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000
FXUS63 KJKL 120845
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
445 AM EDT Fri Apr 12 2024

.KEY MESSAGES...

- A deep low pressure system moving off to the northeast will
  contribute to unsettled weather for another day, in the midst of
  a modest cool-down behind the system`s cold front for today and
  tonight.

- Thunderstorms are possible today into the 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...(Today through Saturday)
Issued at 445 AM EDT FRI APR 12 2024

08Z sfc analysis shows deep low pressure now off to the northeast
of Kentucky. A trough-line/secondary cold front, associated with
this low, is located to the northwest of the area amid persistent
cyclonic low level flow. Ahead of this feature, an area of light
showers is moving east through eastern Kentucky. In addition, a
tight pressure gradient through the region continues to support
breezy and brisk west to northwest winds of 10 to 20 mph with
gusts still approaching 30 mph, at times, early this morning. CAA
on these winds have helped to send temperatures down into the
upper 40s and lower 50s under mostly cloudy skies. Meanwhile,
dewpoints are edging down into the low and mid 40s, most places.

The models, and their individual ensemble suites, continue to be
in very good agreement, aloft through the short term portion of
the forecast. They all depict a deep trough over the Ohio Valley
rotating into northern New England by midday Saturday. During this
process, a fairly intense mid level impulse will track just south
of Kentucky this morning on its way to the Carolina coast by
evening - forestalling a sharper rebound in 5h heights over
eastern Kentucky through 00Z Saturday. The tail of this energy
does slip east through the JKL CWA around 06Z Saturday in
northwest mid level flow. Following this, heights will rebound
more substantially through the day Saturday as the flow relaxes
into the weekend, but remains slightly northwest. On account of
the small model spread the NBM was used as the starting point for
the grids along with a healthy shot of the latest CAMs` ideas for
PoPs through this evening.

Sensible weather will feature a cooler day with brisk and breezy
winds from the west to northwest at 10 to 20 mph and gusts as high
as 40 mph possible into the evening. In addition, showers and
thunderstorms will redevelop through the area today with very
small hail possible due to steep mid level lapse rate - limited by
a lack of decent instability for most of the day. Per forecast
soundings, the best chance may be late afternoon and into the
evening. The convection then fades out by mid evening - passing to
the east and drying/clearing will start to commence. Breezy
conditions will likely keep any fog to a minimum overnight. This
will set up a seasonably chilly night with a small ridge to valley
temperature difference possible - though highly dependent on how
quickly the clouds can clear, and where, after midnight. Saturday
will be a warmer day thanks to returning sunshine and lighter
winds.

The main adjustments to the NBM starting point were focused on the
PoPs with adjustments provided by the latest consensus CAMs
thoughts on PoPs into this evening. Temperatures were not changed
much from the NBM, aside from small terrain based adjustments
made tonight.

.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 06Z TAFS through 06Z Friday night)
ISSUED AT 220 AM EDT FRI APR 12 2024

Decreases to mainly MVFR and IFR ceilings are expected into this
morning as a cold front departs the area and the convection
tapers off from west to east behind it. A secondary front and
upper level disturbance then brings renewed convection after 12Z
that will likely persist through the majority of the TAF period.
In between these times of higher convective potential some VFR
conditions will hold along with mostly shower free weather. Look
for the gusty west to west northwest winds to continue for the
majority of the TAF period peaking in the afternoon at 10 to 20
kts with gusts approaching 30 kts.

&&

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

$$

SHORT TERM...GREIF
LONG TERM...GEERTSON
AVIATION...CMC/GREIF