Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 291723
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
123 PM EDT Sat Apr 29 2017

...Updated Aviation Discussion...

.Forecast Update...
Issued at 1242 PM EDT Sat Apr 29 2017

Outflow boundary from this morning`s storms currently sitting south
of a line from Yeaman to Elizabethtown to Lexington. Temperatures
north of the outflow boundary currently in the upper 60s to low 70s,
while temperatures south of the outflow boundary are in the 80s.
This boundary will create a couple of forecast issues for this
afternoon. 1, High temperature forecasts north of the boundary are
probably too warm, and have adjusted highs downward on the order of
3 to 5 degrees, but this may not be enough, even with the warm front
forecasted to lift north of the CWA by late afternoon. 2, The
outflow boundary could serve as a focal point for an isolated storm
or two this afternoon. Current thinking is that the cap will be too
strong for storms to form, and have kept most areas dry this
afternoon, but this will be closely monitored through the afternoon
hours.

Issued at 1055 AM EDT Sat Apr 29 2017

Will let Flash Flood Watch expire at 15z as rainfall has diminished
across most areas. Areal flood warnings will continue through the
afternoon as waters slowly recede.

Issued at 848 AM EDT Sat Apr 29 2017

Several areas in southern Indiana have picked up tremendous amounts
of rainfall since last night, with some isolated areas seeing as
much as 7 to 8 inches of rainfall. This has led to numerous reports
of flooding and resulted in road closures and even some water
rescues across Dubois County. Showers and thunderstorms along and
north of a warm front/outflow boundary near the IN/KY border are
still ongoing this morning, and will only make flooding issues
worse. The good news is that high-res models show the warm front
lifting north over the next few hours, and precipitation coverage
dropping quickly by the afternoon hours to allow some drying. Still
expecting a hot and muggy afternoon for most areas, with record to
near record high temperatures possible.


Issued at 626 AM EDT Sat Apr 29 2017

The first wave of storms has moved off to the east and dissipated
this morning. However, another round of storms is moving into
southern IN. These will bring additional torrential rainfall and
continuous lightning. They could worsen or renew flooding in some
locations. In addition, these storms are tall enough to produce some
hail. They will continue to work their way across southern IN and
portions of north central KY this morning.

&&

.Short Term...(Today through Sunday)
Issued at 321 AM EDT Sat Apr 29 2017

...Flash Flooding Continuing Early This Morning...

The main concern for early this morning will be the continuing flash
flood threat across portions of southern IN and north central KY. As
of 3 AM thunderstorms with very heavy rainfall were training across
the counties on either side of the Ohio River. Numerous reports of
flooding with roads closed and a few cars stranded with rescues have
been received this morning. The main area of rain has shifted to
just south of where current flash flood warnings currently are, so
more warnings may be warranted this morning. However, back to the
west thunderstorms with torrential rainfall are becoming more
scattered and less continuous, so the threat should diminish
somewhat as we head towards dawn.

Showers and thunderstorms will continue into the morning hours after
sunrise, but the area of rain is expected to lift to the north as we
head towards mid day. Skies will become partly cloudy today to
mostly sunny. We will be solidly in the warm sector today with
continuing southerly winds and warm air advection. High temperatures
will rise into the mid to upper 80s today. Soundings do show plenty
of instability this afternoon, but there will be a bit of a cap and
little trigger in the warm sector so will keep the forecast mainly
dry today except closer to the warm front over portions of southern
IN. With the high instability, if any storms do develop, they could
become strong to severe with damaging winds and large hail.

Tonight will be similar to this afternoon with just a small chance
for storms in southern IN. Low temps will again be on the warm side
only dropping into the upper 60s to around 70.

For Sunday, a low pressure system will start to eject northeast out
of the Plains. A line of showers and storms will develop to our west
ahead of the cold front associated with this system. These storms
will start to move into areas west of I-65 late in the afternoon.
Heavy rain and gusty winds will be possible with these storms.

.Long Term...(Sunday night through Friday)
Issued at 330 AM EDT Fri Apr 28 2017

...Another Round of Heavy Rain and Some Severe Potential Late
Sunday...

Showers and storms ahead of a cold front associated with a low
pressure system will continue to cross the region on Sunday evening
into the overnight hours. Soundings do show some instability and
strong wind shear and helicity. However, they are also very
saturated. Therefore some strong storms will be possible with this
system with damaging winds. Very heavy rainfall will be possible as
well so flash flooding may again be a concern. These storms should
be out of the area by mid day on Monday.

We will have a period of dry and cooler weather Monday night through
Tuesday evening. A deepening trough will then approach from the west
and move through. This looks to become a cutoff low across the
Tennessee Valley through the end of the work week. Rain and a few
thunderstorms will be possible off and on from Wednesday through the
end of the week with this system. It will also bring much cooler
temperatures with highs in the 60s and lows in 40s for the end of
the week.

&&

.Aviation...(18Z TAF Issuance)
Issued at 120 PM EDT Sat Apr 29 2017

Rains have tapered off at SDF, but we still have a weak warm
front/outflow boundary in the vicinity. That should make the winds
variable for another hour or two at LEX before they become more
southerly. Southerly winds continue at all sites overnight, with
some low-level wind shear in place as a 40-45 knot jet develops.
These winds will mix down Sunday morning, bringing gusty conditions,
25-30 knots likely by late morning. Precipitation should hold off
entering the terminals till just after this period.

&&

.Climate...
Issued at 830 AM EST Fri Apr 28 2017

Temperature and rainfall records for the weekend:

            4/29 Warm L   4/29 Record H   4/30 Warm L  4/30 Record H
Louisville   67 (1951)      89 (1899)      70 (1899)    91 (1894)
Lexington    67 (1899)      86 (1899)      70 (1899)    91 (1942)
Bowling G.   67 (1899)      91 (1894)      68 (1899)    92 (1942*)
Frankfort    63 (1899)      89 (1914)      66 (1910)    91 (1942)

            4/29 Rainfall 4/30 Rainfall
Louisville   2.02" (1927)   2.37" (1983)
Lexington    1.31" (2014)   3.21" (1909)
Bowling G.   2.40" (1912)   3.00" (1911)
Frankfort    2.20" (2002)   2.62" (1909)

&&

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

$$

Updates...MJ/DM
Short Term...EER
Long Term....EER
Aviation...RJS
Climate......RJS


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