-- Discussion containing changed information from previous version are highlighted. --
396
FXUS63 KJKL 212143
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
543 PM EDT Sat Sep 21 2024

.KEY MESSAGES...

- A potential for showers and thunderstorms returns today and then
  persists for much of next week.

- High temperatures will approach 90 degrees through the weekend,
  then trend lower as time goes by during the week.

&&

.SHORT TERM...
-- Changed Discussion --
(This evening through Sunday night)
Issued at 543 PM EDT SAT SEP 21 2024

Aloft, ridging in place across the Ohio Valley and Midwest is
gradually being worn down and suppressed by a combination of short
wave energy lifting out of the Four Corners and tracking across
the Northern Tier and Great Lakes during the short term. This
results in some significant height falls across our area as the
eventual lowering of H850 temps from 18-20C to around 16C by the
end of the period. At the surface, a stalled out frontal boundary
just north of our forecast area will lift northeast back towards
the upper Ohio Valley tomorrow...all as another, stronger surface
cold front approaches from the northwest reaches the Ohio River by
late Sunday night or early Monday morning.

Sensible weather features the beginning of a trend towards a more
unstable or unsettled pattern. Showers and thunderstorms have
dissipated across our area late this afternoon. But isolated
convection continues to fire upstream to our northwest, one being
quite healthy as of this writing. Met watch will continue in case
they creep into our area over the next hour. However, the overall
trend is for a continued weakening and activity over the next
couple of hours.

Overnight is expected to be mainly dry with at least some partial
clearing, especially over our northern zones. This may set up
favorable conditions for the development of some fog, especially
for areas that saw some afternoon rainfall. Will be watching for
this potential through the evening.

Expecting one more day of above normal temps tomorrow. With clear
to partly cloudy skies, temperatures should have no problem
climbing back up into the mid to upper 80s. H850 temps are just
slightly lower than the previous few days. That being the case,
and especially with some rainfall over portions of the areas,
thinking is that we may be spared the 90s. However, still would
not be surprised if one or two location eked out a 90 degree
reading somewhere. Otherwise, look for an increase in cloud cover
and PoPs late in the day tomorrow. MLCAPEs increase to between
1000-1500 J/kg by Sunday afternoon. Mid level lapse rates steepen
just a bit as well, particularly over our far southwest. Thus
could not rule out some thunderstorm activity tomorrow afternoon
through tomorrow night, though the best potential will be found
over our southwest tomorrow afternoon where ensemble probabilistic
data shows the highest likelihood of sufficient CAPE.


.LONG TERM...(Monday through Saturday)
Issued at 351 PM EDT SAT SEP 21 2024

The latest model runs are showing pretty much the same pattern in
the extended as the previous few days. A trough of low pressure over
the central Plains will be our primary weather maker to begin the
upcoming work week. Another trough of low pressure is forecast to
intensify over south central Canada and move north, with a cold
front extending southward from it to the central Plains trough. The
Plains trough and cold front will move through our region Monday and
Tuesday and will bring showers and a few storms to eastern Kentucky
to begin the week. Another more developed trough is expected to form
over the northern Plains Tuesday night into Wednesday. This system
is forecast to move slowly eastward into the central Mississippi
Valley and western Tennessee Valley by mid-week. This system will
likely bring another round of showers and storms to our area, along
with cooler temperatures, Wednesday and Thursday. The wild card in
this scenario will be whether or not a tropical system forms over
the Gulf of Mexico. The latest runs of the GFS and GFS Ensembles
have a tc forming over the southwestern Gulf and moving northward
toward the central Gulf Coast Thursday and Thursday night. If this
tropical system does form, its evolution and track will have a
degree of influence on the second Plains trough. For now, we will go
with the general pattern the models are showing, with repeated
rounds of showers and storms moving through eastern Kentucky Monday
through Wednesday, with the rain quickly tapering off to isolated
showers and storms by the end of the week, but having the rain
persist through Friday night.

After a day of slightly warmer than normal temperatures across the
area on Monday, the passing troughs, and their associated widespread
cloud cover and rain, along with winds shifting to the west or
north, will lead to below normal temperatures in the 70s for the
rest of the week past Monday. The overall pattern looks to be
chances of rain each day in the extended, with generally cooler than
normal temperatures, especially during the daytime periods. The only
weather hazard of note will be any cloud to ground lightning
associated with some thunderstorms.
-- End Changed Discussion --

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 210 PM EDT SAT SEP 21 2024

Showers and thunderstorms firing across central and eastern
portions of eastern Kentucky this afternoon. Difficult to capture
where strongest convection is at over the next few hours as storms
do not appear to have a long life cycle. Once this area of
precipitation exits the area, flight conditions should improve
through the remainder of the late afternoon and early evening.
Suspect some terminals that realized rain over the next few hours
may have to deal with some fog at times through the evening. Will
be watching for that potential. Otherwise, in general winds will
be light, around 5 kts or less and variable through the period,
though they could be gusty to around 15-20 kts in the vicinity of
the strongest thunderstorms over the next three hours or so.

&&

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

$$

SHORT TERM...RAY
LONG TERM...AR
AVIATION...RAY