065
FXUS63 KMKX 181010
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
410 AM CST Tue Nov 18 2025

.KEY MESSAGES...

- A northwest to southeast band of rain will slowly move across
  southern Wisconsin today. Areas north of I-94 have a chance
  (15-35%) of a change over to a wintry mix of rain/snow prior
  to sunrise this morning. Most locations that get a wintry mix,
  can expect a couple tenths of an inch of wet heavy snow.

- Additional chances (15-25%) for rain Thursday and Friday as a
  low passes to our north and a second passes to our south in
  quick succession.

&&

.SHORT TERM...
Issued 410 AM CST Tue Nov 18 2025

Today through Wednesday:

Pulling back on snow chances early this morning across southern
Wisconsin. Temperatures have been slow to come down and
dewpoints have been slow to rise early this morning which is
closing the window of opportunity for flurries and/or a
rain/snow mix. The low and mid level WAA looks to be winning out
in this morning. The best chances for any snowfall will be
north of Interstate 94 toward central Wisconsin (the
northwestern portions of our forecast area to be more specific).
Keeping a close eye on the Dells which currently tip toes ever
closer to that rain/snow mix with temps at 33 and dewpoints at
28. These values are the closest we have come to seeing that
evaporative cooling and wetbulbing effect needed for snow to
develop within the Fgen band. Now there are still a couple hours
yet to go this morning before the sun rises and temperatures
start to climb again, so southern Wisconsin is not completely
out of the woods on snow potential, but its looking increasingly
likely that the best timing will be right around or just after
sunrise when temps are at their coolest. Therefore, snowfall
totals were also lowered across the forecast area. Under the
700 mb Fgen and mid level WAA any change over to snowfall could
bring some wet heavy snowfall, but with a short time frame for
snow this is unlikely to develop more than a couple tenths of an
inch. Any accumulations are likely to be limited to grassy
surfaces under the heaviest snowfall band.

QPF did increase a bit across southern Wisconsin this evening
as the 700 mb Fgen is starting to stall out which is resulting
in a slowing of the northward progression. Rain will be very
closely tied to this forcing and large dewpoint depressions of
around 10 degrees or more will cause any precip that moves off
the mid level Fgen to petter out and become mostly virga. All
and all an area stretching from the Dells to Beaver Dam to
Menomonee Falls will likely see QPF totals around a tenth or two
higher when everything is all said and done.

Now to the things that haven`t changed the sfc low will continue
on its path into and through the Ohio River Valley today. Light
rain will linger this afternoon with far eastern Wisconsin
having a 15% chance that it lingers into the early evening. If
high pressure and drier air move in a bit faster than expected
then the rain may end a bit earlier. High pressure will move in
from Canada behind this exiting low bringing drier and quiet
conditions for Tuesday night into Wednesday. Temperatures will
remain near normal with highs in the upper 30s to mid 40s and
overnight lows in the mid 30s to upper 20s.

Patterson

&&

.LONG TERM...
Issued 410 AM CST Tue Nov 18 2025

Wednesday night through Monday:

High pressure gradually shifts east overnight Wednesday and will
see the return of southerly flow into southern WI for Thursday.
Paired with low-level WAA, expect above normal temps back into the
50s. While southern WI enjoys this brief warmup, a mid-level
shortwave trough will traverse across central Canada. This will
bring low pressure across the Hudson Bay region while dragging a
cold front across the Upper Midwest. NBM continues to hold on to
small precip chances ahead of this frontal passage on Thursday,
but is trending drier compared to previous runs. Do think the
downward trend is warranted as the better upper-level
dynamics/forcing remain north of the area while forcing from
another upstream shortwave trough coming up from the southern
Plains remains well to our south. Otherwise this cold front will
bring temps back down for the end of the week as high pressure
fills in behind the frontal passage for Friday.

For the weekend southern WI looks to remain mostly dry despite
another passing system to the north and a weak cold frontal
passage later Saturday. Another bout of high pressure is expected
for the second half of the weekend, but models begin to diverge on
the pattern into the start of next week as things are looking a
bit more active.

Wagner

&&

.AVIATION...
Issued 410 AM CST Tue Nov 18 2025

Largely VFR to MVFR conditions are expected through the period.
Rain is underway across southern Wisconsin this morning with a
northwest to southeast band slowly moving east northeast. A
second line of showers stretching across eastern Iowa into
central Illinois will move through this morning into the
afternoon. This second band hold the only potential for lower
IFR ceilings around 600 to 900 feet. The pockets of lower
ceilings are narrow and associated with the higher reflectivity
on radar and slightly higher rainfall rates (rates around 1/4
inch per hour). There is a small chance for a wintry mix prior
to sunrise this morning, but this will largely be limited to the
far northern portions of our forecast area (northern Sauk,
Marquette and Green Lake). Any accumulations are likely to be
limited to grassy sfcs under the heaviest bands and that if we
get a change over to snow which is looking increasingly
unlikely. Light rain will likely linger into this afternoon.
Dry weather is then expected through the rest of the period.

Breezy east winds this afternoon will become northeasterly by
this evening with gusts up to 25 MPH (20 kts) possible. Tonight
winds become light and variable as high pressure moves in from
the north. Light southeast winds are expected Wednesday.

Patterson

&&

.MARINE...
Issued 410 AM CST Tue Nov 18 2025

Low pressure over northwestern Missouri will continue to move
east early this morning into the Ohio River Valley with east
winds slowly increasing. The breezy winds will become
northeasterly over the southern half of the lake this evening.
The breezy onshore winds will cause waves to build over the
nearshore zones to 3 to 5 feet and thus a Small Craft Advisory
is in effect Tuesday. Winds then ease Wednesday as high
pressure moves over the lake. High pressure exits into Thursday
morning, with winds becoming southwesterly as a low pressure
system progresses eastward across northern Ontario. A cold front
from that low pressure system will shift winds to northwesterly
overnight Thursday into Friday.

Patterson

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644...6 AM Tuesday to 9 PM
     Tuesday.

     Small Craft Advisory...LMZ645-LMZ646...6 AM Tuesday to
     midnight Wednesday.

&&

$$

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