NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 080009 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
709 PM CDT Tue Jul 7 2026

.KEY MESSAGES...

- Marginal to Slight Risk of severe thunderstorms late Wednesday
  afternoon and evening. Damaging winds and large hail are the
  main hazards. Locally heavy rain and urban and small stream
  flooding will be possible well into the night.

- A continuation of scattered storms or redevelopment is
  forecast for Thursday. Locally heavy rain and urban and small
  stream flooding will remain possible.

- Hot and muggy conditions return early next week.

&&

.UPDATE...
Issued 709 PM CDT Tue Jul 7 2026

Quiet weather will continue for the evening and overnight hours
under the influence of surface high pressure centered to the
south of the forecast area. Scattered cumulus early this evening
will diminish, with few to scattered high clouds expected
overnight. Temps are expected to be within a few degrees of
normal overnight. In all, the forecast looks on track for the
evening and overnight hours.

DDV

&&

.SHORT TERM...
Issued 143 PM CDT Tue Jul 7 2026

Tonight through Friday:

A pleasant and seasonal summer day will continue this afternoon
with a lake breeze moving wwd into the inland counties. High
pressure will shift se of the area tnt while a sfc trough
develops from the central high plains into srn MN. Low to mid
level warm, moist advection north of this feature will support
clusters of thunderstorms from the nrn Great Plains into the nrn
half of WI through Wed AM. For later Wed afternoon and night
the sfc trough/cold front will slowly sag sewd toward srn WI
with an upstream and slow moving shortwave trough approaching.
The shortwave trough and cold front will slowly pass on Thu.
MLCAPE will build to 1300-1800 J/KG by late Wed afternoon with
effective shear around 20 kts. CAMs and deterministic models still
have some timing differences but there has been a quicker trend
for the onset of storms. A low end severe threat for damaging
winds and large hail is forecast mainly north of Madison and
Milwaukee.

For later in the evening and overnight, more of a locally
heavy rain and urban and small stream flood potential will
exist. This is supported by a wly 25 kt low level jet and
associated thetae advection within the thermal ridge and the
approaching weak shortwave trough. This is in conjunction with
PWATs of 1.5-2.0 inches and weak corfidi vectors. The CAMs and
model QPF suggest the flood threat should remain isolated.
Ongoing scattered storms and additional storms are then expected
on Thu with the passage of the cold front and shortwave trough.
Only marginal CAPE is expected with rather weak effective shear
continuing. Thus the severe threat will be very low with more of
a concern for urban and small stream flooding once again.

Nely winds will bring a slightly cooler and drier airmass for
Friday as high pressure builds from the nrn Great Lakes into WI.
Seasonal temps and humidity is forecast.

Gehring

&&

.LONG TERM...
Issued 143 PM CDT Tue Jul 7 2026

Friday night through Tuesday:

Synopsis: The slow-moving surface front responsible for Wednesday &
Thursday's thunderstorm chances will be near or just south of the
state line Friday evening. If the feature remains close enough to
the border, it could trigger a few more scattered storms over far
southern Wisconsin Friday evening before shifting south this
weekend. Pronounced upper ridging will build into the northern Great
Plains from the Great Basin this weekend, reaching maximum strength
and amplitude over the Upper Mississippi Valley early next week.
With the center of the ridge in close proximity, large-scale
subsidence will keep conditions dry from the weekend through the
conclusion of the long term period. Beneath the subsidence, south to
southwesterly low level winds will advect a very warm Great Plains
air mass into the area. Heat will thus return to southern Wisconsin
from the weekend into early next week. Elevated humidity will
accompany the hot temperatures.

Friday Evening: Could see a few scattered storms in far southern
Wisconsin (along/south of I-94 & US-18) if a slow-moving surface
front remains close enough to the state line. Precise frontal
progression up to this point in the period will be heavily driven by
afternoon/evening thunderstorms & attendant outflows on Wednesday
and Thursday, which thus makes it difficult to know where exactly it
will set up at this time. Most available guidance suggests it will
be far enough south to preclude any thunderstorm development in
southern Wisconsin Friday evening, though there are a few solutions
hinting that the front could remain closer to the state line. Have
thus maintained 15-20% precip probs from the NBM in the afternoon
update, with further refinements to come as forecast confidence
increases Wednesday-Thursday.

Sunday through Tuesday: Hot and humid conditions return to the area
thanks to renewed ridging building in from the west. Currently
appears that afternoon heat indices in the 90s will be a good bet,
particularly on Monday and Tuesday. How high readings reach and
whether/not heat headlines will become necessary will ultimately
depend on the depth and quality of moisture in place across the
region, which remains a source of uncertainty this far out. Will be
monitoring trends and refining the forecast as this portion of the
period draws closer.

Quigley

&&

.AVIATION...
Issued 709 PM CDT Tue Jul 7 2026

Quiet weather will continue for the evening and overnight hours
under the influence of surface high pressure centered to the
south of the forecast area. Scattered cumulus early this evening
will diminish, with few to scattered high clouds expected
overnight along with light winds.

A chance for shower and storms is expected to gradually increase
from the north late Wednesday morning into the evening hours.
Locations along and north of I-94 have the best chance for
seeing scattered showers/storms tomorrow through the evening
hours. A few strong to severe storms will be possible in the
afternoon and evening hours.

Widespread southwest winds 5-10 knots tomorrow may become south
to southeast by early afternoon near the lake. Scattered to
broken cumulus around 5 kt feet is expected tomorrow, with some
lower ceilings possible north towards Fond du Lac and Sheboygan
by the evening hours.

DDV

&&

.MARINE...
Issued 143 PM CDT Tue Jul 7 2026

High pressure around 30.1 inches over Lake MI and lower MI will
shift southeast into the lower Great Lakes and the Ohio Valley for
Wednesday. Expect light south winds over the northern portions of
the lake this afternoon, with light and variable winds to the
south. Modest south southwest winds will then develop tonight and
continue on Wednesday, as weak low pressure around 29.8 inches
and an accompanying cold front approaches from the Northern Great
Plains. Modest southwest winds Wednesday night will become
northwest to north behind the frontal passage Thursday into
Friday, with high pressure around 30.0 inches building into the
the Upper Great Lakes region.

Gehring

&&

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

$$

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