Area Forecast Discussion
Issued by NWS Chicago, IL

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FXUS63 KLOT 171131

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
631 AM CDT Sun Oct 17 2021

315 AM CDT

Through Monday...

Pleasant, breezy, and slightly warmer conditions to close out the

A dome of high pressure has moved over the area which will keep
our skies cloud-free through the rest of the weekend and
throughout the day on Monday. These clear skies coupled with
warmer temperatures aloft will promote slightly warmer
temperatures at the surface with this afternoon`s highs topping
out in the mid-60s and tonight`s lows in the low to mid-40s. The
warming trend will continue into Monday with highs in the upper
60s and lower 70s.

Winds will be westerly and breezy this afternoon with sustained
winds 10 to 15 MPH and gusts around 25 MPH. The winds will lighten
up after sunset to under 10 MPH and become more southerly heading
into the day on Monday.




Monday night through Saturday...

224 AM...Main forecast concern is precipitation chances/timing
Wednesday into Thursday.

Above normal temps will continue through Wednesday with high temps
Tuesday and Wednesday in the lower 70s with mid 70s possible. Low
temps will be increasing a few degrees, possibly into the lower
50s by Wednesday morning.

A storm system will move from the central Plains Tuesday to the
western Great Lakes region Wednesday night and the overall timing
seems to have sped up just a little. Precipitation chances will
increase Wednesday morning, peaking early Wednesday evening and
then quickly diminishing into early Thursday morning as a cold
front moves across the area. Though precip coverage and amounts
will depend on the overall track of the system and if it were to
track a bit further south, as the ECMWF shows, there could be a
bit better coverage for showers in the wrap around Thursday
morning. A bit early for this level of detail but pops would need
to be increased if this solution were to pan out. Ahead of the
front, on Wednesday, instability increases enough that isolated
thunder is possible and maintained thunder mention.

The trend behind this system is colder, though there remains
quite a bit of uncertainty. The ECMWF is more progressive with the
pattern, pushing the coolest air out Saturday with rain returning
with the next system Saturday night. GFS is almost 24 hours slower
and from this distance, blended pops bring slight chance pops into
the area by Sunday morning. cms


For the 12Z TAFs...

Breezy conditions expected at the terminals this afternoon.

A dome of high pressure resides over the area and will continue to
provide clear skies today and into tomorrow. Winds will stay
westerly today with breezy conditions at the terminals later on
this morning with speeds of 10 to 15 kts and gusts around 20 kts.
Winds will lighten after sunset to under 10 kts with a southerly
shift in direction late in the TAF period at RFD, ORD, and MDW.



LM...Small Craft Advisory...IN nearshore waters until 9 AM Sunday.



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