926
FXUS63 KLMK 122335
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
735 PM EDT Fri Jul 12 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Mostly dry weather and warming temperatures expected for for the
    weekend.

*   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.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 311 PM EDT Fri Jul 12 2024

A clearly defined MCV is rotating into the MO Bootheel at this hour,
and will continue to trigger isolated to widely scattered convection
across western KY late this afternoon into early evening. Some of
that additional convection could survive into our W through around
sunset. Meanwhile, isolated convection across our area has kicked
off late morning into the early afternoon, with chain reaction
outflow kicking off additional coverage. Overall, storms have
remained relatively weak and short-lived given the lack of deep
layer shear, and very poor mid level lapse rates (less than 5.5
C/KM). A few storms have gotten a bit strong mainly along and west
of I-65 where lightning and gusty outflow have been noted.

Expect that H6 subsidence inversion will remain in place through the
evening, and given that don`t expect storms to get too strong. It is
fairly unstable as ML CAPE values will likely peak in the 1500-2000
J/KG range, but again the mid level inversion, poor mid level lapse
rates, and lack of stronger deep layer shear are all limiting
factors. A couple of SPS statement for gusty winds to 40 mph are
still possible through sunset, before we lose heating/instability.

Looking for convection to die off in the evening with the loss of
heating, and a relatively quiet overnight. Temps should be a bit
milder than last night with lows in the upper 60s and low 70s for
most. Seems like a fairly good setup for some patchy fog development
overnight, and will have to assess late afternoon crossover Ts for
whether we think we could have any dense fog potential. Right now,
guidance likes the idea of fog, but isn`t too aggressive with dense
fog. Some uncertainty with upper sky cover hurts confidence a bit in
just how widespread/dense it may become.

Looking for another hot, humid, and mostly dry day on Saturday.
General troughiness remains over the area, but overall this will be
a pretty weak mechanism for triggering. Will carry some isolated
pops across western CWA first of the day, but gradually drying out
through afternoon. Given less convection, expect temps to warm a
degree or two from today. This puts most locations a bit more
solidly into the low 90s.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Issued at 311 PM EDT Fri Jul 12 2024

Sunday - Tuesday

Upper level ridging will remain to our west, with more zonal flow
expected across the eastern half of the US. This pattern will
promote a mostly dry forecast, with the exception of an isolated
shower or storm possible for a few hours north of the Kentucky
Parkways Sunday afternoon. Otherwise, hot and dry weather will be
the story as sfc high pressure holds it`s position to our east.
Temperatures are forecast to rise into the upper 90s each day, with
Monday possibly being our hottest day of the forecast period.
Dewpoints will be in the upper 60s and low 70s, which will translate
to heat indices between 100-105F. Practice heat safety in the coming
days by drinking plenty of water, taking breaks indoors, checking on
vulnerable neighbors, and never leaving children or pets in a
vehicle unattended.

There will be little relief during Sunday night and Monday night,
with temps expected to remain in the 70s. Monday night may even
feature some mid- to upper-70s in the urban areas.

By Tuesday afternoon or evening, we may begin to see PoPs return to
the area ahead of an approaching cold front. The driving upper
trough will remain well north, but the associated cold front will
be diving southward from the upper midwest into the lower Ohio
Valley. An increase in RH along with some weak mid-level forcing
ahead of the front may result in some isolated precip activity late
in the day, but the primary rain chances will come with the front on
Wednesday.


Wednesday - Friday

Best shower and storm chances will be on Wednesday as the cold front
passes through the region. As of now, model soundings show a
marginally unstable airmass, with weak shear and mostly
unidirectional flow. PWATs approaching 2 inches will support heavy
rain rates, but confidence on any organization and severe potential
remain low at this time. Will be something to keep an eye on in the
coming days.

After FROPA, PoPs will linger as the front slowly shifts to our
south. Will keep PoPs going into the end of the week as well, though
chances will not be as high as Wednesday. Temps should rebound to
near-normal for both Thursday and Friday, with highs in the mid- to
upper-80s.

&&

.AVIATION /00Z TAFS THROUGH 06Z MONDAY/...
Issued at 735 PM EDT Fri Jul 12 2024

Winds are beginning to relax and skies are thinning. With these
conditions remaining overnight, fog will begin to develop in the
early morning hours and last until around 12-13Z. Conditions will
likely remain MVFR but could dip into IFR for a time. On Saturday,
light winds out of the west will prevail with diurnal Cu in the
afternoon.

&&

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

&&

$$

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