NWS-Milwaukee/Sullivan Forecast Discussion
FXUS63 KMKX 061953
AFDMKX
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
153 PM CST Fri Mar 6 2026
.KEY MESSAGES...
- Urban and small stream flooding will be possible through this
evening as continuous rounds of rain move across southern
Wisconsin.
- Isolated strong to severe storms possible across far southern
Wisconsin this afternoon and evening, with hail and gusty
winds the primary threats. An isolated tornado is possible,
but less likely.
- Strong to severe storms are expected overnight. Damaging
winds and isolated tornadoes are the main hazards.
- Rain expected Tuesday into Tuesday night. An isolated
thunderstorm cannot be ruled out. As rain exits late Tuesday
night, some wintry mix is possible.
&&
.SHORT TERM...
Issued 153 PM CST Fri Mar 6 2026
This afternoon through Saturday:
Watching an effective warm front wiggle northward through the
Mississippi Valley this afternoon, with expectations of a brief
period of peeks of sunlight and higher clouds this afternoon
as a much warmer airmass arrives in the southern two tiers of
Wisconsin counties. As temperatures rise, isolated to scattered
thunderstorms may develop in the warm sector along the effective
warm front. A few of these cells have already developed in
northern Illinois, with expectations that as the front moves
northward this isolated to scattered activity will develop
across far southern Wisconsin. Within these cells, without much
steering flow, expecting more pulse-tyle convection with primary
hazards of hail and gusty winds. CAPE nearing 500 J/kg, bulk
shear around 35 kt, and moderate mid level lapse rates of 6-7
degrees C/km along with freezing levels near convective cloud
base will set the stage for isolated cells to be able to tap
into all the dynamics and instability this afternoon.
Significant turning in the lowest 5000 ft may allow for an
isolated supercell to develop, but confidence is low. Expecting
isolated storms with hail up to 1 inch and gusty winds.
A brief break in precipitation may develop around sunset into
the early overnight hours as the surface warm front weakens with
the lack of solar heating, and the developing low remains to the
southwest. However, going into the 10 PM to 3 AM timeframe,
expecting the low to rapidly lift northeastward, bringing
convection through all of southern Wisconsin. With LLJ dynamics
in play (nearing 60 kt nosing across far southern Wisconsin,
nearing 50 kt in central Wisconsin), expecting this prefrontal
convection to have plenty of lift (frontal boundary), shear
(bulk shear values near 50 kt, 0-3 helicity 300-400 m2/s2), and
moisture to work with (PWATs nearing 1.5 inches). MUCAPE will
also continue to increase through the overnight hours, nearing
1000 J/kg by the time the prefrontal convection moves in. With
all these ingredients in play, expecting a squall line type
feature with low topped convection and potential for QLCS
tornadoes along the leading edge where individual bowing
segments turn northeastward (along the 0-3 shear vector). Even
with a stable layer near the surface, strong enough cells
embedded in the line are expected to punch through to the
surface, resulting in damaging wind potential along with the low
topped QLCS tornado threat. Hail is less likely for this round,
but not out of the question.
Convection will sweep eastward into the early morning hours
Saturday, with lighter rain and embedded lightning to continue
after the main band of strong thunderstorms moves through. All
activity will exit into Lake Michigan and northern Illinois by 4
AM based on current model guidance. The main cold front lags
behind the convection by several hours, allowing for slight
chances of additional showers (20-30%) through mid-morning
Saturday along the cold frontal boundary. No additional severe
storms are expected. Temperatures will remain in the 50s
throughout the day, falling quickly into the 40s after sunset.
MH
&&
.LONG TERM...
Issued 153 PM CST Fri Mar 6 2026
Saturday night through Friday:
Overall a mild pattern is expected for southern WI through the end
of the weekend into the start of next week with well above normal
temps. Temps regulate closer to normal through the middle of next
week with a more active pattern. Next chance for precip across
southern WI is looking to be later Tuesday into Wednesday.
