Area Forecast Discussion
Issued by NWS Chicago, IL

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FXUS63 KLOT 160710

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
210 AM CDT Mon Oct 16 2017

208 AM CDT

Through tonight...

It feels a bit more like autumn this morning with readings in the
upper 30s to mid 40s or so. Other than some passing mid clouds
this morning, plentiful sunshine will be rule as high pressure
becomes established across the Ohio valley. This will be the
coolest day of the week, but the southwest winds on the back side
of the high will allow temps to recover to around normal, upper
50s to lower 60s. Northwest flow aloft may bring a few passing
clouds tonight, otherwise it will be another relatively cool night
with readings back in the 40s.



208 AM CDT

Tuesday through Sunday...

We re-enter another period of dry and unseasonably warm weather
throughout most of the long term as high pressure settles over
the upper Tennessee Valley. The ridge axis will extend southwest
across Texas and thus prevent moisture from spreading into the
midwest, while southwest flow locally will allow for a gradual
warming trend to occur throughout the week as southwest winds
dominate. A weak front will graze the northern tier of counties on
Thursday which will shift winds around to northerly briefly.
Otherwise the high will strengthen and build across the eastern
third of the county, and in conjunction with low pressure across
the plains will act to reinforce the mild southerly flow across
the region. Afternoon highs are expected to rise into the upper
60s Tuesday and Wednesday, upper 60s to low 70s Thursday, low 70s
Friday, and mid 70s by Saturday. Seasonal highs are typically
around 60/low 60s for the early-latter portion of October.

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
late Saturday night or Sunday, with the latter time frame favored
at this distance. This still looks to be the next decent chance
for showers and possibly a few thunderstorms in the area, though
the t-storm threat appears on the low side as the system is upper
level support is rather broad. A bit more fall-like conditions
return behind this front.



For the 06Z TAFs...

Surface high pressure will dominate across the Central
Mississippi Valley through the period. This will result in quiet
weather across the region, with a westerly wind. VFR conditions
are expected through the period.



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.



LM...Small Craft Advisory...IN nearshore waters until 7 AM Monday.




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