Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 151733
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1133 AM CST Mon Jan 15 2018

Updated aviation portion for 18Z TAF issuance

.SHORT TERM...Today...Tonight...and Tuesday
Issued at 416 AM CST Mon Jan 15 2018

An upper low and inverted surface trof will continue to produce
steady light snow away from Lake Michigan during the day, followed
by a decreasing trend during the late afternoon and evening. Most
places should see 1 to 3 inches of additional accumulation
through the day.

Of much greater concern is lake-enhancement potential near Lake
Michigan. A very impressive north to south band was shifting
steadily west across Door and far northeast Kewaunee counties.
This band produced over a foot of snow in parts of northern Door
county overnight, with snowfall rates likely exceeding 2 inches
an hour at times. Models are in good agreement that this band
will shift southwest and gradually weaken this morning, but not
before producing another 4 to 6 inches of snow across southern
Door, and Kewaunee and Manitowoc counties. Meso-models also
point toward another lake-effect band developing over Door
county by evening, then shifting south along the shoreline
during the overnight hours. this could tack on another 2 to 4
inches along the lakeshore.

Overall looking at storm totals of 3-6 inches inland, 8-12
inches over Kewaunee/Manitowoc and 10-18 inches over Door
county (highest amounts to the north). This will definitely go
down as one of the best lake-enhanced snow events on Lake
Michigan over the past 20 years.

Have made some adjustments to headlines, with an earlier
expiration time (6 pm) for the advisory west of the Fox Valley,
and an extension of Small Craft Advisories until midday Tuesday.
Left the expiration times for the Fox Valley and lakeshore
advisories and warnings alone.

.LONG TERM...Tuesday Night Through Sunday
Issued at 416 AM CST Mon Jan 15 2018

A tranquil pattern is expected across the region for much of the
remainder of the work week. There may be a small chance of light
snow across the north on Friday, although the ECMWF has some light
precipitation on Thursday as well. The official forecast for now
is to keep Thursday dry. The bigger story will be the warming
trend by late in the week. Another cold day is expected on
Wednesday with highs in the teens to lower 20s, 20s on Thursday
and mainly in the 30s Friday into the weekend.

Models continue to bring a storm into the region later in the
weekend. The precipitation should start out as snow, but could
transition to some type of mix Sunday into Sunday night. The ECMWF
and Canadian models bringing warmer air into the area that would
push air temperatures into the 30s and possibly some 40s as well
on Sunday. Will have to wait and see if this scenario
materializes.
&&

.AVIATION...for 18Z TAF Issuance
Issued at 1132 AM CST Mon Jan 15 2018

A wide range of cigs/vsbys expected this afternoon as a surface
low tracks east into southern Lower MI and an inverted surface
trough rotates southward over WI. The most concentrated area of
snow is forecast to be near Lake MI where lake effect snow will
add to the synoptic snow. For the most part, cigs will be high-end
IFR/low-end MVFR, while vsbys may range from LIFR in heavier lake
effect over the GRB/MTW TAF sites, to VFR in pockets over parts of
central/north-central WI. As this system pulls away tonight, cigs
away from Lake MI are forecast to rise to MVFR/VFR conditions.
However, additional lake effect will continue for the GRB/MTW TAF
sites through the night with MVFR conditions to persist. By
Tuesday morning, conditions will gradually improve over eastern WI
as the lake effect ends with cigs generally in the low-end VFR
range.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until midnight CST tonight for WIZ038-
039-048-049-073-074.

Winter Storm Warning until 6 AM CST Tuesday for WIZ022-040-050.

Winter Weather Advisory until 6 PM CST this evening for WIZ005-
010>013-018>021-030-031-035>037-045.
&&

$$

SHORT TERM.....Kieckbusch
LONG TERM......Eckberg
AVIATION.......Kallas


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