574
FXUS63 KLMK 222347
AFDLMK
Area Forecast Discussion
National Weather Service Louisville KY
747 PM EDT Sun Jun 22 2025
.KEY MESSAGES...
* Heat and humidity will continue for the next several days with
heat index values in the upper 90s to the lower triple digits.
* Heat Advisory expanded slightly across Kentucky through Tuesday
evening. Multiple days of heat index values in the low 100s and
overnight lows in the low/mid 70s combined with high humidity can
result in heat-related health impacts.
&&
.UPDATE...
Issued at 747 PM EDT Sun Jun 22 2025
Updrafts are losing their punch, per latest GOES imagery and MRMS
reflectivity at -20C. Still have a couple of stronger cores, but
with loss of daytime heating, expect coverage to wane over the next
hour or two. Kept a 10-20 pop along and south of a Glasgow to
Danville line for that hour, but then drop pops off quickly this
evening. Another warm and muggy night in store, with lows staying in
the mid to upper 70s for most.
&&
.SHORT TERM /THROUGH MONDAY/...
Issued at 241 PM EDT Sun Jun 22 2025
Afternoon conditions across the region were hot and humid with
mostly sunny skies. Temperatures generally were in the upper 80s
with a few 90-91 degree readings here and there. The urban
corridors were hotter with mainly lower 90s reported. Dewpoints
remained in the lower-middle 70s which was producing heat index
readings in the upper 90s to the low 100s across the area.
A few showers/storms have develop down across south-central Kentucky.
For the remainder of the afternoon, no significant weather is
expected across much of the region. The highest chances of a
cooling shower/storm will be generally southeast of a line from
Scottsville (Allen Co) to Lancaster (Garrard Co). Afternoon highs
will top out in the upper 80s to the lower 90s. The urban heat
islands will likely top out in the 93 to 95 degree range.
Temperatures will fall back into the 80s this evening.
For tonight, mostly clear skies and light winds are expected. Lows
will only dip into the lower-middle 70s with the urban heat islands
staying in the 78-80 degree range.
For Monday, another hot and humid day is expected across the region
with afternoon highs in the upper 80s to the lower 90s. The urban
heat islands will probably go a little higher with 94-96. Dewpoints
will remain in the lower-middle 70s producing heat index readings in
the afternoon in the upper 90s to the lower 100s. Based on current
forecasts, we have made a slight eastward expansion of the current
Heat Advisory. This advisory now includes the Lexington Metro area
where afternoon heat indices in the urban areas will likely approach
100-105. Some scattered showers may pop up in the afternoon, with
the best chance south of the Parkways. The coverage does not look
all that widespread with about 14-20% coverage.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 241 PM EDT Sun Jun 22 2025
Moving into the extended period, the upper level pattern is forecast
to remain rather stagnant through about mid-week. Large upper level
ridge will hold sway across the eastern US with continued troughing
out across the west. Locally, high pressure will remain in control
with mostly sunny days and mostly clear nights. There will be a
diurnal Cu field each day with perhaps some very isolated
showers/storms developing across southern KY each afternoon through
at least Wednesday. Daytime highs will again be in the upper 80s to
the lower 90s with the urban corridors warming into the middle 90s.
Dewpoints will remain elevated through the period. However, the
continued dry pattern may allow for continued mixing which may
result in slightly lower dewpoints in Tue/Wed afternoon. Afternoon
heat index readings will continue to be in the upper 90s to the
lower 100s.
While these values remain under the traditional Heat Advisory
criteria, the Heat Advisory will continue through Tuesday evening
based on the extended period of hot/humid conditions. If current
forecast trends hold for a drier pattern on Wednesday and into
Thursday, a further extension of the advisory in time, may be
required in subsequent forecast issuances.
For the later half of the week, an upper level low over the
southwest Atlantic is forecast to move westward time. This low may
undercut the upper level ridge over us and send the core of it
further westward with time. As this occurs, there is some model
data signaling that a frontal boundary may approach the region from
the northwest next weekend which could bring us some relief from the
current heat. Afternoon diurnally driven convection looks
increasingly possible Thursday through Saturday. Model soundings do
show strong instability developing during each afternoon though wind
shear values remain exceptionally weak. So at best, just some
isolated-scattered storms will be possible here.
With the core of the ridge pushing westward, we will see heights
fall across the region which may allow us to cool off slightly.
Highs Thursday through Sunday will again be in the upper 80s to the
lower 90s. Trends in the dewpoints suggest lower values with
readings in the upper 60s/lower 70s, which will still allow
afternoon heat index readings to top out in the upper 90s to near
100.
&&
.AVIATION /00Z TAFS THROUGH 06Z TUESDAY/...
Issued at 702 PM EDT Sun Jun 22 2025
High pressure at the surface and aloft will keep weather relatively
tranquil this period. Winds will be light and variable, with a
general south to southwesterly flow. Do have a few storms across
south central KY this hour, but with loss of daytime heating soon
expect them to start fading. Moisture generating those showers may
be enough for some light vsby restrictions at KLEX/KRGA/KBWG around
daybreak Monday. Cannot rule out more isolated storm coverage Monday
afternoon, again mainly across south central KY.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Heat Advisory until 8 PM EDT /7 PM CDT/ Tuesday for KYZ023>043-
045>049-053-054-057-061>065-070>074.
IN...Heat Advisory until 8 PM EDT /7 PM CDT/ Tuesday for INZ076>079-
083-084-089>092.
&&
$$
UPDATE...RJS
SHORT TERM...MJ
LONG TERM...MJ
AVIATION...RJS