Additional chances are possible for the second half of the week,
but more uncertainty and variance in solutions remains this far
out.
The upper-level trough bringing today's active pattern will exit the
region overnight Saturday into Sunday. Light winds and dry
conditions will linger as another weak dry cold front swings through
early Sunday. Behind this weak front, winds turn more southwesterly
through Sunday as another warm front begins to lift northward while
another surface low develops across Manitoba overnight Sunday into
Monday. This prevailing WAA pattern is looking to warm things up
well above normal Sunday into Monday. Looking at 50s into the lower
60s for Sunday, but even milder temps for Monday with high chances
(<80% from the NBM) to see highs exceed 65F for Monday and even a
potential (20-40%) to even see temps approach and crack 70F. Global
ensembles are not a enthusiastic about the milder temps exceeding
60F, but given the WAA pattern would hedge toward the milder stretch.
Milder temps are expected to tampered down by the Monday low
pressure trekking across Ontario and dragging another dry cold front
through the Upper Great Lakes. Will likely see temps fall for
Tuesday closer to normal ranging from around 50F into the 40F. There
are hints in the models of this cold front stalling somewhere across
the region, so depending on where will ultimately impact overall
temp trends Tuesday.
Meanwhile the next system to bring precip chances to southern WI
will be taking shape across the Plains as an upper-level trough digs
across the Central CONUS. This will be associated with a surface low
developing across the plains and looks to ride up the stalled
boundary into the Great Lakes Region later Tuesday into Wednesday.
Again some uncertainty remains with this system as models hint at an
upper-level cutoff low developing across the southern Plains at
the same time as the main trough, thus if these two systems phase
can alter the track of the surface low along with precip chances
and types. So will have to monitor how trends evolve over the next
few days as southern WI could see snow to wintry mix to rain all
depending on the track of the midweek system.
Otherwise, the pattern becomes more uncertain through the second
half of next week, which is not that uncommon during the spring here
in the Midwest.
Wagner
&&
.AVIATION...
Issued 153 PM CST Fri Mar 6 2026
400-600 ft ceilings are expected to dominate into this
afternoon, with a brief period of recovery into the 1000-2000 ft
range during the later afternoon and evening hours. Winds will
shift to southerly this afternoon and begin to gust near 25 kt.
Isolated to scattered thunderstorms are expected to develop
from MSN to MKE southward during the afternoon hours (2-5 PM),
with a few of these storms becoming strong enough to produce
hail of 0.5 to 1 inch in diameter and briefly gusty winds.
Storms will end into the evening hours. A strong line of storms
will progress west to east during the late overnight hours, with
stronger cells producing damaging winds and isolated tornadoes.
Storms will exit into the early morning hours Saturday, with a
cold front turning winds to northwesterly mid-morning.
MH
&&
.MARINE...
Issued 153 PM CST Fri Mar 6 2026
Low pressure in the central Great Plains will continue to track
northwards into the Upper Mississippi River Valley by this
evening. Southwesterly winds will prevail ahead of this low
through the evening along with widespread rain and embedded
thunderstorms will accompany the approaching low today. Light to
modest winds and milder temps will also create conditions
favorable for marine fog to develop at times through this
evening into Saturday morning. Thus a Marine Dense Fog Advisory
is in effect for periodic drops in visibilities to less than 1
nm at times. Then the low will move near or just north of Lake
Michigan tonight into Saturday morning and drag a cold front
across the Upper Great Lakes into Saturday morning. Will see
breezy west to northwesterly winds behind the front and usher
out the marine fog by late Saturday morning. Westerly winds will
prevail through Saturday night before increasing and turning
more southwesterly for Sunday into Monday as a series of two low
pressure systems develop and track north of Lake Michigan
through this time frame.
Wagner
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...midnight
Saturday to noon Saturday.
Dense Fog Advisory...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 until 9 AM
Saturday.
&&
$$
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