881
FXUS63 KGRB 130737
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
237 AM CDT Wed May 13 2026

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- Windy conditions expected today, with hazardous conditions for
  small craft on the lake and bay.

- Next chance of mainly light rain occurs Thursday night into
  Friday.

- Gusty northwest winds and low relative humidity today, low
  relative humidity on Thursday, and gusty west winds and low
  relative humidity on Saturday will result in periods of elevated
  fire weather conditions this week.

- Periods of heavy rainfall possible late Saturday night through
  Monday night. Potential for severe storms at times from Sunday
  night through Monday evening.

&&

.DISCUSSION...
Issued at 237 AM CDT Wed May 13 2026

Cyclonic northwest flow, CAA and and a pronounced thermal trough
were supporting widespread low cloud cover across the region
early this morning. Many locations were reporting winds gusting
to 20 to 30 mph, with occasional higher gusts. Temperatures
had dropped into the middle to upper 30s in north central WI, but
were still in the 40s and lower 50s elsewhere.

Deep mixing will bring stronger winds aloft to the surface for
most of today, with widespread gusts of 25 to 35 mph expected,
and local higher gusts to 35 to 40 mph across Door County.
Overcast skies should gradually give way to partial sunshine in
the early to mid afternoon, which should help boost high
temperatures into the upper 50s to middle 60s. Winds will
gradually subside later this afternoon as high pressure builds
into the region.

The high will keep dry weather in place tonight through Thursday.
A cool night is anticipated, with frost potential in north
central and parts of central and far northeast WI. However,
temperatures will rebound into the 60s and lower 70s on Thursday,
except near Lake Michigan, where a lake/bay breeze will keep
readings in the middle 50s to lower 60s.

Another frontal system arrives Thursday night into Friday, with
light showers and isolated thunderstorms expected. Most of the
rain will shift east Friday morning, but partial clearing and
daytime heating should allow a few showers and isolated storms to
redevelop as a weak boundary moves through in the afternoon.

After a brief dry period Friday night into Saturday evening, a
pattern change to southwest flow aloft will bring an increasingly
moist and unstable air mass to the region. The leading surge of
moist and marginally unstable air will arrive later Saturday
night, bringing a chance of showers and isolated storms to mainly
central and east central WI. Low pressure developing in the
Central Plains on Sunday will lift northeast along a slow moving
cold front Sunday night through Monday night. This system will
generate periods of showers and storms, and locally heavy
rainfall, in an increasingly moist (PWATs of 1.2 to 1.7 inches)
and unstable air mass. Probabilistic forecasts show a 40-60%
chance of 1+ inch of rain from Sunday through Monday night, with
a 20-30% chance of 2+ inches. Potential for severe thunderstorms
increases Sunday night, as increasing elevated instability and
steep mid-level lapse rates (7-8 C/km) support a threat of large
hail. Surface based instability increases to 1-3K j/kg Monday
afternoon and early evening, leading to potential for surface-
based severe convection, especially as the surface low, a short-
wave trough and a 50 kt low-level jet move into the region in the
late afternoon/evening. The surface low and cold front will pull
out of the region later Monday night, with drier conditions
arriving Tuesday into Wednesday.

Temperatures will remain below normal today, climb to above
normal late this week into early next week, then return to near
normal for the middle of next week.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 946 PM CDT Tue May 12 2026

Clouds have begun to lower and thicken across the north, with MVFR
cigs observed at RHI. MVFR, locally IFR, cigs will continue to
spread south overnight, affecting all terminals by around 10Z. MVFR
to IFR cigs persist in the wake of the departing low through
Wednesday morning, eventually lifting to VFR at all sites by
early Wednesday afternoon.

Front is just east of the forecast area by 06Z, with winds having
shifted to the northwest at all terminals. Gusts between 25 and
30 knots will be possible through Wednesday morning before
subsiding Wednesday afternoon. LLWS may briefly become a concern
up near RHI Wednesday morning as winds between 2 and 3k ft AGL
increase to near 40 knots. However, opted not to include in the
TAF due to low confidence.

&&

.FIRE WEATHER...
Issued at 237 AM CDT Wed May 13 2026

Pine fuels have reached their peak volatility and fine fuels have
still not greened up over northern WI, so upcoming dry and windy
weather today and Saturday, and low relative humidity (RHs
20-30%) on Thursday, will result in elevated fire weather
conditions at times this week.

&&

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

&&

$$

DISCUSSION.....Kieckbusch
AVIATION.......Goodin
FIRE WEATHER...Kieckbusch

NWS GRB Office Area Forecast Discussion