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000
FXUS63 KJKL 121847
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
247 PM EDT Fri Apr 12 2024

.KEY MESSAGES...

- A deep low pressure system moving off to the northeast will
  contribute to unsettled weather through the remainder of the
  day, with a modest cool-down expected behind the exiting system.

- Thunderstorms are possible through this evening and again
  Sunday into Sunday night.

- Well above average high temperatures will affect the area for
  the next week as temperatures are expected to peak in the lower
  80s, each day.

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 247 PM EDT FRI APR 12 2024

Current surface analysis has yesterday`s surface low ejecting
northwest into New England. Lingering showers and isolated
thunderstorms are expected over the next couple of hours as the
trough, responsible for yesterday`s surface low, pivots through the
area. High pressure is firmly entrenched across the central CONUS
and will slowly nudge eastward through the weekend.

The forecast area will remain at the base of an upper-level trough
to start the period. As the trough pivots through the region today,
lingering showers and isolated thunderstorms are possible through
the day today. With lift from the trough and areas of SBCAPE,
upwards of 500 J/kg, isolated to scattered thunderstorms will be
possible throughout the day into the early evening. With these
thunderstorms, gusty winds and pea sized hail/graupel, due to
freezing levels around 5,000 ft, are possible. Also, gusty
environmental winds are expected through the day as the trough moves
through the region. Those winds will begin to diminish toward the
overnight.

Overnight tonight, northwesterly flow with CAA and decreasing clouds
will allow for temperatures to fall into the upper-30s to low-40s
across the JKL CWA. Temperatures will begin to rebound Saturday but
will remain relatively cooler as mean upper-level northwesterly flow
remains in place. However, surface high pressure will nudge into the
region and low-level anticyclonic flow will help to advect in warmer
surface temperatures for Saturday as highs are forecast to climb
into the low-70s across the Cumberland Plateau and upper-60s toward
the Big Sandy Basin. These warmer temperatures will continue to be
place going into Saturday night and through the end of the period.
Overnight lows for Saturday night are expected to dip into the low-
40s in the eastern valleys with mid to upper-40s across the
Bluegrass and less sheltered valleys and low to mid 50s on the
ridgetops. These warmer temperatures are a precursor to the above
average temperatures that`s expected to be in place starting Sunday.

.LONG TERM...(Saturday night through Thursday)
Issued at 421 AM EDT FRI APR 12 2024

The 12/00z model suite analysis beginning Saturday evening shows a
negatively-tilted trough extending from an ~530 dam low over the
southeast Hudson Bay to off the New England coast. Upstream, a
broad zone of upper-level ridging is found across the Plains and
Rockies, though there is an subtle embedded shortwave trough over
the Central/Northern Plains. Futher west, an ~541 dam low is
coming ashore near or just south of the San Francisco Bay.
Meanwhile at the surface, we find a weakening ~987 mb surface low
over Quebec, just east of the Hudson Bay, and an ~1025 mb surface
high pressure centered along/off the Central Gulf Coast. Surface ridging
extends northward across the Tennessee/Ohio valleys and beyond
into the upper Great Lakes. Over the Plains, a weak surface low is
found near/over South Dakota while its cold front trails
southward to over the Edwards Plateau of Texas.

The surface high pressure ridging will shift eastward Saturday
night/Sunday morning as the first upper level trough moves deeper
into eastern Canada. The weak surface low over the Northern
Plains then scoots through the Great Lakes, under its attendant
shortwave trough aloft, on Sunday and lays out a cold frontal
boundary which will sink to near the Ohio river. This boundary
could serve as a focusing mechanism for some isolated deep
convection Sunday night and Monday, with greater probabilities
closer to the Ohio River. Meanwhile, the upper low along the
California coast will pass over the Great Basin on Sunday night
and move over the Central/Southern Rockies on Monday, spawning
cyclogenesis east of the Rocky Mountain Front. As this new low
pressure takes shape, increasing southerly flow in the system`s
warm sector will begin to push the boundary languishing along the
Ohio River back north as a warm front by Monday night.

As the parent upper level low ejects northeastward toward the
Great Lakes mid-week, a new northern stream low/trough will dive
southeastward from the Canadian Rockies, likely phasing by
Thursday or Friday, though substantial differences remain in the
specific modeled details. In general it does appear that surface
low pressure will track northeastward from the Coloradoan Plains
into Ontario while weakening. A cold front trailing behind the
surface low presses eastward before weakening, slowing and
potentially hanging up the Lower Ohio Valley on Wednesday. That
front then makes another much more decisive push to the southeast
on Thursday and Friday as the northern stream trough drops in from
the northwest and absorbs most of of the upper low energy that
tracked into the Great Lakes earlier in the week. Renewed deep
convection is possible when this cold front initially approaches
on Wednesday, but the more widespread and heavier activity
probably holds off until Thursday when the cold front finally
plows through eastern Kentucky. A return to below normal
temperatures is probable just beyond the end of the extended and
there might even be some opportunity for late spring frost.

In the meantime, a warming trend will be well underway for the
second half of the upcoming weekend as high pressure ridging
traverses the Commonwealth. Saturday night`s lows are expected to
range from the lower 40s in the cooler, sheltered hollows ranging
up to the mid 50s in the thermal belts. The dry and pleasant
weather continues Sunday with highs in the upper 70s to near 80
under mostly sunny skies. Spotty showers and thunderstorms,
highest probability north of the Mountain Parkway, are possible
Sunday night and Monday as the first cold front settles to near
the Ohio River. Dry weather follows for Tuesday once that front
retreats. Rain and thunder chances then return on Wednesday and
Thursday as the next cold front approaches from the northwest.
Look for daily high temperatures ranging mainly in the upper 70s
to mid 80s from Monday onward while lows run between 55 and 65.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
ISSUED AT 125 PM EDT FRI APR 12 2024

TAF sites are fluctuation between VFR/MVFR and will continue to do
so over the next few hours as showers and isolated thunderstorms
continue to work across the area. Strong west to northwesterly
sustained winds around 15 knots and gusts to around 25 knots are
expected through the afternoon and early evening before winds
diminish. However, LLWS is expected overnight tonight after
00Z/Saturday. LLWS will persist through 12Z before diminishing.
Winds will pick up again out of the northwest with sustained winds
around 12 knots and gusts up to around 20 knots for the end of the
TAF period.

&&

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

$$

SHORT TERM...VORST
LONG TERM...GEERTSON
AVIATION...VORST