Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 111739
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
1239 PM EST THU FEB 11 2016

...Updated Aviation Discussion...

.SHORT TERM (Now through Friday)...
Issued at 302 AM EST Thu Feb 11 2016

The main forecast concern in the short term is light snow chances
Friday.

As of 3 am, northwest flow aloft remains in place across the Upper
Midwest, Great Lakes and lower Ohio Valley. Fast moving but weak
impulses have been riding through this flow periodically and any
moisture available in the atmosphere lies within the DGZ, so very
light flurries or an occasional snow shower have been reported.
Regional radar mosaic shows light returns across southwest Indiana
and northern Kentucky and this will continue for a few hours early
this morning, without any impacts. Otherwise, morning readings were
in the teens to low 20s with wind chills in the single digits to
around 10 degrees.

For today, plan on mostly cloudy skies this morning giving way to
more sun by afternoon. Highs are expected to reach the upper 20s to
mid 30s, the coldest readings across southern Indiana and the
Bluegrass region of Kentucky. We`ll have light north winds 5 to 10
mph.

The surface high quickly moves from Indiana this evening to Virgina
tonight while upstream a fast moving clipper takes a dive toward the
lower Ohio Valley. The signal in the models for this clipper has
been consistent the past few days. This system remains somewhat
moisture limited but light snow is likely to spread into the area
early Friday morning and last through early afternoon. At this time,
the highest chances look to be across southern Indiana south toward
central Kentucky, where a few tenths of an inch are possible. Since
the recent wave train of clippers have overachieved in some spots, a
localized 0.5 to maybe 1 inch report isn`t out of the question, but
that is on the high end of probability. Some slick spots, especially
on any untreated and less traveled roads, are possible for the
Friday morning commute. Plan on highs in the 30s.

.LONG TERM (Friday Night through Wednesday)...
Issued at 304 AM EST Thu Feb 11 2016

The main forecast concern in the long term is the potential for a
winter system Sunday night into Monday night.

In the wake of the Friday snow clipper system, strong Arctic high
pressure builds across the entire area for Friday night. This will
usher in unseasonably cold air. Plan on lows Friday night to range
from 10 to 15F with the typical colder spots falling into the single
digits. Not much recovery expected for Saturday despite having a
mostly sunny day as highs struggle to reach the low/mid 20s. Morning
wind chills will hover a few degrees either side of 0, only
improving to 10 to 15 by afternoon. For comparison, normal highs for
mid February are 45 to 50 degrees.

The next weather system to impact the area comes Sunday afternoon
through Monday night. Phasing between the northern and southern
stream pieces of energy remains the big hurdle and question mark
within the deterministic and ensemble guidance. The 11.00z model
cycle seemed to favor a faster, less amplified/phased solution
across our area, not phasing the two pieces of energy until passing
over the Appalachians. This idea would still potentially bring
accumulating snow to much of the area, but keep the main deformation
band of precipitation to our south/east. However, it bears closely
watching as this system is still several days away and phasing
sooner may trend the system back to the northwest.

Overall, confidence in seeing some precipitation continues to trend
higher, but details and potential snow amounts remain below normal.
For now, bumped up POPs to the 50 to 70 percent range and kept a
rain/snow mix based on temperatures. Soundings show there could be
the potential for a wintry mix in the south toward the TN border but
will hold off for now mentioning in the weather grids.

Beyond that system, it`s looking likely that we`ll finally get a
pattern change toward above normal temperatures and less winter-like
weather. Will trend temperatures toward the upper 40s by mid week
with 50s possible mid/late week.

&&

.AVIATION (18Z TAF Update)...
Updated at 1230 PM EST Thu Feb 11 2016

Have had some bands of high-end MVFR cumulus develop near LEX and
BWG this hour. May briefly see broken cigs at those sites for the
next few hours. Otherwise focus will be on snow chances early
Friday. A mid-level deck will thicken through the evening hours.
Model guidance at this point shows the best chances for snow at KBWG
so have a prevailing group there for several hours, but went PROB30
for the other two sites. Behind those chances we should see an MVFR
deck that sticks around through then end of the forecast period.
Winds will be variable, but should pick up from the west tomorrow
afternoon.

&&

.LMK Watches/Warnings/Advisories...
KY...NONE.
IN...NONE.
&&

$$

Short Term........ZT
Long Term.........ZT
Aviation..........RJS


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