Sun Prairie, Wisconsin 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

361
FXUS63 KMKX 010850
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
350 AM CDT Sun Jun 1 2025

.KEY MESSAGES...

- Smoke aloft from wildfires in south central Canada will
  continue to move through the area at least through Monday
  night.


- Widespread showers and scattered thunderstorms are expected
  (80-90%) from Tuesday afternoon through Tuesday night. Heavy
  rainfall is possible and maybe a strong storm or two.


&&

.SHORT TERM...
Issued 350 AM CDT Sun Jun 1 2025

Today through Monday:

High pressure over central WI will slowly track to srn Lake MI
today. The high will then slowly shift into the Ohio River
Valley tnt-Mon. Light sly winds will develop tnt as the high
moves away, then increase a bit on Mon as low pressure deepens
to 998 mb over ern SD into MN. Aloft, the upper ridge over the
intermountain west will move across WI and the wrn Great Lakes
on Mon in response to a shortwave trough moving from the Pacific
NW into the nrn USA Rockies. The sky conditions will mostly be
dominated by smoke in the mid to upper levels but should be
translucent. Nevertheless, the smoke could keep high temps down
a bit. Highs in the 70s today away from Lake MI then 80s inland
for Mon but with low relative humidity each day.


Gehring

&&

.LONG TERM...
Issued 350 AM CDT Sun Jun 1 2025

Monday night through Saturday:

An upper trough and Canadian cold front approaching from the
Northern Great Plains will bring our next round of weather to
southern WI. Breezy southwest winds are expected ahead of this
trough on Tuesday, along with very warm and increasingly humid
conditions. Highs will depend on the timing of the incoming
clouds and precip, but at least southeast WI will reach the
lower 80s. Dewpoints should jump into the 60s.

Showers and thunderstorms are expected along the front, with the
arrival time late Tuesday afternoon or evening. How organized and
severe the storms will be is still in question. Multiple
shortwaves are expected to lift from the Plains into MN and WI
just ahead of the upper trough/surface cold front. A strong low
level jet will be present ahead of it as well. In addition, a
strong upper jet will be present along the upper trough, so added
lift from the right entrance region of it will help increase the
overall lift and precip chances along the front. One more
interaction that is less common is that the remnants of Post
Tropical Cyclone Alvin will get pulled into the frontal boundary
region.

The precipitable water values, or the potential amount of moisture
available for precipitation, are expected to be much higher than
normal over southern WI Tue night as the front arrives. The
ensembles of the ECMWF and GFS are in strong agreement of greater
than 1.5 inch but less than 2 inches. While this parameter does
not translate directly to how much rain is expected, it suggests
we will have plenty of moisture in place for efficient rainfall.
The ensemble forecast precip amounts range from 1 to 2 inches,
and they show a less than 10 percent probability of over 2 inches
and a 40-60 percent probability of an inch.

Thunderstorm activity can boost amounts in localized areas. Right
now, the models are suggesting that the stronger storm activity
and higher precip amounts would be over northern IL, but this
location will ultimately depend on where the upper trough and
shortwaves streaming in from the Plains can merge/phase. In
addition, a merger during the afternoon hours would allow for
stronger storms than if everything comes together during the late
evening or overnight.

Showers will be ongoing over southeast WI Wednesday morning as
the front slowly exits. Wednesday afternoon and night should be
dry, although the frontal boundary is expected to stall just to
our south, so we maintain small shower chances in the forecast. A
broad upper trough is expected to sit over the Northern Plains and
Upper Midwest from Thursday through Saturday. It actually looks
like we will get into a subtle wave pattern, or zonal flow with
weak shortwaves, all the way through early next week. This means
there will be chances for showers and storms with each wave, and
they will be difficult to time out accurately well in advance.

Cronce

&&

.AVIATION...
Issued 350 AM CDT Sun Jun 1 2025

VFR conditions are forecast today into Monday. Smoke is expected
aloft.

Gehring

&&

.MARINE...
Issued 350 AM CDT Sun Jun 1 2025

Light and variable winds are expected today as high pressure of
29.9 inches over Wisconsin this morning slowly moves across
southern Lake Michigan this afternoon into the early evening.
The high will then slowly drift across the Ohio River Valley later
tonight through Monday. Light to modest southerly winds will then
develop tonight into Monday night, becoming a bit breezy over the
north half of the lake for Monday afternoon and night. Breezy
southerly winds will then develop over the entire lake for Tuesday
into Tuesday evening as a Canadian cold front approaches from the
northern Great Plains. The cold front will then pass late Tuesday
night into Wednesday morning with winds shifting to the north.

A Small Craft Advisory will likely be needed from Sheboygan to
Winthrop Harbor for Tuesday into Tuesday evening.

Gehring

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...None.
&&

$$

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