Scientific Forecaster Discussion
fxus63 kmkx 141741
Area forecast discussion
National Weather Service Milwaukee/Sullivan WI
1141 am CST Thu Dec 14 2017
Update...slowed cloud increase into the northwest County Warning Area and
removed flurry mention there this afternoon.
Aviation(18z tafs)...MVFR cumulus development across SC WI otherwise
VFR until cloud finally works in tonight with mid level wave. MVFR
cigs are then likely to expand across the area per upstream cloud
deck. Surface/850 trough swings through tonight which also will
help in developing snow showers. Best potential for these will be
in the northern County Warning Area. Otherwise flurries.
Previous discussion... (issued 1000 am CST Thu Dec 14 2017)
Update...no changes to forecast at this time.
Marine...Small Craft Advisory expired at 9 am. Winds had
diminished enough to let go of the headline then.
Previous discussion... (issued 800 am CST Thu Dec 14 2017)
Skies have cleared.
Skies have cleared. Winds diminishing. Stratus will begin to
build in from the west by evening, perhaps dropping conditions
down to MVFR in a few areas.
Previous discussion... (issued 219 am CST Thu Dec 14 2017)
Today and tonight...forecast confidence is high...
Fringe of the lake effect snow band has pushed southeast but was
still over portions of the nearshore waters near Kenosha, and no
additional snow is expected as the lake band continues to push
east. Northwest winds over land Haver decreased with the departure
of the surface low, and will continue to decrease overnight. With
decreasing winds and clearing skies, expect temperatures to fall
a little below guidance before sunrise.
An upper trough axis pushes into southern Wisconsin this evening.
Weak 700 mb upward motion begins this afternoon, and may be
enough for a few flurries as the trough moves across and the lower
and mid level relative humidity increases.
A surface ridge moves across today, with a weak west flow later
Friday through Sunday...forecast confidence is medium:
Models are coming into better agreement in showing a band of snow
developing within a baroclinic zone as milder temps aloft push
into the area Friday evening into Saturday morning. It will
likely be another narrow swath of snow, which makes pinpointing
where the snow will fall tricky. For now, models are targeting the
northeast half of the forecast area. Overall, amounts look on the
low end, with a consensus of models suggesting 1-2 inches. Just
went with medium precip chances for now given some placement
differences among models and the lower confidence with this type
Kept a chance of rain and snow going for the southeast half of the
forecast area Sunday afternoon, as the European model (ecmwf) and Canadian still
bring low pressure across the area. The GFS keeps a much weaker
low well to the south, resulting in dry weather for Sunday.
Below normal temps Friday will warm up to a few degrees above
normal for the weekend.
Monday through Wednesday...forecast confidence is medium:
Models are in decent agreement for Monday, showing dry weather
between waves. Another wave Monday night and/or Tuesday may bring
light snow chances back to southern Wisconsin. Not enough
agreement among models for precip chances at this time though.
High pressure is then expected to build into the area for
Continued above normal temps early in the week are expected to
fall back to around normal by Wednesday as the high builds in.
Skies have cleared for the most part, with a lake effect snow
band off shore now, which will keep moving slowly east.
Thursday should be a generally pleasant day, with light winds and
VFR conditions. Stratus will begin to build in from the northwest
tomorrow evening, perhaps dropping conditions down to MVFR in a
Small Craft Advisory continues into mid morning. Northwest winds
are occasionally gusting to small craft, though should drop to generally
just below criteria north area by sunrise then the rest of the
area. Waves will remain rather high initially but were subsiding.
May be able to cancel small craft north areas early.