LMK issues Area Forecast Discussion (AFD) at Jun 20, 12:58 AM EDT ...Updated Aviation Discussion...741
FXUS63 KLMK 200458
AFDLMK
Area Forecast Discussion
National Weather Service Louisville KY
1258 AM EDT Sat Jun 20 2026
...Updated Aviation Discussion...
.KEY MESSAGES...
* A reprieve from rainfall continues through Saturday before the
next round of widespread rain returns Sunday. A couple brief
showers are possible in southern Indiana Saturday afternoon, but
conditions will be otherwise dry and comfortable.
* Strong to severe storms will be possible later Sunday afternoon
into late Sunday evening. All severe hazards could be in play,
especially along and west of I-65.
* A somewhat unsettled pattern is expected through early week with
temperatures slightly below normal and off and on shower and storm
chances possible, especially across southern KY.
&&
.SHORT TERM /THROUGH SUNDAY/...
Issued at 254 PM EDT Fri Jun 19 2026
It has been a beautiful day today across central Kentucky and
southern Indiana with high pressure currently in place. The
combination of temperatures in the upper 70s/low 80s and dew points
in the upper 50s/low 60s has made for comfortable conditions across
the area that will last into the start of the weekend. A scattered
mid-level cu field currently present will clear after sunset
tonight, and with light winds expected tonight, temperatures will
drop into the upper 50s/low 60s. Saturday will be fairly similar to
today, with comfortable dew points and highs in the low-to-mid 80s.
A weak mid-level shortwave will move over southern Indiana during
the afternoon that may be able to produce a few showers, but chances
remain low at this time (< 20%). Even though the surface high
pressure will begin to shift to the east Saturday night, conditions
will be dry across the area Saturday night, with lows in the low-to-
mid 60s.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 254 PM EDT Fri Jun 19 2026
Sunday - Monday Night...
Sunday will start off dry with with a progressive shortwave ridge
providing a bit of subsidence before it quickly drifts eastward.
Temps are expected to reach into the mid 80s into the afternoon
under increasingly cloudy skies through the day. As we get into the
late afternoon through Sunday night, a shortwave will eject out of
the eastern Plains and into the Ohio River Valley. Meanwhile, the
associated surface low looks to track through the Wabash River
Valley.
Models continue to disagree on the strength of this feature
with European based data suggesting a stronger surface low, and GFS
based data suggesting a weaker surface low. This likely explains why
current AI NWP data supported by the European ensemble data
(Pangu/FengWu) are showing a stronger signal for severe chances, vs.
the GEFS based data with a weaker surface low showing a weaker
overall signal. This same discrepancy shows up between the various
model camps when looking at expected ML CAPE values. The weaker
surface low solution only yields around 500-1000 J/KG of ML CAPE,
with the stronger solution more around 1500-2000 J/KG.
Regardless of what ends up being the case, there does appear
to be enough overlap between deep layer shear values around 35-45
knots and either a modest or moderately unstable atmosphere in our
area. The best overlap is generally along and west of I-65 for the
moment. Could eventually see the Slight Risk being moved a bit
farther east into our NW CWA, if not our western half of the CWA. It
should also be noted that trends with the AI based data have been
steadily more concerning for our western CWA over the past several
days of runs.
Forecast soundings do show a favorable environment for
wind, or perhaps a tornado threat, and given a surface low in the
Wabash River Valley low level winds could easily be backed a bit.
Point forecast soundings up near Jasper IN show a curved low level
hodograph yielding 250-300 m2/s2 of effective SRH. Low topped
supercell storm modes could be in play, however would likely
struggle above 25k feet thanks to 500 lapse rates above 500 mb. Mid
level lapse rates in the 700-500 mb range are quite sufficient
however.
The overall thermodynamic profile should become less favorable into
Sunday night, however shower and storm chances will continue given
plenty of elevated instability. The lead wave pushes east by Monday
morning, however the cold front trailing from the aforementioned
surface low could stall out W-E somewhere along or south of our TN
border. This is expected to set the stage for repeated rounds of
showers and storms through Monday as shortwave progress W-E through
the zonal flow aloft and parallel to the quasi-stationary surface
boundary. We'll have to watch for a hydro threat as the airmass
should be quite moist along and south of that boundary.
Tuesday - Wednesday...
Expect a mostly dry stretch of weather as we head into mid week as
surface high pressure across the Great Lakes region extends enough
influence into our area, the front boundary sags a bit too far south
to trigger showers and storms over our area. Being on the north side
of the boundary, temps will run a bit cooler than normal on these
days, mostly in the low 80s.
Wednesday Night - Friday...
Below normal temperatures in the low 80s continue into the late week
time frame, along with some small chances for a shower or storm.
Generally broad and low amplitude troughiness hangs over the eastern
CONUS during this time. A subtle shortwave or an approaching weak
surface front could be subtle triggers for widely scattered shower
or storm activity.
&&
.AVIATION /00Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1258 AM EDT Sat Jun 20 2026
VFR conditions continue through the TAF forecast period. Light to
calm winds will continue through the night, with a light WNW wind
tomorrow. BKN and SCT high clouds will linger, and a sub 100 level
deck will move in this afternoon. TAFs remain dry however there is a
very low chance (10-15%) of a light shower this afternoon. Dry air
holding at the surface may even lead to a virga scenario instead.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.
&&
$$
SHORT TERM...BEN
LONG TERM...BJS
AVIATION...CAL
Source:
LMK issues Area Forecast Discussion (AFD) at Jun 20, 12:58 AM EDT ...Updated Aviation Discussion...---------------
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