Area Forecast Discussion
Issued by NWS Chicago, IL

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FXUS63 KLOT 151941
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
241 PM CDT Sun Oct 15 2017

.SHORT TERM...
237 PM CDT

Through Monday...

Looking at a much quieter and cooler near term. High pressure
centered over the TX/OK panhandle will spread over the midwest as
low pressure over Quebec continues northeast. Temps will remain
in the low to mid 50s this afternoon and northwest winds will
continue to diminish as the pressure gradient weakens.

A secondary upper level trough will move overhead tonight. No
additional precip is forecast, and any precip associated with the
trough will be over the lake. Cooler 925 mb air around +5C will
move over the region tonight and clouds clear out. This will lead
to Monday morning temps in the upper 30s to around 40 outside of
the city and away from the lake. Patchy frost is possible
northwest of a Amboy to McHenry line.

The dry warming trend begins Monday with weak warm air advection
under high pressure. Expecting sunny skies, light west winds, and
high temps around 60.

JEE

&&

.LONG TERM...
237 PM CDT

Monday night through Sunday...

Another long stretch of dry and unseasonably warm weather is
expected throughout most of the long term time frame as high
pressure settles over the upper Tennessee Valley. The orientation
of the ridge axis southwest across Texas will prevent moisture
from spreading into the midwest while southwest flow locally will
allow for a gradual warming trend to occur throughout the week.
Afternoon highs are expected to rise into the upper 60s Tuesday
and Wednesday, low 70s Thursday and Friday, and mid 70s by
Saturday.

An upper trough is expected to move onshore over the west coast late
in the week and spread across the Great Plains and Midwest over the
weekend. Surface ridge axis will get shunted farther east out ahead
of the wave allowing gulf moisture to flow back up across the plains
and Midwest with dew points pooling back around 60F along a cold
front. The front is expected to sweep across the local area either
Saturday night or Sunday and looks to be the next decent chance for
showers and possibly a few thunderstorms in the area.

Deubelbeiss

&&

.AVIATION...
For the 18Z TAFs...

Cigs are slowly lifting and should be VFR by mid afternoon. There
may be a few more gusts to arnd 25 kt through mid aftn, and then
winds diminish through this evening as high pressure builds
overhead. Gusts will be higher, around 35 MPH, and linger longer
at GYY. Clouds scatter out this evening. SCT VFR clouds and light
west winds are then forecast overnight and Monday.

JEE

&&

.MARINE...
237 PM CDT

Deep low pressure is departing the Great Lakes region today lifting
into Quebec while a broad high builds across the Great Plains. Gale
force winds behind the low will continue to diminish through the day
and should end across Lake Michigan early to mid afternoon. The area
of high pressure will shift to the Ohio Valley Monday allowing winds
to back to the southwest Monday evening and night. Moderate south to
southwest winds will dominate throughout the upcoming week with a
couple windows of gales possible. Southwest flow will increase back
to gale force Monday night, especially over the north end of the
lake, in response to an area of low pressure moving across Manitoba
and James Bay. Yet another low takes a similar track across James
Bay Wednesday and Wednesday night resulting in another window of
southwest gales.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Gale Warning...LMZ777-LMZ779 until 7 PM Sunday.

     Gale Warning...nearshore waters until 4
     PM Sunday.

&&

$$

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