NWS-Milwaukee/Sullivan Forecast Discussion
FXUS63 KMKX 280442
AFDMKX
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1142 PM CDT Fri Mar 27 2026
.KEY MESSAGES...
- Dry and windy Saturday and Sunday, with elevated fire weather
conditions possible each afternoon.
- Warming up Sunday into early next week, with above normal
temperatures expected Monday into Tuesday.
- More active weather is possible Monday night into Tuesday
morning, with chances (around 50 percent) for showers and
thunderstorms. Some hail is possible Monday night.
- There is more uncertainty for thunderstorm and severe weather
chances Tuesday afternoon and evening, depending on where the
low pressure system tracks and the timing of the low and cold
front.
&&
.SHORT TERM...
Issued 1142 PM CDT Fri Mar 27 2026
Overnight through Monday:
Mostly clear skies are expected overnight into Saturday morning.
Lighter northwest winds are expected overnight into early
Saturday morning, as high pressure passes by to the southwest of
the area.
Warm air advection on Saturday is expected, with increasing
south to southwest winds in a tightening pressure gradient. This
should bring dry conditions, with some high clouds moving
through at times. Forecast soundings show a very dry layer below
8000 feet AGL Saturday, with the gusty low level winds bringing
good mixing out potential of dew points.
This should bring very low relative humidity values of 15 to 25
percent over most of the area, lowest in south central
Wisconsin. There could be even lower values in south central
Wisconsin per the HREF ensemble minimum relative humidity and
10th percentile NBM forecasts. The very low relative humidity
values and increasing south to southwest winds may lead to
elevated fire weather conditions Saturday afternoon.
Highs should reach the upper 40s to lower 50s inland, with
south to south southeast winds in the afternoon near the lake
possibly keeping highs in the middle 40s there.
Warm air advection continues Sunday, with gusty south southwest
winds and dry low levels per forecast soundings. This should
bring another round of elevated fire weather conditions, as dew
points mix out and relative humidity values bottom out in the
25 to 32 percent range. They could mix down to 20 to 25 percent
in south central Wisconsin. Warmer highs into the middle 60s are
forecast, and may rise higher if more sunshine and mixing
occurs. These highs may reach to the lakeshore if winds remain
offshore until later in the day.
There is more uncertainty for temperatures, dew points and winds
for Monday, depending on where the warm front sets up across the
region. For now, deterministic models and ensembles seem to
want to bring the front northward into and/or through the area
Monday. For now, will leave the NBM values as is, which brings
warm highs into the middle 70s well inland and 50s to lower 60s
near the lake with onshore winds at times. There should be more
moisture advection and increasing dew points on Monday, so not
anticipating elevated fire weather concerns.
Wood
&&
.LONG TERM...
Issued 1142 PM CDT Fri Mar 27 2026
Monday night through Friday:
Low pressure is expected to track eastward across Wisconsin at
some point Tuesday morning, either over northern Wisconsin (as
per the majority of ECMWF/ENS solutions and NAM) or overhead in
southern Wisconsin (majority of GEFS solutions). In the warm
sector out ahead of this low Monday night, forecast soundings
reveal elevated instability (perhaps up to 1000 to 2000 J/kg of
MUCAPE), with around 50 percent chances for rain and nocturnal
thunderstorms. The main concern with any stronger storms (if
applicable) would be hail given the timing of this system.
There are additional rain chances for southern Wisconsin (50 to
70 percent) into Tuesday, mainly in the afternoon and evening
as the associated cold front swings through. The bulk of the
thunderstorms and heavier rainfall will likely setup downstream
of us (southern Michigan and Indiana) in better alignment with
the diurnal heating cycle. There is lots of uncertainty on the
exact timing of CAA, hence Tuesday afternoon's temperatures
could be anywhere from the lower 70s to around 60 degrees.
Rain chances taper down behind the front Tuesday night, leaving
dry weather into Wednesday, as high pressure passes north of
the region. Northeasterly flow off Lake Michigan on Wednesday
should hold daytime highs to the 40s.
Predictability drops substantially for the later half of the
week, with some potential for either a clipper system or
Colorado low and additional precipitation chances Thursday and
onwards.
Sheppard
&&
.AVIATION...
Issued 1142 PM CDT Fri Mar 27 2026
Mostly clear skies are expected overnight into Saturday
morning. Lighter northwest winds are expected overnight into
early Saturday morning, as high pressure passes by to the
southwest of the area.
Increasing south to southwest winds are expected later Saturday
morning into the afternoon. The winds may try to turn south to
south southeast near the lake, though uncertain at this time if
they may affect the Milwaukee and Kenosha terminals. Some high
clouds may move through at times Saturday into Saturday night.
There should be low level wind shear conditions developing
Saturday evening and lingering overnight, as southwest winds
increase to around 40 knots at 2000 feet AGL.
Wood
&&
.MARINE...
Issued 1142 PM CDT Fri Mar 27 2026
Strong high pressure around 30.7 inches will slowly move
southeast across southern portions of the lake overnight into
Saturday morning, then shifts east southeast of the region in
the afternoon.
Gusty north to northwest winds overnight will decrease and
become west Saturday morning. Winds will shift southwest to
south Saturday afternoon and become gusty once again, as low
pressure around 29.6 inches develops in the central High Plains.
Gusty southwest winds Saturday night will become south and
weaken somewhat on Sunday, as the low remains in the central
High Plains.
Winds look to remain just below Small Craft Advisory levels for
the nearshore waters this weekend, though waves may build above
4 feet for a time Saturday afternoon and evening north of North
Point Lighthouse.
Winds may shift to the north and northeast on Monday, as a warm
front sets up to the south of the region. Winds should turn
more southerly Monday night into Tuesday for southern portions
of the lake, with north to northeast winds to the north. Low
pressure around 29.5 inches should move northeast across the
lake Tuesday, with winds becoming northwest to north and gusty
behind the front later Tuesday into Tuesday night.
A Small Craft Advisory may be needed Monday night into most of
the rest of next week for the nearshore waters, as waves build
with increasing onshore winds.
Wood
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...None.
&&
$$
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