Winter Storm and Winter Weather in Wisconsin, November 25 to 26, 2018

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
1213 PM CST Sun Nov 25 2018

.UPDATE...

Tightened up the gradient of snow amounts as anticipated. This
leaves locations along and northwest of a line from Mineral Point
to Madison to Sheboygan with little to no accumulation. Kept
totals in the 8-10 inch range in the far southeast, highest away
from the lake. Will be coordinating with neighboring offices this
afternoon to make any needed adjustments to the hazards. The most
impactful change would be if an upgrade to a blizzard warning is
needed for locations along the IL border.

&&

.AVIATION(18Z TAFS)...

The snow forecast is generally on track from previous thinking.
The main change this morning is to cut out snow almost entirely
along and northwest of a line from MRJ to MSN to SBM. Totals
increase rapidly toward the southeast, peaking in the 8-10 inch
range toward BUU and ENW. Since there is such a tight gradient in
totals, any slight shift in the storm track will have large
impacts in amounts for locations within the gradient. If anything,
the storm would probably shift a little more southward given
latest trends.

Expect rapidly deteriorating conditions late this afternoon and
into the evening as the snow moves in. Visibilities will likely
drop to 1/4 to 1/2 mile at times, with 1-2 inch an hour rates. The
heaviest snow should fall between 22Z and 06Z. Winds will pick up
this evening into tonight, with blowing snow probably reducing
visibilities into early Monday morning, especially near Lake
Michigan. Snow should come to an end in the far southeast by
10-12Z.

The snow will be on the wet side...with average ratios around 10
to 1. Could see a little mix with rain initially, especially near
Lake Michigan.

&&

.PREV DISCUSSION... (Issued 959 AM CST Sun Nov 25 2018)

UPDATE...

The bulk of 12Z models are in and have overall wobbled back
southward. At first glance, snow amounts will need to be tightened
up due to quite the gradient with this system. Madison may see
little to no snowfall. Amounts toward the southeast still look
reasonable, within an inch or two of the latest forecast models.
Will need to consider if any changes in headlines are needed on
the northern fringe of this system. Also pondering upgrading to a
blizzard warning in the far south/southeast, as conditions will be
close to criteria. Will continue to evaluate 12Z guidance and
monitor current upstream conditions to get a better handle on the
finer details of this system.

MARINE...

Nearshore Waters...Small Craft Advisory continues for this
afternoon, with a Gale Warning for tonight. Strong low pressure
passing by to the southeast will bring increasing north to
northeast winds of 15 to 25 knots this afternoon, with gusts to 30
knots. Winds will become north gales of 35 to 45 knots tonight.
They will back northwest Monday, with gusts of 25 to 30 knots.
Waves of 3 to 6 feet later this afternoon will build to very high
waves of 8 to 11 feet tonight, slowly subsiding to 3 to 6 feet by
late Monday afternoon. Thus, a Small Craft Advisory will be
needed Monday, after the Gale Warning expires.

Open Waters...Gale Warning has been extended northward up to a
Sturgeon Bay to Point Betsie line, from 03Z to 12Z Monday. North
gales of 35 to 40 knots are expected during this period. Very high
waves of 8 to 12 feet, occasionally to 16 feet, are expected
tonight, slowly subsiding to 4 to 6 feet, occasionally to 8 feet
Monday night.

The Gale Warning remains in effect for the south half of Lake
Michigan late this afternoon and tonight. Northeast to north gales
to 35 knots are expected by later this afternoon, becoming north
gales of 40 to 45 knots tonight. Some storm force gusts to 50
knots are possible later this evening toward the south end of the
lake. The duration of these gusts would be a few hours. Will
monitor this potential and the need for a Storm Warning. Gales
will linger Monday morning, before slowly diminishing Monday
afternoon and night. Very high waves of 14 to 18 feet,
occasionally to 23 feet, are expected tonight into Monday morning.

PREV DISCUSSION... (Issued 611 AM CST Sun Nov 25 2018)

UPDATE...

The latest HRRR model (10z) has that initial frontogenesis band a
little further north into Racine/Kenosha/Walworth than the 08z
run. It seems to be picking up on some lake enhancement in the
reflectivity over far southern Milwaukee county, and Racine &
Kenosha counties. These areas are covered in the Winter Storm
Warning. We can expect whiteout conditions in any heavier snow
band this evening due to the gusty winds.

AVIATION(12Z TAFS)...

MVFR ceilings continue to linger in the 1500-2500ft range
throughout southern Wisconsin and are expected to stay there until
perhaps mid-morning when some brief dry air moves in ahead of the
next system. Light snow may begin in the early afternoon, but
temps will be just above freezing during this time.

