836
FXUS63 KMKX 101455 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
955 AM CDT Sun Aug 10 2025

.KEY MESSAGES...

- Flood Watch continues over all of southern Wisconsin now until
  7 AM CDT Monday. More thunderstorms and heavy rain are
  expected over southern Wisconsin today into this evening.
  Flash flooding is possible especially in urban areas including
  the Milwaukee metro area.

- Remaining humid today, but highs will be in the lower 80s
  offering at least some reprieve from the heat.

&&

.UPDATE...
Issued 955 AM CDT Sun Aug 10 2025

The rain is still ongoing across southern WI, and there is no
sign of it letting up through the noon hour. The low level jet
will persist over northern IL and southern WI through at least
mid evening as an upper trough sits over the Upper Midwest and
vorticity advection persists over our area.

That area of storms from an MCS that is currently over
northwest IL is expected to slide across northern IL and also
at least the southern tier of counties of WI. That southern
tier did not get hit as hard with overnight rain. However, it
looks like it is going to lift ENE through southeast WI, but not
sure how far north. If it hits Waukesha and Milwaukee counties,
any additional rain will have more flash flooding impacts.

One thing to note is that the convection over northern IL may
end up being stronger now due to more instability. As it lifts
into southeast WI where the environment has been worked over,
the intensity of the storms may diminish a bit.

As for the afternoon, the overall synoptic forcing will be
weaker, so rainfall rates should be lower. However, we have a
saturated environment with weak synoptic lift, so we will
continue to have at least a light rain chance all afternoon. The
RAP and 12Z NAM are the only models that have this rain
sticking around all day, but it seems to be on the right track.

Cronce

&&

.SHORT TERM...
Issued 428 AM CDT Sun Aug 10 2025

Today through Monday Night:

Incredible rain totals fell Saturday night into early this
morning as storms trained over the Milwaukee Metro. Widespread
reports of 5 to 9 inches of rain occurred with a report of 10
inches of rainfall coming in from northern Milwaukee County.
Rain is still ongoing, mainly focused north of Milwaukee in a
band from Port Washington to Beaver Dam, and over southwest
Wisconsin. RAP Mesoanalysis still depicts the low level jet
axis basically pointed like a fire hose at southern WI. Warm
Moist advection from this feature will continue to support
further scattered storm development through the morning hours.
Any areas that feature the conglomeration and training of
convection will be at risk for flash flooding as PWATs are
between 1.7 and 2 inches.

Convection is expected to continue post-dawn, and a dying MCS is
expected to approach from the west during the late morning
toward noon. Models depict that the outflow push from this
dying MCS and subsidence behind it will clear out any remaining
convection over the area during the early afternoon, before
instability rebuilds and more scattered thunderstorms form
during the late afternoon/early evening along an approaching
trough axis. This trough axis will then pivot through southern
WI tonight, largely giving us our last hurrah with regards to
heavy rain.

Monday then appears mostly dry as we`ll be parked beneath weak
subsidence behind the surface trough and between two shortwaves
aloft.

CMiller

&&

.LONG TERM...
Issued 334 PM CDT Sun Aug 10 2025

Tuesday through Saturday:

A modest 500 mb shortwave trough shifts east across northern
Minnesota and Lake Superior Tuesday into Tuesday night. It appears
that the best differential CVA may remain well north of the area.
A cold front shifts east toward the area Tuesday, crossing the
forecast area Tuesday night. There is a good amount of instability
in area forecast soundings, with warm and humid conditions ahead
of the front. Deep layer bulk shear is modest, around 20 to 25
knots. PoPs in the 15 to 30 percent range remain for most of this
period, as upward vertical motion will be modest at best with the
front being the main forcing mechanism.

It appears that high pressure to the north and northeast of the
region Wednesday into Thursday may develop. There is more
uncertainty in the 500 mb flow, as a ridge axis may build into
the region or remain well to the south. For now, the influence of
the high may keep the area dry Wednesday and Thursday, perhaps
into Friday as well. Ensembles suggest that this dry period may
occur as well. Temperatures should remain near seasonal normal
values for this period.

More uncertainty exists for next weekend, depending on how the 500
mb flow sets up. There may be a cold front that shifts southeast
through the region sometime during this period, if the 500 mb
ridge becomes more amplified to the west of the area. For now,
will keep 15 to 20 percent PoPs in the forecast. Ensembles suggest
that temperatures may become warmer, with middle to upper 80s
possible by Sunday.

Wood

&&

.AVIATION...
Issued 955 AM CDT Sun Aug 10 2025

Thunderstorm activity is ongoing over much of southern Wisconsin
at this time leading to a mixture of VFR, MVFR, and IFR
conditions. Scattered thunderstorm activity is expected to
continue through noon as the low level jet continues to spark
new storm development. This afternoon, expect rain, but lighter
in intensity. This will likely contribute to a continuing mix
of flight rules through the day.

Winds will remain southerly today, with gusts between 15 and 20
knots.

CMiller/Cronce

&&

.MARINE...
Issued 339 AM CDT Sun Aug 10 2025

Light to moderate southerly winds will continue this weekend
into early next week. Locally, winds are expected to stay below
small craft advisory criteria. Numerous showers and
thunderstorms will continue over the southern half of the lake
this morning. More showers and storms are then expected this
afternoon, and again on Monday and Tuesday. Patchy dense fog may
occur at times due to the abundant moist conditions.

CMiller

&&

.HYDROLOGY...

Issued 955 AM CDT Sun Aug 10 2025

Another round of showers and thunderstorms moved into northern
portions of the Milwaukee Metro area this morning and is
exacerbating the ongoing flooding situation. MRMS and surface
reports show totals 9 and 14 inches over much of the Milwaukee
Metro, with reports of road flooding and cars stranded in
scattered spots. River flooding is now occurring in this area,
with several exceeding or forecast to exceed record levels.

At this time, RAP mesoanalysis depicts a 25 to 30 knot 925-850
mb jet oriented from northwest IL into southern Wisconsin.
Theta-e advection into southern WI and moisture transport
vectors support the continued redevelopment of showers and
thunderstorms capable of heavy rain through the late morning
hours. An MCS over northwest IL will track ENE through southern
WI through noon. This will likely include the hard-hit areas of
Waukesha and Milwaukee Counties. The overall precipitation rates
are expected to diminish as this MCS moves into the worked-over
area of east central WI.

CMiller/Cronce

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Flood Watch...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-WIZ057-WIZ058-
     WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-WIZ066-WIZ067-
     WIZ068-WIZ069-WIZ070-WIZ071-WIZ072 until 7 AM Monday.

LM...None.
&&

$$

Visit us at weather.gov/milwaukee

Follow us on Facebook, X, and YouTube at:
www.facebook.com/NWSMilwaukee
www.x.com/NWSMilwaukee
www.youtube.com/NWSMilwaukee