Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 121957

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
300 PM CDT MON MAR 12 2018

.THIS AFTERNOON through TUESDAY...Forecast Confidence -

Lingering low level moisture and instability allowing cumulus and
stratocumulus to redevelop this afternoon. Low level lapse rates
reaching 8-9 degrees. Deeper moisture and better low level
convergence producing scattered light rain and snow showers over
northeast into east central WI early this afternoon. Some of these
light showers will spread southeast into eastern CWA rest of the
afternoon.  Small area of 30 DBZ echoes have just developed around
KSBM.  Expect scattered flurries and sprinkles to carry into the
early evening but with loss of sunshine, should dissipate by mid-
evening.  Upstream compact short wave north of the border will sweep
rapidly southeast and clip eastern CWA later tonight.  NAM and RAP
soundings showing column moisture increase to 4-5K feet deep in the
low levels, partially in the dendritic growth zone.  Brief period of
layer q-vector convergence clips far east after 06Z as well.  Enough
expected to be in place to warrant adding schc pops for -shsn in the
east from 06Z-12z.

Reinforcing push of cold air late tonight and Tuesday will result in
more flurries and sprinkles and partly to mostly cloudy skies for
much of the day.  The clouds, northwest breezes and 925H temps of -6
to -9 will result in temperatures 5 to 10 degrees colder than

.TUESDAY NIGHT THROUGH THURSDAY...Forecast Confidence - Medium to

A quiet and dry period is expected with slight warming. Another
weaker cold front will sweep across the area on Wednesday. However
thinner mid-high level clouds and west to southwest winds will
result in daytime temperatures warming back into the 40s on
Wednesday.  Slightly cooler temperatures return on Thursday with
northeast winds as high pressure builds into the western Great
Lakes.  This high will help suppress a low pressure system and
baroclinic zone well south of the area across the mid-MS valley
region...resulting in continued dry conditions for the bulk of the
upper midwest.


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

Medium range guidance in general agreement on upstream blocking
ridge finally weakening and flattening across the central CONUS
early this period. This should allow milder air to spread into the
upper midwest for the weekend.  However the guidance is in
disagreement on strength and location of short waves getting ejected
from upstream long wave trof over the western CONUS.  ECMWF takes
more eastern track of this feature across central plains early in
the weekend, while CMC moves this wave into the northern plains and
western Great Lakes.  This more northern solution would increase the
rain threat across WI on Saturday.  Meanwhile, the GFS is much
weaker with ejecting short wave and holds off on main precipitation
threat until around Monday, with precursor period of warm air
advection light precipitation on Sunday. GFS ensembles show
considerable and increasing uncertainty regarding location and
strength of short wave and resultant precipitation over the weekend.
HPC blend reasonable agreement on slightly milder, drier scenario
for the weekend. Due to uncertainty, wl carry small pops late in the
weekend into Monday.



Isolated light rain and snow showers will affect eastern CWA the
rest of the afternoon.  Ceilings should remain mostly VFR but may
briefly be reduced to MVFR close to these showers.  More low VFR and
possibly MVFR stratocumulus can be expected on Tuesday along with a
chance for flurries or sprinkles.



Reinforcing push of cold air across Lake Michigan tonight along with
a tightening pressure gradient will result in backing winds to the
NNW tonight and winds becoming more gusty.  Frequent gusts of 22 to
25 knots will develop tonight and continue into Tuesday, with
building waves.  A few light rain or snow showers are possible late
this afternoon and early evening, and again later tonight.



LM...Small Craft Advisory from 1 AM to 11 PM CDT Tuesday for LMZ645-
     Small Craft Advisory from 10 PM this evening to 11 PM CDT
     Tuesday for LMZ643-644.


TUESDAY NIGHT THROUGH MONDAY...MBK is the U.S. government's official web portal to all federal, state and local government web resources and services.