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fxus63 kmkx 110954 

Area forecast discussion
National Weather Service Milwaukee/Sullivan WI
355 am CST Wednesday Dec 11 2019

Short term...

Today through Thursday - forecast confidence...high.

A weak surface low currently located over Iowa will progress eastward
through the morning and skirt south of our area. This has brought
increased cloud cover and could bring some isolated flurries across
our southern counties later this morning, but confidence on seeing
any flurries in our County Warning Area is low. Otherwise, can expect mostly dry and
frigid conditions across the area today as the surface high builds
into the upper Midwest. Subsidence associated with the surface high
should help clear out the morning clouds by the afternoon.
Temperatures today will top off in mid teens to around 20 degrees,
while tonight will yield lows in the upper single digits to mid

Warmer temperatures return Thursday as southerly flow develops
across the region. Highs will range from the low 30s up north to low
40s near the WI/Illinois border. In addition to the warmer temperatures,
expect another mid-level shortwave trough and a weak surface low to
work its way into the upper Midwest Thursday morning. Lift from the
associated 500mb DCVA combined with 850mb warm air advection and 700mb
frontogenesis should be enough to support precipitation across
central and northern WI Thursday morning/afternoon. Models still
vary a bit on the track of the surface feature, but the latest runs
generally have it moving over southern WI. Although the favorable
upper-level dynamics to support accumulating snows remain north of
our cwa, the northern half of the County Warning Area may still see some snow with
minimal accumulations generally less than an inch, while areas to
the south will likely see little precipitaion of mostly rain with a
few flakes mixed in. As this system pushes northeastward, dryer air
is progged to filter in aloft and freezing drizzle will be possible
at times Thursday afternoon.

Thursday night and Friday - forecast confidence...medium.

May be some patchy drizzle or flurries lingering across the area
Thursday night due to weakening low level trof remaining over the
area. The better synoptic forcing and deeper moisture will be
moving off to the north and east so only very light precipitation
would be expected in the evening. A little freezing drizzle is
possible as temps will likely be in the low 30s. Small chance some
drizzle may linger into Friday morning as the low pressure
trof/convergence will remain over the area. Initially dry
conditions in the mid-level will moisten during the day ahead of
upstream weak low pressure trof moving through the northern plains.
Increasing moisture advection may bring a mix of light rain and snow
to the area Friday afternoon ahead of this approaching trof.

Long term...

Friday night through Tuesday - forecast confidence...medium.

A sharpening short wave trof will move from the Southern Plains into
the eastern Continental U.S. Over the weekend. A weaker mid-level short wave
digging into the backside of this amplifying long wave trof may
bring some light precipitation to the area Friday night and Saturday
but the stronger dynamics will remain well to the south and east of
the area. Moisture deepens as precipitable water increases to
around one half inch later Friday which is approaching 150% of
normal for 00z.14. A number of GFS ensemble members show a weak low
pressure trof moving through the area Friday night and Saturday with
a lower deviation in the model solutions for this area. For now, wl
have mid-level chance pops with the potential for light snow

High pressure and colder air re-asserts itself over the area
Saturday night and Sunday with temps slipping into the single digits
and teens. Farther south, low pressure is expected to form in the
Southern Plains along a strengthening baroclinic zone extending into
the Ohio and Tennessee valleys. The European model (ecmwf) and Gem-New Hampshire take this
strengthening low pressure system into the northeast Continental U.S. Later
Monday night and Tuesday. The 00z.11 GFS deterministic run shows a
farther west track and a resultant winter weather event for southern
WI. However this GFS solution is on the northwest periphery of the
earlier GFS ensembles and the European model (ecmwf) ensemble are also showing
considerable variability with the track of this system Monday night.
Looking at the last several deterministic runs of the ECMWF, there
has been a slight trend westward. With uncertainty regarding the
phasing of a southern Canada short wave, and this second wave in the
Central Plains, there remains a chance this system could take a more
westerly track and have more of an affect on southern WI early next


Aviation(09z taf update)...

Swath of high clouds remains in place over the south WI terminals
this morning. Current satellite trends are beginning to show the
cloud deck breaking up a bit. This clearing trend will likely
continue through mid-morning as the surface high pushes into the
upper Midwest. Otherwise, can expect VFR conditions to prevail with
light to moderate westerly winds through the remainder of the



Moderate westerly winds will continue this morning/afternoon and
combined with the colder temperatures, freezing spray will be
possible through this evening across the open waters of Lake
Michigan. A surface high pressure will push across the northern
Great Plains then across Lake Michigan this evening. The winds will
diminish and shift to the south overnight as another weak surface
low approaches the region from the southwest. Southerly winds will
increase for Thursday as the low pushes across Lake Michigan. Gale
force gusts are possible, especially over the center and south half
of the lake, thus a gale watch is in effect for the southern 2/3rds
of Lake Michigan Thursday morning through Thursday afternoon. Small
Craft Advisory conditions are expected across our nearshore waters
on Thursday as well. The low will then move east of the lake
Thursday night and lighter winds are expected by Friday with
northwesterly winds developing by the weekend.


Mkx watches/warnings/advisories...

Lm...gale watch from Thursday morning through Thursday afternoon for

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