Seymour Wisconsin Weather Forecast Discussion

628
FXUS63 KGRB 112326
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
626 PM CDT Sat Oct 11 2025
Updated aviation portion for 00Z TAF issuance
.KEY MESSAGES...
- Above average temperatures continue through early next week,
  becoming slightly cooler mid-week.
- Mostly dry this weekend, with chances for light rain returning
  Sunday night into Monday, and again late next week.
&&
.DISCUSSION...
Issued at 202 PM CDT Sat Oct 11 2025
Nothing has been able to get going off of Lake Michigan this
afternoon, so have opted to keep PoPs sub-15 while not removing
entirely. Any shower/sprinkle activity should be isolated in
nature regardless, before coming to an end this evening as 850 mb
temperatures increase and winds veer to southeasterly. Said
cyclonic flow has resulted in a low stratus deck expanding over a
good portion of northeast Wisconsin.
Rain chances... Better chances for more widespread precip, albeit
light, arrive Sunday night into Monday as a decaying cold front
arrives from the west. As with our previous system, dynamics
remain unimpressive, with deeper moisture being an issue. As
such, probabilistic guidance continues to show a meager 10 to 30%
chance of receiving 0.25" of rain through Monday, with the best
signal over north-central Wisconsin. Thunder chances will remain
rather limited as cold FROPA moves through with little to no
instability. Omega block then establishes itself over the CONUS
mid-week, keeping us predominantly dry heading into next weekend.
Details become unclear beyond this point (especially as we
approach the end of the forecast period), though ensembles hint at
the possibility of a more robust system arriving next weekend as
upper flow becomes split and a lee cyclone develops over the
Intermountain West.
Temperatures... Temperatures warm into the 60s for many, and even
into the low 70s in/around the Fox Valley, by Monday afternoon
under persistent southerly flow and a slew of WAA. Post-frontal
highs then fall back into the 50s and 60s on Tuesday. Overnight
lows should be slightly more mild than previous nights,
eliminating the need for additional frost headlines until at least
mid-week.
Fog/low stratus... As winds continue to veer to southeasterly,
expect moist, upslope flow to result in fog/low stratus
development over the majority of the forecast area early Sunday
morning. Suspect that this would manifest mainly as a low stratus
deck as winds will be slow to decouple, if at all. Winds
continue to increase later Sunday morning as the pressure
gradient tightens up over Wisconsin, further limiting fog
potential. Some patchy fog wouldn`t be out of the question,
though no significant impacts to visibility are expected.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 624 PM CDT Sat Oct 11 2025
MVFR to lower VFR stratus (025-035) hanging tough over northeast
and east-central WI will only *slowly* scatter out this evening.
As this occurs, clouds will increase into the overnight across
central and north-central WI, though RHI may even flirt with BKN
MVFR deck briefly this evening as the clouds over northeast WI
drift west. Cloud bases lower late tonight into early Sunday
morning over the north, including at RHI. A mix of ceilings of
MVFR north to lower VFR elsewhere will be around on Sunday
morning, then just as the lower clouds scatter out by midday, a
blanket of mid and high clouds will spread over the entire area.
Winds will be light from the east-southeast tonight, then increase
from the southeast on Sunday. Gusts of 15-22 kts will occur late
morning through the afternoon, strongest over central and north-
central WI as a cold front approaches from the west. Any rain with
this front will hold off until after nightfall.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....Goodin
AVIATION.......JLA

NWS GRB Office Area Forecast Discussion