Scientific Forecaster Discussion
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Area forecast discussion...updated
National Weather Service Milwaukee/Sullivan WI
104 PM CDT Wed may 24 2017
Showers have diminished across the area, and it should remain dry
for the rest of the afternoon. Low ceilings early this afternoon
should rise to around or above 3000 feet above ground level by
later this afternoon at most locations. Gusty north winds should
linger, especially near Lake Michigan. Visibilities should remain
above 6 miles at most sites.
Ceilings will gradually lower again tonight, with values near
alternate minimums by later tonight into Thursday morning. They
should rise above 3000 feet once again during the afternoon.
Visibilities should lower to 3 to 5 miles later tonight into
Thursday morning, with light fog. May see lower values near Lake
Michigan at times. They will rise again by midday Thursday. North
winds should weaken somewhat tonight into Thursday, though may
become gusty near Lake Michigan again on Thursday.
Previous discussion... (issued 1024 am CDT Wed may 24 2017)
Area of rain showers continues to slowly weaken as it pivots
around 500 mb low over northeast Missouri. Push of differential
cyclonic vorticity advection, along with some low level warm air
advection, was helping drive these showers. As these features
weaken into this afternoon, expect the showers to slowly scatter
out and eventually dissipate.
Clouds are expected to remain today into tonight, with some
breaks possible Thursday as the low levels finally start drying
out. Some fog may develop later tonight into Thursday morning, as
winds weaken and moist air remains in the low levels. Cool
temperatures are expected today with brisk north winds. Milder
temperatures are anticipated on Thursday, with more sunshine.
A tight pressure gradient today into this evening will allow for
gusty north winds of 15 to 20 knots. A few gusts up to 25 knots
are possible during this time. Waves of 3 to 4 feet are expected
as well. For now, will hold off on a Small Craft Advisory and will
monitor the winds and waves closely. Small craft should exercise
caution if venturing out into the nearshore waters of Lake
Michigan during this time.
There may be some fog development later tonight into Thursday
morning across the lake, as winds weaken somewhat and moist air
There is a high swim risk for the beaches of Lake Michigan today
into this evening. Waves of 3 to 4 feet are expected, along with
gusty north winds of 15 to 20-plus miles per hour. No beach hazards
statement will be issued, as the water temperatures remain below
50 degrees fahrenheit. However, life threatening waves and
currents are still expected along the shore. Stay out of the
Previous discussion... (issued 539 am CDT Wed may 24 2017)
Showers across the southeast will gradually diminish this morning
into the afternoon. Widespread IFR ceilings early this morning will
also gradually lift to MVFR levels by early afternoon and VFR
levels toward evening. However, cool northerly winds coupled with
continue damp low level conditions tonight will lead to a
redevelopment of IFR ceilings from about 06-15z Thursday.
Previous discussion... (issued 302 am CDT Wed may 24 2017)
Thursday through Saturday...forecast confidence is medium.
The surface and upper lows will move away from the region and a col
will shift across the state. Low levels will remain fairly saturated
and steep low level lapse rates will support continued cloud cover
on Thursday but dry weather.
Models diverge already by Friday. A surface low will move south of
the state by models vary on its strength and whether precip will
brush the south. There are also low precip chances associated with a
weak frontal boundary that moves through Friday or Saturday,
depending on the model. Temperatures will change litter with this
front. Overall it will be dry through Saturday morning. Low
pressure passing south of the region along with divergence from an
upper jet bring better precip chances later Saturday. There is a
slight chance of thunder both days due to some elevated
Sunday through Wednesday...forecast confidence is medium.
An upper low will move from Canada and drop through the upper Great
Lakes. This will bring slightly cooler temperatures. Several waves
of vorticity will bring precip and thunder chances through Tuesday.
Instability becomes surface based but there is lack of any organized
synoptic forcing right now. The closed low will become an open wave
around midweek losing its grip across the region. This will allow
surface high pressure to slide across the region bringing dry
IFR conditions will persist through early to mid afternoon with
conditions gradually lifting to MVFR and possibly VFR levels for a
time this afternoon into the early evening. But, it looks like
the cool northeast winds will result in lower
conditions...MVFR/IFR again tonight...lingering into Thursday
morning. Light northeast winds this morning, will increase this
afternoon as low pressure intensifies over Indiana/Ohio. The
strongest winds will be across the southeast, lower out toward
A marine dense fog advisory is in effect through 9 am this
morning. Increasing northeast winds will bring conditions
approaching Small Craft Advisory levels today into tonight. Small
craft should exercise caution until winds and waves subside.