Conditions will quickly deteriorate late this afternoon through
the evening hours, particularly in southeast Wisconsin (Including
MKE, RAC, ENW) where some 1/4SM visibility is likely at times in
any heavy snow band that develops, exacerbated by strong northeast
winds. Winds will be on the increase through the afternoon and
evening hours during our period of heaviest snow. There will be a
sharp cutoff to the snow over south central WI, right around MSN.

Snow will taper off late tonight over southeast WI and we should
see VFR ceilings or even some breaks in the clouds by late
morning to mid afternoon west to east. Winds will remain breezy
out of the northwest on Monday, so there could be some drifting
snow.

PREV DISCUSSION... (Issued 437 AM CST Sun Nov 25 2018)

SHORT TERM...

Today and Tonight...Forecast Confidence is Medium to High.

Low pressure over south central KS this morning will slide
northeast through central IL this evening and across northern
Indiana overnight. There is an impressive upper low, so expect the
system to take on a negative tilt as it reaches IL and set up a
heavy snow band on the northwest side. This is a slower system
than what was previously forecast. The system will bring a swath
of heavy snow and blustery winds to southeast Wisconsin from late
afternoon through the overnight hours. Expect travel difficulties,
especially during the early evening hours. Near- blizzard
conditions are expected in the Racine and Kenosha area this
evening.

We could see a band of light snow spread into southern WI as early
as noon today with an initial band of mid level frontogenesis, but
temperatures will be fairly mild, so adjusted the warning/advisory
times to begin mid afternoon when the snow would have a higher
impact on travel. Some minor changes in the track could mean some
big differences in snow totals for the region. There will be a
tight gradient between heavy snow and no snow in the Iowa,
Lafayette, Dane, Dodge, and Sheboygan county areas. I opted to
leave these counties out of an advisory for now. The latest HRRR
model took a little shift to the south.

Far southeast WI (Racine and Kenosha) will have a solid 6-hr
period with at least moderate snow this evening (6 pm to midnight)
due to deep and strong frontogenesis, along with warm air
advection within the left front quadrant of the upper jet.
Northeast winds straight off the lake will be sustained at 20 to
25 mph with gusts of 40 to possibly 45 mph, mainly between 9 pm
and 3 am. The high winds with heavy snow will lead to white-out
conditions for a period of time. We held off issuing a blizzard
warning for now due to collaboration and slight uncertainty of
when/where the heaviest snow band will occur.

Monday afternoon through Wednesday night...Forecast confidence
high.

The large occlusion over the Great Lakes and se Canada will be
slow to move out of the area. Cyclonic flow and cold temps will
continue with perhaps flurries at times. High pressure will build
into srn WI Wed aft-nt.

LONG TERM...Thursday through Saturday...Forecast confidence
low to medium.

There remains low confidence of the upper air pattern and
pressure pattern for end of the week. It does appear though a
shortwave trough and associated warm advection will bring good chances
for light snow Thu-Thu nt. Afterward, much uncertainty on whether
a deep cyclone will develop over the Great Plains Fri-Fri nt and
move into the Upper MS River Valley for Saturday. Chances of rain
and snow is forecast at this time.

AVIATION(09Z TAFS)...

MVFR ceilings continue to linger in the 1500-2500ft range
throughout southern Wisconsin and are expected to stay there until
perhaps mid-morning when some brief dry air moves in ahead of the
next system. Conditions will quickly deteriorate through the
afternoon and evening hours, particularly in southeast Wisconsin
where some 1/4sm visibility snows are possible. Winds will be on
the increase through the afternoon and evening hours as some of
the heaviest snows occur.

MARINE...

Another period of gales to potentially storm force gusts are
expected for the south half of Lake Michigan this afternoon
through Monday morning as a deepening low pressure system
approaches the region. Held off on a storm warning as the period
for the potential storm force winds is small tonight and confined
to the far southern portion of the lake.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Storm Warning from 3 PM this afternoon to 6 AM CST Monday
     for WIZ065-066-068>070.

     Winter Weather Advisory from 3 PM this afternoon to 6 AM CST
     Monday for WIZ059-060-064.

     Winter Storm Warning from 3 PM this afternoon to 9 AM CST Monday
     for WIZ071-072.

LM...Gale Warning from 3 PM this afternoon to noon CST Monday for
 	 LMZ366-565-567-868-080-669-671-673-675-777-779-870-
	 872-874-876-878

     Small Craft Advisory until 6 PM CST this evening for LMZ643>646.

     Gale Warning from 6 PM this evening to 6 AM CST Monday for
     LMZ643>646.

