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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS63 KJKL 221908
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
308 PM EDT Mon Apr 22 2024

.KEY MESSAGES...

- Fair weather lasts at least into Tuesday afternoon.

- Frost is expected in many sheltered valley locations again late
  tonight into early Tuesday morning.

- A moisture-starved cold front is forecast to pass Tuesday night
  into Wednesday morning, bringing a round of light rain mainly
  for northern locations.

- Below normal temperatures return from Wednesday into Thursday
  morning before a warm front arrives on Friday and ushers in
  well above normal temperatures for the weekend.

&&

.SHORT TERM...
-- Changed Discussion --
(This evening through Tuesday night)
Issued at 308 PM EDT MON APR 22 2024

The afternoon surface analysis shows high pressure has settled
into the Lower Mississippi River Valley this afternoon, and in the
mid-levels, we see a shortwave ridge nosing into the Ohio Valley.
This surface high will transition to the southeast states
tonight, leading to some return flow at the surface, and an upper-
level low will begin pushing toward the Great Lakes, leading to
some mid- to high-level clouds pushing into the Ohio Valley. This
could limit the temperatures from dropping off tonight,
particularly on the ridges, where we will remain more mixed
through the night. However, in the valleys, there is some ability
to get lower temperature wise if the clouds are thinner and mixing
is less of a factor. Given the uncertainty, we opted to keep
mostly lower to mid-30s for lows in the valleys tonight, but we
could see some upper 20s if the clouds are thinner. Meanwhile, the
ridges will most likely decrease into the upper 30s to lower 40s.
Even in the fifth percentile, the NBM appears to be struggling
with that idea, so it leaned more toward COOP MOS guidance to
obtain a better sense of the possibility tonight. Therefore, we
will keep the Frost Advisory going late tonight into Tuesday
morning.

The previously mentioned cold front will slowly push toward
eastern Kentucky, and mid-level ridging will push east on Tuesday.
This will mainly lead to increased cloud cover throughout the day,
from northwest to southeast. However, ample mixing will be
possible through the day before thicker clouds arrive, and this
could lead to wind gusts of 20 to perhaps 25 mph through the late
morning and afternoon. The mixing being deeper and the dry air
noted just above could lead to a dry day and did undercut
dewpoints some from the sometimes too high NBM. This cold front
will finally push across the area Tuesday night, bringing in a 60
to 80 percent chance of showers. The ensembles and even the
usually overdone NAM couldn`t muster up enough instability to
support any thunderstorms with this round of convection,
particularly since this front becomes more anemic with time. Also,
overall amounts will be on the lighter side, with the probability
of PWAT values above 1 inch only around 40 percent less for most
locations from the HREF CAMs. Also, LPMM rainfall totals from the
HREF are generally less than a tenth of an inch for most locations
as well.

.LONG TERM...(Tuesday night through Sunday)
Issued at 321 AM EDT MON APR 22 2024

To start the period, a cold front extending from a surface low
moving across the Great Lakes will slowly be diving southeast into
the CWA. Showers and thunderstorms are forecast to increase ahead of
the front but due a widespread lack of instability due to the timing
of the front, severe weather looks to be limited. Models have
increased QPF slightly across the Bluegrass counties which through
FROPA are forecast to see about 0.30" with decreasing amounts moving
southward toward the TN/KY state line.

High pressure builds back into the region for late Wednesday and
persists through early Friday morning. Frost may be possible
Thursday morning as northwesterly flow and clear skies will allow
for temperatures to fall across the area. The more sheltered eastern
valleys are the most likely to see the increase frost potential.
Models have backed off a little bit on the previously mentioned
active forecast for the end of the period. The GFS continues to keep
the pattern active while the ECMWF opts to keep the area mainly dry.
They do agree on temperatures climbing into the upper-70s to low 80s
but differ on how several perturbations will move through the area.
However, due to the differences in model agreement, opted to go
with the NBM solution that favors 20-40% chance of showers and
storms through the end of the period.

Overall, a relatively active and cool start to the forecast period
is expected but toward the end of next week, model differences begin
to arise leading to a messy solution. However, PoP chances do seem
possible through the end of the period with temperatures becoming
more seasonal by the start of the weekend.
-- End Changed Discussion --

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 127 PM EDT MON APR 22 2024

Surface high nearby and dry air in place will keep it VFR through
the period outside of some high clouds that move in tonight. The
winds will generally be variable at 5 knots or less through the
period, but we begin the period more northwest shifting to the
southwest to end the period.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from 1 AM to 9 AM EDT Tuesday for KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.

&&

$$

SHORT TERM...DJ
LONG TERM...VORST
AVIATION...DJ