450
FXUS63 KLMK 210513
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
113 AM EDT Fri Jun 21 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Heat continues for the end of the week into the weekend with
    near-record highs for some locations Friday into Sunday.

*   Scattered showers and storms possible Sunday, and again by the
    middle of next week.

&&

.UPDATE...
Issued at 944 PM EDT Thu Jun 20 2024

Satellite imagery continues to show mostly clear skycover across the
region as high pressure remains overhead. Temperatures are in the
upper 70s and low 80s this evening, and will only drop a few more
degrees into the low 70s overnight. No changes to the forecast are
planned at this time.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 338 PM EDT Thu Jun 20 2024

Center of the anomalous 500mb ridge will continue to slowly
retrograde westward over the Commonwealth tonight into tomorrow as
the region remains under the influence of strong 1020-1024mb sfc
high. Temperatures were already near 90 as of 3pm EDT and when you
factored in current dew points in the upper 60s/low 70s the heat
index values were already in the low and in some places the mid 90s.
Current visible satellite imagery shows a nice scattered to broken
Cu field over the region but looking at current SDF ACAR soundings
there is a strong capping inversion  at 800mb and strong subsidence
aloft. Given these conditions, don`t expect any shower/storm
development this afternoon.

Skies will clear with the loss of daytime heating and winds will
continue to remain light and calm as the boundary layer stabilizes.
It will remain warm overnight, lows will only fall into the low 70s
with urban locations warmer in the mid 70s. Could see some valley
fog once again form but should remain overall very isolated.
Tomorrow looks to be the hottest day for the week and even into the
weekend thanks to the strength of upper level ridge. Could once
again see some scattered mid level cu form in the afternoon but
highs are expected to be in the mid/upper 90s with widespread heat
index values in the upper 90s to low 100s. This is just shy of heat
advisory category but if we continue to see heat index values near
100 into the weekend, a headline may be warranted due to the very
warm overnights in the 70s.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 338 PM EDT Thu Jun 20 2024

Friday night - Saturday night...

Strong, elongated upper level ridging will remain in place over the
southern half of the United States Friday night and Saturday. We`ll
start to see gradual height falls as multiple shortwave disturbances
to the northwest break down the ridge. Multiple upper level
shortwave impulses are forecast to ripple across portions of the
Plains and Upper Midwest as a stronger upper level trough drops ESE
across Saskatchewan.

Plenty of lingering dry air and subsidence aloft will keep us hot
and dry during this time frame. Lows in the lower 70s will be common
Friday night, with low to mid 70s Saturday night. For Saturday,
temperatures are forecast to max out in the low to mid 90s in the
afternoon and early evening. Heat index values are likely to climb
into the 95-100 degree range, and some spots will likely top out
just above 100.


Sunday - Monday...

By Sunday, the primary northern stream upper level trough will be
rotating southeast over the Great Lakes with sfc low pressure
deepening eastward over far SE Ontario. A weak sfc cold front is
likely to approach the Ohio River by late in the day. This front
will interact with a hot, humid airmass with increasing SW low-level
flow ahead of the boundary. Scattered showers and thunderstorms are
expected Sunday afternoon and evening, some of which could produce
gusty winds and heavy rainfall. The threat for organized severe
weather is low due to weak shear.

Temperatures are still likely to soar into the low to mid 90s Sunday
with the highest rain chances (30-40%) confined to the second half
of the day. Lows Sunday night will range from the upper 60s to mid
70s.

Conditions dry out once again Monday in the wake of the front. High
pressure noses in from the west. Look for highs in the upper 80s to
lower 90s.


Tuesday - Wednesday...

Hot, dry weather will likely linger into Tuesday. Notable warm air
is pumped into the region ahead of another weak cold front. While
several days out, some guidance suggests Tuesday could be one of our
hotter days with highs well into the 90s.

However, multiple upper level shortwave impulses rotating through
deepening eastern US troughing will help provide increasing rain
chances by the middle of next week. Ensemble data points to
Wednesday as our best shot at rain with temperatures cooling off
slightly late next week.

&&

.AVIATION /06Z TAFS THROUGH 12Z SATURDAY/...
Issued at 112 AM EDT Fri Jun 21 2024

Discussion...Prevailing VFR conditions for this TAF period.
Strong surface high pressure over the region will keep stable
conditions with light, variable winds at the terminals. On the other
hand, a brief period of MVFR visibility could be possible at HNB and
RGA this morning due to localized fog as both sites show decreasing
dewpoint depression values with lower confidence at BWG and LEX.

&&

.CLIMATE...
Issued at 338 PM EDT Thu Jun 20 2024

================== Near-Record Heat This Weekend ==================


               Friday 6/21/2024
          Max T Fcst/Record (Year)

Louisville:       99/98     (1988)

Bowling Green:    97/102    (1933)

Lexington:        97/97     (1988)


             Saturday 6/22/2024
          Max T Fcst/Record (Year)

Louisville:       97/100    (2022)

Bowling Green:    97/102    (1901)

Lexington:        96/99     (1988)


               Sunday 6/23/2024
          Max T Fcst/Record (Year)

Louisville:       95/98     (1988)

Bowling Green:    96/104    (1930)

Lexington:        93/96     (1988)


Some records may have occurred in multiple years. The latest year
the record was tied is displayed.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Air Quality Alert until 1 AM EDT Saturday for KYZ029>031.
IN...Air Quality Alert until 1 AM EDT /midnight CDT/ Saturday for
     INZ076>079-083-084-089>092.

&&

$$

UPDATE...CJP
SHORT TERM...BTN
LONG TERM...EBW
AVIATION...ALL
CLIMATE...EBW