locations toward the 25 percentile.
Outside this the post frontal stratus noted upstream will be
somewhat a challenge tonight, as the models including the HREF are
struggling to handle the progression southward of this. Overall
seems like it has been behaving and staying just short of eastern
Kentucky. This will be particularly interesting as ensembles and
deterministic guidance show a shortwave pushing southward late
tonight. This will put overnight lows in question, with more
clouds it could limit the ridge/valley splits. However, right now
we will keep the mid to upper 40s in the valleys and upper 40s to
lower 50s elsewhere.

This frontal boundary will usher in drier and cooler airmass for
Tuesday, with PWAT values in the 0.5 to 0.6 range based on the
HREF. This is around 2 standard deviations below normal for June.
In the mid-levels, ensembles and deterministic guidance are in
good agreement that we will see shortwave ridging leading to
rising heights. There could be a few pancake cumulus at around 4
kft, but expect mostly sunny skies Tuesday, with highs in the low
to mid 70s. Afternoon highs like this are around 5-10 degrees
below normals for JKL and LOZ climate sites for this time of year.
The skies will clear for Tuesday night and could once again lead
to ridge/valley temperatures splits with lows in the upper 40s to
lower 50s in the valleys and low to mid 50s on the ridges.

.LONG TERM...(Wednesday night through Monday)
Issued at 346 AM EDT TUE JUN 11 2024

Weak upper-level northwesterly flow will be in place to start the
forecast period. At the surface, a dome a high pressure will exist
and will keep the forecast area hot and dry. Through the day
Thursday, an upper-level perturbation will move into the northern
Plains and through the Great Lakes. At the surface, a cold front is
forecast to extend southwest toward the Commonwealth and will slowly
track into the region. The front will provide enough lift to fire
off a few thunderstorms but mainly north of the CWA. However, can`t
rule out a stray thunderstorm along and east of the Mountain
Parkway. Surface high pressure will build back into the region post-
frontal with temperatures climbing into the 90s and heat indices
approaching 100 degrees for the end of the weekend into early next
week.

Models begin to diverge for the start of next week as the heat
begins to break as a potential system moves into the region. The
ECMWF is dry going into next week with the GFS being the more
aggressive of the two models. For the forecast package, opted with
the NBM solution that keeps slight chances of showers and
thunderstorms through the end of the period.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 150 AM EDT TUE JUN 11 2024

Low stratus clouds continue to slowly erode in the southeast parts
of the area. Have timed that for JKL and SJS otherwise skc
conditions will prevail through the period. A small window for
valley fog development this morning as those clouds clear will
keep the terminals unrestricted. Winds will be through the morning
before picking up a bit at less than 10 kts from the north this
afternoon - diminishing to light in the evening.

&&

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

$$

UPDATE...GREIF
SHORT TERM...DJ
LONG TERM...VORST
AVIATION...CMC/GREIF