193
FXUS63 KLMK 151031
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
631 AM EDT Mon Jul 15 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Triple-digit heat index values between 100-105 degrees today and
    Tuesday.

*   Shower and storm chances look to increase by the middle of this
    week as a frontal boundary sinks into the area.

*   Cooler temps in the 80s for Thursday into Saturday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 308 AM EDT Mon Jul 15 2024

The main weather impact for today remains the heat and humidity.
The combination of afternoon temperatures warming into the mid/upper
90s and once again a steamy, muggy airmass with dew points ranging
from the upper 60s to widespread low 70s. All of this leading to
heat index values ranging between 100-105 degrees. It is possible
there could be a few isolated places that reach 105 or above heat
index values but it appears to be very isolated. There are also some
potential limiting factors to the heat today and this afternoon. MCS
currently working through northern IL/northern IN will approach
southern IN and the Ohio River close to daybreak. ACAR soundings out
of SDF showed a nice capping inversion around 850mb and hi-res
models agree on weakening and dissipating this activity before it
reaches the Ohio. While the trend in the models is to keep the CWA
dry this morning into the afternoon, current KLVX radar image shows
a few returns across southern IN. Decided to bring a 20 PoP to parts
of southern IN by around 12z. high/mid clouds associated with the
convective debris will likely linger this morning, especially across
the northern half of the CWA. Depending on how long the clouds stick
around even if they are SCT/FEW could impact how hot it gets at the
sfc. Due to the lack of wide spread heat advisory criteria and
talking with surrounding WFOs, made the decision to continue the SPS
today for the low triple digit heat index values.

Cold front coming out of the Great Lakes tonight will spark another
MCS over eastern IA and northern IL. Like the one this morning, this
will work towards southern IN and the Ohio River between 10-12z.
Once again models break and dissipate the activity before it reaches
the CWA but went ahead and kept low end PoPs for southern IN towards
the pre-dawn hour tomorrow. Lows will remain very warm overnight
only dropping into the low/mid 70s with a few of our more urban
areas in the upper 70s to even 80.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 308 AM EDT Mon Jul 15 2024

Periods of active weather are anticipated through midweek as a slow
moving frontal boundary steadily sinks southward from the Midwest
and Great Lakes region. At the start of the forecast period (Tuesday
morning), showers and storms may be ongoing across portions of
Midwest and Ohio Valley as a decaying MCS pushes southward. Most
models prog this activity to weaken and `dry up` as it moves into
our CWA, though lingering cloud cover associated with any convection
could slow heating down Tuesday. Should we end up with more clear
skies vs clouds, Tuesday is shaping up to be a hot one, with many
locations reaching mid 90s and heat indices likely exceeding 100
degrees by the afternoon. Models prog new convective development
along various mesoscale boundaries by the afternoon that could
linger into the overnight hours. Weak/Marginal deep layer shear will
limit any sort of severe threat, but gusty winds in downbursts along
with heavy rainfall are likely in the strongest storms.

The frontal boundary will likely be near the Ohio River by 12z
Wednesday morning. Additional convective development is likely along
it as it continues its southward trek, and the rain/clouds will keep
temperatures a bit cooler compared to previous days readings. The
front itself may not push out of the region until Thursday, so
expect rain chances to linger through then. Slightly cooler air
along with drier conditions and lower dewpoints will gradually work
in behind the front to give us a much needed break from the
hot/humid conditions experienced earlier in the week.

Chances for rain begin to creep back up for some going into the
weekend as the frontal boundary begins to waver and slowly lift
northward. Models understandably vary on the position of the front
this far out in time, but it appears the best chances for any sort
of rain/storms will be across our southern/eastern zones (Lake
Cumberland region points northeastward).

&&

.AVIATION /12Z TAFS THROUGH 18Z TUESDAY/...
Issued at 630 AM EDT Mon Jul 15 2024

Current satellite imagery as well as WSR-88D shows what is left from
the MCS from overnight currently in southern and central IN. There
remains scattered showers and storms mostly north of our area. It is
expected for this activity to continue to dissipate before working
into our area. The only impacts appear to be some high to mid clouds
around the area and increased winds out of the south-southwest
between 5-10kts and gusting to around 15kts this afternoon. Despite
the passing systems this morning and again later tonight VFR flight
categories remain the prevailing forecast for all TAF sites through
the period.

&&

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

&&

$$

SHORT TERM...BTN
LONG TERM...DM
AVIATION...BTN