Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 251543
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
943 AM CST Sun Feb 25 2018

.UPDATE...Subsidence and cold advection has mostly cleared out the
broken cloud cover. Few-sct clouds will clear into the early
afternoon. Will continue the Wind Advisory today as 925 mb winds
will remain around 35 kts. The winds will reasonably subside when
the mixing ceases late today. Sunny skies in the dry airmass
should be able to boost temps into the upper 30s to lower 40s for
the afternoon.


&&

.MARINE...A Gale Warning will continue today as 925 mb winds
remain around 35 kts. The strong low just north of Lake Superior
will move to James Bay, Canada by 00Z Mon. Thus the winds will
decrease tonight but a Small Craft Advisory may be needed for the
evening hours as gusty winds may continue. High waves will be over
the open waters.


&&

.PREV DISCUSSION... (Issued 518 AM CST Sun Feb 25 2018)

UPDATE...

West wind gusts have been between 30 and 45 MPH this morning
across much of the area, with the highest gusts observed over the
eastern counties. Went ahead and added Waukesha County to the
Advisory given a few obs around 45 MPH. The period of highest wind
should be between now and about 10 or 11 AM, with a steady
dropoff expected after that.

AVIATION(12Z TAFS)...

West winds will remain quite gusty this morning across the region,
with gusts of 35-40 knots at times for KMKE, KUES and KENW. Winds
should slowly begin to decrease late this morning into the
afternoon hours, but will remain gusty into this evening.

Ceilings this morning will start out MVFR, but should scatter out
fairly rapidly.  Expect mostly clear skies by this afternoon.

PREV DISCUSSION... (Issued 302 AM CST Sun Feb 25 2018)

SHORT TERM...

Today And Tonight...Forecast Confidence Is High.

Precipitation has cleared the area as of 2 AM, with increasing
westerly winds behind the front. Expect widespread gusts of
between 30 and 40 MPH through the afternoon, with a few gusts to
45 MPH across the far eastern forecast area, where a Wind Advisory
remains in effect until 3 PM.

Post-frontal stratus should clear fairly rapidly over the next
few hours, given strong subsidence behind a departing shortwave.
Most of today should feature partly to mostly sunny skies.

Temperatures will top out in the mid 30s today, but given the
wind, it will feel considerably cooler.

Winds should settle down quite a bit after sunset, though will
remain steady into the overnight hours. There will be some fog
potential overnight tonight, especially across far southern
Wisconsin, where winds will be lightest. Right now, winds and T/Td
spreads seem a little marginal, so it`s possible that fog ends up
being most prevalent in protected areas like river valleys. Lows
tonight will range from the low 20s north and west to around 30
near the lake.

Monday Through Tuesday Night...Forecast Confidence Is Medium.

Models are in pretty good agreement with showing warm air
advection developing on south southwest winds Monday into Tuesday
across the area. Sunshine during each day should help bring
warming temperatures into the area. Combination of 925 mb and 2
meter temperatures from models suggest highs into the middle to
upper 40s Monday, and the lower to middle 50s Tuesday. Could get a
little warmer each day as well.

Models then show a weak inverted trough or cold front sliding
eastward through the area late Tuesday into Tuesday night. There
is an 850 mb trough that slides east through the area as well,
with a southwesterly low level jet pointing into the area. Low
level frontogenesis response also crosses the area with the front.
Forecast soundings are not showing a deep layer of moisture,
which is a limiting factor. Continued with the lower end PoPs for
rain mainly Tuesday night.

Temperatures may fall to freezing or below in far northwestern
portions of the area later Tuesday night, with a lack of ice
crystals. This may allow for light freezing rain there. It would
be on the back edge, so not concerned about it too much at this
time.

LONG TERM...

Wednesday Through Saturday...Forecast Confidence Is Medium.

Lowered highs quite a bit on Wednesday, as easterly flow in the
low levels is expected. This should bring cooler temperatures
into the area. Lowered highs into the lower to middle 40s after
coordination with neighboring offices.

Models are in better agreement with low pressure undergoing
cyclogenesis as is shifts northeast toward central Illinois
Wednesday night, then sliding to the east on Thursday and
Thursday night. They all have a strong shortwave trough at 500 mb
that becomes more of a closed 500 mb low during this time. The GFS
is the furthest north with these features, with the Canadian a bit
further south, and the ECMWF furthest south. Despite these
differences, it looks to bring deep moisture and pretty good
upward vertical motion with it.

Forecast soundings look to be supportive of mainly rain for
Wednesday night into Thursday across the area. However, there
could be some rain and snow mix in the north Wednesday night into
early Thursday, where wet bulb profiles are more supportive.
Tight pressure gradient will also bring windy conditions to the
area during this time.

There should be a good amount of rain from this system, on the
order of 0.75 to 1.10 inches. This may bring another round of
river and lowland flooding, and will need to be watched closely as
this period draws closer.

Passing high pressure to the north should bring quiet weather for
the end of the week and into Saturday. Temperatures look to remain
near or a little above seasonal normals.

MARINE...

West winds will gust to gale force this morning and afternoon,
diminishing this evening and tonight. Winds will be westerly
today, before becoming southwesterly and then southerly by
Monday.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Wind Advisory until 3 PM CST this afternoon for WIZ051-052-059-
     060-065-066-071-072.

LM...Gale Warning until 6 PM CST this evening for LMZ643>646.

&&

$$

Update...Gehring
Today/Tonight and Aviation/Marine...Wood
Monday THROUGH Saturday...Boxell



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