Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 162039
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
239 PM CST Mon Jan 16 2017

Forecast discussion for routine afternoon forecast issuance

.SHORT TERM...Tonight and Tuesday
Issued at 238 PM CST Mon Jan 16 2017

A messy forecast to say the least with a variety of precipitation
types to discern with temperatures a couple of degrees either side
of freezing across central and east-central WI. Road temperatures
are also a couple of degrees either side of freezing, so this
could also play a large role in precipitation type.

The 20z MSAS surface analysis showed a weakening area of high
pressure that extended from central MN east-southeast through the
Great Lakes to the New England states. Low pressure was situated
over northeast KS with an arc of mixed precipitation extended from
eastern Nebraska to southern WI to western Indiana.

Models agree in taking the surface low from northeast KS to
southern Lake MI tonight and bring a wintry mix of precipitation
to most of northeast WI. Model forecast soundings indicate that
temperatures will hover around the freezing mark from 7K ft to the
surface across central/east-central WI, thus a continued threat
for a variety of precipitation types through the night. For
northern WI where temperatures will be colder, expect to see
mainly a snow/freezing rain mix. For central/east-central WI,
expect a full complement of freezing rain, sleet and a little snow
with ice accumulations in the 1/10 to 2/10 range. Locations closer
to Lake MI may see more of a rain/freezing rain combination as
east-northeast winds pull slightly warmer air inland. Snow
accumulations of an inch or two are possible between highways 64
and 54. Do not plan on making any changes to current headlines
based on projected QPF amounts. Look for min temperatures to range
from the middle to upper teens over north-central WI near the
Upper MI border, to the lower and middle 30s across east-central
WI.

The surface low will continue to track northeast across Lower MI
into extreme southeast Ontario on Tuesday. Mixed precipitation is
forecast to carry over into Tuesday morning central/east-central
WI, while northern WI should see a chance for light snow. All of
the precipitation should gradually come to an end Tuesday
afternoon with even some peeks of sunshine possible over north-
central WI later in the day. Since stronger forcing/lift to be to
our east by daybreak, do not anticipate much in the way of
additional icing (< 0.05"), but still enough to make for hazardous
travel conditions for the morning commute (especially secondary
roads, bridges, overpasses, driveways and sidewalks). Max
temperatures for Tuesday will mainly be in the middle 30s across
the entire forecast area.

.LONG TERM...Tuesday Night Through Monday
Issued at 238 PM CST Mon Jan 16 2017

Ridging will bring a period of quiet weather to northeast
Wisconsin during the middle to late part of the work week.
Temperatures during this period will slowly warm from the middle
30s, to around 40 degrees by the end of the week. There will be a
slight chance for rain to sneak into the far southern cwa on
Friday, however the best chance for rain will not arrive until the
weekend when a weak upper level system lifts north through the
western Great Lakes region. Even then the weak system will only
warrant chancy pops as moisture and dynamics are fairly limited.

A fairly strong low pressure system developing out over the
southern Plains and tracking through the Ohio Valley early next
week could make things interesting in the far portion of the
extended. The ECMWF pushes this system through the Ohio Valley
with minimal impact to the western Great Lakes, while the GFS
curves the system back north towards Chicago by next Monday. It is
difficult at best to determine how this system will track through
the CONUS, however given the different solutions it certain bears
watching as it draws closer.
&&

.AVIATION...for 18Z TAF Issuance
Issued at 1122 AM CST Mon Jan 16 2017

Flying conditions are expected to deteriorate from south to north
this afternoon as an area of low pressure approaches from the
central Plains. Surface temperatures around freezing, combined
with road/runway temperatures below freezing, will lead to mix of
precipitation types this afternoon through tonight. Icing of 1/10
to 2/10 of an inch is anticipated for all TAF sites, except RHI
where the precipitation type would be mainly snow with a light
accumulation. Cigs/vsbys are forecast to start at VFR, but quickly
drop into the IFR category by early evening and IFR conditions for
the overnight hours. As the surface low continues to track
northeast across Lower Michigan on Tuesday, the precipitation will
gradually dissipate with improving conditions later in the day.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until noon CST Tuesday for WIZ035>040-
045-048>050.

Winter Weather Advisory until noon CST Tuesday for WIZ020-022-
030-031-074.

Winter Weather Advisory from 7 PM this evening to noon CST
Tuesday for WIZ013-018-019-021-073.
&&

$$

SHORT TERM.....Kallas
LONG TERM......Kurimski
AVIATION.......Kallas



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