369
FXUS63 KLMK 131734
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
134 PM EDT Thu Jun 13 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Above normal temperatures expected Sunday into next week. Rain
    chances return early next week as southerly flow draws moisture
    northward from the Gulf.

&&

.UPDATE...
Issued at 1141 AM EDT Thu Jun 13 2024

Another comfortably cool start this morning in the 50s and lower 60s
is transitioning into another warm afternoon as temperatures have
already risen into the upper 70s and lower 80s at this hour. Latest
visible satellite imagery shows little in the way of cloud cover
across central Kentucky and southern Indiana this morning, with
sunny skies expected to continue into the afternoon hours. Dew point
temperatures in the upper 50s and lower 60s will help limit heat
indices this afternoon, with slightly higher dewpoints being
observed across southern KY. The current forecast is generally on
track; high temperatures were revised upward by 1-2 degrees to
account for latest trends, with maximum readings this afternoon
expected to reach the upper 80s to around 90.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 317 AM EDT Thu Jun 13 2024

Currently, the skies over southern Indiana and central Kentucky are
clear, and with high pressure over the region, this trend will
continue through the rest of the day. This morning, after the few
dry days, most areas should be dry enough to remain fog free this
morning, but the light winds and clear skies could cause enough
radiative cooling for a few valleys to see some patchy light fog,
mainly across southern Kentucky.

Later today, with the surface high pressure centered to our
southeast, a mostly south to southwest 5-10 mph wind will remain
over the Lower Ohio Valley. This will help the abundant amount of
sunshine lift high temperatures into the mid to upper 80s for most
across the region.

Tonight will begin with clear skies, easing winds, and cooling
temperatures, but ahead of an approaching cold front, expect a layer
of mid-level clouds to work in from the northwest over southern
Indiana after midnight. This will bring some light dissipating
showers that could make it just south of the river before coming to
an end. With a decent dry layer below 700mb, any precipitation will
be light with limited accumulations, a few hundredths to an isolated
tenth of an inch. Expecting lows to only drop into the mid to upper
60s.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 317 AM EDT Thu Jun 13 2024

Friday through Sunday Night...

Surface cold front is still progged to push through the region
during the day on Friday.  Weak convergence along that front may
spark isolated to scattered convection across the region Friday
afternoon.  Not everyone will see rainfall in this scenario however.
Model soundings do show some MLCAPE and weak shear across the region
and DCAPE values from the CAMs are still pretty decent, so any storm
that goes up could produce gusty winds.  Expect convection to fade
by sunset with cool advection coming into the region.  Highs Friday
will generally be in the upper 80s with overnight lows cooling back
into the low-mid 60s.  A few spots across southern IN and in the
valleys could drop into the upper 50s Saturday morning.

For Saturday and Sunday, dry conditions are expected as high
pressure at the surface and aloft build into the region.  Cooler
temperatures are expected for Saturday with lower humidity values.
Will need to watch temps Saturday as there are large differences in
the GFS and Euro guidance.  The GFS is attempting to hold some cloud
cover in across the region behind the front.  If this were to occur,
highs on Saturday may be as low as the upper 70s to the lower 80s.
On the other hand, the Euro is quite a bit warmer suggesting upper
80s and lower 90s.  Will go slightly below NBM here and go lower 80s
in the Bluegrass/eastern sections with 85-90 in areas west of I-65.
Lows Saturday night will be in the 60-65 degree range.  Sunny and
warm temperatures are expected for Sunday.  Just how warm we get is
still to be determined.  While thickness progs would suggest at
least 10-13 degrees of additional warmth compared to Saturday, we
will still will not have much in the way of humidity just yet and
we`re still very green from all the May rains, but things are
starting to dry out across the region.  For now will go with temps
in the upper 80s to the lower 90s.  Lows Sunday night will be in the
upper 60s to the lower 70s.

Monday through Wednesday...

Heading into the new work week, the general consensus of the model
guidance shows a fairly strong ridge over the eastern US with a
large trough axis over the western US.  Some differences continue to
show up in the placement of the ridge axis on Monday with the Euro
continuing to be a little further west than the GFS/GEM.  Still
looking at two different scenarios that could occur next week.  In
the first scenario, the GFS/GEM solutions argue for a ridge axis
centered further east over the Mid-Atlantic with a plume of Gulf
moisture coming up the MS Valley into the Ohio Valley.  Daytime
heating with that moisture would lead to diurnally driven convection
each afternoon with coverage in the 20-30% range.  In the second
scenario, the Euro has a much stronger ridge across the
eastern/southeastern US and attempts to drive heights up near death
ridge levels.  With the lack of convection in the Euro, the model
simply bakes the Ohio and Tennessee Valleys with excessive heat.

Trying to determine which scenario will win out remains tough.
Taking into account the ensemble data, the ensembles suggest that
the GEM/GFS solution looks a bit more likely here with just isolated-
scattered convection firing in the afternoon.  The Euro had a bad
habit last summer of overdoing heat ridges with it`s excessive heat
not verifying all that well.  So for now, will go on the cooler end
of the guidance here and keep temps in the lower 90s in the Monday-
Wednesday period.  The typical heat islands will likely end up being
warmer with some mid 90s being possible.

Storms that do fire Monday-Wednesday afternoon look to be of the
pulse variety which could produce locally heavy rainfall, gusty
winds and plenty of cloud to ground lightning.

&&

.AVIATION /18Z TAFS THROUGH 00Z SATURDAY/...
Issued at 134 PM EDT Thu Jun 13 2024

This afternoon and evening, light SW winds are expected to continue
across the region with clear skies as high pressure will remain
centered just to the southeast of the area. Tonight, a cold front
will approach the region from the north, with high clouds from
showers and storms over Indiana and Illinois reaching local
terminals by 02-06Z. Any showers and storms along the front will be
dissipating as they approach the area; however, a few showers could
reach HNB and SDF early Friday morning. Little to no impacts are
expected from these rain showers. Toward the end of the forecast
period, the cold front will pass through the region, with winds
expected to shift from S/SW to NW as the front passes. Additionally,
a BKN 5-7 kft stratus deck is expected to move in behind the front.
Tomorrow afternoon, isolated showers and possibly a storm will try
to develop along the cold front, but confidence is too low in timing
and location to mention in the current forecast.

&&

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

&&

$$

UPDATE...CSG
SHORT TERM...KDW
LONG TERM...MJ
AVIATION...CSG