108
FXUS63 KLMK 030541
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
141 AM EDT Mon Jun 3 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Showers and storms ending by midnight, but fog will develop
    overnight.

*   Scattered storms will be possible Tuesday and Wednesday. A few
    strong to severe storms will be possible, especially Wednesday.
    The main threats will be heavy downpours and gusty winds.

&&

.UPDATE...
Issued at 1002 PM EDT Sun Jun 2 2024

Last of the showers will be winding down over the next hour in the
US 127 corridor south of Liberty. The rest of the night should be
dry, with the main question hinging on fog. Muggy air mass with
potential for moisture pooling near the quasi-stationary front will
play in favor of fog, especially over the Bluegrass region and
south toward Lake Cumberland. Will monitor visibilities over the
next couple hrs, but otherwise just ride with mention of
patchy/areas of fog in the forecasts. No significant changes
planned.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 254 PM EDT Sun Jun 2 2024

Synoptically, 5h shortwave responsible for today`s weather will
continue to exit to our east allowing for zonal flow aloft and weak
ridging to advect over the OH Valley. Low level cyclonic flow is
evident on radar as showers pinwheel around the base of the surface
low centered over south central Indiana, while GOES-16 satellite
imagery reveals breaks in the clouds.

This increased sunshine will help destabilize the region allowing
for isolated to scattered showers and possible thunderstorms
throughout the afternoon and into the the early evening. SPC
mesoanalysis shows a ridge of instability over our CWA with SBCAPE
values around 1500 J/kg. Shear is minimal with VWX VWP and AMDAR
soundings out of SDF showing light winds throughout the column.
Slight veering within the column is indicative of the weak warm
advective pattern in place, but updrafts will struggle due to weak
mid level lapse rates. With that said, sufficient dry air aloft and
DCAPE values around 1000 J/kg along and west of I-65 could produce
some strong winds with any stronger convection. With that said, not
expecting any severe weather with today`s activity.

Tonight, expect winds to subside and clouds to clear as weak high
pressure briefly builds over the region. Some models suggest fog
development by early Monday morning so will add mention of patchy
fog, which could affect the morning commute.

Monday is shaping up to be a rather pleasant day with partly cloudy
skies and afternoon temps rising into the mid 80s, while light SSW
winds push dewpoints into the mid to upper 60s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 254 PM EDT Sun Jun 2 2024

Dry weather will continue into Monday night, with some patchy valley
fog possible in the Blue Grass and Lake Cumberland regions with
mostly clear skies and nearly calm winds. Lows will be in the lower
and middle 60s.

Rain chances return on Tuesday as a small 5H vort max crosses
Illinois helping to spark showers and storms in 1.75" precipitable
water air. Shear and mid-level lapse rates will be weak, but there
will be enough instability to get thunderstorms going in the
afternoon as the mercury meets or slightly exceeds convective
temperatures in the middle 80s with dew points in the middle and
upper 60s. Scattered pulse storms are expected, with the most likely
threats, other than the lightning threat that accompanies all
thunderstorms, being locally heavy downpours and precipitation
loading induced gusty winds.

On Wednesday vapor transport from the western Gulf will increase
into the Ohio Valley ahead of a cold front approaching from the
northwest. A spoke of lower 5H heights reaching southeast from the
main upper low over southern Manitoba will reach southeast into our
region as well. Deep layer shear may be a little stronger on
Wednesday in association with swifter 500mb flow south of the
Manitoba low, but still shouldn`t be terribly impressive. CAPE is
progged to be a bit weaker on Wednesday with continuing weak mid-
level lapse rates, possibly partly a result of morning clouds and
showers. CSU-ML has been very consistent over the past four days
pegging Wednesday as our most likely day for severe weather this
week. This is still the case, but probabilities have decreased
slightly. The best upper level divergence will remain well to our
north, and the surface low will be far off in western Ontario.
Nevertheless, we`ll still have plenty of instability and moisture
for showers and storms, and with the incoming cold front, some
strong to severe storms do still appear possible. Again the main
threat would be gusty winds given the expected pulse nature of the
storms and high freezing heights.

Thursday through Sunday will lean drier as the Canadian upper low
pushes east into New England and surface high pressure tries to
build in from the Plains and Midwest. Will hold on to some chance of
rain given our position on the edge of cyclonic flow aloft, but will
keep PoPs low.

Temperatures will cool off a bit as we head into the weekend. Highs
are expected to slip from the mid 80s Thursday to around 80 Friday
and Saturday. CPC outlooks show increased chances of cooler than
normal temperatures for much of the first two weeks of the month.

&&

.AVIATION /06Z TAFS THROUGH 12Z TUESDAY/...
Issued at 141 AM EDT Mon Jun 3 2024

Calm winds and mostly clear skies have promoted patchy fog
development this morning, which is impacting some terminals. Through
the predawn hours, fog could reduce vis to IFR or even LIFR for a
few hours. After sunrise, we should begin to see improvements to
flight categories, eventually returning to VFR by mid-morning. VFR
conditions will continue for the rest of the period, with winds
mainly from the south and under 8kts.

&&

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

&&

$$

UPDATE...RAS/CRG
SHORT TERM...CRG
LONG TERM...13
AVIATION...CJP