Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 241041

Area Forecast Discussion
National Weather Service Louisville KY
641 AM EDT Wed Apr 24 2019

...Updated Aviation Discussion...

.Short Term...(Today and tonight)
Issued at 300 AM EDT Wed Apr 24 2019

...Another Round Of Storms Later Today, A Few Possibly Strong...

Convection has died off overnight with the loss of instability,
however a few light showers remain. The weak frontal boundary has
stalled across south central KY at this hour. Most spots will stay
dry early this morning with temps in the 50s north of the boundary
and around 60 south of the boundary.

We`ll remain mostly dry for the remainder of the morning and into
the first part of the afternoon. Expect to see a few peeks at the
sun, however we`ll likely stay under pretty heavy mid level cloud
cover for much of the day. This will keep most of southern IN and
northern KY in the low to mid 70s for highs. Meanwhile, southern KY
should jump to the upper 70s to near 80 under less overall sky cover.

As we move through the afternoon, the weak frontal boundary
mentioned above will lift north as a warm front ahead of an
approaching shortwave (this feature is currently over the central
Plains). Although heating/destabilization will be somewhat limited
by sky cover, still expect pockets of 500-1000 J/KG of ML CAPE by
late afternoon, and given a little kick in forcing ahead of the
shortwave should see numerous showers and storms develop as we head
toward sunset. A notable H85-H7 inversion seems to disappear on
forecast soundings around this time as well. Overall, deep layer
shear is a bit stronger today (~40 knots) so any of the more robust
updrafts could organize a bit better. That being said, instability
should be a little weaker. Overall, the severe threat isn`t zero but
it isn`t overly high either. Imagine there will be a few strong to
marginally severe storms to deal with the through evening, with an
isolated damaging wind and marginally severe hail threat. Expect
that our area might get upgraded to a Marginal Risk if some modest
pockets of instability are able to develop this afternoon.

Another concern is that rain may train over the same areas to the
point where some nuisance flooding may occur. Overall, the best
coverage will be across southern IN and northern KY, closest to the
best shortwave energy and frontal boundary and these areas have seen
a lot of rainfall recently.

Coverage may diminish a bit after Midnight with the loss of the the
best instability, however will likely keep chances in overnight as
models still show some ongoing convection. Lows should mostly settle
around 60 degrees.

.Long Term...(Thursday through Tuesday)
Issued at 322 AM EDT Wed Apr 24 2019

Thursday through Saturday Night...

Stalled out frontal boundary is forecast to remain in the vicinity
Thursday morning.  Some scattered convection may be in progress
along the boundary during the morning hours before diminishing by
mid-late morning.  We should see an uptick in convection Thursday
afternoon and evening as mid-level trough axis and associated surface
cold front push into the region.  A band of showers and
thunderstorms looks to cross the region Thursday evening and into
early Friday morning.  Some of the storms with this activity could
be strong with heavy rainfall, gusty winds, and small hail being the
primary weather hazards.  Convection should quickly push east and
out of the area by Friday morning with some partial clearing
expected by afternoon/evening.  Some flat ridging aloft will move
into the region late Friday and into Saturday keeping the region
generally dry.  However, a quick moving system in the Midwest will
slide eastward and may bring a threat of additional rain showers
Saturday evening and Saturday night.

Highs on Thursday will likely top out in the low-mid 70s with
overnight lows dropping back into the lower to middle 50s.  We`ll
see some slightly cooler temps on Friday behind the front with
readings topping out in the upper 60s to the lower 70s.  Highs
Saturday look to range from the upper 60s over southern IN and
northern KY with mainly lower 70s across southern KY.

Sunday through Tuesday...

Moving into Sunday, a rather zonal flow aloft is expected across the
CONUS.  This zonal flow looks to continue through midweek with the
Ohio Valley remaining on the northern periphery of a Gulf Coast
upper ridge.  Several perturbations will move through within the
mean flow and this will likely bring a return of unsettled weather
to the region for Monday afternoon and into Tuesday.  For now, have
generally kept the blended model PoPs here with just slight to
chance PoPs.

Highs Sunday look to warm into the upper 60s across southern IN and
northern KY with mainly lower 70s across southern KY.  Highs Monday
and Tuesday are expected to moderate into the mid-upper 70s possibly
pushing into the lower 80s by Tuesday afternoon.  Lows through the
period will start off the 40s while eventually moderating into the
50s by Tuesday/Wednesday morning.


.Aviation...(12Z TAF Issuance)
Updated at 641 AM EDT Wed Apr 24 2019

A weak frontal boundary is stalled across central KY, with light
northerly winds noted at HNB/SDF/LEX. Meanwhile, BWG is seeing a
general S wind. Still can`t rule out a stray shower this morning,
but chances of hitting negatively impacting a TAF site are very low.

Otherwise, expect mostly dry and VFR conditions to prevail through
at least mid to late afternoon, although VFR ceilings will likely be
around 4-6 K feet at times. Light winds through the morning will
eventually find their way to a light S component by this afternoon
as the frontal boundary lifts back to the north as a warm front.
Late afternoon and especially by evening, a cluster of showers and
storms is expected to affect the northern TAF sites (SDF/HNB/LEX).




Short Term...BJS
Long Term...MJ
Aviation...BJS is the U.S. government's official web portal to all federal, state and local government web resources and services.