220
FXUS63 KJKL 301941
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
341 PM EDT Thu May 30 2024

.KEY MESSAGES...

- Below normal temperatures and dry weather can be expected
  through the rest of the work week.

- It will become warmer and more humid with chances of showers and
  thunderstorms returning from late Saturday into the middle of
  next week.

&&

.SHORT TERM...(This evening through Friday night)
Issued at 341 PM EDT THU MAY 30 2024

Highly amplified ridging moves across the forecast area through
Saturday afternoon bringing dry and comfortable weather.

Backdoor cool front has moved into the region from the north on the
downstream side of the high pressure centered to the north this
morning and early afternoon. A reinforcing cool front drops south
across the forecast area and will bring an even drier air mass to
region after midnight tonight and lasting through much of Friday
before modifying late Friday night as return flow begins to usher
increasing humidity back into the region.

With the dry air mass moving over the area tonight, excellent
radiational cooling is expected with widespread lows in the 40s,
with a few lower 40s reading in the typically coldest most sheltered
valleys. Warmer overnight temperatures in the upper 40s to near 60
degrees are expected Friday night as flow aloft begins a warming and
moistening trend. Highs Friday will reach the mid to upper 70s.

.LONG TERM...(Friday night through Wednesday)
Issued at 435 AM EDT THU MAY 30 2024

The period is expected to begin with a shortwave ridge from the Gulf
of Mexico into the Southeast/Southern Appalachians across the OH
Valley to the Great Lakes. Further west, a shortwave trough is
expected to be working across portions of the Central Conus/Ozarks
vicinity and approaching the Lower to Mid MS Valley preceding a broad
500 mb trough that extended from Canada south to the High Plains
vicinity. Another shortwave ridge is expected to be in place across
portions of the western Conus  with a shortwave trough nearing the
Pacific Northwest coast with the the upper level flow somewhat
zonal/westerly to start the period from the western to central
Conus. At the surface, the period will begin with a surface ridge
extending from the eastern Great Lakes to southeastern Conus, a
surface wave of low pressure moving from OK toward the Ozark region
with a trailing frontal zone into the Southern Plains. Another
frontal zone is expected to extend from the Hudson Bay region to the
upper MS Valley to portions of the Central Plains as the period
begins.

The upper level ridge axis and the corresponding sfc ridge are
expected to shift east as the period begins Friday night and
Saturday with the shortwave trough moving into the mid MS Valley and
then the OH Valley region including the Commonwealth. This shortwave
should continue east and northeast crossing the area on Saturday
night as the associated weakening sfc low moves to OH/Lake Ontario
vicinity and the associated cold front becomes rather diffuse north
of the OH River. Over the weekend, the upper level pattern will
trend to more or less zonal across the Conus. After the ridge axis
shift east of the area Friday night and Saturday, return flow will
lead to a warmer airmass to advecting into the Southern
Appalachians, OH Valley, and the Commonwealth with moisture
transported in as well as the shortwave nears. The LREF PW mean
rises from the 0.5 inch or less range to begin to start the period
to the 1 to 1.3 inch range 24 hours later on Saturday evening.

Generally zone flow is expected from the Plains to the eastern Conus
through Monday night or Tuesday, with periodic passing shortwaves.
However, the axis of a shortwave/upper low that will have moved into
the Northwest Conus and western Canada over the weekend should move
to Alberta and Saskatchewan to the Northern Plains through Tuesday.
This upper low should near the Great Lakes to end the period per the
guidance consensus with the associated trough axis nearing or
perhaps moving east of the MS Valley by Wednesday evening. The
region will remain in the warm sector south of a frontal zone that
waffles north and south across the Great Lakes and portions of
the St Lawrence Valley with passing waves from Sunday into
Wednesday. However, as sfc low associated with the upper
low/shortwave trough that nears the Great Lakes and MS Valley tracks
to the Great Lakes to end the period, the cold front should near and
perhaps enter the Commonwealth to end the period. A moist airmass
will remain in place, with PW generally in the 1.1 to 1.5 inch
range per LREF mean with values peaking on Wednesday. The
periodic shortwaves will be able to interact with the moist
airmass for off an on rounds of showers and thunderstorms with
possible increases in coverage each afternoon and evening with the
diurnal cycle. Some heavy rain could occur if some areas receive
multiple rounds of showers and thunderstorms as the week progress
and this potential peaking at midweek will continue to be
monitored.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 111 PM EDT THU MAY 30 2024

VFR conditions and light winds are expected through the TAF
period under surface high pressure. With nearly ideal radiational
cooling conditions, expect there will be some patchy fog develop
in the typical valley locations from midnight to just after dawn.
With relatively low coverage, have left out of the TAFs for
now, though can`t rule out very brief visibility restrictions
near dawn Friday, especially at SYM, SME, and SJS.

&&

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

$$

SHORT TERM...CMC
LONG TERM...JP
AVIATION...CMC