Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 052120

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
320 PM CST Mon Dec 5 2016


TONIGHT and TUESDAY...Forecast confidence is high.

High pressure to the southest will continue to move away from the
region as low presure moves across MN. Winds stay 5 to 10 knots
overnight with this pressure gradient, but due to the low level
moisture in place and fresh snow, it looks like fog will stick
around thorugh the night. Soundings show moisture trapped beneath an
inversion around 1000ft. It may be dense in some spots late tonight
and Tuesday morning. Fog will create slippery conditions on
untreated roads with temperatures near or below freezing.

The cloud cover may stick around through Tuesday. An upper low moves
across MN with sheared vorticity brushing the northern CWA. During
the day a cold front moves through. Behind it winds will be brisk
out of the west. There is a small chance for freezing drizzle and
snow north and west of Madison in the morning. The GFS shows a
partial loss of ice crystals resulting in freezing drizzle while the
NAM shows snow.


TUESDAY NIGHT THROUGH FRIDAY... Forecast confidence is medium.

Winds will be picking up out of the west Tue night as cold air
advection ensues. Lows will drop down to around 20 with a possible
window of time with clear skies toward WI border due to weak ridging.

The brisk west winds and cold temperatures will be the main story
for the latter half of the week. Models are now in good agreement on
the location of a closed upper low sliding across Ontario Canada
though Wed and into Ontario on Thu.

An upper jet will strengthen over the Midwest Thu morning which will
produce some upward motion over southern WI. This combined with the
500mb trough and surface trough could lead to some light scattered
snow showers or at least flurries in srn WI.

The coldest air will drop into southern WI on Friday with 850 mb
temps around -14C. Highs will be in the 20s Wed and Thu... then
struggle to reach 20 on Friday. Lows will be in the teens each night.

SATURDAY THROUGH MONDAY... Forecast confidence is low.

We will get into more of a zonal flow pattern for the weekend. A
ripple in the flow will bring a weak surface low through the Upper
Midwest/Great Lakes on Saturday.  This feature now looks very light
on the ECMWF and GFS, but the Canadian model is still painting
higher qpf with a much more amplified system.

The GFS and ECMWF are now showing their more amplified system
crossing WI on Sunday. This bears watching for the potential of
accumulating snow.



Soundings show moisture trapped beneath an inversion around 1000ft
sticking around through the night, so expect low stratus to persist.
Winds along the lake will pick up slightly and become southeast
tonight which may help raise ceilings and visibilities somewhat,
mainly in the east. Given curren trends, confidence is low in this
happening. A cold front will come through on Tuesday bring stronger
west winds and this should help scour out low clouds somewhat during
the afternoon.



Brisk south winds are expected tonight, reaching Small Craft
Advisory levels north of Port Washington. There will be a lull in
winds Tuesday morning as a cold front moves through. Then winds will
become westerly and increase to Small Craft Adivosry levels once
again later on Tuesday. All zones are expected to reach advisory
criteria at this time and these strong winds could persist through
Thursday. Think waves will stay below 4 feet due to the westerly


LM...SMALL CRAFT ADVISORY until 6 PM CST Wednesday for LMZ643.



Tuesday NIGHT THROUGH Monday...MRC is the U.S. government's official web portal to all federal, state and local government web resources and services.