Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 211530 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
930 AM CST Tue Feb 21 2017

.UPDATE...

High clouds across the southeast half of the forecast area will
continue to exit this morning. Meanwhile, low clouds are hanging
around across a good portion of southern Wisconsin, but should
diminish late morning into early afternoon as daytime mixing
increases. The increasing sunshine should help temps to warm to
forecast highs, with record temps likely to fall again.

&&

.AVIATION/18Z TAFS/...

Low clouds are expected to diminish late morning into the
afternoon as daytime mixing increases. Should see a return to VFR
by early afternoon, with VFR conditions likely to persist then
through Wednesday.

&&

.MARINE...

South to southwest winds may gust to 20 knots at times tonight and
Wednesday, but otherwise quiet weather will continue.

Strong low pressure passing through the region will likely result
in Small Craft Advisory conditions at times Thursday night through
Saturday night. Could even see a period of gale force winds Friday
night into Saturday morning.

&&

.PREV DISCUSSION... /Issued 318 AM CST Tue Feb 21 2017/

SHORT TERM...

TODAY AND TONIGHT...Forecast Confidence Is High.

Area of rain showers continues to push eastward through the area
early this morning. This was being driven by 500 mb differential
cyclonic vorticity advection, as well as some low level
frontogenesis response. These features will shift east of the area
around or soon after 12Z this morning, which will take the rain
showers along with it. The relatively baggy pressure gradient with
the passing cold front should allow for patchy fog to linger into
the early morning as well.

Clouds should gradually clear out of the area from west to east this
morning, with mostly sunny skies expected this afternoon and mostly
clear skies tonight. Warm air advection does develop during the
afternoon hours, which combined with the sunshine should help
temperatures reach record highs in the lower to middle 60s across
most of the area. There may be a lake breeze forming later in the
day, which may bring temperatures down near the lake. Lows tonight
should remain mild in the lower to middle 40s. These are still above
the average highs for this time of year.

LONG TERM...

WEDNESDAY... Forecast confidence is high.

A weak surface low will track across northern WI Wed in response to
a shortwave. Precip associated with the low will remain well to our
north, but an extra push of warm air on a southwest breeze will give
us a chance at highs around 70 across southern WI.

THURSDAY THROUGH SATURDAY... Forecast confidence is medium.

The next shortwave is expected to cross the Midwest and dig through
the Great Lakes Region late this week. This will bring a stronger
low pressure system across northern IL and southeast WI. Precip type
will be rain in southern WI ahead of the low beginning Thu
afternoon. The transition between all rain and all snow Thu night is
expected to be just north of a line from the Dells to Fond du Lac
and Sheboygan.

The surface low and dry slot will likely reach srn WI midday Fri.
Temps within the warm sector could reach mid 50s in far southeast WI
Fri, but that will depend on strength of east winds off Lake
Michigan and amount of sunshine. Colder air on the back side will
lead to a changeover from rain to snow Fri night. Accumulating snow
is expected across southern WI in the trowal region Fri night. At
this time, it looks like 1 to 3 inches is possible north of a line
from Monroe to Milwaukee. Highest amounts will be in central WI.

SUNDAY AND BEYOND... Forecast confidence is medium.

Southern WI will be in a colder pattern for early next week. We
could see a few flurries in this northwest flow pattern. The next
system to watch should arrive in southern WI Monday night.

AVIATION/12Z TAFS/...

Area of rain showers is expected to shift east of the area around or
soon after 12Z this morning. Should continue to see periodic IFR
category ceilings and MVFR visibilities until the rain moves out.
Clouds should move out of the area from west to east by later this
morning, with mostly clear skies this afternoon and tonight. A
passing cold front this morning will veer the relatively light winds
to the west this morning, and southwest this afternoon and tonight.
VFR conditions are then expected later this morning into tonight.

MARINE...

The Small Craft Advisory will be allowed to expire at 09Z this
morning. The pressure gradient has slackened, as a cold front moves
toward the area. Thus, winds have weakened below criteria. Waves are
likely subsiding below Small Craft Advisory levels as well.

Winds and waves may reach Small Craft Advisory levels at times
Thursday night into Saturday night. Models are still showing some
disagreement with the exact low track for this period across the
region. The low strengthens and has a pretty tight pressure gradient
associated with it. Some gale force gusts may be possible Saturday
morning.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...None.
&&

$$

UPDATE...DDV
TODAY/TONIGHT AND AVIATION/MARINE...Wood
Wednesday THROUGH Monday...MRC


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