278
FXUS63 KJKL 291135
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
735 AM EDT Sat Jun 29 2024

.KEY MESSAGES...

- Hot and humid weather is expected today, with afternoon highs
  around 90 degrees and heat indices peaking around 100 degrees in
  some places.

- There is potential for thunderstorms Saturday into Sunday as a
  cold front approaches and moves through. A few storms on
  Saturday afternoon and evening 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 some locations
  as well during this time period.

&&

.UPDATE...
Issued at 735 AM EDT SAT JUN 29 2024

Based on obs, only made minor changes to sky cover and
temperatures during the morning.

&&

.SHORT TERM...(Today through Sunday)
Issued at 510 AM 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 will be on the southern edge of the
prevailing westerlies aloft associated with the trough. The
trough will support a surface cold front which will approach today
and tonight and then pass through from northwest to southeast on
Sunday. Low level southwest flow ahead of the front will carry
warm and humid air across the region. Forecast soundings show an
uncapped atmosphere as heating occurs today, and thunderstorms are
expected to bubble up. Features are weak with little to focus
development, and winds aloft are unimpressive with nothing more
than 20-30 kts below 500 mb. However, what flow there is should
yield enough cell movement to give decent precip coverage in the
end, and a likely POP was used for the afternoon/early evening.
With the weak features, will look for convection to wane during
the night. 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 northwest
part of the forecast area is likely to have fropa before
sufficient heating to support development.

.LONG TERM...(Sunday night through Friday)
Issued at 510 AM EDT SAT JUN 29 2024

Models are in good agreement with the main synoptic features and
pattern evolution aloft through the extended. Low amplitude trough
will be passing from the Great Lakes through the Upper Ohio Valley
and New England at the start of the period. Southern CONUS ridging
aloft will shift eastward and amplify as the center of the high
transitions to the southeastern CONUS. This results in ridging
building over our region within 24 hours of the start of the period.
Ridging remain generally over the eastern CONUS through the first
half of the extended. Short wave energy then begins to ride across
the northern periphery of the ridge and suppresses it southward
through the latter half of the extended, putting eastern Kentucky
under an increasing threat of unsettled weather with each passing
day. At the surface, Canadian high pressure will move into the
region behind an exiting surface cold front, transiting the Ohio
Valley, moving from the Upper Midwest to the east coast by
Wednesday. Thereafter, southerly return flow kick in for the
remainder of the forecast window.

Sensible weather features a continuation of seasonably hot, muggy
weather in general. However, the Canadian high pressure system will
provide another temporary (day or so) break from the summer heat and
humidity (lower dew points) from Sunday night through Tuesday
morning. This brief cool off will be very similar to the recent 1-2
day breaks from the humid, hot summer weather we have experienced on
and off over the past few weeks. Southerly flow will bring moisture
back into the area by midweek. Combined with the heat, the muggy
conditions will make our environment ripe for additional shower and
thunderstorm activity through the latter half of the extended.

For hazards, afternoon MLCAPES increase to between 1000 and 1500
J/kg on from Wednesday through Friday. However, as has often been
the case of late, bulk shear is marginal at best, less than 25 kts
on Wednesday and Thursday. The exception is our Bluegrass Counties,
where the shear creeps up to around 30 kts late Thursday. Bulk shear
increased more readily across the entire area by Friday, to around
30 kts. Thus while there will be the potential for strong to severe
storms, prefer to see overall better bulk shear (35 kts or more) for
the stronger more widespread or organized convection. In addition,
mid-level lapse rates and wind fields are rather unimpressive. Thus
at this time, any severe thunderstorm potential will be limited and
generally restricted to a wind threat. PWATS increase to around the
90th percentile of climatology by Thursday and Friday. Therefore can
not rule out some locally heavy rain, especially with any stronger
storms.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 735 AM EDT SAT JUN 29 2024

Clouds are obscuring the surface view from satellite early this
morning, but without any visibility restrictions at airport sites
it would seem that any fog is very limited. What there is should
be gone shortly. Scattered to numerous thunderstorms are forecast
to develop this afternoon and last into tonight. There is not
enough confidence in timing/placement to include more than VCTS in
TAFs. Fog will probably affect some valleys tonight, but it`s not
been included in any TAFs. Aside from fog and precipitation, VFR
conditions are expected.

&&

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

$$

UPDATE...HAL
SHORT TERM...HAL
LONG TERM...RAY
AVIATION...HAL