137
FXUS63 KGRB 020630
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
130 AM CDT Sat May 2 2026

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- Rain chances will increase late tonight into Sunday morning. The
  highest probabilities for precipitation are currently focused
  over north-central Wisconsin (60-80% chance).

- A stronger cold front will move through the region on Monday.
  This system will bring a high chance for rain, along with a few
  thunderstorms, Monday afternoon (50-70% chance).

- Other than Sunday and Monday, below normal temperatures will
  will return mid to late next week, with several opportunities
  for frost and freeze conditions.

- Minor flooding lingers on the Wolf River and Winnebago system.
  Water levels will continue to slowly recede given lack of
  significant rainfall.

&&

.DISCUSSION...
Issued at 1234 AM CDT Sat May 2 2026

The high pressure system will slide southeast of the area today,
allowing southerly return flow to develop. This will lead to a
modest warming trend with highs reaching the mid to upper 50s.
Troughing aloft will likely support the development of fair-
weather cumulus clouds by late morning, similar to the coverage of
Minnesota yesterday.

Attention then turns to a clipper system progged to approach
tonight. Low-level convergence and a surge of moisture will
increase precipitation chances, particularly for areas north of
Highway 29. Rain chances have steadily increased over the past 24
hours, and have increased again tonight (now up to 60-80%). As
such, have opted to boost NBM PoPs for the late tonight into
Sunday timeframe. Most of this activity should exit the region by
midday Sunday, leading to decreasing clouds and high temperatures
returning to the 60s for inland locations on Sunday afternoon.

For the early to middle part of next week, the pattern will be
dominated by an anomalous closed upper low spinning over northern
Ontario and the Hudson Bay. A more robust cold front associated
with this feature is forecast to sweep across Wisconsin on Monday.
Probability of precipitation has increased to 70-80 percent with
this front. While overall moisture remains somewhat limited, weak
instability up to 100 J/kg during the afternoon hours may be
sufficient to support a few isolated thunderstorms. Precip amounts
will generally be light as there is a less than 20% chance of
1/4" of rain. But with thunderstorms, high end amounts (95
percentile) up to 1/2 inch are possible.

Behind this front, another surge of cold air will drop
temperatures back below seasonal normals from Tuesday through
Friday. Under the cold pool of the upper trough, scattered
diurnally enhanced showers are possible during the afternoons from
Wednesday through Friday though confidence in coverage is low.
Frost and freeze potential will peak again during the early
morning hours of Wednesday through Friday.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1153 PM CDT Fri May 1 2026

Skies have cleared across most of the region as expected, except
for a patch of 7000-9000 ft clouds over central WI that will graze
KAUW and KCWA over the next 1-2 hours. Regardless, good flying
weather is expected into Saturday morning across the region.

Expect fair weather clouds to build with the heat of the day by
late Saturday morning. Similar to what occurred over Minnesota,
cloud bases should be high based and coverage should be not as
widespread as today.

Mid and high clouds will increase on Saturday evening ahead of the
next clipper system. Light rain showers will be approaching
KRHI/KAUW/KCWA by the end of the taf period and have included a
prob30 at KRHI for -shra. No deterioration of flight conditions
are expected.

Lastly, low level wind shear will be increasing over north-central
WI by the end of the taf period as well.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Freeze Warning until 8 AM CDT this morning for WIZ022-030-031-
035>040-045-048>050.
&&

$$

DISCUSSION.....MPC/Goodin
AVIATION.......MPC

NWS GRB Office Area Forecast Discussion