954 
FXUS63 KMKX 221646
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1146 AM CDT Sat Aug 22 2026

.KEY MESSAGES...

- Scattered showers & thundershowers over east-central and
  southeast Wisconsin ~1-7 PM this afternoon. A few 
  thundershowers could produce gusty winds to 40 MPH. 

- Cool, fall-like nights tonight & Sunday night. 

- Dry and pleasant conditions into the beginning of next week.
  Storm chances return Tuesday evening into Wednesday.

&&

.SHORT TERM...
Issued 1145 AM CDT Sat Aug 22 2026

This afternoon through Sunday night:

Synopsis/Mesoanalysis: Fair weather cumulus are developing late this 
morning as surface heating commences within modest low level 
moisture still in place. While subtle, 11 AM surface observations 
identify a weak surface boundary extending from near Green Bay west 
toward the Black River Falls vicinity. Modest north-south moisture 
differences, in addition to slight cyclonic surface convergence, 
have been noted across the boundary through the late morning hours. 
Anticipate that this surface front will continue to sag south into 
east-central and southeast Wisconsin this afternoon, with its 
affiliated surface convergence providing just enough lift for 
scattered showers and thundershowers mainly along/east of a Ripon-
Lake Mills-Lake Geneva line. Not expecting much in the way of 
hazards in any activity, although the strongest thundershowers could 
produce a few cloud to ground lightning strikes and wind gusts to 40 
MPH. Keep an eye on the sky if planning to be outdoors across the 
east this afternoon. Currently centered along the North Dakota-
Manitoba border, high pressure will gradually shift into the Upper 
Mississippi Valley tonight, ultimately moving overhead on Sunday 
night. The high's approach & arrival will maintain a Canadian air 
mass across southern Wisconsin tonight through Sunday night, leading 
to fall-like conditions during the overnight periods.   

This Afternoon: Monitoring for a gradual increase in 
shower/thundershower coverage across the east as a weak surface 
boundary works in from the north. Expect that most activity will 
generate as the aforementioned boundary impinges upon the more 
focused area of cumulus clouds currently evident from Ripon-
Sheboygan south to Burlington-Milwaukee. Have thus continued 20-40% 
precip probabilities along & east of a Ripon-Lake Mills-Lake Geneva 
line in the mid-day update. Severe weather threat is low in any 
development given modest instability & weaker along-boundary 
convergence, though steep low level lapse rates & deeply mixed 
boundary layers could support isolated wind gusts to 40 MPH in any 
collapsing precip cores. A few cloud to ground lightning strikes are 
possible as well. Keep an eye on the radar if planning to be 
outdoors across the east this afternoon. 

Quigley

&&

.LONG TERM...
Issued 1145 AM CDT Sat Aug 22 2026

Monday through Saturday:

Synopsis: High pressure will continue across the state on Monday, 
leading to plentiful sunshine & continued dry conditions with low 
humidity. The high will shift east of the region on Tuesday, with 
southerly return flow allowing for gradual moisture returns and 
slight increases in humidity. The next upper disturbance and surface 
front will drift into the western Great Lakes from the Canadian 
Prairies Tuesday evening through Wednesday, bringing the next 
chances for showers and thunderstorms to southern Wisconsin. 
Disagreement amongst global guidance regarding the timing of the 
forcing mechanisms casts some uncertainty over how many rounds of 
storm development will occur, in addition to storm intensity. Trends 
will be monitored over coming forecasts. A new area of high pressure 
will move into the western Great Lakes during the second half of the 
week, leading to pleasant and mostly dry weather conditions Thursday 
into Friday. The high will shift east by Saturday.  

