NWS-Green Bay Forecast Discussion

 

						FXUS63 KGRB 282218
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
418 PM CST Sun Nov 28 2021

Forecast discussion for routine afternoon forecast issuance

.SHORT TERM...Tonight and Monday
Issued at 418 PM CST Sun Nov 28 2021

The next clipper system is the main focus of this forecast period,
as it will bring the next chance for accumulating snow.

Tonight...Lingering lake-effect clouds across north-central and far
northeast WI will dissipate into this evening as a surface ridge
moves over the region. This high will provide a dry forecast for
tonight and clear to mostly clear skies through late this evening.
Clouds will then increase from west to east starting around midnight
as a result of increasing WAA and isentropic lift ahead of the
clipper system.

Monday...Generally, the clipper system will track southeast from MN
into southwest WI during this time. This will put north-central and
far northeast WI in the best location for accumulating snow. Looking
at the finer details, models have delayed the start of the snow by a
couple hours compared to the previous forecast due to the amount of
dry air near the surface. Snow is looking more likely to start in
central and north-central WI sometime after 12z during the morning
commute. The snow will then reach east-central and far northeast WI
closer to late morning once the morning commute has ended. Since
this system is fast-moving, the snow will end in central WI during
the afternoon before completely ending late Monday afternoon/early
evening. To continue with the finer details, models have come to a
consensus with slightly higher QPF, especially in far northeast WI.
While this results in slightly higher snowfall amounts, there is
still a concern with the exact track of the clipper, which will be
the deciding factor for the location of highest snowfall. However,
it's still looking like an inch or less south of Highway 29, and 1
to 3 inches north of Highway 29 with the highest amounts towards the
Upper MI border in far northeast WI. Would not be surprised to see
slightly higher snowfall amounts in the next forecast issuance,
which would then result in a headline issuance. Decided to not issue
a headline with this forecast due to the differences in the
clipper's track. As the snow nears it's end in central WI, forecast
soundings indicate a warm-layer in the lower levels for a few hours,
which may present the possibility for freezing rain. To the north,
forecast soundings show a loss of ice aloft as the snow comes to an
end, causing freezing drizzle to mix in with the snow.

.LONG TERM...Monday Night Through Sunday
Issued at 418 PM CST Sun Nov 28 2021

Light snow should diminish across far Northeast
Wisconsin Monday evening, with scattered lake effect snow showers
in far Northcentral Wisconsin overnight into early Tuesday.

Jet streaks moving through the Northwest upper flow will make for
a tricky forecast for the middle and end of the week, as there
are big differences in timing and precipitation amounts with
Clipper systems Wednesday and friday.

Precipitation Wednesday will probably be mostly rain as
temperatures will be mild. Light snow is possible Friday, but
amounts look very light.
&&

.AVIATION...for 18Z TAF Issuance
Issued at 1158 AM CST Sun Nov 28 2021

Although the lake effect snow showers in far north-central WI
have ended late this morning, MVFR cigs will stick around at the
RHI TAF site for a couple hours until clouds slide east and
dissipate. Elsewhere, clear skies and gusty northwest winds,
between 20 to 30 kts, will remain in place through this
afternoon.

High and mid clouds are expected to move into the area from west
to east early Monday morning ahead of the next snow maker. As the
light snow follows shortly after, cigs and visibilities will
lower. The light snow will come to an end from west to east Monday
evening.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM.....Hykin
LONG TERM......RDM
AVIATION.......Hykin