Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 202316

Area Forecast Discussion
National Weather Service Green Bay WI
616 PM CDT Tue Mar 20 2018

Updated aviation portion for 00Z TAF issuance

.SHORT TERM...Tonight and Wednesday
Issued at 229 PM CDT Tue Mar 20 2018

Plenty of mid-upper level clouds across the region this
afternoon, as a weak upper trough remained nearly stationary over
Minnesota. Lower clouds pushed across portions of central and
eastern WI, with the greatest coverage across east central WI as
flow over Lake Michigan provided a little increased moisture under
the inversion. No flurries were noted on radar or surface
observations, as dry air associated with the Hudson Bay high
pressure is too much to overcome.

The lower clouds should continue to dissipate through the late
afternoon and evening hours as daytime "heating" wanes, with the
exception being closer to Lake Michigan, where lake effect clouds
could linger. Model guidance is all over the place for low temps
tonight across the north, ranging from the single digits to the
lower 20s. Some of the better performing models are split, so
hard to pick which way to lean. Temps were in the upper 20s to
around 30 as of 2 PM, so the upper teens/lower 20s seem a little
warm. Light winds and snow still on the ground favor the colder
temps, while plenty of mid-upper level clouds favor temps staying
up. Ended up using a blend of the best performing models, which
drops lows into the lower and middle teens for much of northern
WI. Models in better agreement across the Fox Valley where temps
should drop into the lower 20s.

For Wednesday, clouds are expected slowly clear from west to east
through the day as the trough weakens and exits the area and
ridging builds in, allowing for drier air to move into the area.
Mixing to between 850-800mb should allow highs to climb into the
upper 30s to lower 40s.

.LONG TERM...Wednesday Night Through Tuesday
Issued at 229 PM CDT Tue Mar 20 2018

Hudson Bay high will dominate the weather pattern through the
weekend. However, a system passing to the south of the state
could possibly bring some light rain or snow to our far southwest
counties late Friday night and Saturday. Confidence is low that
precipitation will make it that far north due to the amount of
dry air filtering southward from the Hudson Bay high.

The next system is expected to bring a chance of rain or snow to
the area next Monday or Tuesday. Low confidence in the timing of
the system this far out. Only minor changes made to high/low
temperatures during the period.

.AVIATION...for 00Z TAF Issuance
Issued at 615 PM CDT Tue Mar 20 2018

Mostly just middle and high clouds across the region tonight
through midday Wednesday. Some lake effect clouds with bases of
2500 to 3500 feet are possible at times at MTW/SUE. They could
drift as far west as OSH and ATW. Mostly clear skies are expected
over all of the area Wednesday afternoon through Thursday.



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