-- Discussion containing changed information from previous version are highlighted. --
183
FXUS63 KLMK 271717
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
117 PM EDT Thu Jun 27 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Patchy dense fog this morning will cause rapid changes to
    visibility. Conditions will improve after sunrise.

*   Shower and storm chances return Saturday through early Sunday.
    Locally heavy rain and gusty winds will be the main threats.
    Above normal temperatures return by early/mid next week.

&&

.UPDATE...
Issued at 1010 AM EDT Thu Jun 27 2024

Surface observations and webcams confirm dissipation of early
morning patchy dense fog with a scattered low-level cloud deck still
lingering over south-central Kentucky. Expect mostly clear skies and
a less humid environment as northeast winds keep advecting a
modified continental airmass to the Lower Ohio Valley.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 303 AM EDT Thu Jun 27 2024

The cold front that brought showers and storms to the region
yesterday is now to our south, though lingering low-level saturation
has supported low stratus and patchy dense fog development in the
early morning hours. Early morning commuters may encounter some
patches of fog that reduce visibility rapidly, though we should see
conditions improve around or shortly after sunrise.

For today, sfc high pressure will be building across the Great Lakes
region, which will promote a slightly cooler NNE flow into the Ohio
River vicinity and mostly sunny skycover. Forecast temps this
afternoon will reach the mid- to upper-80s, which will be normal for
late June. However, our dewpoints will be rather pleasant, with most
readings in the lower 60s this afternoon.

Mostly clear skies will continue into tonight as high pressure
remains just to our north. The combination of mostly clear skycover
and calm winds will promote a good radiational cooling night, so
overnight lows will dip into the lower 60s for most. South-central
Kentucky counties may be a touch warmer tonight with temps in the
upper-60s.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 303 AM EDT Thu Jun 27 2024

Friday - Friday Night...

Mostly dry conditions are expected to continue through the end of
the work week, however surface high pressure will lose influence
over our area, and a weak warm front will lift slide through later
Friday into Friday night. Will keep silent pops going, but not
totally out of the question that a few spots will see some very
light qpf. Outside of that, looking for a pretty unremarkable end to
the work week with highs in the upper 80s and low 90s. Friday night
lows will be quite mild in the low to mid 70s.

Saturday - Sunday Morning...

A shortwave trough will track from the upper Midwest through the
Great Lakes region on Saturday, and will quickly push into New
England by Sunday. Meanwhile, a cold front trailing from the
associated surface low will approach on Saturday and then sink
southward through our area early Sunday. Ahead of this cold front,
we look to get pretty warm and moist on Saturday. Max heat indices
are expected to reach into the upper 90s and low 100s. Not only will
the moist airmass be noted by high surface dew points, but we`ll
also see some pretty deep moisture throughout the column as PWATS
jump above 2" through the column. A look at forecast soundings
continues to show a tall/skinny CAPE profile with very high freezing
levels (possibly above 16K feet?). Given fairly weak flow through
the column (0-8 km shear around 25 knots), and expected efficient
rainfall processes, think that any robust shower or storm would be
capable of torrential rain. A localized flash flood threat could be
a possibility if current data holds for the later Saturday evening
into Saturday night time frame. In addition to locally heavy rain,
there could be a marginal strong/severe threat that develops with
any stronger storm given water-loaded wet microburst potential. At
this time, feel it would be a secondary threat to locally heavy
rainfall, but wouldn`t be surprised to see a Marginal Risk from SPC
at some point. ERO from WPC will likely also continue to advertise a
threat.

Sunday Afternoon - Tuesday Night...

Cold front sinks south of the area as we move through Sunday, and
any shower and storm chances will taper from N to S as it does so.
So, expecting a mostly dry day for the northern half of the CWA,
with improving conditions, but still some chance pops across the
south. As we head into the first part of the new work week, dry NW
flow will dominate the upper pattern, and ~1025mb Canadian high
pressure will control at the surface. We will see an initial "cool
down" behind the front on Sunday and Monday, with highs back in the
80s. By Tuesday, shortwave ridging will traverse our region with dry
conditions still expected. Given the increase in heights/thicknesses
by this time, expect temperatures to pop back into the 90s by
Tuesday.

Wednesday...

The shortwave ridge axis is east of our area on Wednesday, and we`ll
find ourselves on the northern periphery of an expansive ~595
decameter high centered over the Gulf Coast states. Meanwhile, a
surface cold front extending from an eastern Canada storm system
will approach our area. Pattern suggests a warm, moist, and strongly
unstable airmass will be in place across our area ahead of this
front. As a result, expect shower and thunderstorm chances to
increase once again. Given that there could be a lot of instability
and we will be on the southern fringes of the stronger westerlies
aloft, a few strong to severe storms could be possible by this time.
Plenty of time to hammer out those details, but the setup would seem
to support the possibility.

&&

.AVIATION /18Z TAFS THROUGH 00Z SATURDAY/...
-- Changed Discussion --
Issued at 116 PM EDT Thu Jun 27 2024

Discussion...VFR conditions will continue through this TAF period as
surface high pressure and dry air remain in control. On the other
hand, winds will stay light with a gradual shift from the northeast
this afternoon to the south-southeast tomorrow afternoon. Finally,
today`s mixing and increasing upper cloud cover tonight will limit
radiational cooling and potentially fog formation at the terminals.
-- End Changed Discussion --

&&

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

&&

$$

UPDATE...ALL
SHORT TERM...CJP
LONG TERM...BJS
AVIATION...ALL