Appleton, Wisconsin 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

962
FXUS63 KGRB 250246
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
946 PM CDT Sun May 24 2026

New Information added to update section

.UPDATE...
Issued at 934 PM CDT Sun May 24 2026

Dense marine fog will impact Lake Michigan, and a Marine Dense
Fog Advisory is in effect through 10 am Monday. Some of the
fog is working its way inland along the lakeshore, so have issued
a Special Weather Statement to alert for locally hazardous travel
conditions through Monday morning. If the fog becomes more
extensive over the lakeshore counties, a Dense Fog Advisory may
need to be issued later tonight.

Attempted to adjust pops a bit based on ongoing activity and
satellite trends. Weakening cluster of showers moving into NE WI
should continue to fall apart over the next couple hours. Have
backed off on pops over our western counties late tonight, and
focused more on the 12z-18z/Mon period, when a short-wave
(currently over the Dakotas), increased H8 flow and a warm front
will be moving through. The best precip chances look to occur over
the northwest half of the forecast area.

&&

.KEY MESSAGES...

- Dense marine fog will continue on Lake Michigan into Monday
  morning. A Marine Dense Fog Advisory is in effect through 10 am
  Monday. Some of the fog will work its way inland, resulting in
  hazardous travel over portions of Door, Kewaunee and Manitowoc
  counties.

- 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
  80s forecast for Memorial Day, Tuesday, and Wednesday. A few
  spots may approach or reach 90 on Tuesday and Wednesday.

&&

.DISCUSSION...
Issued at 221 PM CDT Sun May 24 2026

Daytime cu popping up this afternoon, otherwise dry and
seasonable weather with temperatures at 19Z in the upper 60s to
mid 70s away from Lake Michigan (closer to 60 degrees near the
lake). Expect temps to rise a few more degrees throughout the
afternoon.

Precipitation: Clouds clear early this evening, followed by mid
clouds moving in from the west generated by some weak warm
advection. Additionally, 850mb jet increases late tonight which
may provide enough forcing to generate some widely scattered
showers. CAMs remain mixed on this potential, and moisture is also
limited. Continued to carry mainly slight chance PoPs (15-25%)
from late tonight into Monday. There are also small isolated
thunder chances (~15%) with 500-1000 J/kg of MUCAPE, but severe
storms are not expected.

Continue to see small precipitation potential both Tuesday and
Wednesday, mainly during the afternoon and early evenings, from
weak features and daytime heated. Isolated, non-severe
thunderstorms are also possible (~15-20% probability) with some
instability present.

Surface high pressure dominates the area from Thursday through
next weekend which will result in little to no precipitation.

Temperatures...Readings will trend above normal for the next week,
peaking on Tuesday with highs the 80s to possibly low 90s. NBM
shows a 50-70% probability for parts of central into northeast WI
reaching or exceeding 90 degrees. 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.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 642 PM CDT Sun May 24 2026

SCT cumulus clouds were eroding with the loss of daytime heating.
A small cluster of showers and thunderstorms was moving through NW
WI, but gradually weakening as it approached NC WI and the RHI TAF
site. Widespread dense marine fog was evident over Lake Michigan
per satellite and web cams, and was edging toward the MTW TAF
site.

Expect the marine fog to move farther inland this evening,
eventually bringing LIFR flight conditions to MTW through most of
the night, 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, given generally
weak forcing. Have focused on the weakening convection in NW WI,
which should briefly impact the RHI TAF area between 01z-03z/Mon.
Confidence is not high enough to mention thunderstorms in the RHI
TAF, as instability should wane quickly by sunset. Another area of
focus will be the northwest 1/2 of the forecast area late tonight
into Monday morning, as a warm front and moisture convergence
with a 30-35 knot low-level jet bring a chance of showers and
thunderstorms. Have added showers to the western TAF sites to
account for this potential. The low-level jet may also bring a
brief period of LLWS to the western TAF sites, but for now, have
only mentioned it at RHI.

Light S-SW winds tonight will become quite gusty after the warm
front moves through on Monday.

&&

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

&&

$$

UPDATE.........Kieckbusch
DISCUSSION.....KLJ
AVIATION.......Kieckbusch