Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 211418
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
1018 AM EDT Wed Oct 21 2020

.Forecast Update...
Issued at 1017 AM EDT Wed Oct 21 2020

Current radar shows light showers along the stalled boundary across
southern IN/IL. Some of those light showers could still clip our
most northern Indiana counties, so will keep slight chance mention
in for the next couple hours. Otherwise, current forecast remains on
track with mostly sunny skies over much of KY and mostly cloudy
skies becoming more sunny later this afternoon across southern
Indiana as that boundary drifts northward. Have updated near term
grids with no need for updated products at this time.

&&

.Short Term...(Today and tonight)
Issued at 320 AM EDT Wed Oct 21 2020

The stalled boundary that brought beneficial rain to the region
yesterday has remained just to the north of the CWA this morning.
Sfc low pressure currently located over the Windy City is forecast
to propagate across the Great Lakes and into Canada this morning,
which will drag another weak cold front into the Ohio Valley. It
appears this front will stall along the Ohio River and wash out
without making it through the entire CWA. Sfc winds will remain
primarily from the SSW this morning, but will eventually turn SE by
the evening hours. There will be a temperature gradient along the
Ohio River today, with southern Indiana temperatures topping out in
around 70 due to persistent cloud cover. For Kentucky folks,
temperatures will rise to the mid to upper 70s today thanks to
southerly flow and more clearing from clouds. Our southern Kentucky
county along the Tennessee state line could even see 80F today.

A few models do hint at possibly seeing an isolated or scattered
shower or two in central Kentucky this afternoon, but blended
guidance keeps Kentucky dry, which is consistent with previous
forecast. Best chance (while still slim) will be this morning for
southern Indiana counties. Any rainfall should amount to light
accumulation, with a quarter of an inch being on the high end of
the spectrum.

Clouds will eventually lift north of our southern Indiana counties
this evening. Clear skies across the entire CWA are expected for
tonight, with temperatures forecast to bottom out in the upper 50s
to low 60s.

.Long Term...(Thursday through Tuesday)
Issued at 320 AM EDT Wed Oct 21 2020

Thursday through Saturday Night...

Mid-level ridging is forecast to increase across the region on
Thursday as mid-level heights fall out across the western US.  We`ll
be in a deep southwesterly flow at the surface and aloft which
should result in warm and mainly dry conditions across the region.
Highs on Thursday should top out in the upper 70s to the lower 80s
in most areas.  With the area in a strong warm advection scheme,
can`t rule out an isolated shower or storm popping up across the
area.  However, the coverage at this time would generally be less
than 15 percent.  Mild conditions will continue into Thursday night
with lows in the upper 50s over the Bluegrass region and lower 60s
elsewhere.

By Friday, mid-level wave out over the western US will head into the
Plains states.  A cold front draped from Michigan to Texas will
advance eastward during the day.  Within the deep southwest flow
ahead of this system, expect scattered showers with some embedded
thunderstorms to develop by Friday morning and persisting into the
evening hours. The front looks to cross through Kentucky late Friday
and into early Saturday morning. Despite the front moving on
through, plenty of moisture looks to remain behind the front with
additional scattered rain showers lingering throughout the day and
possibly into the evening hours. So for this forecast, have gone
above the NBM guidance here with PoPs.

Highs on Friday should be quite warm with upper 70s across the
region and a few spots could hit 80 prior to precipitation arriving.
Cooler air will start to arrive late Friday night with lows dropping
into the upper 40s to around 50 across southern Indiana with mid 50s
across Kentucky.  Saturday looks to be a rather cool day with
perhaps a gradient of temperature across the region.  Highs in
southern Indiana will likely stay in the 50s with upper 50s to
around 60 across much of Kentucky.  Southern KY may be the warmest
with lower-mid 60s down along the border.  Lows Saturday night will
drop back into the 50s.

Sunday through Wednesday...

We may get a little bit of a break in the weather pattern on Sunday
as we`ll be in between weather systems.  Probably will see a bit of
cloud cover across the area and still can`t rule out any scattered
showers across the region.

Next weather system, in the form of another cold front will push
into the region Sunday night bringing yet another round of showers
and possibly a few thunderstorms.  This front looks to stall out
though as mid-level ridging across southern Texas and the Gulf holds
sway.  It is possible that a large baroclinic zone may set up from
Texas northeastward through the Ohio Valley for much of the first
half of the week.  With numerous waves translating through within
the mean flow, periods of rain showers looks like a good bet here.
So have gone ahead and gone above the NBM guidance with PoPs again.

Temperatures are going to be very tough to pin down depending on
where the baroclinic boundary sets up.  More than likely we`ll have
a gradient of temperature across the region.  Highs across southern
IN may only top out in the upper 50s to low 60s, while southern
Kentucky may see readings climb into the mid-upper 60s each day.

&&

.Aviation...(12Z TAF Issuance)
Issued at 630 AM EDT Wed Oct 21 2020

VFR conditions are forecast for the region today, with the exception
being at HNB. Another frontal boundary will approach the Ohio River
Valley this morning, which could bring MVFR ceilings for a few hours
in southern IN. HNB also has the best chances of seeing any rain
this morning, but with some uncertainty, will carry VCSH for now.
While BWG should have mostly clear skies, SDF and LEX may see more
clouds due to the nearby boundary. Eventually skies clear out later
this afternoon and evening. Winds will start out the period from the
south, then from the SW by 16z, and eventually SE by 00z.


&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&

$$

Update...CG
Short Term...CJP
Long Term...MJ
Aviation...CJP



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