773
FXUS63 KJKL 300852
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
452 AM EDT Sun Jun 30 2024

.KEY MESSAGES...

- Thunderstorms are possible through Sunday as a cold front
  approaches and moves through. A few storms through the early
  overnight could produce strong wind gusts and heavy rain.

- A short-lived break from the heat and humidity is forecast on
  Monday behind the cold front, quickly followed by a return of
  sultry conditions.

- An active period of showers and thunderstorms may impact the
  Fourth of July holiday period from Wednesday through Friday.
  Best chances for showers and thunderstorms as of now are
  expected Thursday July 4th during the afternoon and evening.
  Heat indices will return to near 100 degrees for many locations
  as well during this time period.

&&

.UPDATE...
Issued at 1155 PM EDT SAT JUN 29 2024

A cluster of showers with a few rumbles of thunder are dropping
south through the heart of the JKL CWA. Could still see some
additional showers and storms moving in from the northwest later
this night as the front creeps closer. Have updated the forecast
mainly to fine tune the PoPs through the rest of the night as well
as including the latest obs and trends for the T/Td/Sky grids. It
is worth noting that the low temperature for the date has been
only 76 degrees here at JKL so far and would set a monthly warm
minimum and tie the highest on record. However, an outflow and now
increasing rain chances through 1 am put all that in doubt.
Anyways, the updated grids have been sent to the NDFD and web
servers along with a freshening of the zones, HWO, and SAFs.

UPDATE Issued at 645 PM EDT SAT JUN 29 2024

22Z sfc analysis shows low pressure off to the northwest of the
area. This placed eastern Kentucky in a large warm sector out
ahead of a slow approaching cold front. For the most part, this
area has been capped at mid levels limiting the extent of any
convection despite high levels of instability. To the north,
closer to the better mid level flow, larger storms clusters - some
strong to severe - are moving just south of east. These may yet
threaten at least the northern parts of the JKL CWA later this
evening per trends and the latest CAMs. Should that occur, high
DCAPE and PWs could lead to damaging wind gusts and localized
flooding. Have updated the forecast with these ideas in mind and a
general timing for increased PoPs along and north of I-64 -
through midnight. Otherwise, its a very warm and humid start to
the evening with heat indices still around 100 degrees in many
locations - mostly owing to the high dewpoints. Specifically,
temperatures are running in the upper 80s to lower 90s while
dewpoints are in the low to mid 70s. Under partly sunny skies
winds are generally from the southwest to west at 5 to 10 mph. Did
also add in the latest obs and trends for the T/Td/Sky grids with
this update. These adjustments have been sent to the NDFD and web
servers along with a freshening of the zones and SAFs.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 253 PM EDT SAT JUN 29 2024

A series of shortwaves will maintain a broader upper level trough
moving east across the Midwest, northeast CONUS, Ontario, and Quebec
this weekend. We are on the southern edge of the prevailing
westerlies aloft associated with the trough. The trough will support
a surface cold front which will approach tonight and then pass
through from northwest to southeast on Sunday. Low level southwest
flow ahead of the front has transported warm and humid air across
the region, with highs in the upper 80s to lower 90s and dew points
in the mid 70s, with heat indices in the upper 90s to lower 100s
this afternoon.

Forecast soundings indicate capping in the middle atmosphere this
afternoon as mid-level heights continue to rise, which has
seemingly thus far prevented anything more than spotty shower
activity. However, by mid-evening height falls occur as a strong
shortwave moves across the Great Lakes region, and all models
indicate the atmosphere becomes uncapped, with CAMS depicting one
of more thunderstorm clusters moving across the forecast area from
northwest to southeast, likely emanating from upstream
development. As for the severe threat, the 20 to 30 kts of shear
with moderate instability supports a Marginal Risk especially as
any potential MCS moves southeast into the forecast area primarily
this evening.

With expected shower and thunderstorm activity occurring mainly
this evening into the overnight, any rain followed by partial
clearing toward dawn will support fog development. Regardless,
expect warm and "soupy" conditions through the overnight with even
the valleys remaining at 70 degrees or higher.

