Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 171753

Area Forecast Discussion
National Weather Service Green Bay WI
1153 AM CST Wed Jan 17 2018

Updated aviation portion for 18Z TAF issuance

.SHORT TERM...Today...Tonight...and Thursday
Issued at 356 AM CST Wed Jan 17 2018

Blowing snow will be the main concern today, as increasing
southwest winds blow around the fresh snow that fell Sunday
night through Monday night. A foot or more of snow fell across the
lakeshore counties, so that`s where the greatest potential for
significant blowing and drifting snow will be.

Decided to issue a winter weather advisory for Door county, which
is typically windy and has as much as two feet of powdery snow on
the ground and adjacent frozen bay. Travel on north south roads
such as highways 42 and 57 cold become difficult this afternoon
and early evening. Elsewhere drifting snow and some blowing snow
is expected in rural areas.

Warm advection should make for near normal high temperatures today,
despite considerable cloud cover. Steady temperatures are expected
tonight with a wind and continued warm advection. A small clipper
system should pass north of Wisconsin Thursday, but limited
moisture should keep it from producing any snow here. Highs will
be above normal.

.LONG TERM...Thursday Night Through Tuesday
Issued at 356 AM CST Wed Jan 17 2018

The main forecast concern revolves around the potential of a
cyclone to pass across the region late in the weekend into early
next week. The gfs and canadian models have trended north with
the track of the cyclone over the past 24 hours, while the ecmwf
has trended further south. Prefer a track more similar to the gfs
ensemble mean, which is a decent compromise between the
operational gfs and canadian.

Thursday night through Friday night...As a shortwave trough exits
to the east on Thursday night, should see any lingering clouds
over northern WI depart during the evening or early overnight.
Thereafter, will see periods of broken mid and high clouds
overhead for the rest of Thursday night into Friday night.
Southwest winds will be gusty on Friday, though they will
continue to bring in warmer air. Highs on Friday should reach into
the mid and upper 30s. Winds remain breezy on Friday night so
temps should not fall much.

Rest of the forecast....Low pressure will be emerging from the
Rockies on Saturday, but still looks too far away for any impacts
on our weather. Should see mid and high clouds become overcast
through the day though. Low level moisture doesn`t arrive until
Saturday night as a warm front lifts into southern WI. Light
precip appears possible then (wintry mix or freezing drizzle?),
but heavier precip is due to arrive on Sunday as low pressure
moves into the mid- Mississippi Valley. The heavy precip will then
continue for Sunday night into Monday before ending on Monday
night. The track of the cyclone will play a large role in
determining which locations see heavy snow versus a wintry mix,
and expect to see some adjustments over the coming days. Even a
slight change of the track could make a huge difference in the
forecast weather. &&

.AVIATION...for 18Z TAF Issuance
Issued at 1152 AM CST Wed Jan 17 2018

VFR conditions are expected to prevail in most areas this
afternoon into Thursday. High clouds will slowly exit the area
this afternoon from northwest to southeast, then additional mid to
upper level clouds will spread back across the area late tonight
and Thursday. Some lower clouds (MVFR) are possible Thursday as a
upper level disturbance approaches.

Gusty west to southwest winds will continue to create some blowing
and drifting snow and could reduce visibility into the IFR range
at K2P2, K3D2, and KSUE this afternoon and evening. Elsewhere,
less snow from the last snow event and lighter winds should limit
the blowing snow potential, but minor blowing/drifting will still
be possible at times in the strongest gusts.

Low level wind shear will continue through the evening across the
area as 50+ knot winds persist near 2000 ft AGL.

Winter Weather Advisory until 9 PM CST this evening for WIZ022-


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