Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 272352

Area Forecast Discussion
National Weather Service Green Bay WI
652 PM CDT Sat May 27 2017

Updated aviation portion for 00Z TAF issuance

.SHORT TERM...Tonight and Sunday
Issued at 241 PM CDT Sat May 27 2017

A line of showers developed late this morning/early this afternoon
and extended from Upper Michigan into far northeast Wisconsin in
an axis of surface moisture convergence coincident with elevated

The models had QPF in the general location of the current rain and
pretty much had it across the entire state during the day on
Sunday, though there were some differences in the exact location
and timing. Have PoPs increasing through Sunday as a mid level
short wave moves across Wisconsin and a surface boundary moves
into the state.

Temperatures tonight should only drop into the 50s due to
increasing clouds, precipitation, and dew points ranging from the
upper 40s to upper 50s. Clouds and rain will hold temperatures
down on Sunday but highs should still be in the upper 60s to
lower 70s at most inland locations.

.LONG TERM...Sunday Night Through Saturday
Issued at 241 PM CDT Sat May 27 2017

The main weather feature that will impact northeast WI continues
to be a closed upper low that is forecast to slowly move from
Ontario to Quebec during the better part of the upcoming week.
Several disturbances will move through the trof and enhance
precipitation chances from time-to-time.

Thanks to the vicinity of the upper low and general NW flow, temps
for most of the work week will be below norm more times than not,
especially in the first half of the week.

By the end of the work week, the upper low finally loses its grip
on the region`s weather and some flattening of the central U.S.
ridge follows per the ECMWF. While there are some differences
between the GFS and ECMWF with respect to the sharpness of the
upper ridge, temps should be a couple degrees warmer than the
early part of the week.

.AVIATION...for 00Z TAF Issuance
Issued at 642 PM CDT Sat May 27 2017

Most of the region will be dry early, though shower activity
moving into southwest WI will reach parts of central and east
central later this evening. A steadier light rain may develop
over the southeast half of the forecast area late tonight into
Sunday morning, as a short-wave trof and upper level jet streak
move through. Flight conditions could drop to MVFR in parts of
east central WI early Sunday morning, but for now, have kept VFR
in the TAFs.

As the first batch of rain exits eastern WI, another band of
showers and possible thunderstorms will push into north central
and central WI. These will be triggered by the arrival of a cold
frontal boundary and associated upper level disturbance. Have
decided to add a prob30 for thunderstorms at the RHI/AUW/CWA
TAF sites during the early to mid afternoon.


Issued at 241 PM CDT Sat May 27 2017

Westerly winds, occasionally gusting to near 25 knots, are
expected on Memorial Day through Tuesday as low pressure meanders
across Ontario.



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