Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Green Bay WI
317 am CST sun Nov 29 2015
Forecast discussion for routine morning forecast issuance
Short term...today...tonight...and Monday
issued at 303 am CST sun Nov 29 2015
Quiet weather to continue today into tonight as a ridge of high
pressure drifts southeast over the region. A short wave passing
over the northern Great Lakes region will drop a frontal boundary
over northeast Wisconsin today. MVFR or lower end VFR clouds were
developing over Eastern Lake Superior and drifting southward. Will
likely need to consider expanding clouds over far northeast
Wisconsin including Door County today. Otherwise the rest of the
region can expect a shift of the winds to the northeast with
plenty of sunshine. With the northeast to east flow tonight...potential
of clouds developing over Lake Michigan and expanding inland.
Forecast issue turns to precipitation chance for Monday with the approach
of the upper low and frontal system from the plains. Middle level
clouds were already over Iowa and southern Minnesota early this
morning and will continue to drift into the southwest Wisconsin
this morning. Some light mixed precipitation noted from South Dakota to
southern Iowa. The forecasts initialized this well and keeps the precipitation
well southwest of the area trough Monday morning. 850 warm air advection begins
to spread from south to north on Monday. With a cold start and
some dry layers to overcome...expect the precipitation to gradually spread
north as a light mix of rain and sleet over eastern sections...and
light rain...sleet and snow over central and north central
Long term...Monday night through Saturday
issued at 303 am CST sun Nov 29 2015
Mixed precipitation with system Monday night through Tuesday night
is the main concern as 500mb closed low moves across the region.
Warm air ahead of the system will make for a complicated precipitation
type forecast Monday evening...then middle level moisture may get scoured
out late Monday night into Tuesday morning where precipitation may
change over to a drizzle or freezing drizzle/rain (far north).
Gusty southeast winds ahead of the main system will help pull mild
air into the region Monday afternoon. Surface temperatures also
problematic as temperatures will only be a few degrees above
freezing at the onset of the precipitation across the north. Once
the precipitation starts...temperatures across the north will be
around 32 degrees. Do expect more sleet than freezing rain in this
region based on temperature/moisture profiles on BUFKIT. The
mixed precipitation will also lower snowfall totals. Current
projections are for 1 to 3 inches north of Wausau to Iron Mountain
line with locally higher amounts across Vilas County. Only a minor
ice accumulation is possible due to the sleet and freezing rain.
Despite boundary temperatures several degrees above freezing Tuesday
afternoon...cold 850mb temperatures would support some snow in the
heavier convective showers across northeast and east-central
Wisconsin. Snow or rain showers will linger into Tuesday night
and possibly across the far east/north on Wednesday morning.
The remainder of the period will be tranquil with above normal
temperatures. No real Arctic air is in sight.
Aviation...for 06z taf issuance
issued at 1040 PM CST Sat Nov 28 2015
Quiet weather with generally good flight conditions expected the
next 24 hours. Temperatures could fall off enough to allow some patchy fog
to form tonight. That would be most likely to affect the rhi taf
site. Otherwise...a lake cloud band may develop over Lake Michigan
tonight...but seems unlikely to shift far enough westward to bring more
than scattered clouds to mtw.
VFR conditions will prevail into Sunday...however a deck of middle
clouds located over Iowa is expected to advect in over Wisconsin
later Sunday afternoon and into Sunday evening. Conditions are
expected to remain VFR with bases in the 6-8k feet range.