Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 112025
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
225 PM CST Thu Jan 11 2018

.Discussion...

Rest of this afternoon into this evening - Confidence...Medium
Strong cold front will continue to make its way through the area
with mid level wave providing the bulk of forcing for the precipitation.
The west to east changeover appears on track as temps crash in
the wake of the front. Best overlay of coldest surface temps with
precip is within going advisory area so will leave area as is with
the lakeshore counties also the last to cool down so less of a
concern there.

Temps will continue to fall overnight, with single digits and
teens by sunrise. Any lingering water on roads/sidewalks will
freeze hard overnight...unless treated.

Friday through Sunday...Forecast confidence is high.

Arctic high pressure will build across the area bringing another
round of very cold winter temperatures to the area. After enjoying
highs in the 40s and 50s today (Thursday), highs on Friday will
only hit the teens. Despite the bitter cold, look for dry weather
and plenty of sunshine.

By Sunday, we start to see the impacts of a large, digging upper low
pressure system pushing south into the Upper Midwest. This low
will eventually carve out into a huge, closed, stacked system over
the Great Lakes region early next week. We could see some light
snow spread into areas west of Madison Sunday afternoon.

Sunday night through Monday night...Forecast confidence is
medium.

We expect to see a long duration light snow event as the upper
low stalls for a while over the area and the associated surface
low arrives and pivots across the region. Upper lows are often
very difficult to forecast with respect to precip trends. Precip
type isn`t a question, it will be snow given the cold temps. But,
the forcing isn`t very impressive. On the plus side for snow
lovers, the dendrite region is rather deep and this coupled with
the cold air should allow light snow to fall during this long
period. Right now, we have amounts in the 2-3 inch range with some
4 inchers possible in the far eastern counties where the pivot
would have greater impact for a longer duration.

This will be a dry snow with ratios in the 20:1 range.

Tuesday through Thursday...Forecast confidence is medium.

High pressure will build in as the upper low pulls away. We dry
out on Tuesday and remain dry through Thursday. The arctic cold
continues for Tuesday and Wednesday, but we start to get into a
return southerly flow on Thursday which will help to bring some
modifying temperatures.  Right now no wind chill advisories are
anticipated through the cold wave.

&&

.AVIATION(21Z TAFS)... Strong cold front continues to march
through srn WI this afternoon. MVFR cigs widespread though expect
some lowering with some IFR cigs becoming a bit more numerous.
Gusty southwest winds will turn sharply to the west and northwest.
Any rain will become mixed with FZRA/IP and eventually to a
little snow. Not expecting much in the way of accumulation as bulk
of moisture being spent in warmer environment. Models dry things
out pretty quickly this evening with ceilings expected to
transition to MVFR and eventually VFR.

&&

.MARINE...
Going small craft advisory looks reasonable. The big
wind shift and temp drop still on track.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory until 8 PM CST this evening for WIZ046-
     047-051-056>059-062>065-067>070.

LM...Small Craft Advisory until 3 PM CST Saturday for LMZ643>646.

&&

$$

Tonight/Friday and Aviation/Marine...Collar
Friday Night through Thursday...Davis



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