355
FXUS63 KGRB 031130
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
630 AM CDT Wed Jun 3 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Elevated fire weather conditions this afternoon due to low
  relative humidity, above normal temperatures, and increasing
  winds.

- Showers and storms return Thursday, lasting into the weekend.
  Marginal risk (level 1 of 5) for severe storms on Thursday.

- Above normal temperatures persist for the next week. Chance for
  highs in the low 90s increases early next week, along with
  potential for heat-related impacts.

&&

.DISCUSSION...
Issued at 1243 AM CDT Wed Jun 3 2026

Rain/storm chances... Pattern shift looks to occur beginning on
Thursday as blocking ridge breaks down and upper flow levels out.
Result will be a stretch of unsettled weather as several
shortwaves migrate through the mean flow and a surface low spins
up over the US/Canada border. Return flow from high pressure
shifting to the east will tap into abundant moisture reserve to
the south, with PWATs generally exceeding 1.5" (90th percentile)
Friday into Saturday. Brunt of the QPF looks to fall Friday
afternoon into Saturday morning across our southern tiers of
counties as aforementioned moisture interacts with instability
reservoir near the surface low. Probabilistic guidance shows a
widespread 50 to 70% chance for receiving 0.5" of rain, with a
30 to 50% signal for one inch of rain over portions of central to
east-central Wisconsin. WPC highlights the majority of the state
in a marginal (level one) risk for excessive rainfall during this
time.

Strong or severe storm potential will accompany the heavy rain
threat Thursday and Friday afternoons as the driving shortwave
passes over the northern Plains. SPC continues to highlight
central and north-central Wisconsin in its Day 2 Outlook as
modest instability (500 to 1,000 J/kg) builds ahead of the front
and the low-level jet ramps up. However, current thinking is that
the better chance for stronger storms would be Friday afternoon as
shear increases, mid-level lapse rates steepen, and greater
surface-based instability (1,500 to 2,000 J/kg) builds pre-FROPA.
In this case, main threats would be wind and hail. Biggest
questions will be frontal placement and how upstream convection
modifies the environment later in the afternoon.

Temperatures... Temperatures will remain steady in the upper 70s
to mid 80s (around 5 to 10 degrees above average) over the course
of the next week as a warming ridge dominates the Midwest. Highs
peak in the mid to upper 80s in/around the Fox Valley and into far
northeast Wisconsin on Thursday, though the chances for a 90
degree reading remain low (10 to 20%). Shower/storm timing and
associated cloud cover may also mitigate temperatures. Dewpoints
will read comfortably in the mid to upper 50s during this time,
resulting in a low heat risk of 1 out of 4. Greater potential for
heat-related impacts will come late this weekend into early next
week as upper flow re-amplifies and building heat ridge/Hudson
Bay high set us up under southerly flow regime. Ample moisture
transport from an open Gulf will likewise cause dewpoints to rise
into the 60s, which would put us under a level 2 out of 4
(moderate risk) for heat-related impacts early next week.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 427 AM CDT Wed Jun 3 2026

VFR conditions prevail through the TAF period as high pressure
continues to shift east. High clouds may give way to SCT to BKN
cu field with bases at around 5 to 6k ft late this morning into
this afternoon, though no change in flight category is expected.
Light southwest winds will tick up slightly this afternoon, with
gusts to 15 knots possible. Locally onshore winds will be possible
near MTW. LLWS may briefly become a concern up near RHI early
Thursday morning as 850 mb winds increase, though have withheld
from the TAF for the time being. Scattered rain/storms encroach on
the western terminals by 12Z Thursday, though should arrive
beyond this TAF period.

&&

.FIRE WEATHER...
Issued at 1243 AM CDT Wed Jun 3 2026

Prolonged stretch of dry weather will result in elevated to near
critical fire weather potential through this evening as RHs fall
into the 18 to 25% range, lowest across the sandy soil regions.
Despite widespread green up, fine fuels remain volatile given the
absence of soaking rainfall, with increasing gradient winds
coinciding with low RHs this afternoon. Though winds remain
marginal, the combination of above normal temperatures, dry
fuels, and low humidity will result in the potential for wildfires
to spread quickly. As such, have issued an SPS for elevated
wildfire conditions across portions of north-central and far
northeast Wisconsin. Fire weather threat then diminishes toward
the end of the week with the arrival of rain/storms.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement from Thursday morning through Thursday
evening for WIZ022-040-050.
&&

$$

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

NWS GRB Office Area Forecast Discussion