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000
FXUS63 KLMK 121744
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
144 PM EDT Fri Apr 12 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*  Another round of light rain today before skies begin to clear.

*  Above normal temperatures expected this weekend through much of
   next week. Strong to severe storm potential exists for portions
   of next week as well.

&&

.UPDATE...
Issued at 1045 AM EDT Fri Apr 12 2024

An area of light to moderate rain showers is currently moving into
our southern Indiana counties at this hour, supported by a shortwave
trough which is diving southeast across the Ohio Valley this
morning. This wave of rain and clouds has generally been well-
forecasted, and is expected to continue southeastward across central
Kentucky later this morning and into the afternoon hours. Behind
this leading wave of rain, colder temperatures aloft will steepen
lapse rates later this afternoon, leading to a second wave of
scattered showers and one or two rumbles of thunder. One or two
stronger cells may produce graupel or small hail given relatively
low freezing heights; however, this should be fairly limited given
warm temperatures near the surface. Winds will remain gusty, veering
slightly from WSW to WNW after the shortwave axis crosses through
this afternoon. Clouds will gradually dissipate late this afternoon
and into the early evening hours as the 850 mb thermal trough axis
moves east of the region.

Otherwise, the forecast remains on track at this hour. Only minor
tweaks to near-term temperatures and PoPs were made at this time.
Updated products will be sent shortly.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 327 AM EDT Fri Apr 12 2024

Currently, the surface low that brought rain yesterday and during
the overnight is sitting over the eastern Great Lakes on the leading
edge of the upper level trough. The axis of that slightly negatively
tilted trough is cutting through the CWA. The tight pressure
gradient between the aforementioned surface low and surface high
pressure, centered over eastern Texas, is keeping winds over the
Lower Ohio Valley out of the west around 10-15 mph. Gusts
during the rest of the night could reach to around 25 mph.

For the rest of the day, the upper trough will slowly slide eastward
as it pushes the surface low farther to the northeast into Canada.
While doing this, a shortwave on the backside of the upper trough
will cut from the northwest to southeast over southern Indiana and
central Kentucky, and with deep layer moisture reaching above 500 mb
and PWATs approaching 0.7 inches remaining around the low pressure
system, another round of rain showers is expected to begin entering
our southern Indiana counties from the north around 13-14z. It will
continue to the southeast and is expected to exit our central
Kentucky counties mostly by around 20z. A few isolated showers or
even one or two rumbles of thunder will be possible for a few hours
after this, mainly in the Bluegrass region. Model soundings show a
very stable airmass with very little shear, so most will see only a
light rain today. Believe Warren County, Kentucky will be about the
limited on the southwest extend of any light precipitation.

Behind the precipitation, skies will begin clearing late this
afternoon into the evening hours. This could slightly boost high
temperatures across the western parts of the CWA into the low to mid
60s while areas farther to the east that see more rain and cloud
cover are expected to only see the mid 50s to near 60. Winds will
continue to be 15 to 20 MPH with gusts around 30 to 35 MPH from the
west to west-northwest.

Heading into tonight, skies will clear as the low pressure system
works its way farther from the region and high pressure expands from
the south over the CWA. This will help to ease west winds to 5 to 10
MPH with gusts to 15 to 20 MPH, and by 12z Saturday, most of these
gusts will die down too. Lows are expected to dip into the low to
mid 40s.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 327 AM EDT Fri Apr 12 2024

The weekend looks to start out dry and pleasant as surface high
pressure over the Gulf Coast states exerts its influence over the
Tennessee/Ohio Valleys. Flow will take on a more southwesterly to
southerly component as the surface high shifts toward the
Southeastern U.S., allowing warmer air to advect into the region.
Pressure gradient tightens on Sunday as a low pressure system passes
by to the north, and surface gusts during the afternoon could push
near 30-35mph. A weak frontal boundary will be trailing the low and
should slowly slide southward toward central IL/IN/OH Sunday night
before stalling and lifting northward Monday. Precipitation may
develop near this frontal boundary, some of which could clip our
northern zones Sunday into Monday depending on how far south the
boundary drops, but overall model ensemble consensus is for us to
stay dry. As such, forecast reflects only small (~20%) chances or
rain for this timeframe.

By Monday, a strong trough will eject out of the Four Corners region
and quickly take on a negative tilt as it swings into the
central/southern Plains. This trough will then slide into the
Midwest by Tuesday. Low level flow trajectories ahead of the trough
support a good moisture fetch off of the Gulf of Mexico, and within
its broad warm sector strong shear profiles co-located with the
plume of higher dewpoints/instability will likely support strong to
severe convection in the Plains on Monday and across much of the
Midwest to Mid-South Tuesday. We could receive a glancing blow from
an arcing line of convection with some strong/severe storm potential
late Tuesday into Wednesday, depending on how far south and east the
trough and surface low tracks.

Another trough/shortwave may pass through the region during the mid
to late week timeframe, bringing an additional round of showers and
storms with more strong to severe storm potential. Outside of the
storm potential, temperatures for much of next week will likely be
above climatological norms as we stay within the warm sector of
these systems.

&&

.AVIATION /18Z TAFS THROUGH 00Z SUNDAY/...
Issued at 144 PM EDT Fri Apr 12 2024

An area of MVFR stratus and scattered rain showers will continue to
move across the region this afternoon, quickly exiting by 19-20Z.
Another wave of isolated showers may develop later in the afternoon
and make a run at SDF/LEX/RGA through 23-00Z, but confidence and
coverage of these showers is low enough to leave out of the current
forecast. Later this afternoon, drier air will work in from the
north and west, gradually scattering out low clouds before skies
clear later this evening. Westerly winds will remain gusty through
sunset before gradually diminishing overnight tonight. After low
stratus scatters out this afternoon/evening, forecast confidence is
high in VFR conditions through the remainder of the current forecast
period.

&&

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

&&

$$

UPDATE...CSG
SHORT TERM...KDW
LONG TERM...DM
AVIATION...CSG