Area Forecast Discussion
Issued by NWS Chicago, IL
FXUS63 KLOT 210723
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
223 AM CDT SUN AUG 21 2016
223 AM CDT
A cool and breezy day is on tap for the area today. While the day
will start out on the sunny side, diurnal CU will develop over the
area by early afternoon. This will result in a partly cloudy to
partly sunny afternoon over the area. We also cannot rule out a
few isolated sprinkles or light rain showers this afternoon,
particularly over northeastern Illinois and points north. These
areas will be in better proximity to an afternoon disturbance
propogating through the northwest flow aloft. However, these
should not make much of an impact to the day, with most areas
likely staying dry. High temperatures this afternoon are only
expected to warm into the middle 70s.
A surface ridge of high pressure will set up over the region
tonight. This will result in light winds and clear skies over the
area, which should set up a chilly Monday morning over the area.
The coldest areas will be outside the warming effects of the city,
where temperatures could drop near 50. This could also result in
some patchy fog late tonight into early Monday morning.
250 PM CDT
Sunday through Saturday...
Sunday will be cooler with a slight chance of light rain showers.
Have low confidence in coverage and occurrence of rain showers.
However, the vorticity associated with the back side of the upper
level trough could cause a few showers to form. Most of the day
will be dry and only expecting minimal if any accumulating precip.
High pressure then builds over the region Sunday night before
shifting over the Ohio valley Monday night. Dry conditions are
expected through Tuesday with highs around 80.
Have low confidence in precip Tuesday night. An upper level
shortwave pushes through overhead and could see some precip. The
better chance for precip will be Wednesday into Thursday as a
stronger vort streamer shifts northeast over the CWA. In addition, a
cold front shifts through Thursday. The main low will pass north
over southern Ontario. High pressure returns late next week along
with cooler air.
For the 06Z TAFs...
Skies have remained clear early this morning, and look to persist
until shortly after daybreak. High pressure centered to the west
of the area will allow for a west/northwest wind around 5 to 8 kt
overnight to increase after daybreak with increased mixing and
turning winds northwest with speeds around 10-12kt and gusts
nearing 20kt. In addition some patchy MVFR cigs may approach TAF
sites; however, for now have held onto low end VFR conds. There is
a low possibility of seeing a few sprinkles this afternoon, then
clouds will dissipate around sunset with diminishing winds.
250 PM CDT
Headlines: No changes were made to the going gale warning and small
The low over the lake will deepen as it continues northeast tonight,
and winds will become west this evening behind it. Gale force gusts
are still expected for the far northern end of the lake behind the
low. Waterspouts are possible across the lake Sunday. Northwest
winds diminish Sunday night as a high pressure ridge shifts over the
region. Winds back to southwest as the high shifts east Monday
afternoon/night. Winds also increase to 30 kt as the pressure
gradient tightens between the high over the east coast and a low over
south central Canada. The low passes north of the lake Thursday,
and its cold front also swings over the lake Thursday. High
pressure returns to the western Great Lakes Friday night.
IN...Beach Hazards Statement...INZ001-INZ002 UNTIL 7 PM Sunday.
LM...Small Craft Advisory...NEARSHORE WINTHROP HARBOR TO BURNS HARBOR UNTIL
10 AM Sunday.
Small Craft Advisory...NEARSHORE BURNS HARBOR TO MICHIGAN CITY IN UNTIL 4 PM Sunday.
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