086
FXUS63 KLMK 301741
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
141 PM EDT Tue Apr 30 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Showers east of Interstate 65 to start the day, ending mid to
    late morning.

*   Dry and warm Wednesday and Thursday with highs in the 80s.

*   Showers and thunderstorms likely Friday, with a chance of rain
    lingering over the weekend. Forecast confidence in detailed
    timing remains low.

&&

.UPDATE...
Issued at 1207 PM EDT Tue Apr 30 2024

Current satellite imagery continues to show a layer of stratus that
is dissipating behind showers that continue to work off to the east.
The bulk of the showers will exit the CWA in the next hour or two. A
few sprinkles could stick around the Lake Cumberland area for a
little longer, but overall, skies are clearing and will become
sunny. The forecast remain on track with only minor tweaks needed.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 308 AM EDT Tue Apr 30 2024

Upper low is opening up as it lifts NE from the MN Arrowhead into
Canada, with a weak sfc reflection over Lake Superior and cold front
trailing SSW through Illinois into SE Missouri. Pre-frontal band of
showers supported by a weak, progressive southern stream wave, is
making slow but steady progress through the Ohio Valley, with the
main axis of precip now getting into the I-75 corridor.

Main impact this morning will be a steady soaking rain, mainly
affecting the Bluegrass region and south-central Kentucky. Precip
should end by midday, but stratus will linger behind the departing
precip shield until fropa this afternoon. Areas west of I-65 will
be Pre-frontal band of showers still moving through LEX and
RGA, but should depart to the east by mid/late morning. There`s
still a smattering of scattered showers back to the west, but
the bigger impact ahead of the actual front is IFR stratus
currently observed in SDF and HNB. Stratus will linger for a few
hours behind the departing precip shield, so will carry IFR to
low-end MVFR cigs for most of the morning. Initial state will be
an issuance time decision as conditions continue to oscillate.

Look for fropa near midday with a wind shift from SW to more of a NW
direction. Cigs will also lift to VFR and quickly scatter out during
the early/mid-afternoon.

With clear skies and light winds expected tonight, some of the
guidance is starting to show a fog signature toward Wed morning. Dry
air advection in the boundary-layer today is the main factor working
against it, but that`s the only real negative. Will leave it for
later shifts to determine which will win out as far as vis late
tonight.the first to see clearing, and temps will reach the
mid/upper 70s, while the Bluegrass region might barely reach 70
if the clouds hang on long enough.

Expect clear skies and light winds tonight as a weak bubble of high
pressure builds across the region. Model guidance is not really
hitting fog overnight, but will have to watch dewpoint trends
through the day to confirm whether dry advection will truly win out.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 308 AM EDT Tue Apr 30 2024

Wednesday...

Upper level ridging is still forecast to amplify over the Southeast
and Ohio Valley as a compact wave lifts across Lake Superior into
southern Ontario. This northern stream wave leaves behind a diffuse
cold front that sinks toward the Ohio River Wednesday afternoon.
While there is some moisture pooling along the boundary, lift looks
very weak to negligible and is unlikely to overcome mid-level
capping. At this point, just expect a cu field with limited vertical
development. This should leave us with a partly to mostly sunny day
with afternoon highs in the low to mid 80s.

Wednesday night - Thursday...

A lee-side low develops northeast across the central Plains in
response to an upper level trough swinging east from the Rockies.
The upper level pattern continues to amplify during this time frame
with a downstream ridge building over the eastern US. The subtle sfc
boundary in the region lifts well to our north as a warm front as
Pre-frontal band of showers still moving through LEX and RGA,
but should depart to the east by mid/late morning. There`s still
a smattering of scattered showers back to the west, but the
bigger impact ahead of the actual front is IFR stratus currently
observed in SDF and HNB. Stratus will linger for a few hours
behind the departing precip shield, so will carry IFR to low-end
MVFR cigs for most of the morning. Initial state will be an
issuance time decision as conditions continue to oscillate.

Look for fropa near midday with a wind shift from SW to more of a NW
direction. Cigs will also lift to VFR and quickly scatter out during
the early/mid-afternoon.

With clear skies and light winds expected tonight, some of the
guidance is starting to show a fog signature toward Wed morning. Dry
air advection in the boundary-layer today is the main factor working
against it, but that`s the only real negative. Will leave it for
later shifts to determine which will win out as far as vis late
tonight.the Plains low races northeastward. With dry air,
subsidence aloft, and an absence of any low-level forcing, dry
and warm weather continues to look likely through Thursday.
Expect morning lows in the mid 50s to around 60 degrees, and
afternoon highs in the mid to upper 80s.

Thursday night - Monday...

A low pressure system continues to develop northeast across portions
of the Upper Midwest Thursday night. A cold front advances across
the Mississippi River Valley and appears likely to cross central
Kentucky and southern Indiana on Friday. A mid-level shortwave
disturbance is forecast to lift northeast from the ArkLaTex
vicinity, potentially moving over the forecast area Friday morning.
As height falls overspread the region and southwesterly flow advects
in deeper moisture, expect increasing rain chances Thursday night.
Rain and thunderstorm chances are still highest Friday into Friday
night. Based on available instability and shear parameters at this
time range, the severe weather threat is rather low. After the
rather warm day Thursday, abundant cloud cover and precipitation
will likely keep highs in the mid 70s to near 80 Friday.

We should at least briefly dry out in the wake of the cold front
heading into the first part of the weekend. However, synoptic scale
model spread remains large Saturday and beyond. Run-to-run model
consistency is still lacking, and ensemble guidance presents a broad
range of solutions. Forecast confidence in the details and timing is
low, and this forecast maintains a chance of rain (generally 30-60%)
throughout the weekend.

&&

.AVIATION /18Z TAFS THROUGH 00Z THURSDAY/...
Issued at 140 PM EDT Tue Apr 30 2024

All forecasted TAF sites have returned to VFR conditions except for
RGA, and over the next hour or two, RGA is expected to return to VFR
conditions. This trend of improvement is expected to continue with
high pressure over the region. The surface high will also help to
keep winds light out of the northwest for the rest of the day, but
tonight under clear skies, it will likely cause some fogging.
Currently, believe fog will develop over eastern Kentucky and expand
westward. BWG, LEX, and RGA will likely be impacted.

&&

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

&&

$$

UPDATE...KDW
SHORT TERM...RAS
LONG TERM...EBW
AVIATION...KDW