Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 122101
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
301 PM CST Sun Feb 12 2017

.TONIGHT AND MONDAY...Forecast Confidence Is Medium.

Sharpening mid/upper trough will continue digging into the upper
Midwest and western Great Lakes, before departing to our east
tonight. Surface high pressure will be the predominant influence
on our weather as it slides south into the Mid Mississippi valley.

Strong and gusty winds peaked for most areas early this afternoon
behind a cold frontal passage, during a period of pressure rises
of 3-4 mb per 3 hours. Winds will remain elevated into early this
evening, with gusts in the 30 to 40 mph range. Winds will drop
off a little after sunset, as the pressure gradient relaxes and
low-level mixing decreases. Given how winds have over performed a
bit from model guidance today, decided to keep the higher gusts
going for a few hours beyond what a consensus of models would
suggest.

High pressure to our south will bring anticyclonic low-level flow
and cold advection for tonight, with lows dropping into the 20s.
Winds will back southwesterly on Monday, in response to low
pressure sliding southeast through Ontario. This will bring low-
level warming, keeping mild temperatures around with highs
mostly in the lower 40s.

.MONDAY NIGHT THROUGH WEDNESDAY...Forecast Confidence Is Medium.

Models are showing warm air advection continuing into Monday
night into Tuesday morning. Mild temperatures are expected ahead
of the front Monday night into Tuesday. A fairly strong 500 mb
shortwave trough slides southeast through the area Monday night,
but the air is quite dry, so kept dry forecast going.

A fairly strong cold front then pushes southeast through the area
Tuesday afternoon, with gusty northwest winds developing Tuesday
night. A deep 500 mb low slides southeast across southeast Canada,
and brings a shot of differential cyclonic vorticity advection
through the area later Tuesday or Tuesday evening. Some model
differences exist with timing and moisture profiles.

The NAM has trended more towards the GFS with steep and moist low
level lapse rates Tuesday night, with the GFS having this Tuesday
afternoon as well. There is some low to mid level frontogenesis
response moving through the area later Tuesday afternoon and
evening.

For now, have some clouds and no precipitation, though may need
some PoPs eventually for the northeast counties. The soundings
have the look for some rain or snow showers, if there is enough
upward vertical motion and moisture available. Temperatures drop,
but not a lot, for Tuesday night into Wednesday.

.WEDNESDAY NIGHT THROUGH SUNDAY...Forecast Confidence Is Medium.

The models are showing a fairly dry and mild pattern for this
portion of the forecast. There are some timing differences between
the models with the warm frontal passage and subsequent warm air
advection Thursday into Friday. The GFS is quicker with this
evolution in the pattern during this time, with the ECMWF and
Canadian models slower. The warmer temperatures then linger into
the upcoming weekend, with south to southwest winds.

There is no precipitation in the forecast for now, as the 500 mb
pattern shifts from northwest flow Thursday, to a ridge Friday
night, to southwest flow over the weekend. The air is fairly dry
during this period. Temperatures were raised several degrees this
weekend, focusing on gradual warm air advection. Highs well into
the 50s are looking more probable this weekend, which would
approach record highs.

&&

.AVIATION/00Z TAFS/...

Strong gusty winds will decrease around sunset. Until then, gusts
to around 35 knots remain possible. VFR conditions will continue
for tonight into Monday.

&&

.MARINE...

A Gale Warning remains in effect until 9 PM for the nearshore
waters. Frequent gusts up to around 40 knots are expected during
this time, with waves of around 3 to 5 feet. The highest waves
will be towards the open waters. A Small Craft Advisory will
likely be needed after the Gale Warning ends, as the winds and
waves slowly subside.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...GALE WARNING until 9 PM CST this evening for LMZ643>646.

&&

$$

TONIGHT/Monday AND AVIATION/MARINE...SPM
Monday NIGHT THROUGH Sunday...Wood



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