Plainfield, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

656
FXUS63 KLOT 100815
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
315 AM CDT Tue Jun 10 2025

.KEY MESSAGES...

- Dry conditions are expected through Wednesday, along with
  warming temperatures.

- Shower and thunderstorm chances return Wednesday night and
  last through at least the weekend.

- There is a signal for hot and humid conditions to develop
  across the general region next week.

&&

.DISCUSSION...
Issued at 315 AM CDT Tue Jun 10 2025

Through Wednesday:

The Great Lakes upper trough will exit to the northeast today
while a surface ridge of high pressure over the Ozarks this
morning gradually shifts eastward across our region. This will
foster a period of dry and quintessential weather across our
area today through the daylight hours of Wednesday. The only
weather item of note for today is the Canadian wildfire smoke,
which should be streaming overhead area again today. With the
increased particulates overhead through the day, the sky is
likely to have a hazy look in spite of an otherwise mostly sunny
to partly cloudy day. It also remains plausible that some of
smoke particulates could mix down to the surface this afternoon
as boundary layer depths increase to around 5,000 feet. As such,
the surface air quality forecast today (courtesy of AirNow.gov)
will be in the moderate category.

Otherwise, expect somewhat breezy westerly winds this
afternoon, with gusts of 20 to 25 mph. Temperatures will top out
well into the 70s to around 80 in some locations.

A quasi-zonal upper-level pattern characterized by broad but
low amplitude ridging over the northern CONUS will expand
eastward toward the Great Lakes on Wednesday as the surface high
settles over the southeastern CONUS. This shift in the pattern
will promote a much warmer day across the area Wednesday as a
lower-level thermal ridge (featuring 850 mb temps of +18 to
+19C) advects eastward from the Plains into the lower Great
Lakes. Currently, we are anticipating lower smoke concentrations
for Wednesday, which should support mostly sunny skies for the
area. Altogether, this is expected to result in temperatures
topping out in the upper 80s in most locations, including along
the Lake Michigan lakeshore areas due to the breezy offshore
winds.

KJB


Wednesday Night through Monday:

An active stretch of weather is forecast to be getting underway
Wednesday night as a stalled baroclinic/frontal zone
establishes across portions of the Mississippi Valley and
western Great Lakes. While there remains a near 50/50 split as
to whether or not this frontal zone will be in northern IL or
just to the north in southern WI, there has been a notable trend
in the deterministic guidance to favor the zone setting up more
into IL. Regardless, a cluster of thunderstorms is expected to
develop Wednesday afternoon in northeast NE and western IA
beneath a modest shortwave impulse and then track along the
boundary into southern WI and/or northern IL Wednesday night.
Given that the thunderstorm cluster will likely arrive well
after dark, guidance continues to show the cluster weakening
with eastward progress due to lack of surface instability and
drier mid-level air. However, forecast soundings do show a
modest elevated mixed layer in place across northern IL and
southern WI characterized by 6-7 C/km mid-level lapse rates and
around 1000 J/kg of MUCAPE. Meaning that if the cluster is
indeed organized as guidance suggests then it should be able to
overcome the mid-level dry air and utilize the instability to
maintain itself. Couple this with the fact that modest 500 mb
flow will be overhead generating 30- 35 kts of bulk shear,
conditions do look to be in place for a conditional threat for
severe weather mainly in the form of damaging winds and hail
Wednesday night. Again whether or not this threat is our problem
or that of our neighbors to the north is still uncertain, but
the marginal (level 1 of 5) risk from the Storm Prediction
Center for the northern half of our CWA during this period seems
appropriate.

The thunderstorm cluster should move east of the area early
Thursday morning and give us a break in the weather as weak mid-
level ridging builds in. However, the storms will likely push
the aforementioned frontal boundary further into northern IL (if
it is not already) which may allow for the development of
diurnally driven scattered showers and thunderstorms Thursday
afternoon/evening especially across the northern half to two-
thirds of the area. While the kinematic parameters on Thursday
do not look as impressive due to the weaker flow aloft, there is
still forecast to be around 20-30 kts of shear which could
support an isolated strong to possibly severe storm. Otherwise,
temperatures on Thursday likely to be near to slightly above
average of mid-June with highs in the lower to mid-80s. Though
areas to the north of the boundary and near the lake will likely
be notably cooler (highs in the mid to upper 70s and mid-60s
respectively) due to onshore winds.

For the Thursday night through Sunday time period, the forecast
becomes much more uncertain as not only will we be dealing with
the vacationing frontal boundary but also potentially a
developing upper low forecast to be ejecting out of the southern
Plains towards the Ohio River Valley. That said, if the arrival
of the upper low is slower as some guidance (roughly 60% of the
members) suggest then Thursday night may end of drier than
currently forecast with Friday looking nearly identical to
Thursday with diurnally driven showers and storms. Though with
storm coverage on Friday being a bit further south due to
convective modification of the frontal zone. However, if the
faster solution pans out (as roughly 40% of ensemble members
suggest) then a much broader coverage of showers and storms
would materialize on Friday. With these uncertainties, have
maintained the 40-60% POPs offered by the NBM Thursday night
through Friday night which seem reasonable at this point but
suspect further refinement will be made over the coming days as
trends converge on a solution.

Regardless of which solution comes to fruition, Saturday and
Sunday basically look the same in either scenario. Thus, expect
showers and thunderstorms to linger through the day on Saturday
as the upper low moves through the region and the front begins
to get pushed south by another shortwave diving in from the
Upper Midwest. Rain will gradually taper through the day on
Sunday as the front pushes the better moisture and instability
out of our area. Outside of the rain, temperatures for Friday,
Saturday, and Sunday will be nearly identical with highs in the
upper 70s to lower 80s inland and cooler near the lake due to
onshore winds. Overnight lows to remain in the lower to mid-60s
during this period.

Heading into next week, guidance remains in good agreement that
a broad upper ridge will begin to build across the central
CONUS on Monday and persist through a good portion of the week.
This pattern is forecast to favor a period of above average and
humid conditions with highs in the 80s and possibly 90s at
times. Given that northern IL and northwest IN looks to be on
the eastern periphery of the ridge, there will also be periods
of showers and thunderstorms next week too especially towards
midweek.

Yack

&&

.AVIATION /06Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 1241 AM CDT Tue Jun 10 2025

Forecast concern for the terminals...

- Breezy west winds Tuesday gusting into the lower 20 kt range.


Overall quiet conditions are expected for the TAF period as a
surface high will build into the region on Tuesday. However,
there is an upper trough still pivoting across the Great Lakes
tonight which may result in a period of SCT to BKN clouds
between 09z and 15z as a plume of mid-level moisture moves in
from WI. While there are some MVFR ceilings in eastern MN and
northern WI with this moisture, recent satellite trends do show
the ceilings rising and eroding a bit with southward extent as
they encounter drier air. Thus have left TAFs VFR for now but
will keep an eye on trends. Any ceilings that do manifest
tonight will scatter into a 4500-5000 ft cumulus deck as diurnal
mixing develops Tuesday morning and remain VFR through the end
of the forecast period.

As for winds, light west-southwest winds tonight will increasing
and become more westerly on Tuesday with the aforementioned
diurnal mixing. Gusts are expected to top out in the lower 20 kt
range through mid-afternoon Tuesday before tapering through
Tuesday evening. Light southwest winds will then close out the
period.

Yack

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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