NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 022331
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
631 PM CDT Tue Jun 2 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

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

- Above normal temperatures for the next week. Isolated highs of
  90 Thursday and Sunday. Chance for highs in the lower 90s
  increases next week, as does potential for heat related
  impacts.

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

&&

.DISCUSSION...
Issued at 219 PM CDT Tue Jun 2 2026

Rain/storm chances...Blocking mid to upper level ridge of late
breaks down Thursday into the weekend. A period of unsettled
weather will result, starting up as early as late Wednesday night,
but more likely Thursday through Saturday as several shortwaves
and stronger low-mid level wind maxes cross the western Great
Lakes while interacting with reservoir of building instability
over the central Plains. As high over the region early this week
moves east and trough over the northern Plains begins to encroach,
return flow will pump Gulf moisture into the western Great Lakes
with PWATs by Friday ahead of the pushing well above the 90th
percentile for the day. Though exact timing and placement of
heaviest rain is uncertain, ensembles point to Friday afternoon
through Saturday morning for seeing a 30 to 50% chance for
receiving half an inch of rain. Chances for rain decrease markedly
moving into Saturday night into early next week.

SPC has highlighted parts of central to north-central WI for a
Marginal Risk (level 1 of 5) for Day3 (Thursday into Thursday
night) as 500mb speed max and increasing low-level jet aims into
WI even as greater elevated instability remains over northern
Plains. Additional storms will also be possible on Friday as
surface-based instability (1500-2500 J/kg) builds in just ahead
of the sfc low and trough, though it is still too soon to determine
severe potential Friday as storm intensity and development will
hinge on frontal placement and timing of mid-level shortwaves
(which could be modulated by upstream convection).

Temperatures...Temperatures will remain steady in the upper 70s
to mid 80s (around 5 to 10 degrees above average) for the next
week as a warming ridge dominates the Midwest. Highs peak in the
mid to upper 80s in/around the Fox Valley into far northeast WI
on Thursday, though the chances for a 90 degree reading remain
low (10 to 20%). Cloud cover tied to rounds of showers and storms
could mitigate temperatures Friday into Saturday. Temperatures
increase again Sunday into early next week though, with
probabilities of highs 90+ reaching 30-50% by Monday. However,
with high nearby to the east, winds off Lake Michigan will keep
eastern WI/lakeshore cooler. Based on NWS Heat Risk output, it
appears that as dewpoints increase into the 60s early next week,
the potential for heat related impacts will tick upward as well
with level 2 impacts (moderate level) showing up.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 630 PM CDT Tue Jun 2 2026

VFR conditions will continue through the TAF period with high
pressure in control. Scattered high clouds tonight, will be followed
by scattered cu developing late Wednesday morning into Wednesday
afternoon. Light and variable winds are expected tonight. Winds then
become predominantly southwesterly Wednesday with locally onshore
winds near Lake Michigan and the bay.

Beyond the TAF period the next chance for showers and thunderstorms
is forecast to arrive late Wednesday night into Thursday morning.

&&

.FIRE WEATHER...
Issued at 219 PM CDT Tue Jun 2 2026

Prolonged stretch of dry weather will result in elevated to near
critical fire weather potential through Wednesday as afternoon
RHs fall into the 20 to 30% range across the sandy soil regions.
Despite widespread green up, fuels remain volatile given the absence
of soaking rainfall, with the main period of concern being Wednesday
afternoon when low RHs coincide with increasing gradient wind.
Winds currently look to remain just below critical thresholds,
though issuance of an SPS could still occur. Fire weather threat
then diminishes toward the end of the week with the arrival of
scattered rain/storms.

&&

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

&&

$$

DISCUSSION.....JLA
AVIATION.......GK
FIRE WEATHER...JLA