Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 190522

Area Forecast Discussion
National Weather Service Louisville KY
122 AM EDT Thu Apr 19 2018

...Updated Aviation Discussion...

.Forecast Update...
Issued at 910 PM EDT Wed Apr 18 2018

As of 9 pm EDT, radar shows the line of showers from near Lexington
southwest to Hodgenville, moving quickly east. Highest gusts
reported across the area with its passage has been 48 mph at SDF
with several 40-45 mph gusts across southern IN and north central
KY. Timing the line puts it through the rest of the forecast area
between 10-11 pm EDT. A few rumbles of thunder remain possible in
addition to the gusty winds.

In its wake, expect a sharp temperature drop along with gusts 30-40
mph through the rest of the evening and into the first part of the
overnight. Upstream gusts across southwest IN and southern IL have
been 35-45 mph. As a result, no changes made to the Wind Advisory at
this time.

After some clearing, clouds will fill back in overnight with a low
stratus deck that will likely persist through Thursday morning
across southern IN and north central KY. Lows tonight will be in the
upper 30s to around 40 degrees.

Issued at 630 PM EDT Wed Apr 18 2018

Line of low-topped showers has developed across southern Indiana and
and extreme north central Kentucky. It formed in an area of higher
dewpoints where the recent SPC mesoanalysis shows a bubble of 500
J/kg SB CAPE. It`s racing across the area in a higher shear
environment so the main concern is gusty winds mixing down over the
next few hours. So far however wind gusts have remained at or below
40 mph. Recent HRRR and other hi-res models handling this line
fairly well. Adjusted hourly PoPs to match reality and to
extrapolate the line through the evening hours. Minor other
adjustments were made.


.Short Term...(This evening through Thursday night)
Issued at 315 PM EDT Wed Apr 18 2018

...Strong Winds and Gusty Showers Through This Evening...

Strong and fast-moving sfc low has filled in a little bit, now
1004mb over west-central Indiana. Main challenge through about
midnight tonight will be precip chances and wind potential. Very
high-momentum air is available aloft as the closed upper low makes
its way across Iowa and into northern Illinois. Starting to see wind
gusts around 30 mph already, and these winds will continue to ramp
up as the low passes to our north and its trailing cold front drops

Deep moisture has so far been unavailable to generate precip, but
dewpoints over Kentucky have risen solidly into the 50s. Expect to
have some shallow scattered showers develop later this afternoon
through about mid-evening as the front pushes in. QPF is very light
and convection will be too shallow for any thunder, but these could
get quite gusty. Wind Advisory is already in effect for widespread
recurring 40 mph gusts, and any showers could mix down localized 50
mph gusts.

Steep low-level lapse rates in the post-frontal cold advection will
keep the gusts up around 40 mph through about midnight. Valid time
of the wind advisory looks good.

Precip ends and winds slowly diminish after midnight, and Thursday
will be as much below climo as today is above. Leaned on raw model
consensus in the chilly NW flow and substantial cloud cover, which
will limit max temps to lower/mid 50s.

Another frost/freeze on tap for Thursday night into Friday morning,
as the Bluegrass region looks to bottom out around 29-30 degrees.
Recent cold nights have not seen quite the temp crash advertised in
the models, and we don`t have to miss by much to avoid a freeze, so
will hold off on any Freeze Watch for now. However, widespread frost
is possible throughout the area.

.Long Term...(Friday through Wednesday)
Issued at 325 PM EDT Wed Apr 18 2018

Sfc and upper ridging will dominate through the weekend, with the
upper low trying to come out of the Plains remaining well suppressed
to the south. Temps will run on the low side of climo with no
sensible weather impacts beyond increasing mid/high clouds on

Early next week, the upper low tries to lift into the Tennessee
Valley, so precip chances will be on the increase as lobes of
vorticity pinwheel around the closed low. Expect plenty of cloud
cover and off and on precip chances, with temps close to normal for
late April.


.Aviation...(06Z TAF Issuance)
Issued at 120 AM EDT Thu Apr 19 2018

Expect gusty conditions the remainder of the overnight hours. A
stratus deck will develop early this morning with MVFR ceilings
likely, also should see some fuel-alternate levels. Conditions are
expected to improve to VFR by tomorrow mid afternoon with wind gusts
subsiding as well.


IN...Wind Advisory until 2 AM EDT /1 AM CDT/ early this morning for

KY...Wind Advisory until 2 AM EDT /1 AM CDT/ early this morning for



Short Term...RAS
Long Term...RAS
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