094
FXUS63 KJKL 222150
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
450 PM EST Wed Jan 22 2025

.KEY MESSAGES...

- Temperatures gradually moderate back toward normal by this
  weekend.

- There is a small potential (<50% chance any given period) for
  rain and/or snow at times Thursday night, Sunday-Monday, and on
  Wednesday.

&&

.SHORT TERM...(This evening through Thursday night)
Issued at 450 PM EST WED JAN 22 2025

Surface high pressure/ridging was present over the region today,
and with a lack of significant upper level features, allowed for
plenty of sunshine. The high/ridging will slip away to the east
tonight and warm air advection will return. The low level flow
will also be enhanced by the next approaching cold front,
associated with a shortwave trough moving southeast toward us.
This pattern will be favorable for more significant ridge/valley
low temperature differences, assuming winds are light enough for
valleys to decouple from the flow. Based on today`s highs and
expected dew points, have gone with lows around zero in the
coldest valleys. Western valleys (which have a harder time
remaining decoupled) and valleys without significant snow cover
should not be as cold.

Sunshine for much of the day on Thursday, along with continued
warm air advection, will allow for warmer temps than on Wednesday.
Forecast temps aloft suggest we`ll see 30s for highs, with most
places above freezing.

Clouds should increase in the afternoon as the aforementioned cold
front gets closer and enters the area late in the day. Behind the
front on Thursday night, low level lapse rates will steepen.
Forecast profiles in soundings look favorable for at least
flurries if not snow showers during the night, as the moist
convective layer extends well into the dendritic growth zone for
much of the forecast area for a time.

.LONG TERM...(Friday through Wednesday)
Issued at 402 PM EST WED JAN 22 2025

Overall it`s a quiet extended period. Temperatures will continue to
moderate warmer into the weekend, first as high pressure takes hold
Friday, including clearing skies, followed by SW return flow
Saturday and Sunday as it exits to our east. This pattern will also
be accompanied by the reduction of the strong arctic airmass aloft
and NW flow by the weekend, with rising heights and more zonal flow.

By Sunday afternoon, the pattern begins to shift, however. A very
strong upper level and surface low moving across James Bay will
bring a sharp trough across much of the eastern Conus. This system
will continue to track eastward throughout the day Monday, with a
cold front extending southward towards the Ohio Valley and the
Commonwealth. Meanwhile, another low pressure system will be forming
across the Southern Plains and Gulf Coast Sunday night, making it`s
way across the Deep South through the day Monday. There is an
argument that these two systems may be tied together by the above-
mentioned frontal boundary, which could be the epicenter for lift
and precipitation. However, there has been a lot of uncertainty in
the models leading up to this point, and the uncertainty seems to
persist into this forecast package. The ECMWF keeps these as two
separate systems, one northern stream, one southern stream, with no
moisture from either one making it into the Commonwealth from Sunday
through Monday (despite the potential for a weak frontal passage).
Meanwhile, the GFS shows precipitation developing along the boundary
and impacting a large portion of the CWA late Sunday night into the
first part of Monday. Do want to note that despite the persistence
in the GFS, it actually has trended down a bit in state and CWA
coverage compared to the last couple of days, now more focused
across the far southeast portion of the state. The NBM, therefore,
has also followed suit with it`s pops, having them enter later (late
Sunday) and exit sooner (Monday morning through mid-day), and
possibly not impacting all of the CWA. The NBM is also only showing
chance pops, likely a result of splitting the difference between the
dry and wet model solutions. All this to say, this forecast is still
highly uncertain.

Based on the current forecast and trends, continued SW flow at the
surface during this period (despite the potential boundary passage),
will keep temperatures fairly steady state Sunday and Monday, with
daytime highs generally in the upper 30s and low 40s, and lows in
the 20s. If precip moves in during the afternoon Sunday, it should
start out as rain, then transition to snow overnight as temps drop
back below freezing, then above freezing once more by the time it
tapers off Monday. Overall, as the NBM and WPC has trended down on
qpf and pops, so too has the potential snow amounts, with most
overnight totals under half an inch. Expect these amounts to
continue to fluctuate, as models, hopefully, come into a better
agreement soon.

A strong area of high pressure will overtake the state for the
second half of the day Monday, continuing through the end of the
forecast period, Tuesday and Wednesday. Surface winds will remain
out of the SW during this time according to the NBM - however, the
long-range models both agree on a split flow aloft, with western
Canadian air advecting SE towards the Ohio Valley, and more zonal to
southwest flow across the low half of the U.S. Kentucky seems to be
wedged between the two, which will prevent the best CAA if this
holds true. In fact, the NBM actually has a warming trend of
temperatures, with Wednesday reaching the low 50s in most locations.
Again, these models may shift some as we get closer to onset, and a
small shift southward in the upper level stream could result in
cooler temperatures across the Commonwealth.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 410 PM EST WED JAN 22 2025

VFR conditions and winds around 10 kts or less are forecast
through the period.

&&

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

$$

SHORT TERM...HAL
LONG TERM...JMW
AVIATION...HAL