Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 161753 AAB
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
1253 PM CDT Mon Apr 16 2018

.UPDATE...

The snow showers continue to diminish from northwest to southeast
across the area, as drier air works into the area. Some light snow
showers with a few tenths of an inch of accumulation may linger in
the southeast counties for the next few hours. There may still be
some light snow showers or flurries that linger in spots this
afternoon, but those should be rather short lived. A dusting at
best is expected with any additional light snow showers this
afternoon. Cloudy skies will linger this afternoon, with gusty
northwest winds. Temperatures should remain in the lower 30s for
highs.

&&

.AVIATION(18Z TAFS)...

Light snow showers with a few tenths of an inch of accumulation
may linger for the next few hours in the southeast parts of the
area. Otherwise, light snow showers or flurries may linger in
spots this afternoon, with a dusting at best expected. These
should come to an end by early this evening. Gusty northwest winds
will remain this afternoon, with ceilings of 2000 to 2500 feet
above ground level.

Ceilings should improve above 3000 feet by middle evening, though
may return for a time later tonight in southern portions of the
area. Should see ceilings scatter out from west to east later
tonight for a time, before gradually filling back in by Tuesday
afternoon. They may drop to 2500 feet during this time. Gusty
northwest winds will remain tonight, gradually weakening Tuesday
from west to east across the area.

&&

.PREV DISCUSSION... (Issued 933 AM CDT Mon Apr 16 2018)

UPDATE...
Our month-long April Fools weather continues today with additional
snow showers and well below average temperatures.

The upper low will gradually move east northeast today. Subtle
vort lobes noted on at 700/500mb will result in general light snow
into early this afternoon, but with embedded pockets of snow that
will limit visibility to 1-2 miles on occasion. Given variable
snow rates and strong sun angle, additional accumulation will be
less than an inch and dependent on getting underneath a better
snow shower.

Flow aloft should finally lose convergent bands later heading
through the afternoon. As a result, lingering scattered snow
showers should be more focused on eastern Wisconsin. Temperatures
should warm into the low/mid 30s. With gusty northwest winds,
wind chill values will be around 20 degrees (give or take).

Will go ahead and let the Advisory expire at 10 AM.

AVIATION...
Snow showers, gusty northwest winds and mainly MVFR ceilings are
expected into this afternoon. Snow showers will become more
scattered as we head into the late afternoon/evening hours. The
risk for MVFR ceilings will persist into the evening hours with
gradual improvement heading into Tuesday. Northwest winds will
remain gusty through tonight.

MARINE...
Northwest winds will remain brisk over the next 24 hours, with
sustained winds in the 15 to 20 kt range and wind gusts to 30kt
this afternoon. This will persist until the daylight hours of
Tuesday morning, with winds lessening late Tuesday morning. This
will result in waves in the 5 to 7 feet range much of today,
dropping to 3 to 5 feet this evening. A Small Craft Advisory
remains in effect through Tuesday morning.

Heading into Wednesday, winds will increase once again out of the
southeast. Onshore flow will result in building waves across the
nearshore waters. Another Small craft Advisory may be needed.

PREV DISCUSSION... (Issued 315 AM CDT Mon Apr 16 2018)

UPDATE...

Decided to put up a quick small winter weather advisory for a
band of snow that will affect parts of southeast Wisconsin through
the morning rush. mainly 1 inch with local 2 inch amounts, but
main impact will be a slippery morning commute.

PREV DISCUSSION... (Issued 240 AM CDT Mon Apr 16 2018)

SHORT TERM...

TODAY AND TONIGHT...Forecast Confidence - High.

The light snow is near the mid level trough axis early this
morning. This moves east/southeast today, but still close enough
for lingering light snow east into Could see up to another half
an inch today east.

Temps will remain well below normal values for mid-April. The
clouds and fresh snowpack will help to keep temps down today,
with highs only expected to top out in the mid 30s. Average high
temps this time of the year are in the mid 50s!

Low level moisture remains as thr mid/upper trough is slow to push
off to the eastern Great lakes, with the cyclonic flow continuing
over southern Wisconsin. Expect clouds to persist for the most
part, with some decrease in clouds west areas late tonight.

Tuesday THROUGH WEDNESDAY NIGHT...Forecast Confidence - High.

Some clouds will persist into Tuesday, despite the upper ridge
moving across.

Quiet weather will be brief, as models in good agreement on
sharpening eastward moving mid/upper level short wave trof
located over the northern Plains Tuesday night, moving eastward
into the upper Mississippi River valley early Wednesday morning.
Further deepening is expected as the mid/upper low moves across
the western Great Lakes Wednesday and Wednesday night. Thinking
precip will spread in during the morning on Wednesday, with the
heaviest period of QPF and strongest lift in the afternoon and
evening. There is a pronounced warm push ahead of the
precipitation in the 700-850 mb layers. Surface Temperatures will
also be warming Wednesday morning, but there will be a 1-3 hour
window when some freezing rain may occur.  Mean QPF is around a
quarter to a half inch.  Colder air will funnel back into
southern WI as the low pressure system moves off to the east with
a period of snow possible Wednesday night, with minor accumulations.

LONG TERM...

THURSDAY...Forecast Confidence - Medium.

The Bulk of Thursday should be dry as low pressure moves rapidly
away from the area as high pressure builds into southern
Wisconsin.

THURSDAY NIGHT THROUGH SUNDAY...Forecast Confidence - Medium.

A quiet period is expected with some moderation in temperature.
Amplifying high pressure ridge will move into the central CONUS this
period and then shift eastward into the east over the weekend.
Better agreement in Medium range guidance in deepening slow moving
upper low moving through the central and southern Plains with
precipitation shield from this system remaining south of
southern Wisconsin. Daytime temperatures should return to the 40s
and possibly lower 50s pending cloud cover. However with surface
high pressure over the Upper great Lakes, a lake breeze will keep
areas near lake michigan cooler.

HYDROLOGY...Expect fresh snow cover over southern WI to slowly
melt this coming week with daytime temperatures rising above
freezing and below freezing at night. Warmest temperatures in the
next week from Friday through the weekend. Latest river
contingency forecasts keep river levels below flood stage through
the week so no significant river rises expected in the next few
days. However will need to watch closely the melting of the much
deeper fresh snowpack over central WI which will drain into the WI
River basin. This could eventually push the WI river at Portage
above flood stage.

AVIATION(09Z TAFS)...

Light snow with MVFR/IFR will remain early this morning,
especially east areas. with vis dropping from MVFR to IFR at times
within the heavier bands of snow. Snow should gradually move east
later in the morning or early afternoon.

Winds will initially be from the north, becoming more
northwesterly early in the morning. Expect gusts to pick back up
as surface low pressure pulls east of the region.

MARINE...

North winds will become more northwesterly with time tonight and
tomorrow, with gusts picking back up to 25 knots or so continuing.
Waves will slowly diminish tomorrow. A Small Craft Advisory
remains in effect through Tuesday morning.

Winds will increase again on Wednesday from the southeast. This
onshore flow will also lead to building waves across the nearshore
waters, then back to north as low pressure moves off. This may
lead to another Small craft Advisory.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory until 1 PM CDT Tuesday for LMZ643>646.

&&

$$

Update...Wood
Today/Tonight and Aviation/Marine...Hentz
Tuesday THROUGH Sunday...Cronce



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