121
FXUS63 KLMK 140505
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
105 AM EDT Sun Jul 14 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Scattered thunderstorms mainly along and west of I-65 this
    afternoon. Brief heavy rain, gusty winds, and lightning will be
    main threats.

*   Triple-digit heat index values could return Sunday afternoon and
    are likely early next week.

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

&&

.UPDATE...
Issued at 903 PM EDT Sat Jul 13 2024

At this hour, all showers and storms have dissipated over the
region after scattered pulse thunderstorms lead to some heavy rain,
small hail, and gusty winds up to 35mph. The remainder of the
evening and overnight hours will consist of calm to light winds and
clearing skies. These ingredients, coupled with recent rainfall in
some areas, may lead to some patchy fog development. Temperatures in
rain cooled areas are already down to the low 70s. By the early
morning, temperatures will fall into the upper 60s and low 70s over
the region. Sunday continues to trend warm and muggy with high
temperatures expected in the low-mid 90s and dew points in the upper
60s and low 70s. An SPS for heat indices in the low 100s has been
reissued for Sunday. The current forecast remains on track.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 324 PM EDT Sat Jul 13 2024

One cluster of thunderstorms has developed in the moderately
unstable airmass over the region, and is likely triggered by the
weakened, but still present, MCV left over from yesterday/last
night. These storms should mainly pose a lighting, brief heavy
rainfall, and gusty wind threat. Overall, expecting sub-severe type
of activity given the lack of deep layer shear and weak mid level
lapse rates. Can`t rule out an isolated severe, but it is not
anticipated at this time.

Otherwise, convection should taper off this evening as it slowly
progresses mainly in areas along and west of I-65. This is where 20-
30% chances will be advertised. Looking for another mild night with
lows in the 60s and low 70s. Given mostly clear skies, and
light/calm winds, do think some fog will be worth monitoring. Have
patchy/areas of fog advertised for now.

Looking for heat and humidity to continue ramping up tomorrow as
high temperatures are expected to be more solidly into the mid 90s.
In addition, dew points are expected to be in the lower 70s across
portions of our NW CWA. This will likely yield peak indices into the
100 to 105 degree range during the afternoon. Will issue a Special
Weather Statement to advertise the heat/humidity. Could get some
relief in the afternoon as a passing shortwave possibly sparks
isolated to scattered thunderstorms across our N CWA. We are close
on Heat Advisory criteria, but given the chances for convection not
confident enough to go with a headline. Plus, most of the area
should stay just below the 105 degree threshold, while a few areas
may briefly touch it.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 324 PM EDT Sat Jul 13 2024

Sunday Night - Tuesday

Dry weather is expected for Sunday night and
into the first half of next week, thanks to sfc high pressure
sitting over the southeastern US and quasi-zonal flow aloft.
Temperatures will be well above normal for Monday and Tuesday, with
highs forecast to hit the upper-90s. Dewpoints hitting the low-70s
will likely translate to heat indices above 100F, and possibly
topping out around 105F. Not much relief will be expected Monday
night as temperatures will struggle to get into the low-70s. The
urban islands may even stay in the upper 70s overnight. Hot and
mostly dry expected for Tuesday as well, though will introduce a 15-
20% PoP beginning in the afternoon and into the evening as a weak
impulse rides through the flow aloft. A few isolated storms will be
possible, but the better chances will come Wednesday.


Wednesday - Saturday

An upper low well north of the Great Lakes will be the driving force
for a cold front to sag southward through the Ohio Valley. This will
bring enough forcing and moisture convergence to develop showers and
storms for the mid-late week. PWATs will increase to nearly 2
inches, supporting heavy rainfall. Soundings continue to show
instability peaking around 2500 J/kg but meager shear values, so a
few storms are expected, but just not too confident on severe
potential yet. DCAPEs may be high enough for a marginal wind threat
with storms collapsing, but organized convection still appears
unfavorable.

PoPs may linger through Thursday morning as the front pushes south
of our area. In a post-frontal regime, temps on Thursday should be
quite nice for mid-July, with low-80s expected. Dry weather settles
back into the forecast by Thursday evening, and is expected to
continue for Friday and into the weekend. Temps will warm back to
near normals and in  the upper-80s as we get into the weekend.

&&

.AVIATION /06Z TAFS THROUGH 12Z MONDAY/...
Issued at 105 AM EDT Sun Jul 14 2024

Skies will remain mostly clear with prevailing VFR flight categories
overnight and the TAF reflects that. While some patchy fog can`t be
ruled out again overnight, confidence compared to the previous
nights/mornings are not as high. The other thing that will need to be
monitored will be any residual outflow boundaries associated with an
MCS coming off Lake Michigan. Some of the hi-res models have showers
and storms developing as the boundary works south through central
and southern Indiana late tomorrow afternoon. This could spark late
day showers and storms across southern IN and northern KY. The main
area would be around SDF but for now confidence is not high enough
to include them in the current TAF. Winds will also increase during
the day to between 5-10kts out of the south-southwest during the
afternoon.

&&

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

&&

$$

UPDATE...SRM
SHORT TERM...BJS
LONG TERM...CJP
AVIATION...BTN