&&

Update...DDV
Today/Tonight and Aviation/Marine...Gehring
Monday THROUGH Saturday...Cronce

Hazardous Weather Outlook...UPDATED
National Weather Service Milwaukee/Sullivan WI
938 AM CST Sun Nov 25 2018

WIZ046-047-051-052-056>060-062>072-261545-
Marquette-Green Lake-Fond Du Lac-Sheboygan-Sauk-Columbia-Dodge-
Washington-Ozaukee-Iowa-Dane-Jefferson-Waukesha-Milwaukee-
Lafayette-Green-Rock-Walworth-Racine-Kenosha-
938 AM CST Sun Nov 25 2018

This Hazardous Weather Outlook is for portions of east central
Wisconsin, south central Wisconsin and southeast Wisconsin.

.DAY ONE...This Afternoon and Tonight

A winter storm will impact the area late this afternoon and
tonight. A Winter Storm Warning and Winter Weather Advisory has
been issued for portions of southeast and south central Wisconsin.
The heavier snowfall amounts are expected to be toward far
southeast Wisconsin, including the Milwaukee area.

Strong wind gusts of 35 to 45 mph will combine with moderate to
heavy snow tonight to bring near blizzard conditions from
Milwaukee, to Kenosha and west to Janesville. The heavy snow and
strong winds could still shift farther north or south, so changes
in winter weather impacts and headlines are still possible.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Snow and high winds may linger into Monday morning over far
southeast Wisconsin.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed, but snowfall reports this
afternoon through Monday morning will be appreciated.

LMZ643>646-261545-
Sheboygan to Port Washington WI-
Port Washington to North Point Light WI-
North Point Light to Wind Point WI-
Wind Point WI to Winthrop Harbor IL-
938 AM CST Sun Nov 25 2018

This Hazardous Weather Outlook is for the nearshore waters from
Sheboygan Wisconsin to Winthrop Harbor Illinois.

.DAY ONE...This Afternoon and Tonight

A Small Craft Advisory is in effect this afternoon, followed by a
Gale Warning for tonight. Brisk north to northeast winds and high
waves will develop this afternoon and become northerly gales
tonight with very high waves expected.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Brisk northwest winds and high waves will continue for Monday. A
Small Craft Advisory will likely be needed.

LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-261545-
Lake Michigan Michigan City IN to St. Joseph MI 5 NM offshore to
mid-line of lake.-
Lake Michigan from Seul Choix Point to Rock Island Passage 5NM
offshore to Mid Lake-
Lake Michigan South of a line from Seul Choix Point to the
Mackinac Bridge and North of a line from Charlevoix MI to South
Fox Island 5NM offshore-
Lake Michigan from Charlevoix to Point Betsie MI 5NM Offshore to
mid lake-
Lake Michigan from Point Betsie to Manistee MI 5NM offshore to
Mid Lake-
Lake Michigan from Rock Island Passage to Sturgeon Bay WI 5NM
offshore to mid lake-
Lake Michigan from Sturgeon Bay to Two Rivers WI 5NM offshore to
Mid Lake-
Lake Michigan from Two Rivers to Sheboygan WI 5NM offshore to Mid
Lake-
Lake Michigan from Sheboygan to Port Washington WI 5NM offshore
to Mid Lake-
Lake Michigan from Port Washington to North Point Light WI 5NM
offshore to Mid Lake-
Lake Michigan from North Point Light to Wind Point WI 5NM
offshore to Mid Lake-
Lake Michigan from Wind Point WI to Winthrop Harbor IL 5NM
offshore to Mid Lake-
Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5NM
offshore to Mid Lake-
Lake Michigan from Wilmette Harbor to Michigan City in 5NM
offshore to Mid Lake-
Lake Michigan from Pentwater to Manistee MI 5NM offshore to Mid
Lake-
Lake Michigan from Whitehall to Pentwater MI 5NM offshore to Mid
Lake-
Lake Michigan from Grand Haven to Whitehall MI 5NM offshore to
Mid Lake-
Lake Michigan from Holland to Grand Haven MI 5NM offshore to Mid
Lake-
Lake Michigan from South Haven to Holland MI 5NM offshore to Mid
lake-
Lake Michigan from St Joseph to South Haven MI 5NM offshore to
Mid Lake-
938 AM CST Sun Nov 25 2018

This Hazardous Weather Outlook is for the open waters of Lake Michigan.

.DAY ONE...This Afternoon and Tonight

A Gale Warning is in effect for the south two thirds of Lake
Michigan tonight, as strong low pressure tracks from central
Illinois to Lake Erie. Northerly gales of 35 to 45 knots are
expected, along with very high waves.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

The Gale Warning continues through Monday morning for northerly
gales and very high waves.

Wood
www.weather.gov/mkx