Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 222318
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
718 PM EDT Thu Jun 22 2017

.Forecast Update...
Issued at 637 PM EDT Thu Jun 22 2017

The widespread area of light to moderate rainfall has lifted to the
north of the Cumberland Parkway early this evening. To the south of
this area, scattered showers continue to move north out of TN. There
looks to be a relative lull in precipitation later this evening as
the larger rain shield lifts out. Thereafter, rain chances will be
on the increase again, particularly across southern IN during the
early morning hours as discussed in the short term discussion below.
Some changes were made to the pops for this evening to better
reflect the expected lull, though at least slight chances were left
in everywhere through the night.

&&

.Short Term...(This evening through Friday night)
Issued at 223 PM EDT Thu Jun 22 2017

...Torrential Downpours Expected...
...Minor Flooding of Small Rivers and Streams Possible...
...Isolated Tornado Not Out of the Question...

~~Main Threats and Timing~~

The best chance for heavy rain in southern Indiana will be from
after midnight tonight through Friday. The best chance for heavy
rain in central Kentucky will be Friday afternoon and evening.

The best chance for isolated tornadoes or damaging wind gusts will
be Friday afternoon in central Kentucky, especially the Lake
Cumberland region. There is also a small chance of an isolated brief
spin-up or wind gust over southern Kentucky this evening.

~~Summary~~

A cold front coming in from the northwest will meet up with the
remnants of Tropical Storm Cindy coming up from the southwest,
leading to widespread rain. Plentiful atmospheric moisture will
result in locally torrential downpours.

~~Rainfall Amounts~~

General amounts of 1 to 3 inches are expected, with embedded bands
of heavier rain. Today`s model runs, with some exceptions, have come
into decent agreement showing the band of heaviest rain between I-64
and the Cumberland Parkway.

~~Confidence~~

At this time, confidence is high that a band of heavy rain will set
up, likely over central Kentucky. Confidence of heavy rain is less
in southern Indiana and southeastern sections of central Kentucky
(Lake Cumberland area).

Small changes in the track and timing of Cindy will lead to
significant changes in where the heavy rain sets up.

~~Details~~

Tropical Depression Cindy, centered near Shreveport, Louisiana at
the start of the short term, will head north into Arkansas tonight
and then northeast into southern Kentucky Friday afternoon.
Meanwhile, a cold front will approach from the northwest, reaching
the Ohio River by Friday evening. It will then pick up Cindy`s
remnants and whisk them off to northern Virginia by dawn Saturday.
The models, including the HWRF, have come into pretty good agreement
with this.

The rain this afternoon has been efficient, with moderate to
briefly heavy rain despite radar dbz`s only in the 40s. As of 1pm
CDT the Kentucky Mesonet site in Simpson County already received
nearly an inch and a half of rain. The rain will continue to move to
the northeast late this afternoon and evening. The HRRR has been
very consistent with the idea of sprouting isolated convection
behind the departing steady rain early this evening. The chance of
isolated showers/storms will be enhanced during a brief window
before sunset if the breaks in the overcast currently over the lower
Mississippi Valley can work their way in. Isolated wind gusts or
even a brief, weak spin-up wouldn`t be out of the question given
strong low level shear and stronger winds aloft as seen on OHX VWP.

After midnight rain chances will increase significantly over
southern Indiana as moisture pools ahead of a cold front approaching
from the northwest and low level jetting increases. Precipitable
water values will increase to 2 to 2.5 inches, leading to locally
heavy downpours.

On Friday the front and Cindy`s circulation will feed on deep
moisture to produce widespread showers and scattered thunderstorms
with torrential downpours. Low and mid level winds will increase
Friday afternoon and low level shear will be strong ahead of and to
the right of the circulation. Though insolation will be at a premium
and instability will be weak, rotation will be possible in the low-
topped convection and could result in isolated wind gusts or brief,
weak tornadoes in central Kentucky. If we get some breaks in the
cloudcover to increase instability, severe chances will increase.
The best chances will be in the Lake Cumberland region.

.Long Term...(Saturday through Thursday)
Issued at 229 PM EDT Thu Jun 22 2017

The long term will be quiet as Canadian high pressure slowly makes
its way across the central and eastern United States. Could see some
valley fog in the Lake Cumberland region Saturday morning.

Temperatures will be very mild for early summer, with highs in the
70s to around 80 through Wednesday, then warming up a bit late in
the week.

&&

.Aviation...(00Z TAF Issuance)
Issued at 717 PM EDT Thu Jun 22 2017

A large area of light to moderate rain will continue to lift north
this evening. This rain may drop visibility at SDF and LEX to 2SM or
less at times over the next couple of hours. Thereafter, there
should be a lull in precipitation at all the TAF sites. There may be
some brief improvement in the ceilings to VFR during this time as
well.

However, as the remnants of Cindy approach early tomorrow morning,
ceilings will lower to MVFR once again. Rain chances will be on the
increase from the morning into the afternoon with a few
thunderstorms possible. Rain will be heavy at times which could
lower visibilities to IFR or below temporarily in the heaviest
showers, mainly tomorrow afternoon. Winds will be gusty out of the
south-southwest through the day Friday.

&&

.Hydrology...
Issued at 259 PM EDT Thu Jun 22 2017

Areas of heavy rain will extend northward tonight. The rain will end
after midnight early Saturday morning. This is due to a combination
of the remnants of Tropical Storm Cindy coming up from the south and
a cold front sweeping in from the northwest. Between 1 and 3 inches
of rain are expected with the entire system. It is important to
note, though, that within this general area of rain there may be
narrow bands of higher amounts where thunderstorms train over the
same locations.

This will lead to rises streams in the area with minor flooding
possible. The largest threat will be in the Green, Barren, and Rough
basins. However, only minor flood levels are expected.

In addition, thunderstorms will produce locally torrential downpours
which could lead to flash flooding.

If you live in a flood prone area, watch water levels closely over
the next few days.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...Flash Flood Watch from 2 AM EDT /1 AM CDT/ Friday through late
     Friday night for INZ076>079-083-084-089>092.

KY...Flash Flood Watch from Friday morning through Saturday morning
     for KYZ023>043-045>049-053>057-061>067-070>078-081-082.

&&

$$

Update...EER
Short Term...13
Long Term...13
Aviation...EER
Hydrology...CMC



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