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352
FXUS63 KJKL 191510 AAB
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1110 AM EDT Mon Apr 19 2021

.UPDATE...
Issued at 1110 AM EDT MON APR 19 2021

Forecast is in good shape this morning. Updated grids for latest
hourly obs. Also freshened up zone wording and removed morning
fog. Removed PoPs as well since light rain has ended across the
area. Still looking at some CU development through at least early
afternoon before drier air filters into the area. No other changes
at this time.

UPDATE Issued at 834 AM EDT MON APR 19 2021

A few light showers continue to linger over the area, however
these should dissipate within the next couple of hours. Tweaked
the sky grids to fine tune the clearing based on recent guidance,
but otherwise the forecast appears to be on track and the only
other edits were to blend in recent obs. Updates were sent and
fresh zones were generated.

&&

.SHORT TERM...(This afternoon through Tuesday evening)
Issued at 615 AM EDT MON APR 19 2021

As of 8z, spotty rain showers are scattered across the southern half
of the CWA, supported aloft by a weak passing wave. This activity is
expected to diminish as we head through the early morning and the
shortwave continues to dampen as it moves east. Though fog
development might be somewhat inhibited by the continuing cloud
cover, Some patchy fog is still possible early this morning,
especially down in our southwest where there has been more rain.
Temperatures display quite a range this morning at 8z. Areas in the
northeast, where cloud cover has been a little less opaque, are down
in the upper 30s to around 40. Meanwhile, down in the southwest
where more of the rain and thicker cloud cover resides, temperatures
are warmer in the mid to upper 40s.

Models are in fair agreement, with some slight differences emerging
near the end of the period. They depict the exit and continued
dampening of the shortwave that is currently passing over the area.
This feature should be off to our east by roughly mid-afternoon. On
a larger scale, a broad trough can be seen across much of the CONUS.
An initial wave moves across the Great Lakes region this afternoon
into early Tuesday morning, supporting a surface low over roughly
the same region, if not slightly north. By Tuesday morning, a front
extending down from this low lies over the northern Ohio Valley down
into the Southern Plains, where a reinforcing upper level wave is
aiding the development of another surface low along the front. This
low then moves northeast into the Tennessee and Ohio Valleys Tuesday
afternoon, bringing the cold front to Kentucky`s door step. However,
the GFS is a little faster and has the front further into Kentucky
by the end of the short term. However, it does appear to be more of
an outlier in this regard, so didn`t put as much weight into it`s
timing of things.

In terms of sensible weather, showers should exit this morning and
skies should clear going through the day, becoming partly cloudy by
the afternoon. Temperatures are expected to reach the mid 60s for
highs. Overall, a pretty pleasant day. The continued cloud clearing
will help facilitate a decent ridge-valley split tonight.
Temperatures are expected to range from the upper 30s in the
valleys, up to the mid 40s along the ridges. Given the better
radiative conditions, some patchy fog is also possible down in the
river valleys. With the warm air advection out ahead of the front,
Tuesday will be warmer, with highs generally from the upper 60s to
low 70s. Cloud cover will increase slightly through the afternoon
with the front`s approach, generally increasing from northwest to
southeast. Most guidance was in agreement that rain would stay to
the northwest through the day Tuesday, so held off PoPs accordingly.
The GFS was a little faster, with PoPs nearing the edge of the CWA
by the end of the period, but again, leaned a little slower with the
majority of guidance. Things could also get a little bit gustier
than we have seen recently ahead of the front Tuesday afternoon,
with gusts expected to peak between 15 and 20 kts.

.LONG TERM...(Tuesday night through Sunday)
Issued at 616 AM EDT MON APR 19 2021

An upper level trough will make its way from the Northern Plains,
entering the Ohio Valley Tuesday night into Wednesday, and bringing
an increased potential for wet weather with it. At the surface, a
low will track right over Eastern KY with an associated cold front
passing through Tuesday night. Light rain showers are expected with
the passing of the front late Tuesday night into early Wednesday.
Broad upper level ridging will move in behind the trough ahead of
another disturbance which is expected to impact our area over the
weekend. Confidence in the large scale pattern has increased for the
weekend system, but onset of precipitation is still up in the air at
this time.

The GFS continues to be the most progressive Tuesday night, bringing
precipitation into the eastern portion of the CWA by 06z Wednesday,
while the other models hold off until closer to 12z. The NBM was
more aggressive with high PoPs across the area, and have adjusted
them down slightly due to the disagreement in model timing. The
quick round of showers for Thursday has persisted in the GFS, with
the ECMWF and Canadian also picking up more so on the potential for
showers, but not nearly as aggressively as the GFS has. If showers
do develop Thursday, they will likely be in the northern and eastern
portions of the CWA. Overall, the models show another disturbance
moving into our area Saturday into Sunday. The GFS has a more
amplified pattern, while the ECMWF and Canadian have a broader wave
solution. The NBM continued to be aggressive with PoPs Saturday into
Sunday, and have knocked values down to a more reasonable value for
this late in the period.

CAA behind the cold front will keep high temperatures well below
normal on Wednesday, with highs only reaching the mid to upper 40s.
A modest temperature rebound is expected Thursday with highs reaching
the low 50s and more gradual rebounds through the weekend. Have
adjusted low temps Thursday night, including more of a ridge/valley
split, given the southwesterly flow and mostly clear skies through
at least the first half of the night. Areas of frost are expected
Thursday and Friday morning, as low temps drop into the upper 20s to
low 30s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 834 AM EDT MON APR 19 2021

VFR conditions prevail across TAF sites this morning. A few light
showers are still lingering near KJKL and areas south and east but
should be dissipating within the next couple of hours. Ceilings
range anywhere from 5 to 10K ft AGL and will gradually raise
during the day as skies clear. Winds will remain generally out of
the west, peaking this afternoon to between 5 and 10 kts before
relaxing again after sunset. Some fog is possible down in the
river valleys late tonight into early Tuesday morning. However, at
this time, TAF sites look to remain unaffected.

&&

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

&&

$$

UPDATE...RAY
SHORT TERM...HAS
LONG TERM...BATZ/GEOGERIAN
AVIATION...HAS