Scientific Forecaster Discussion
fxus63 kmkx 161115
Area forecast discussion
National Weather Service Milwaukee/Sullivan WI
515 am CST Tue Jan 16 2018
Lake effect snow showers will continue through the morning hours.
The snow showers should become better organized into a band of
lake effect snow, then gradually push south, then out over Lake
Michigan around noon as low level winds become more
north/northwest. Look for an additional 2 inches of snow in Lake
Shore County areas. Snow will end north areas mid/late morning.
Lake effect IFR vsby/MVFR cig snow showers will continue through
the morning hours. The snow showers should eventually become
better organized into a band of lake effect snow, then gradually
push out over Lake Michigan. Otherwise, MVFR would be expected
to improve to VFR with time.
Over south central Wisconsin areas of MVFR cigs/flurries will
gradually become more scattered.
Previous discussion... (issued 234 am CST Tue Jan 16 2018)
Today and tonight...forecast confidence is medium...
No real changes to the overall forecast at this point. The
remnants of the Large Lake enhanced snow area with the surface
trough will push south by sunrise. Now the main concern is the
northeast winds behind this trough. This was causing More Lake
effect snows, and should become better organized and eventually
form a single band of snow. This band is expected to brush the
shoreline tomorrow morning, bringing a quick shot of additional
snow. Up to 2 inches of additional snow is expected in areas where
this brushes the land. Lesser amounts more inland. Farther inland
most of the light snow has ended.
The upper level trough sharpens with the trough axis exiting
southeast Wisconsin this morning. The mid level trough has
A brief clear period is likely tonight, and this would cause
temperatures to drop due to the fresh snow cover across the area.
Wednesday through Friday - confidence...medium to high
overall broad scale mid level ridging this period. There is a 500
millibar shortwave that swings across the upper Midwest on
Thursday however it looks pretty dry throughout the column per
BUFKIT soundings. The 925 temps start off around -10c Wednesday
and modify into positive territory for Thursday and especially
Friday. So a warming trend is in the offing with fairly persistent
west/southwest winds this period.
Saturday - confidence...medium
850/925 boundary may set up across the area with an uptick in
column moisture noted.Overall still looks mild though the European model (ecmwf)
does shift surface/925 winds off the lake.
Sunday and Monday - confidence...medium
still decent agreement on a fairly potent storm system moving
across the western lakes region. As of the 00z runs the European model (ecmwf) has
the warmest track of the low through northern WI while the GFS is
coldest across northern Illinois. The Gem splits the difference but has
trended more towards the colder GFS from prior runs. Bottom line
confidence pretty high now that a system will be impacting the
region but track/details of precip types still a ways off from
being finalized. For now anyways, all types are on The Table for
Aviation(06z tafs)...for msn...just a few light snow showers will
continue for a few more hours, before snow dissipates overnight.
Expect an improvement to VFR after sunrise. Winds should remain
For kmke, kues, and kenw...things are a bit more complicated for
the terminals near the lake, as lake effect snow showers will
continue through the overnight hours. Initial showery activity
should eventually become better organized into a band of lake
effect snow by daybreak, which is currently expected to brush the
shoreline area. Variable flight conditions are likely overnight,
with vis coming in and out of IFR as snow Showers Pass through.
Once the more organized band forms, all will depend on where
exactly the band tracks. If it tracks over any terminals, IFR
conditions with light to moderate snow will be likely. Otherwise,
MVFR would be expected to improve to VFR with time. Updates are
likely overnight as the track of the lake effect snow band becomes
Marine...Small Craft Advisory is in effect from 6 am to 3 PM Tuesday
for areas north of North Point light for higher waves. Expect 3
to 5 ft waves associated with north-northeast winds.
Expect northerly winds to persist through Tuesday, before they
become westerly and then southwesterly by Wednesday. Another Small
Craft Advisory will likely be required by this time.
WI...Winter Weather Advisory until noon CST today for wiz059-065-066-
Winter Storm Warning until noon CST today for wiz052-060.
Lm...Small Craft Advisory until 3 PM CST this afternoon for lmz643-