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268
FXUS63 KJKL 201808 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
208 PM EDT Mon May 20 2024

.KEY MESSAGES...

- Dry weather is expected area wide through Wednesday morning.

- There is a potential for showers and thunderstorms at times from
  Wednesday afternoon through Sunday.

- Very warm temperatures will persist through Wednesday. An
  increase in clouds and the possibility of rain will bring
  somewhat lower temperature after that, especially Thursday and
  Friday.

&&

.UPDATE...
-- Changed Discussion --
Issued at 208 PM EDT MON MAY 20 2024

Cumulus production has been more prevalent this afternoon. As
such, have increased the sky cover through late today, before
diminishment ensues with the loss of heating. Forecast highs still
look on target. Updates have been sent.

UPDATE Issued at 1046 AM EDT MON MAY 20 2024

Valley fog burned off by 10 am. Mostly sunny skies will reign,
besides some passing very thin high clouds and perhaps a few
cumulus that form closer to peak heating. Temperatures were
running a bit behind the forecast, so have lowered the highs just
a touch. Most locations will achieve mid 80s, with a few spots
reaching upper 80s. Updates have been sent.

UPDATE Issued at 727 AM EDT MON MAY 20 2024

The forecast is on track so no changes were made with the mid-
morning update.
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&&

.SHORT TERM...(Today through Tuesday)
Issued at 313 AM EDT MON MAY 20 2024

Southwest/northeast oriented ridging at all levels will slowly pass
east over the region during the period, resulting in dry weather
with mainly clear skies through this evening. Strong, nearly full
sun (within about a month of summer solstice) will result in very
warm afternoon temperatures on Monday, well into the 80s. Our
atmosphere aloft will continue to be very dry, creating good
radiating conditions despite a potential modest increase in high
clouds after midnight tonight. With light low levels winds,
valleys will readily decouple from the flow this evening, leading
to typical ridge/valley minimum temperature differences, as well
as valley fog. The temperatures differences will be greatest
tonight with weak warm air advection keeping ridges warmer.

A shortwave begins to move into the upper ridge over the area
Tuesday, resulting in a modest increase in moisture and
instability. This has resulted in a modest increase in PoPs, but
still below the 15 threshold needed to warrant a mention of any
precipitation the forecast.

.LONG TERM...(Tuesday night through Sunday)
Issued at 512 AM EDT MON MAY 20 2024

The 20/00z model suite is in good agreement at the beginning of the
forecast period (Tuesday evening) showing a 500H ridge axis
extending from an ~592 dam high over Central Mexico northeastward
across the Gulf Coast states, over the Carolinas, and then off
the Mid-Atlantic Coast. The corresponding surface high pressure
ridging axis, though still influencing the weather over eastern
Kentucky, will be solidly off the Atlantic Coast. To our
northwest, a weak 500H low will be transiting the Upper Midwest
while a trailing shortwave trough ejects off the Central Rockies.
At the surface, low pressure will be passing over the Great Lakes
while its attendant cold front trails back to the southwest
through the Mid-Mississippi Valley and on into the Central/Southern
Plains.

The ridging will continue to make a slow southeastward retreat on
Wednesday and Thursday while the low pressure to our northwest
lifts toward/into Quebec. The system`s associated cold front will
sag south of the Ohio River and eventually stall over the
Commonwealth on Thursday. A southern stream upper level
disturbance will then ride over the frontal boundary and through
the Ohio Valley on Friday and Friday night. The unsettled pattern
continues right into the weekend as another shortwave trough
tracks from the Central Rockies into the Great Lakes, attended by
another surface low. This system will briefly lifts the boundary
back north as a warm front on Saturday before cyclonic flow on
the back side of the system pushes the boundary back southeast as
cold front early next week.

Sensible weather will feature warm and dry weather through Wednesday
morning, before shower and thunderstorm chances slowly creep
southward later Wednesday and Wednesday night. At this point, shear
and instability appear modest but may be sufficient to support a few
strong to marginally severe thunderstorms on Wednesday afternoon and
possibly again on Thursday, if the front makes particularly slow
southward progress. Temperatures will run well above normal
through Wednesday night with high temperatures climbing well into
the middle and even upper 80s while nighttime lows range mainly in
the 60s. A few of the coldest sheltered northeastern valleys
could still dip into the upper 50s early Tuesday morning. While it
won`t be raining all of the time, daily shower and thunderstorm
chances are forecast through the remainder of the time period
with the afternoon and evening hours being favored for the most
widespread activity. Forecast maximum temperatures retreat to the
mid 70s to around 80 on Thursday and Friday before warming back
int the middle 80s by Sunday. Daily minimum temperatures should
generally range in the lower and middle 60s for most locations
from Thursday night on through the upcoming weekend.

&&

.AVIATION...
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(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 208 PM EDT MON MAY 20 2024

VFR conditions will continue to prevail through the majority of
the period. The only exception will be some MVFR or lower fog that
will occur in the river valleys between 05 and 13z. Crossover
temperatures are a bit lower this afternoon overall, which should
keep the fog a bit more confined late tonight into early Tuesday
morning. Did include a tempo MVFR group at KSME, which stands the
best chance at seeing some temporary dips in visibility between 09
and 12z, given the slightly higher crossover temperatures. Winds
will average around 5 kts or less through the period.
-- End Changed Discussion --

&&

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

$$

UPDATE...GEOGERIAN
SHORT TERM...CMC
LONG TERM...GEERTSON
AVIATION...GEOGERIAN