Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 080251

Area Forecast Discussion
National Weather Service Louisville KY
951 PM EST SUN FEB 7 2016

...Forecast Update...
Updated at 940 PM EST Sun Feb 7 2016

Cold front continues to make steady progress through the mid-
Mississippi Valley, and we`re finally starting to see radar returns
that could be reaching the ground over southern Illinois. However,
there remains a great deal of low-level dry air to overcome across
southern Indiana and central Kentucky.

Models remain in two camps regarding overnight precip, with the hi-
res models not developing anything until after 09Z, and then closer
to the Cumberland Escarpment, while the synoptic models start to
break out precip by 06Z over central Kentucky.

Will stay close to the current forecast, just pulling all areas into
the chance category with the highest POPs east. Will keep precip
type mixed, as low-level temps remain too warm for all snow.

.SHORT TERM (Now through Tuesday Night)...
Issued at 330 PM EST Sun Feb 7 2016

...Winter Returns Tonight...

Enjoy the last bit of 50 degree weather late this afternoon, because
Winter returns overnight. Latest water vapor imagery shows a potent
shortwave dropping out of the northern Plains/upper Midwest. Could
see some light rain/snow showers overnight, mainly in our eastern
CWA. Could pick up a dusting on a grassy or elevated surface but
not expecting any real accums from this initial wave of rain/snow.

Along and West of the I-65 Corridor...

After a brief morning lull, expect a couple rounds of scattered
numerous rain/snow shower activity through the afternoon. These
showers are tricky as surface temps are expected to be in the upper
30s and low 40s. However, steep low level lapse rates should support
a rain/snow mix in the 37-40 degree range and likely all snow below
37 degrees. Periods of moderate snow are possible, especially in the
afternoon hours, however given the warm surface temps not expecting
a whole lot in the way of accumulation. Rates could be briefly hard
enough to cause a light dusting so use caution through the
afternoon. Will issue a Special Weather Statement over the western
two-thirds of the CWA to account for this.

...Winter Weather Advisory Along I-75 Corridor Monday Evening -
Tuesday Evening...

Over our eastern third of the CWA, expect that scattered to numerous
moderate snow showers don`t arrive until early evening. With surface
temperatures falling by this time, moderate snow showers could begin
to have an impact. With this in mind, elected to go with a Winter
Weather Advisory starting at 5 PM EST in coordination with OHX/JKL.
This is mainly an impact based advisory as actual 1 inch criteria
will be hard to meet except for in isolated locations with each snow
shower. However, with several rounds of snow showers expected
through at least Tuesday evening, amounts of 1 to 3 inches are
possible over the whole time span. More importantly, any moderate to
briefly heavy snow shower could cause travel impacts over a quick
period of time, which is the main reason the advisory is being

One note on the advisory. Could see it possibly needing extended
westward if surface temps don`t get as high on Monday or if main
batch of snow showers arrive later. Also, if snow showers end up
more intense than expected (which they have potential to do given
the steep low level lapse rates and saturation up through a good
portion of the DGZ) look for a potential upgrade. Mid shift will
have more data to look at and can refine headlines as needed.

Most accumulations are expected Monday night and Tuesday as
temperatures stay in the 20s. This will lead to snow ratios likely
in the 15 to 20:1 ration and help squeeze some additional light
accumuations with each passing shower. Please note that snow shower
activity will be off and on and hit or miss. Bottom line, travel
will be impacted AT TIMES.

Lows drop into the teens Tuesday night with some light snow showers
still lingering.

.LONG TERM (Wednesday through Sunday)...
Issued at 330 PM EST Sun Feb 7 2016

Wednesday - Sunday...

Persistent NW flow aloft between NE CONUS troughing and SW CONUS
ridging will result in a cold but mostly dry forecast through the
extended. Will be dealing with a few lingering light snow showers
across our east on Wednesday, with some very light additional
accumulations possible. Temperatures will struggle on Wednesday
under mostly cloudy skies and steady cold advection. Look for highs
only in the low 20s.

Look for cold and dry conditions Wednesday night through Thursday
night as Arctic high pressure settles into the region. Lows will
mostly be in the 10 to 15 degree range Wednesday night, and in the
teens again Thursday night. Highs Thursday will be in the mid 20s to
low 30s.

Will continue to mention slight chances for rain on snow on Friday
as a fast moving clipper dives through the NW flow. Highs should be
in the 30s.

Another Arctic high centers over the Great Lakes through the
weekend. with more cold and dry conditions. Lows Friday night and
Saturday night will be mostly in the teens. Saturday and Sunday
highs will likely be in the 30s.


.AVIATION (00Z TAF Update)...
Updated at 615 PM EST Sun Feb 7 2016

Expect VFR conditions this evening with diminishing SW winds.
Increasingly moist SW flow aloft will bring in a mid-level ceiling
during the evening, but timing any onset of precip will be tricky
due to a very dry boundary layer.

Looks like we will finally have sufficient moisture around midnight
or just after, with precip starting off as all rain. VFR ceilings
and no restrictions to visibility early on, but that will change
through the day.

An impulse diving into the base of the upper trof will arrive early
in the afternoon, and will steepen the lapse rates enough to
introduce the threat of convective snow showers, but mixed precip
will still prevail. Greatest threat will be in LEX, where we are
carrying fuel-alternate ceilings, while SDF and BWG will stay at or
just above the 2000 foot threshold. When it goes all snow, which is
possible in the heaviest precip, wind gusts near 20 kt will
aggravate conditions, and intermittent IFR is likely late in the
afternoon, especially in LEX. However, confidence is not high enough
to include it at this time.


.LMK Watches/Warnings/Advisories...
KY...Winter Weather Advisory from 5 PM EST /4 PM CST/ Monday to 6 PM
     EST /5 PM CST/ Tuesday for KYZ036-037-040>043-047>049-



Short Term.....BJS
Long Term......BJS
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