NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 271153 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
553 AM CST Fri Feb 27 2026

.KEY MESSAGES...

- Gusty southwest winds and temperatures in the 50s to low 60s
  today, with very low relative humidity values.

- Accumulating snow is expected on Saturday, with 1 to 2 inches
  across much of southern Wisconsin. A more narrow band of 3 to
  4 inches is expected, but exact placement of this band is
  uncertain. Trends have been north of I-94.

- Additional chances for precipitation develop Sunday night, and
  again Tuesday through the end of the work week, with the most
  confidence in rain Thursday into Friday.

&&

.UPDATE...
Issued 553 AM CST Fri Feb 27 2026

Patchy ground fog may linger for another few hours, before
southwest winds pick up by middle morning. Gusty southwest winds
will linger today, with warm temperatures in the 50s to around
60 degrees. Highest values will be in far southeast Wisconsin.
Highs may rise a few degrees above current forecast values,
especially if deep mixing occurs with more sunshine. The cold
frontal passage is expected to be dry later today into this
evening, with gusty northwest winds behind it for tonight.

Trends with the frontogenesis snow band for Saturday continue to
fluctuate, with 06Z deterministic models focusing more on
southern Wisconsin than the 00Z runs that were further to the
north. The 06Z HRRR remains focused in northern portions of the
area and into central Wisconsin, as does the higher resolution
versions of the NAM. The 06Z and 09Z RAP and ARW runs remain
focused more over southern Wisconsin or a little further south.

So, a good amount of uncertainty remains with where the moderate
snow band with the strongest frontogenesis response will set
up. It does look like most of the area will see a one to two
inch snowfall Saturday. Later shifts may need to consider a
Winter Weather Advisory if more certainty in the moderate snow
band location is found.

Wood

&&

.SHORT TERM...
Issued 1244 AM CST Fri Feb 27 2026

Today through Saturday night:

Southwesterly winds will increase through this morning as
occluding low pressure progresses into southwestern Ontario.
This will bring plenty of dry WAA into southern Wisconsin,
dropping dewpoints and resulting in relative humidity values in
the low 30s, especially in southeastern Wisconsin where
temperatures rise to around 60 degrees. Elsewhere, expect highs
in the mid 50s. Southwesterly winds will gust between 25 and 30
mph. With potential for dewpoints to drop farther than currently
forecast, potential for some fire weather concerns may develop
during the afternoon hours.

A cold front from the occluded low will progress southeastward
through Wisconsin late this afternoon into tonight, bringing
falling temperatures and northwesterly wind gusts to 20 mph.
Expecting dry conditions to persist, and no precipitation is
expected. Lows in the 20s.

Saturday, the cold front is expected to stall across the Middle
Mississippi Valley as strong high pressure builds into the
northern Plains and low pressure develops across the southern
Plains. This will allow a region of gently sloping frontogenesis
to develop across northern Illinois through central Wisconsin as
a shortwave moves through the flow. Within the zone of
frontogenesis, plenty of moisture is available within a deep
dendritic growth zone (2000 to 3000 ft). Ratios therefore may be
quite high (up to 18:1) within a narrow band where the majority
of the frontogenesis lines up vertically. The question remains
exactly where that region sets up, or with latest 00Z runs
whether it sets up in one region or remains more diffuse. With a
more broad area of frontogenesis with the latest runs, am
comfortable calling for a widespread 1 to 2 inches of snow
across southern Wisconsin. A narrow band of 3 to 4 inches is
possible, with the latest trends in mesoscale modeling showing a
northward shift to north of I-94. Snow will taper off from west
to east during the late afternoon to evening hours as the
shortwave exits.

Arctic high pressure will dominate into Saturday night, with
clearing skies and light northerly winds leading to lows in the
upper single digits to the low teens. Wind chills in the single
digits.

MH

&&

.LONG TERM...
Issued 1244 AM CST Fri Feb 27 2026

Sunday through Thursday:

Sunday will feature a cold start with light northerly winds
persisting through the day. Highs will be in the upper 20s. Expect
increasing clouds from the south in the afternoon as a weak
shortwave trough approaches from the Northern Plains. The upper
jet will be right over southern WI, and the 850mb frontogenesis
should be over northern IL. A different shortwave tracking across
the central Plains may phase with that northern wave and if it
does (like ECMWF suggests), southern WI has a better chance of
getting some light snow accumulation. If there is no phasing (GFS),
the precip will remain to the south of the WI/IL border. The blend
of solutions (NBM) gives southern WI a 15 to 35% chance of light
snow, which is a little higher than the previous run.

The next shortwave tracking across the mid Mississippi Valley
Monday night or Tuesday will give us our next chance of precip
over southern WI, as there is a potential for phasing with a
northern stream shortwave once again. The temperatures look a
little warmer than the previous system, so we may be dealing with
a wintry mix.

A deeper, more amplified shortwave trough will lift into the
Midwest Wed afternoon/evening. Temperatures would be warm enough
for rain through Thursday morning. There is strong agreement
between models for this particular system.

Cronce

&&

.AVIATION...
Issued 553 AM CST Fri Feb 27 2026

Patchy ground fog with 4 to 5 mile visibility may linger for
another few hours at Madison and Janesville, before southwest
winds pick up by middle morning. Some middle to high clouds may
move through at times today into this evening. Gusty southwest
winds will linger today. The cold frontal passage is expected to
be dry later today into this evening, with gusty northwest
winds behind it for tonight. More middle to high clouds will
move into the area later this evening and overnight.

The area of light snow should move east into the area Saturday
morning, lingering through the day before ending from west to
east later in the day and early Saturday evening. Visibility of
1 to 2 miles is generally expected, lower at times within more
moderate snow bands. Ceilings should be in the 500 to 1000 foot
AGL range with the snow. The snow character will be fluffy and
powdery, though winds should be light and northerly.

At this time, snowfall rates of one quarter to one half inch
per hour are expected Saturday, with rates to three quarters of
an inch per hour possible in more moderate snow bands. A
general one to two inches is anticipated, with up to 4 inches
possible in the more moderate snow bands. The location of this
heavier snow band is uncertain at this time.

Wood

&&

.MARINE...
Issued 1244 AM CST Fri Feb 27 2026

Light southwesterly winds continue through daybreak, with gusts
increasing through the morning into the afternoon as low pressure
of 29.2 inches moves eastward through Ontario. A few
southwesterly gales to 35 kt are possible during the afternoon
hours in the northern third of the open waters, but not
anticipating widespread gales warranting any headlines. In
southern Wisconsin nearshore waters, expect gusts up to 30 kt. A
Small Craft Advisory is in effect from mid-morning through late
tonight.

Winds shift to become northwesterly tonight as low pressure
exits to the east. Again, a few gale force gusts to 35 kt are
possible in the northern third. Winds will slowly diminish and
shift to northerly into Saturday morning as high pressure of
30.6 inches builds into the northern Plains. High pressure
builds eastward into Sunday, leading to light and variable winds
through Sunday night before winds shift southerly ahead of an
additional low pressure system progresses through Ontario on
Monday.

MH

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...10 AM
     Friday to 2 AM Saturday.

&&

$$

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