Tuesday Evening through Wednesday: The best thunderstorm chances of 
the long term period enter the forecast ahead of an upper wave and 
cold front. Current blended & ensemble guidance generally points to 
a warm sector spreading into the area Tuesday evening/night, with 
the trailing cold front then pushing through at some point during 
the day Wednesday. Precip forecasts from the NBM thus like the idea 
of an initial batch of storm development within the warm advection 
regime Tuesday evening/night, followed by additional development 
along the passing cold front at some point on Wednesday. Available 
deterministic guidance, however, muddies this picture, with a number 
of different scenarios being depicted regarding the evolution of 
both the surface pattern & flow aloft. Have thus trended the precip 
forecast toward the blended/ensemble scenario at this point, with 
the understanding that some changes are likely to occur into early 
next week given the noted range of solutions in the deterministic 
suite. Aforementioned questions regarding the extent and quality of 
the warm sector make the potential for any strong/severe storms 
unclear in this forecast, though prevailing deep layer shear would 
be sufficient for at least some storm organization in the event 
timing & spacing allowed for enough destabilization. Will be 
monitoring trends and providing more details as this portion of the 
period draws closer.

Quigley

&&

.AVIATION...
Issued 1145 AM CDT Sat Aug 22 2026

VFR flight categories prevail through the period at most southern 
Wisconsin terminals. Fair weather cumulus will continue to develop 
into the afternoon hours, with bases between FL040 and FL060 
anticipated. Currently extending from near Green Bay toward central 
Wisconsin, a weak surface front/wind shift will work through 
southern Wisconsin through the afternoon, bringing chances for 
scattered SHRA and TSRA to east-central and southeastern locations. 
SHRA/TSRA could bring brief VIS & categorical reductions, with 
improvements to VFR quickly occurring after precip passage. Have 
accounted for this anticipated development at lakeshore fields in 
the 18Z forecast. Elected to insert TEMPO SHRA groups at SBM, with 
PROB30 groups further south at MKE and ENW given higher relative 
confidence in the development of precip in the vicinity. Have 
withheld any mentions of CB given lower confidence in thunder. Will 
be monitoring radar trends into the afternoon & amending forecasts 
as necessary. Fair weather cumulus and eastern precip chances will 
wane during the early evening hours, giving way to mostly clear 
skies. 

Quigley

&&

.MARINE...
Issued 1145 AM CDT Sat Aug 22 2026

1010 mb low pressure is centered over the southern Hudson Bay this 
morning, resulting in generally northeast winds across the open 
waters of Lake Michigan. These winds will continue into this evening 
as a weak cold front moves across the lake and 1023 mb high pressure 
builds into the northern Great Plains. Isolated showers and 
thunderstorms are possible along the passing front this afternoon & 
evening. Severe weather potential is low in this activity, though an 
isolated stronger storm with gusty winds or a waterspout can't be 
entirely ruled out. Will be watching radar trends for any potential 
marine weather statements or special marine warnings through this 
evening. Northwest winds will continue through the day Sunday, 
ultimately weakening by Sunday night as the aforementioned area of 
high pressure approaches Lake Michigan. 

Light and variable winds will continue Monday with high pressure 
lingering in the vicinity. The high will shift east into Ontario by 
Tuesday, resulting in a south-southwest wind shift across the 
waters. 1005 mb low pressure will approach from the northern Great 
Plains Tuesday night into Wednesday, reinforcing the south-
southwesterly wind pattern. The low will cross Lake Michigan during 
the second half of the day Wednesday, bringing a northwest wind 
shift. Gales are not expected as this occurs. Showers and 
thunderstorms will accompany the approaching/passing surface low 
Tuesday night into Wednesday afternoon. It remains too early to tell 
if any of these storms could be severe, with trends being monitored 
into the beginning of next week.  

Scattered showers and thunderstorms are possible in nearshore zones 
this afternoon as a weak cold front moves south across Lake 
Michigan. An isolated stronger storm with gusty winds or an isolated 
waterspout can't be entirely ruled out. Increasing southerly winds 
and wave heights may lead to a brief period of Small Craft Advisory 
conditions Tuesday afternoon & evening, particularly to the north of 
Milwaukee. Will be monitoring trends & evaluating the need for any 
headlines through the beginning of next week. The next thunderstorm 
chances arrive Tuesday evening through Wednesday, with severe 
weather potential uncertain at this time.

Quigley

&&

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

$$

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