Area Forecast Discussion
Issued by NWS Louisville, KY

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
973
FXUS63 KLMK 081732
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
1232 PM EST MON FEB 8 2016

...Updated Aviation Discussion...

...Forecast Update...
Updated at 1100 AM EST Mon Feb 8 2016

Watching upstream to see how plentiful/widespread snow showers
become this afternoon. This morning`s snows had some 1-2 inch totals
but roads came away looking clear afterward. Think that would be the
case initially again with showers mid to late afternoon, ahead of
the temperature drop associated with our next cold front passing.
Coordinated with PAH and IND and decided to continue our special
weather statement wording for now, but be ready to upgrade to an
advisory for areas outside our current advisory, should snow rates
show up heavy enough and/or temperatures drop faster than expected,
and consequently cause more of a road impact. Otherwise will run
another update blending temperatures with ongoing conditions and
matching current radar trends.

Updated at 755 AM EST Mon Feb 8 2016

A webcam up in French Lick as well as a few others have indicated a
dusting of snow.  Have updated the forecast for current radar trends
as well as bumped down temperatures a degree or two from the model
blend.

Updated at 655 AM EST Mon Feb 8 2016

As of 645 am, radar imagery showed an area of light rain moving east
out of southeast Indiana/east central KY and another area of a mix
of rain/snow moving into southwest Indiana and west central KY.
Increased POPs to better depict these areas of precip moving through
this morning.  The latest HRRR run has a good handle on it. The
second batch of precip is expected to stay a mix of rain/snow as it
moves through southern IN/central KY this morning, but it should
have little to no impact on the morning commute as sfc temps are
above freezing and will likely rise a bit after sunrise.  Also road
temps are in the upper 30s/lower 40s which should prevent any travel
hazards this morning.

.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
Mon/Tues.

&&

.AVIATION (18Z TAF Update)...
Updated at 1232 PM EST Mon Feb 8 2016

Another upper disturbance will rotate through the TAF sites this
afternoon and early evening, bringing numerous rain/snow showers
despite surface temperatures being in the upper 30s to around 40.
Some of the snow showers will be moderate to briefly heavy with
quick light accumulations possible. Winds will also be steady out of
the W and WSW with gusts up around 20 to 25 mph at times. Snow
showers may be heavy enough to reduce visibilities below a mile at
times, although are too spotty to mention prevailing for now. Will
amend as necessary when better returns approach a terminal.

Have included best timing for most intense snow shower activity with
BWG/SDF through sunset. LEX will be later from around sunset through
Midnight. After that, lingering light snow showers are expected to
be around, although will keep vis up. Ceilings will range between
MVFR/VFR in the evening, then dropping to low MVFR toward dawn on
Tuesday. LEX will have the best shot at a period of IFR this
evening.

&&

.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-
     054>057-065>067-077-078-081-082.

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

&&

$$

Update.........RJS/AMS
Short Term.....AMS
Long Term......AMS
Aviation.......BJS



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.