The cold front will move southeast through the forecast area on
Sunday with a similar atmospheric set-up ahead of the front.
Southeast KY won`t have fropa until late Sunday and stands the best
shot at seeing more thunderstorms, while the far northwest part of
the forecast area is likely to have fropa before sufficient heating
to support development.

A much cooler and drier air mass moves into the region behind the
front, with temperatures falling into the mid 50s to lower 60s, with
warmer conditions in the valleys, especially if mixing from cool air
advection continues through the night.

.LONG TERM...(Monday night through Saturday)
Issued at 452 AM EDT SUN JUN 30 2024

The large scale flow pattern aloft at the beginning of the extended
will feature a large ridge of high pressure aloft extending from the
northern Great Lakes southward through the Mississippi Valley,
western and central Ohio Valley into the southern Plains. A surface
ridge is forecast to be in place over the eastern Great Lakes into
western New England. A large trough of low pressure is progged to be
in place just offshore of northern New England and moving further
offshore as the ridge to the west pushes east. The northeastern
trough will also have a cold front extending southwestward down the
eastern seaboard and into the far southeastern CONUS and into the
western and central Gulf of Mexico. Another large and well developed
trough is forecast to be moving eastward across Montana, Wyoming
and portions of the interior west to start the period.

The upper ridge will slowly progress to the east through mid-week,
as the western trough also pushes east, allowing hot and dry weather
to persist. As the upper trough strengthens to our west, it will
pick up speed and push the upper level ridge off to our east, likely
by early Wednesday night. Once the ridge has been displaced far
enough, we should see a cold front moving in from the west. This
boundary will be associated with an upper trough that will also be
moving eastward just north of the Canadian border. By early
Wednesday evening, the surface front should be close enough to allow
a few showers and storms to fire and begin moving into our northwest
counties. The showers and storms will steadily increase in coverage
Wednesday night, as the front moves closer. The front should finally
make a solid push into our area by late Thursday morning, and will
continue through the area through out the day on Thursday. The
afternoon and evening hours will see widespread showers and storms
around the front. The front will eventually stall, as another trough
moves in from the west along the front. The combination of the
trough and front will allow showers and storms to persist across
eastern Kentucky the end of the forecast period early Sunday.
Another increase in showers and storms is expected for very late
Thursday night through Friday, as the upper trough makes a strong
eastward push. The activity should finally begin to taper of heading
into the weekend, as the surface boundary shears out and moisture
begins to dwindle.

Temperatures will generally be slightly above normal through
Thursday, with daily maxes in the upper 80s to at times lower 90s on
tap, as high pressure will be the primary feature in place over the
region. Friday could also be a bit warmer than normal, but Saturday
should finally see a cool down, as the front moves through the area,
allowing cooler air to filter in on western winds.

We will watch the forecast for Thursday and Friday closely, for the
potential for locally heavy rainfall, as showers and storms could be
robust at times. With dewpoints also forecast to be in the upper 60s
and lower 70s, hot and muggy conditions will be possible across the
area.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
ISSUED AT 254 AM EDT SUN JUN 30 2024

A few showers and thunderstorms persisted over eastern KY at the
start of the period, but they are on an overall decline. The
probability of a direct hit at a TAF site is low and it`s not been
included. However, where they do occur, IFR or worse conditions
can be expected in the heaviest rain. Where significant rain
occurred, a touch of fog may occur, but it doesn`t look to be
widespread. Outside of this, VFR conditions are forecast
overnight.

MVFR ceilings are forecast to develop on Sunday morning between
about 13Z-15Z as daytime heating kicks in. A cold front will also
be moving southeast through the forecast area at the time, and may
help to kick off some more thunderstorms. With time, the front
will progress southeast and ceilings will rise and break up and
any precip will end during the afternoon. This should leave VFR
conditions by evening.

&&

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

$$

UPDATE...GREIF
SHORT TERM...CMC
LONG TERM...AR
AVIATION...HAL