984
FXUS63 KGRB 181935
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
235 PM CDT Fri Apr 18 2025

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Showers and thunderstorms are again possible late this afternoon
  into this evening. Some storms could become strong in and around
  the Fox Valley, with hail and gusty winds being the primary
  concerns.

- Next chances for widespread precipitation arrive Sunday night
  into Monday. Mixed precip types possible, mainly across north-
  central Wisconsin.

&&

.DISCUSSION...
Issued at 234 PM CDT Fri Apr 18 2025

Cloudy to mostly cloudy skies and low ceilings continue to plague
the forecast area late this afternoon. Despite these conditions,
CAMs models continue to develop showers, and a few thunderstorms,
across the area late this afternoon and this evening. Mesoanalysis
shows that despite very strong shear across the region, with bulk
shear values of 75 knots, instability is wanting across our area
with the best instability well to our south in northern Illinois
and only a few hundred J/kg of MUCAPE across our area. Therefore,
while thunderstorms will be possible, severe weather is not
anticipated across our area this evening as any thunderstorms that
develop should be elevated in nature.

High pressure will provide a break in the active pattern late
tonight through Sunday morning as it tracks across the northern
Great Lakes. Meanwhile, a low pressure system developing across
the southern Plains will track north-northeast towards the western
Great Lakes region Sunday night and Monday. Some light rain is
possible Sunday afternoon ahead of the main low with isentropic
lift across the region; however, the main swath of precipitation
is expected to hold off until Sunday night and Monday.
Precipitation with this system should mainly be rain across much
of the area, with a mix of rain and snow across north-central
Wisconsin. The latest probabilistic guidance has cut back on the
amount of snow quite a bit this run with only a 10-20% chance of 2
inches or more of snow across far north-central Wisconsin and a
20-40% chance of an inch or more of snow.

After a brief break in the action late Monday night into Tuesday
morning, the next system will track through the region Tuesday
afternoon into Tuesday night. This system will have fairly weak
dynamics; therefore, only light rain is expected from this next
low pressure system. Yet another low pressure system looks to
affect the area Wednesday night through Thursday night. Beyond
this part of the forecast there is quite a bit of uncertainty as
there are discrepancies on if a Canadian high pressure can keep
the weather dry to end next week.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1228 PM CDT Fri Apr 18 2025

Conditions ranged from MVFR to LIFR early this afternoon with some
light rain across far north-central Wisconsin. CAMs models
continue to develop showers across the area this afternoon with
thunderstorms and possibly strong storms with locally heavy rain.
gusty winds, and large hail across far east-central Wisconsin.
Reduced vsbys of 2 to 3 SM will likely accompany heavy rain within
areas of convection. Opted to include TEMPOs for the eastern TAF
sites when thunder seems most likely. Conditions then gradually
improve to MVFR and even VFR overnight as high pressure ends
precipitation from west to east.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION.....Kurimski
AVIATION.......Kurimski