Sun Prairie, Wisconsin 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

558
FXUS63 KMKX 141946
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
246 PM CDT Mon Jul 14 2025

.KEY MESSAGES...

- Increasingly very warm and humid conditions into Wed. Maximum
  heat index values reaching the lower 90s for Tue-Wed.

- Thunderstorms are looking likely for Wed afternoon and evening
  due to a wave of low pressure and cold front moving through
  srn WI. Severe thunderstorms and heavy rainfall are possible.

- Looking drier and cooler for Friday if the cold front pushes
  and stalls further south in IL, but unsettle weather with
  20-40% shower/storm chances return for the weekend.

&&

.SHORT TERM...
Issued 245 PM CDT Mon Jul 14 2025

Tonight through Tuesday night:

High pressure over the nrn Ohio Valley will slowly move to the
lower Great Lakes and Mid Atlantic States into Tue, while a sfc
trough and cold front over the nrn Great Plains slowly advances
east and south toward the Upper MS River Valley and wrn Great
Lakes. Lgt swly winds and warm, moist advection will boost
temps and dewpoints during this period. High temps in the mid to
upper 80s for Tue-Wed with maximum heat index values in the
lower 90s. Lake breezes will occur each day but not penetrate
too far inland. Nights will becoming milder and muggy especially
Tue nt.

Gehring

&&

.LONG TERM...
Issued 245 PM CDT Mon Jul 14 2025

Wednesday through Monday:

A shortwave trough will approach from the west for Wed afternoon
and evening with a wave of low pressure at the surface. Mid
level lapse rates will be rather poor at 5.5-6.0 C/KM, but
middle 80s temps and dewpoints around 70F should still yield
MLCAPE of 1500 J/KG or more. Deep layer shear of 30-40 kts is
forecast while low level shear will be weak. A strong to severe
MCS will certainly be possible with damaging winds as the main
hazard. There are differences among the models on the passage of
the low and cold front so a slower version could result in a
few lingering showers or isolated storms on Thu. Otherwise nly
winds and cold advection will prevail on Thu with high pressure
building into WI and the wrn Great Lakes for late on Thu and
into Fri. Pleasant high temps in the 70s will return for this
period.

Slight upper ridging will then set up over the nrn USA Rockies
for the weekend into early next week yielding wnwly flow aloft
from the nrn Great Plains into the Great Lakes. At the sfc a
stationary front will mainly set up along the Mid MO River
Valley but it could shift farther north and east at times. A few
MCS`s could occur along and just north of the front during this
period which includes 30-40 percent chances each day or night
for srn WI.


Gehring

&&

.AVIATION...
Issued 245 PM CDT Mon Jul 14 2025

VFR conditions this afternoon through Tue. Few-sct035-040 fair
wx cumulus over srn WI this afternoon. Areas of fog will be
possible in the WI River Valley early Tue AM along the Sauk and
Iowa County border. Sct030-040 fair wx cumulus may occur again
late Tue AM into the afternoon over srn WI.

Gehring

&&

.MARINE...
Issued 245 PM CDT Mon Jul 14 2025

Light to modest southerly winds will continue tonight into Tuesday
night as high pressure over the northern Ohio Valley slides east
to the Mid Atlantic States. A wave of low pressure around 29.8
inches will then move east across central or southern Wisconsin
Wednesday afternoon or evening and cross Lake Michigan into lower
Michigan Wednesday night. Numerous showers and storms will likely
occur with the passage of the low and its cold front.

Modest northerly winds will take hold after the passage of the low
and cold front Wednesday night and continue into Thursday and
possibly Friday.

Gehring

&&

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

$$

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