Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 160726
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
326 AM EDT Mon Apr 16 2018

.Short Term...(Today through Tuesday)
Issued at 311 AM EDT Mon Apr 16 2018

The center of the strong upper level low (ULL) that has brought the
country a variety of weather is beginning to move into the Ohio
Valley at this hour. Low level moisture wrapping around the ULL
combined with steep low level lapse rates have led to the
development of showers for the past several hours, though recent
radar scans indicate a relative lull in activity. Models indicate
another wave of moisture to swing into southern Indiana and
central Kentucky after 13-14z this morning, and this should help
to kick off the development of scattered precipitation through the
afternoon.

Temperatures have been steadily decreasing this morning, and we
should see the p-type switch from rain to snow and/or graupel in the
next few hours. Snow should be the dominant p-type of the day after
sunrise as steep low level lapse rates and some dry air near the
surface help evaporatively cool the lower atmosphere to keep the
precipitation frozen. These conditions could lead to many places
observing snow showers with surface temperatures initially as warm
as 40 degrees. Ground temperatures remain quite warm, so we
shouldn`t see any issues with snow sticking to roads. However, we
could see some very, very light accumulations on grassy or elevated
surfaces in some of the stronger snow showers this morning and early
afternoon. Give the scattered nature of the snow showers, expect any
accumulations to be spotty and not widespread.

The cold temperatures will also be quite noticeable today. Afternoon
highs will struggle to get into the 40s for many locations, and when
you factor in breezy westerly winds, wind chills will only be in the
20s to 30s. We could come close to tying or breaking some record
cold max temperatures for today, as they are as follows:

SDF 42, 1905
LEX 38, 1905
BWG 48, 1984
FFT 40, 1952

The ULL will begin to depart our region tonight, and slowly take the
clouds with it. Model have come in slightly cooler with
temperatures, to where now a majority of the CWA will drop into the
upper 20s or right around 30 degrees tonight into tomorrow morning.
As a result, a freeze warning will be in effect for much of the
overnight and early Tuesday morning hours.

Upper level ridging will result in much warmer temperatures for
Tuesday. Warmest highs will be across southwestern portions of the
CWA near Bowling Green, where highs could top out in the mid 60s.

&&

.Long Term...(Tuesday night through Sunday)
Issued at 321 AM EDT Mon Apr 16 2018

An approaching cold front will bring the chance for a few showers
Wednesday afternoon into the evening hours. Model QPF is generally
around or less than a tenth of an inch. Thursday and Friday will be
cooler again behind the cold front, with highs in the mid 50s to
around 60 and lows in the mid 30s to lower 40s.

A strong wave will eject into the southern Plains late Friday into
Saturday, and could bring some potentially wet and cloudy weather to
the lower Ohio Valley. The latest 00z GFS is a bit quicker than
other guidance in ejecting the wave, and has some light rain
beginning to impact southern Indiana and northern Kentucky Saturday
afternoon and evening. The ECMWF keeps the CWA dry Saturday, but
brings moisture to central Kentucky Sunday afternoon. Meanwhile, the
Canadian model takes the wave much further south than the GFS and
ECMWF and keeps all of central Kentucky and southern Indiana dry for
the weekend. Those with plans this upcoming weekend should certainly
stay tuned to the latest weather forecasts, as spread in timing and
placement of this system amongst models makes this a low confidence
forecast.

&&

.Aviation...(06Z TAF Issuance)
Issued at 110 AM EDT Mon Apr 16 2018

An area of low pressure moving through the upper Ohio Valley and
Great Lakes will bring gusty west winds to the region.  Showers
currently moving through southern IN and into central KY will
continue to move east.  These will affect KSDF at the very start of
the period and then affect KLEX after 16/07Z.  MVFR ceilings are
expected overnight and into the morning hours.  We expect to see
those MVFR cigs improve to VFR by the afternoon.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...Freeze Warning from 10 PM EDT /9 PM CDT/ this evening to 10 AM
     EDT /9 AM CDT/ Tuesday for INZ076>079-083-084-089>092.

KY...Freeze Warning from 10 PM EDT /9 PM CDT/ this evening to 10 AM
     EDT /9 AM CDT/ Tuesday for KYZ023>043-045>049-053>057-
     061>067-070>078-081-082.

&&

$$

Short Term...DM
Long Term...DM
Aviation...MJ



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