Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 182337

Area Forecast Discussion
National Weather Service Green Bay WI
637 PM CDT Sun Mar 18 2018

Updated aviation portion for 00Z TAF issuance

Issued at 232 PM CDT Sun Mar 18 2018

Quiet weather will continue for at least several more days.

The large scale flow across North America will remain split
throughout the forecast period. For the most part, the area is
likely to remain positioned between the main branches of the flow.
A series of anticyclones passing through the Hudson Bay region
will dominate the weather across the forecast area, driving cool
dry Canadian air into the region. The warm weather of today is
departing, with temperatures expected to return to near or a
little below seasonal normals for the upcoming work week.
Precipitation chances will be minimal until at least the end of
the work week and the upcoming weekend, when a southern stream
cyclone heads east from the Plains. Even then, it`s quite possible
that system will pass by to the south.

.SHORT TERM...Tonight and Monday
Issued at 232 PM CDT Sun Mar 18 2018

Another mild day with very low afternoon relative humidity
readings. Temperatures were in the middle 40s to middle 50s as of
mid afternoon. Relative humidity readings away from the lake were
in the 15 to 30 percent range.

For the remainder of the afternoon and this evening, a backdoor
cold front is expected to drop southwestward across the area
bringing an end to the mild weather. Skies are expected to become
mostly cloudy across the entire region tonight with decreasing
cloudiness late Monday morning into Monday afternoon. Took blend
of the better performing guidance for lows tonight and highs on

.LONG TERM...Monday Night Through Sunday
Issued at 232 PM CDT Sun Mar 18 2018

Colder air associated with the Hudson Bay high will continue to
surge into the area Monday night. Blustery conditions are expected
as well as the pressure gradient tightens between the anticyclone
building southeast across Canada and a cyclone tracking through
the Ohio Valley. The air flowing across the Great Lakes could be
cold enough to result in flurries off Lake Superior and Lake
Michigan, which may linger into Tuesday.

Most of the precipitation from a weak northern stream shortwave
breaking away and merging into the southern stream mid-week still
appears likely to stay mainly west of the area, though it`s
possible some flurries will reach the area.

The medium range guidance continues to suggest a strong southern
stream cyclone heading east across the Plains late in the week and
next weekend will affect the area. The GFS and Canadian models
have been pretty consistent with the track, while the ECMWF has
been oscillating between a similar track to the other models and
one farther south. Given that all but one of the significant
cyclones crossing the region in the past 3 weeks have passed the
area by to the south, it seems most likely that the more
southerly ECMWF runs are going to end up being the most accurate.
Even if a more northerly track materializes, the system will have
to contend with very dry air feeding into the area from the
Hudson Bay high. Given the degree of uncertainty out toward the
end of the forecast period, stuck with the standard forecast
initialization grids and maintained a mention of the system as in
the previous HWO.

.AVIATION...for 00Z TAF Issuance
Issued at 637 PM CDT Sun Mar 18 2018

A cold front will move south across the area this
evening. It will be accompanied by VFR mid level clouds and be
followed by some MVFR ceilings mostly north of a Wausau to Iron
Mountain line late tonight and early Monday. VFR conditions are
expected monday afternoon and Monday night.



SHORT TERM.....Eckberg
LONG TERM......Skowronski
AVIATION.......RDM is the U.S. government's official web portal to all federal, state and local government web resources and services.