Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 270218
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
1018 PM EDT Mon Jun 26 2017

.Forecast Update...
Issued at 1010 PM EDT Mon Jun 26 2017

Updated the forecast to limit POPs to 20% overnight.  Although the
lower levels are still quite dry, enough forcing exists along subtle
waves associated with the upper trough to our north to produce
storms over central IL/IN this evening.  Thus, think that there is
some chance for lesser convection overnight over southern IN/central
KY as the trough drops southeast.  Most high-res models indicate
this as well but to a lesser intensity/coverage than what`s
currently out there. So will continue slight chances for
showers/sprinkles overnight with lows in the 50s.

&&

.Short Term...(This evening through Tuesday night)
Issued at 310 PM EDT Mon Jun 26 2017

Pleasant conditions continue for the rest of the afternoon/evening
however do expect to see some increase in mid/upper sky cover as
sunset approaches. Will note 25-30 degree T/Td spreads across the
area, so expect to see some of the upstream precipitation struggle
as it enters our dry airmass. So, with that in mind we`ll keep
measurable pops in the forecast later this evening into the
overnight, but they will be low.

Water Vapor imagery shows a shortwave currently over the upper
midwest. It quickly passes through the region overnight with
isolated to widely scattered showers expected. There is a very
outside shot at a few rumbles of thunder, but not enough to warrant
mention. In fact, still not overly confident how many places will
measure given the dry low levels. On the other hand, there is a 90-
100 knot upper level jet with sporadic LLJ responses that should
provide enough moisture convergence and lift to squeeze out a few
light measurable showers.

Overnight lows will be a bit tricky given sky cover, but mid 50s in
most spots seems pretty reasonable. The southern Indiana counties
could get down to the low 50s if clouds clear out quick enough
toward dawn.

Shortwave trough axis quickly moves through by morning, with surface
high pressure and dry NW flow aloft taking hold behind. This will
keep us dry Tuesday and Tuesday night. High temps on Tuesday will be
similar to today with mid and upper 70s. Lows Tuesday night will
again be in the mid 50s.

.Long Term...(Wednesday through Monday)
Issued at 310 PM EDT Mon Jun 26 2017

Wednesday - Thursday Night...

Zonal flow aloft and surface high pressure will control the pattern
through Wednesday, keeping things dry. A frontal boundary looks to
stall out across northern IL/IN/OH on Thursday, but should be far
enough north to not play a factor. Light southerly flow on the
western edge of surface and upper ridging will lead to moisture
return and continued warmer temperatures. Wednesday will feature
highs in the low to mid 80s, with Thursday topping out in the mid to
upper 80s. Wednesday night lows should mostly be in the mid to upper
60s, and around 70 by Thursday night.

By Thursday afternoon, enough moisture return combined with peak
heating should result in enough instability to trigger a few showers
and storms. The lack of noticeable triggering features will limit
higher coverage/chances at this time. Any convection should die off
with sunset.

Friday - Monday...

Things look to be more active as we go into the weekend. Deeper
southwest flow in response to an amplifying central CONUS trough
will result in considerable moisture/instability return. These
factors combined with a cold front trailing from a Great Lakes
surface low should provide enough triggering for more coverage of
showers and storms. Best chance for scattered coverage on Friday
afternoon/evening will be across southern IN and the Lake Cumberland
region. By Saturday, scattered to numerous showers and storms are
expected. Sunday, the best focus should be across southern KY as the
front stalls out. Scattered chances may linger into Monday as the
stalled frontal boundary remains in the region.

Temperatures during this time should consistently be in the mid 80s
for highs and lows mostly in the 65-70 range. We may be slightly
cooler by Sunday/Monday as the frontal boundary stalls or washes out
over the area. Saturday temperatures may also be mitigated a bit by
more widespread convection.

&&

.Aviation...(00Z TAF Issuance)
Issued at 705 PM EDT Mon June 26 2017

VFR conditions are forecast for this TAF period.  Light disturbances
associated with a passing upper level trough my result in some
showers/sprinkles across the area tonight.  However, none should
cause any restrictions.  Sfc high pressure will move into the Ohio
Valley tomorrow making light winds variable but generally from a
northerly direction for most of the day.


&&

.Climate...
Issued at 245 AM EDT Mon Jun 26 2017

Here are some record low max and record low climate data for the
early part of this week for SDF, LEX, and BWG ASOS sites.

Record Lows        Louisville      Lexington       Bowling Green
June 27th              52              51                52
June 28th              53              50                50

&&

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

$$

Update...AMS
Short Term...BJS
Long Term...BJS
Aviation...AMS
Climate...DM



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