Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 270651
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
251 AM EDT Tue Jul 27 2021

.Short Term...(Today and tonight)
Issued at 245 AM EDT Tue Jul 27 2021

East-west oriented ridging at the sfc and aloft over Illinois and
Indiana will give us a hot and vaguely humid day with virtually no
rain in sight. Sharp PWAT gradient across Kentucky, so not quite as
confident in staying dry over the far south, but still expect any
convection to remain over Tennessee. Thickness progs suggest
persistence is a good starting point for max temps. Heat index
values could touch 100 in the more humid locations in south central
Kentucky, but should only be a degree or two higher than the actual
temperature farther north.

&&

.Long Term...(Wednesday through Monday)
Issued at 250 AM EDT Tue Jul 27 2021

Wednesday - Thursday...

Strong and persistent upper ridge centered over the Central Plains
will continue to expand eastward towards the region to start the
period, providing hot and dry conditions through Thursday. Highs for
Wednesday and Thursday will be in the lower to mid 90s across the
area, with Thursday expected to be the hottest day of the period.
Additionally, heat indices of 100-105 degrees will be possible both
days, especially along and west of I-65. Wednesday night will not
provide much relief either as overnight lows remain in the lower
70s.

Thursday Night - Beyond...

The upper-level pattern will amplify towards the end of the week and
into the weekend as a series of shortwaves help carve out a deeper
trough over the Northeast. As these waves rotate through the flow
aloft, the upper ridge will be suppressed to our south and east,
allowing for more unsettled conditions. Our first chance of precip
will come Thursday night into Friday as an upper wave drops SE
through the Great Lakes region, sending a frontal boundary southward
towards the area. Showers and storms will be possible ahead of and
along the front, with cooler air moving into the area in its wake. A
bit more uncertainty then as we move into the weekend and early next
week, with the general idea being that rain chances may continue
Saturday and Sunday as pockets of energy drop through the
northwesterly flow aloft. Things may then dry out again by early
next week as surface high pressure builds in across the Great
Lakes/OH Valley regions. As far as temps go, afternoon highs are
generally expected to be in the 80s with overnight lows in the 60s.

&&

.Aviation...(06Z TAF Issuance)
Issued at 110 AM EDT Tue Jul 27 2021

Main challenge in this TAF set is fog potential at BWG and HNB. Dry
air advection has not really made itself known at HNB through the
evening, but there`s just enough of a NE breeze and dewpoints did
mix down into the upper 60s in the late afternoon. Will not mention
any restrictions to vis there.  However, BWG is still on track to
cross over the afternoon dewpoints for a couple hrs around daybreak.
Still just a bit of wind to mitigate fog formation there, so will go
with a TEMPO for MVFR vis.

Otherwise expect VFR conditions with clear skies and light NE winds
through the valid TAF period.


&&

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

$$

Short Term...RAS
Long Term...JML
Aviation...RAS


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