Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 081115

Area Forecast Discussion
National Weather Service Louisville KY
615 AM EST MON FEB 8 2016

...Updated Aviation Discussion...

.SHORT TERM (Now through Tuesday)...
Issued at 300 AM EST Mon Feb 8 2016

...Winter Weather Advisory this Evening - Tuesday Evening...

The biggest change for this forecast package will be to expand the
Winter Wx Advy westward into the Louisville Metro area.  According
to the latest model data, a change over from rain to snow is still
expected this evening probably during the latter half of the evening
rush hour.  Although snow shower activity will be hit and miss, the
latest WRFs and NAM indicate sct-numerous snow showers over our
region this evening.  Soundings still exhibit a convective nature
with bursts of moderate snow reducing vsbys and causing quick, light
accums so feel the risk of impact to the evening rush warrants the
advisory expansion.  The Winter Wx Advy expansion will extend from
Lake Cumberland region to Louisville Metro to Scott County, IN and
points eastward.  According to the latest model data, this area also
has the best chance at seeing 2-2.5 day (Mon evening - Wed morning)
snow accums between 1-3 inches with the highest numbers still
expected in the Bluegrass region. Also, some of the latest model
data indicates a slightly longer period of light accumulating snow
into Wed morning especially across the Bluegrass region.  A time
extension to the advisory was considered, but in coordination with
neighboring offices decided to hold off for now.  Will need to
consider the time extension again though especially for our east
central KY counties and especially if Wed morning commute looks to
be impacted.

Mon-Tues Overview

An anomalous upper low over the Midwest with many shortwaves
rotating around it will cause on and off showery activity today
through Tues.  With boundary layer temps in the upper 30s/lower 40s
through this afternoon, many locations will see mainly rain showers
this morning/afternoon.  Colder air will filter into the region from
W to E across the area late afternoon through this evening changing
rain showers to snow showers.  P-type will remain snow showers Mon
night-Tues as the cold airmass settles in the region.  Model
soundings indicate that late this afternoon/evening and Tues
afternoon/evening may be time periods where snow shower intensity
increases to moderate in spots causing travel difficulties. Light
accumulating snows this evening through Tues look to total up to 2
inches.  These accums will be spotty however in the showery regime.

Temps should top out in the mid 30s to lower 40s early-mid afternoon
today before taking a dive into the lower 30s this evening.  Lows
tonight should drop into the lower 20s...possibly colder in
locations that see a light accumulation of snow this
evening/overnight.  Highs for Tues will be limited to the mid to
upper 20s.

.LONG TERM (Tuesday Night through Sunday)...
Issued at 325 AM EST Mon Feb 8 2016

Tuesday Night - Wednesday...

Light on and off snow showers will continue Tues night into Wed in
the active northwest flow although the upper trough will begin to
pull farther east of the region by mid week.  As mentioned in the
short term discussion, the Winter Wx Advy may need a time extension
for east central KY as light accumulating snow will continue through
Wed am and may impact the Wed morning commute.  Total snow accums
through Wed should range from 1-3 inches with some spots that get
missed seeing less than that and others that see repeated bouts of
snow showers seeing a little more than that.  Low clouds and
flurries should stick around through much of the day Wed and into
Wed evening.

Temps will be quite chilly for mid week with highs on Wed only
reaching the lower 20s possibly some upper teens over southern IN.
Wed night lows will drop into the upper single digits and lower 10s
with winds chills near zero.

Thursday - Sunday...

Models diverge for the latter half of the week.  Both the GFS/ECMWF
have a signal for a late week clipper.  However, the GFS brings it
through on Thu/Thu night and the ECMWF brings it through on Fri/Fri
night.  Will stick with low POPs in the Fri/Fri night time frame as
that has been the more consistent signal.  Of note though, ECMWF has
a very robust clipper in that time frame and won`t totally buy that
intensity quite yet.  Temps look to moderate a little for Thu/Fri
with highs in the 30s by Fri.

Sat/Sun look dry but another surge of cold air is apparent in the
long range models with the ECMWF being the coldest.  Another
potential wintry weather system that has had a consistent signal in
the long range data may affect the Ohio Valley the following


.AVIATION (12Z TAF Update)...
Updated at 613 AM EST Mon Feb 8 2016

A couple waves of precip, mainly rain, will move through central
Kentucky this morning, gradually moistening the low level dry
environment. VFR ceilings will lower throughout the day, dropping
into the MVFR range solidly this afternoon as the upper level system
passes overhead. Plan on scattered to numerous showers developing by
19-20z. This should be initially a rain/snow mix but go over to all
snow by 21z or so. Periods of IFR are expected in the heavier snow
showers. Precipitation should linger into the evening hours before
diminishing however lower ceilings will persist through the end of
the TAF period.

Winds will be out of the west for the entire period, gusting to near
20 kts this afternoon.


.LMK Watches/Warnings/Advisories...
KY...Winter Weather Advisory from 5 PM EST /4 PM CST/ this afternoon
     to 6 PM EST /5 PM CST/ Tuesday for KYZ029>043-045>049-

IN...Winter Weather Advisory from 5 PM this afternoon to 6 PM EST
     Tuesday for INZ078-079-091-092.



Short Term........AMS
Long Term.........AMS
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