Area Forecast Discussion
Issued by NWS Chicago, IL

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FXUS63 KLOT 211930

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
230 PM CDT SAT MAY 21 2016


Minimal adjustments to the going forecast. High pressure continues
to be in control of the weather today centered across Iowa and
drifting Southeast. Winds will continue to be light from the
Northeast...however with a lake breeze pushing inland the winds
may pick-up in speeds for a couple hours midday through early this
afternoon. Then after sunset winds will then diminish and become
light and variable overnight. Skies will also remain mostly sunny
due to the very dry airmass aloft with only a few cirrus clouds
overhead. Temperatures inland will be in the lower to middle
70s...meanwhile along the areas adjacent to Lake Michigan
temperatures fall be in the upper 50s to lower 60s.



215 PM CDT

Through Sunday...

Rather benign pattern will continue this evening through Sunday.
Broad surface high pressure centered over the upper midwest
continues to allow a light East to Northeast wind. Mixing
continues to be good this afternoon with some occcasional gusts
being pulled down to the surface to 20 mph. Expect around sunset
mixing will decouple and result in light to at times variable
winds overnight. Clouds will continue to be minimal
overnight...however a thin cirrus shield will likely help to keep
temps elevated overnight in the lower 50s to upper 40s across the
forecast area. With dew points this afternoon falling into the
lower to middle 40s and a few upper 30s...temperatures overnight
may be able to quickly fall and could allow lows to be a few
degrees cooler than currently forecasting.

A high amplitude mid-level ridge extends North through Central
Canada early Sunday and will drift east over the Western Great
Lakes. Surface high pressure will become centered over Northern
Illinois Sunday midday...with a light East/Northeast wind around
5 to 10 mph. Skies will remain mostly clear through much of Sunday
again...with temperatures expected to warm further into the 70s
and a few sites away from Lake Michigan could warm to around 80
degrees Sunday afternoon. Areas adjacent to Lake Michigan will
likely be several degrees cooler with a light onshore flow in the
afternoon...with highs in the lower to middle 60s.




Monday night through Friday...

300 am...High pressure slowly moving east/southeast Monday night
and Tuesday will delay the moisture return as well as the chance
of thunderstorms. Monday night now looking dry for much of the
area and backed off to just slight chance pops in the far west
overnight. Much of this activity is then progged to lift north
across the western lakes during the day Tuesday...which could end
up being dry locally. While slower...dewpoints do increase into
the lower 60s by Tuesday afternoon and with less precip high temps
will probably reach 80. Southwesterly winds appear strong enough
to prevent any lake cooling but lower confidence from this

Precip chances increase Tuesday night into Wednesday but still not
too confident on timing/duration and there could be various waves
of showers/thunderstorms through the end of the week with high
chance pops from Tuesday night onward. Dewpoints expected to surge
into the upper 60s Wednesday...though likely aided by possible
precip Tuesday humidity levels will begin to feel much
more summer-like. If there are dry periods combined with some
partial sunshine during the day...highs could easily reach the
lower/mid 80s each day in the extended. cms



High pressure continues to be in control of the weather over
Northern Illinois and Northwest Indiana this afternoon...resulting
in VFR conditions for all airfields. With the high pressure
centered to the West/Northwest...winds will continue to be
Northeasterly off of Lake Michigan into ORD/MDW. At times there
have been a few gusts to 20kt...however the frequency is very low
and expect around sunset for winds to diminish considerably to
a light North/Northeast wind around 3-5kt. Skies will remain
mostly clear overnight through much of Sunday. Winds will then
turn Northeasterly Sunday midday through the afternoon with a
light increase to 8-10kt.



104 AM CDT

Quiet conditions over lake Michigan will continue through the
weekend with nearby expansive high pressure centered across the
Mississippi River Valley. This high center will move over the
lake Sunday afternoon and evening bringing light and variable to
near calm conditions over the open waters during that period.
Next week brings southerly flow for much if not all of it. We
are not seeing any strong wind periods during at least the first
half of the week. The latter half becomes more uncertain as
computer model guidance indicates the likelihood of one...maybe a
couple...low pressure centers tracking into the western Great
Lakes but significantly varied low magnitude and timing at this






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