Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 201930

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

Forecast discussion for routine afternoon forecast 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 18Z TAF Issuance
Issued at 1237 PM CDT Tue Mar 20 2018

Quiet weather continues through the TAF period with MVFR CIGS the
only aviation issue/concern. Low clouds between 2500 and 3500
feet will continue across the area through the afternoon. Look for
more a isolated/scattered deck across central WI, and a broken
deck at times across eastern WI where some added low level
moisture due to the flow across Lake Michigan. Flow will remain
northeast tonight into early Wednesday, so lake clouds will be
possible across eastern WI. Winds turn more northerly on
Wednesday, so lake clouds look to be confined closer to the shore.
No VSBY restrictions are expected.

Otherwise, middle-upper clouds will continue to spread across the
area. The gusty northeast winds across the Fox Valley and
lakeshore will slowly diminish this evening/overnight.



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