NWS-Green Bay Forecast Discussion
FXUS63 KGRB 250829
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
329 AM CDT Mon May 25 2026
Forecast discussion for routine morning forecast issuance
.KEY MESSAGES...
- Intermittent chances for rain (20-40%) and thunderstorms are
forecast through Wednesday. The risk for organized heavier rain
or severe weather is low.
- Above normal temperatures are expected through the week, with
highs forecast mainly in the upper 70s and 80s. A few spots may
approach or reach 90 on Tuesday and Wednesday.
- Dense marine fog will continue along the Lake Michigan shoreline
and nearshore waters through mid-morning. A Marine Dense Fog
Advisory remains in effect. Persistent southerly winds today
will produce high waves along the Lake Michigan shoreline. A
Small Craft Advisory and Beach Hazards Statement have been
issued from late this afternoon through early Tuesday morning.
&&
.DISCUSSION...
Issued at 329 AM CDT Mon May 25 2026
Memorial Day...Satellite imagery early this morning indicating a few
mid-high clouds over the area with dense fog covering almost all of
Lake Michigan. This fog is expected to remain mainly offshore, but
may creep inland at times through the mid-morning. Kept the Special
Weather Statement for the lakeshore counties through the mid-morning
when the fog is expected to dissipate/end.
The combination of a shortwave moving over central MN early this
morning and an increasing 850mb jet and WAA will result in a chance
of showers (15-35%) mainly between 12-18z this morning. The best
chances look to occur over the northwest half of the forecast area.
Some guidance is also indicating these showers will continue into
the afternoon into far northeast WI, however, not all guidance has
this occurring. But, given the presence of the shortwave, increased
850mb jet/WAA, and diurnal instability, cannot rule out the
possibility for this redevelopment of isolated showers and storms.
If they develop, a few gusts to 40 mph will be possible with 0-6km
bulk shear around 30 kts and inverted V soundings present. But, the
majority of the area will remain dry, breezy (SW winds gusting to 20-
25 mph), and very warm for Memorial Day. High temps will climb into
the 80s away from the lakeshore, with 70s along the lakeshore.
Precipitation Chances...Additional chances for showers and non-
severe storms are forecast for Tuesday afternoon/evening as an area
of convergence develops during the afternoon from a boundary
dropping into northern WI. Models are not in exact agreement where
this boundary will end up Tuesday night into Wednesday, as there are
indications it may stall over the central portion of the state.
Additional development of showers and non-severe storms is then
anticipated Wednesday afternoon along this boundary or (more likely)
from a cold front dropping south from the north.
Upper-level ridging and surface high pressure dominates the area
from Thursday through the weekend, resulting in little to no
precipitation.
Temperatures...Above normal temperatures are expected through this
forecast period, peaking Tuesday with highs in the upper 80s to low
90s. While dew points will be tolerable in the 50s to low 60s, there
is a moderate (level 2 of 4) heat risk, meaning prolonged periods
outside could affect those who are sensitive to heat. Another very
warm day is forecast for Wednesday with highs mainly in the 80s and
70s along and near the lakeshore. Temperatures moderate in the 70s
to mid 80s for the remainder of the week.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1135 PM CDT Sun May 24 2026
Showers that moved through northern WI this evening dissipated as
they moved through far NE WI, leaving dry conditions across the
forecast area. Widespread dense marine fog was evident over Lake
Michigan per satellite and web cams, but has not pushed inland
enough to impact the MTW TAF site.
Still expect the marine fog to move farther inland overnight,
eventually bringing LIFR flight conditions to MTW before
dissipating Monday morning. Other than the marine fog along the
lakeshore, VFR conditions are anticipated for the rest of the
forecast area.
Precipitation trends are a bit tough to discern. Have backed off
on additional precipitation development overnight, but a short-
wave moving through the eastern Dakotas should bring at least
scattered showers and isolated storms to at least the western TAF
sites Monday morning.
Light SE-S winds tonight will become quite gusty from the
southwest after a warm front moves through on Monday. It appears
that some LLWS will develop over the region later Monday evening.
&&
.MARINE...
Issued at 329 AM CDT Mon May 25 2026
Dense marine fog over Lake Michigan and along the nearshore zones
was very evident based on satellite imagery and webcams. Based on
model guidance, this fog is expected to begin lifting/dissipating
around 7am for the southern nearshore zones and working its way
north, completely ending around 8-10am. No changes made to the
current Marine Dense Fog Advisory, which remains in effect until
10am for all nearshore zones along Lake Michigan.
Persistent southerly winds gusting to 20-25 kts late this afternoon
into this evening will result in building waves to 3 to 5 ft along
the Lake Michigan nearshore waters. Decided to issue a Small Craft
Advisory from 21z/4pm today through 12z/7am Tuesday for only the
Lake Michigan nearshore waters. Given the higher waves and the
holiday, also issued a Beach Hazards Statement for the Lake Michigan
beaches in Manitowoc, Kewaunee, and Door counties for the same time
frame despite the swim risk being moderate.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement from this afternoon through Tuesday
morning for WIZ022-040-050.
&&
$$
DISCUSSION.....Kruk
AVIATION.......Kieckbusch
MARINE.........Kruk