NWS-Green Bay Forecast Discussion
FXUS63 KGRB 270357
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
1057 PM CDT Sun Apr 26 2026
Updated aviation portion for 06Z TAF issuance
.KEY MESSAGES...
- Strong to severe storms are possible Monday afternoon and Monday
evening, especially south of a line from Rhinelander to Sturgeon
Bay. The primary threat would be large hail and damaging winds.
- Moderate to heavy rain with embedded storms is expected Monday
and Monday night. Locally heavy rainfall between 0.75 to 1.5"
expected at most locations.
- Rivers are expected to rise this week after a round of moderate
to heavy rain on Monday.
&&
.DISCUSSION...
Issued at 256 PM CDT Sun Apr 26 2026
Stubborn low clouds continued across portions of northeast WI
early this afternoon, otherwise skies were partly cloudy.
Temperatures were in the middle 50s to lower 60s.
For tonight, tranquil conditions should prevail. There is a small
chance of rain towards daybreak across portions of central and
east-central WI. There is still lingering questions if there
would be another night of low clouds and patchy fog. Guidance is
suggesting low clouds would arrive tomorrow morning as dew points
increase. However, will trend for low lower clouds late tonight
and tomorrow with the next round of showers and storms on Monday.
Severe Weather Risk; Monday and Monday night
Showers and a few storms will move across the area during the
morning into the early afternoon, any storms are not expected to
be severe. The main concern will be the late Monday afternoon
into Monday evening as a cold front moves across the area. Strong
shear 0-6 km around 60 knots, MUCAPEs of 1,000 to 1,500 J/KG and
strong winds off the deck from 40-50 knots support the potential
for strong or severe storms. The Storm Prediction Center Day 2
Outlook has a Marginal Risk of severe storms south of a
Rhinelander to Sturgeon Bay line, with even a Slight Right into
portions of Winnebago and Waushara counties. The greatest risk of
severe weather will be from 6 pm to 10 pm. Showers will linger
into the overnight hours after the storms depart.
Rest of the week:
Except for a small chance of rain on Thursday, dry conditions
should prevail into next weekend, allowing for river levels to
recede after the rain on Monday. Several afternoons will also
feature low humidity readings, which could lead to an increase
risk of fires heading into next weekend.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1057 PM CDT Sun Apr 26 2026
VFR conditions with high and mid-level clouds will prevail across
all TAF sites through late tonight. MVFR cigs arrive Monday
morning across all terminals, except MTW. Some rain showers will
also accompany the MVFR cigs at the central and north-central WI
TAF sites. Around midday, the rain showers will expand across the
entire area with cigs dropping to IFR. IFR vsbys will accompany
the rain showers with LIFR vsbys occurring within the heavier
showers. Confidence remains to low to include any mention of
thunder within these showers at this time. A brief lull in the
showers looks to occur sometime Monday afternoon, with chances
for showers and possible thunderstorms moving into the area late
Monday afternoon into Monday evening. Decided to include PROB30
groups at all TAF sites, except RHI where confidence is lower. A
few of the storms could become strong and produce strong winds and
hail.
Surface winds will remain out of the east/southeast through most
of this TAF period, before turning southerly towards the end of
the period. Winds will increase throughout Monday
morning/afternoon, gusting to 25-30 kts. A few periods of LLWS are
expected as winds off the deck will be from the south, at RHI
around the start of this TAF period, at RHI around 17z-20z Mon,
and across all TAF sites after 22z Mon.
&&
.HYDROLOGY...
Issued at 256 PM CDT Sun Apr 26 2026
Minor flooding continues on several rivers, namely the Wolf,
Menominee, and the Fox River at Oshkosh. Dry conditions should
prevail through this evening, with increasing chances of rain late
tonight into Monday. Widespread rainfall amounts of 0.75 to 1.50
inches is expected with locally higher amounts. There is a 40-80%
chance of more than 1" of rain across much of the region, with a
15 to 35% chance of more than 2" across central Wisconsin.
Per RFC forecasts and HEFS guidance, several points along the
Menominee River could return to moderate flood stage. Continuing
snow melt from the Upper Peninsula would lend some confidence for
at least a return to moderate flood stage.
The Wolf River is expected to stay below moderate flood stage
during this event, with some points rising back to minor flood
stage. Levels on the Lake Winnebago system continue to rise due
to inflow from the Wolf and Fox Rivers, with minor flooding
already occurring from Lake Poygan to Winnebago and minor
flooding forecast to occur through the weekend. Those living near
rivers or streams should continue to monitor the latest Flood
Warnings and statements from the National Weather Service in
Green Bay.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....Eckberg
AVIATION.......Kruk
HYDROLOGY......Eckberg