Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 280539

Area Forecast Discussion
National Weather Service Louisville KY
139 AM EDT WED SEP 28 2016

...Updated Aviation Discussion...

...Forecast Update...
Issued at 835 PM EDT Tue Sep 27 2016

Synoptic and hi-res models alike remain quite bullish on precip for
Wednesday as the closed upper low dives into Indiana, and a vort
lobe strong enough to have a surface reflection swings through the
Ohio Valley. Expect POPs to ramp up quickly around midday, and now
confidence is high enough to bump to 60-70%, only tapering down to
40-50% in south-central Kentucky. Still expecting the best focus in
the afternoon, with small hail remaining in play.

.SHORT TERM (Now through Wednesday Night)...
Issued at 255 PM EDT Tue Sep 27 2016

A deep 500mb closed low centered over the Great Lakes region this
afternoon will sink south into the lower Ohio Valley through the
short term period. A couple of vorticity lobes rotating around this
upper low will bring some rain chances to the region through
Wednesday night.

A strong vortmax will approach and move through during the day
tomorrow. Showers will develop across Indiana on Wednesday morning.
They will become more numerous through the morning hours across
southern IN and move through central Kentucky through the afternoon
hours. Steeper lapse rates, especially across central KY in the
afternoon will lead to some instability. With freezing levels around
8-9 kft, a few rumbles of thunder are possible. Some very small hail
also cannot be ruled out tomorrow afternoon. The scattered line of
showers will move east of the area late tomorrow afternoon, but some
more showers could develop overnight, mainly across southern IN and
north central KY as another weaker disturbance moves through.

Lows tonight should be a bit warmer than last night in the lower to
mid 50s. Tomorrow`s highs are tricky as they will depend on rain
coverage and cloud cover. Lows tomorrow night will be back into the
upper 40s to around 50.

.LONG TERM (Thursday through Tuesday)...
Issued at 308 PM EDT Tue Sep 27 2016

Thursday - Saturday...

The upper low will stall out and meander around the lower Ohio
Valley through the beginning of the weekend. This will lead to cool
temperatures and rounds of showers and a few rumbles of thunder
through Saturday. Rain will not be continuous through this period as
the timing of showers will depend on the vortmaxes rotating around
the upper low. In general, precipitation chances have been
increased further to the south and west through this period as models
get a better handle on the position of the upper low and moisture
associated with it.

Thursday and Friday will be cool with highs topping out in the 60s
across the region. There will be a small diurnal spread with lows in
the 50s. We could start to see a bit of a warm up by Saturday as
the upper low begins to lift off to the northeast.

Sunday and Monday...

The upper low will continue to lift out through Sunday. As it does
we will see a return to a drier forecast along with moderating
temperatures. Highs look to climb back into the 70s with lows in the


.AVIATION (06Z TAF Update)...
Issued at 138 AM EDT Wed Sep 28 2016

Not much change in the ongoing forecast for aviation.  Clear skies
will be present tonight with VFR conditions expected through sunrise.

Strong closed upper low still on target to dive southward into
Indiana this afternoon.  Cloud cover will increase rapidly after
sunrise with a lowering ceiling setting in by afternoon.
Precipitation is expected to break out by mid-late morning across
southern Indiana and into northern KY and will impact the KSDF and
KLEX terminals. No restrictions expected initially, but as the rain
gets better established, look for MVFR visibility and ceilings,
albeit just above the fuel-alternate threshold. Winds come around to
the west and eventually the NW late in the afternoon, with gusts
just shy of 20 kt.

KBWG may not see much active weather in this forecast period given
its farther south relative position.  Some VCSH will be possible at
KBWG after 28/21Z.


.LMK Watches/Warnings/Advisories...


Short Term.....EER
Long Term......EER
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