841
FXUS63 KLMK 141832
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
232 PM EDT Fri Jun 14 2024

.KEY MESSAGES...

*   Isolated showers and storms possible through the evening hours.
    Gusty winds possible in the strongest storms.

*   Above normal temperatures expected Sunday into next week. Spotty
    showers and storms possible next week as well, particularly on
    Monday, though confidence in their development remains low.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 231 PM EDT Fri Jun 14 2024

Weak frontal boundary is pushing through our southern Indiana
counties and is nearing the Ohio River at this hour (1830z). As is
typical with June `cold` fronts, there is a minimal temperature
gradient but lower dewpoints (50s) have been observed in central
Illinois. Models still indicate we could see some very isolated
convection develop this afternoon near the frontal boundary, and a
cu-field has recently developed as the low levels have destabilized.
AMDAR soundings from SDF reveal a weak capping inversion near 850mb
that has steadily eroded through the day, and once this erodes a bit
more, we should start to see the potential for isolated
showers/storms increase. A quick environmental analysis shows
marginal deep layer shear (20-30kts) co-located with modest MLCAPE
(1000-1500 J/KG), but very high DCAPE (1000-1400 J/KG). If we are
able to get a storm with a modest core aloft, given the high DCAPEs,
it would have the potential to produce very gusty winds along with
heavy rainfall.

Shower/Storm chances should taper off this evening with the setting
sun and an increasing nocturnal inversion. Drier air will filter in
from the northwest behind the front, and we`ll stay dry and mostly
clear going into tomorrow. Temperatures behind the front won`t
change much as we`re expecting another warm day Saturday (highs in
the mid/upper 80s), but dewpoints should steadily decrease into the
50s for most spots to help make the warmer temperatures a bit more
bearable.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 231 PM EDT Fri Jun 14 2024

Saturday night - Sunday night...

Upper level ridging centered over the Southeast US slowly builds
eastward late in the weekend. At 850 mb, southwesterly low-level
flow develops by late Saturday night into Sunday as ridging slips
east across the Appalachians. Warmer air is advected northward into
the region, and 1000-850 mb thicknesses rise quite a bit relative to
Saturday. With a dry airmass in place, temperatures will likely end
up several degrees warmer with afternoon highs in the low to mid
90s.

Sunday morning lows are forecast to be in the low to mid 60s, fairly
typical for this time of year. Increasing low-level moisture via
steady southerly return flow late Sunday into Monday will result in
a warmer night with Monday morning lows in the lower 70s in most
places.

Monday - Tuesday...

Upper level ridging amplifies over the eastern United States next
week and will be very slow to progress eastward. Southerly low-level
flow will continue to bring a stream of moisture up the Mississippi
River Valley and into the Lower OH Valley. PW values push past 1.5
inches, around 1 SD above normal. LREF members do show a notable
uptick in SBCAPE Monday afternoon and evening with median values
above 1000 J/kg. However, there isn`t really any forcing of note
other than pure convection. Isolated pulse showers/storms will be
possible, which could briefly knock back the heat and humidity.
However, precip coverage should remain fairly limited.

Given the increased low-level moisture on Monday and potential for
an expanding diurnal cumulus field, confidence in afternoon high
temperatures is a bit lower. Still think we could see low to mid 90s
once again, but this forecast is toward the upper end of the model
distribution. These values would yield heat indices near 100 Monday
afternoon and early evening.

Tuesday still looks mainly dry and hot with highs in the low to mid
90s.

Tuesday night - Thursday...

Strong ridging aloft will expand its influence over our region
through the middle of next week, even as it becomes centered further
northeast. Dry weather appears likely at this time with our heat
wave continuing. Highs in the 90s are likely each day with morning
lows in the upper 60s and lower 70s.

&&

.AVIATION /18Z TAFS THROUGH 00Z SUNDAY/...
Issued at 108 PM EDT Fri Jun 14 2024

Mostly VFR conditions expected through the period. A very weak
frontal boundary is pushing into the region, shifting winds from the
southwest to the north. A very isolated storm or two will be
possible as the front pushes through the region, though coverage of
any shower/storm activity will be very limited and not high enough
to warrant mention in TAF. If a storm were to impact a TAF site,
expect briefly reduced cigs/vis. Shower/Storm chances should subside
near sunset.

Overnight into tomorrow, winds will gradually veer from the north to
the east. Skies should be mostly clear during this timeframe and
winds generally under 10kts.

&&

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

&&

$$

SHORT TERM...DM
LONG TERM...EBW
AVIATION...DM