Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 111142

Area Forecast Discussion
National Weather Service Green Bay WI
642 AM CDT Sun Apr 11 2021

Updated aviation portion for 12Z TAF issuance

.SHORT TERM...Today...Tonight...and Monday
Issued at 346 AM CDT Sun Apr 11 2021

The main focus of the short-term portion of the forecast continues
to revolve around rain chances.

Today: A surface low is expected to steadily weaken as it and and an
upper-level low shift into southern lower Michigan. Continued wrap-
around moisture and weak forcing across the area, will lead to
scattered rain showers throughout the day, with the main focus being
across central/north-central Wisconsin as the remnants of an FGEN
band linger. East-central and far northeast Wisconsin may actually
see a break in the rainfall and possibly even a few peeks of
sunshine as some drier air rotates around the low. Additional
rainfall is expected to be around a tenth of an inch for this time
period. High temperatures are expected to be in the 50s, warmest
across the east-central.

Tonight into Monday: As the aforementioned low continues to shift
east through this time period, models continue to show a surface
trough lingering across much of northeast Wisconsin. Aloft, a broad
trough is expected to remain in place. This will keep scattered
showers in the forecast across much of the area under mostly cloudy
skies. The main focus for steadier rain showers will be near the
surface trough, where slightly better low-level convergence
develops. Not expecting a lot of rainfall out of these features;
however, locations near the aforementioned surface trough could see
up to a quarter of an inch of rainfall from late tonight through at
least Monday morning. Overnight lows are forecast to be in the 40s.
Highs are expected to be in the upper 40s to low 50s on Monday.

.LONG TERM...Monday Night Through Saturday
Issued at 346 AM CDT Sun Apr 11 2021

The 500mb upper low across the western Great Lakes region at the
beginning of the period will gradually shift east of the area
Wednesday night into Thursday. Meanwhile, 500mb ridging across
western Canada will gradually shift south into the Pacific
northwest with the evolution of a downstream trough across the
north-central United States by next weekend.

Upper level disturbances rotating around the upper low will bring
chances of rain, and possibly some snow north, Monday night into
Tuesday morning. The chances of rain showers will continue during
the day Tuesday into Tuesday night. Confidence in the dry forecast
Wednesday is waning as the ECMWF model continues to bring a chance
of showers during the day Wednesday. Will hold off on adding rain
to the forecast for this period for now to see if the model trends
are consistent. Dry conditions are expected for most of the
forecast period. The only exception may some small precipitation
chances next Saturday. Per coordination with surrounding offices
and latest numerical guidance values, lowered high temperatures a
few degrees from Tuesday through Thursday.

.AVIATION...for 12Z TAF Issuance
Issued at 642 AM CDT Sun Apr 11 2021

A low pressure system will linger across the region through this
TAF issuance, resulting in MVFR/IFR conditions at times. Some fog
development is also possible tonight into Monday morning, which
may result in IFR/LIFR conditions. Otherwise, winds will be fairly
light and scattered showers will intermittently impact the TAF



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