Bolingbrook, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

508
FXUS63 KLOT 290628 CCA
AFDLOT

Area Forecast Discussion...CORRECTED
National Weather Service Chicago/Romeoville, IL
128 AM CDT Thu May 29 2025

.KEY MESSAGES...

- Patchy fog likely overnight, especially south of I-80. Some
  locally dense fog (visibility under 1 mile) possible.

- A pattern change is anticipated during the first week of June
  and will likely result in the arrival of more summer-like
  temperatures.

&&

.UPDATE...
Issued at 935 PM CDT Wed May 28 2025

A baggy upper lower continues to spiral over the western Great
Lakes and upper Midwest this evening with embedded shortwaves
pivoting around the low. While the initial shortwave
disturbance that brought us the showers earlier has lifted into
Lower MI, a secondary shortwave continues to pivot across SD and
northern NE. Our area is currently in between these two waves
which has generated some subsidence and allowed a weak surface
ridge to develop over WI, northern IL, and northwest IN. As a
result skies have largely cleared out across the area with just
a few lower clouds being observed near the lake with otherwise
light and somewhat variable winds. However, some isolated light
showers/drizzle are being noted along the lakeshore in southern
WI and far northeast IL which should taper over the next 1-2 hours
as winds turn more offshore.

Regardless, the light winds and clear skies in combination with
the lingering moisture from today`s showers will make for
favorable conditions for fog especially for areas south of I-80
where dew points remain highest. While there remains some
uncertainty as to how dense the fog will become tonight, there
is a notable signal for sub-mile visibilities (30-40% chance)
especially near the Illinois and Kankakee River Valleys. That
said, have decided to expand formal fog mention in the forecast
for basically our entire western and southern CWA with a
highlighted area of higher fog coverage south of I-80 to hint at
the dense fog possibility. At this time confidence is still too
low to warrant the issuance of a Dense Fog Advisory, but one may
be needed later if trends verify as expected.

Heading into Thursday, fog will gradually erode by mid-morning
(9-10 AM) as deeper mixing commences. Winds will also become
more northwesterly with speeds in the 5-10 mph range before a
lake breeze turns winds northeast near the lake during the
afternoon. Additionally, the aforementioned secondary shortwave
will also bring the chance (20-30%) for isolated to widely
scattered showers along the lake breeze Thursday afternoon.
Otherwise, expect partly to mostly cloudy skies with
temperatures in the 70s inland and lower 60s near the lake.

Yack

&&

.DISCUSSION...
Issued at 216 PM CDT Wed May 28 2025

Through Thursday:

A notable disturbance pinwheeling around the southeastern
periphery of the upper low centered over the Upper Midwest
resulted in an area of widespread rain across our area this
morning. This activity continues to shift northeastward away
into Lower Michigan early this afternoon. In its wake, expect
mostly cloudy skies to persist through the afternoon with
temperatures topping out in the low to mid 60s away from the
lake. Aside from a low (~20%) chance for some isolated hit and
miss showers this afternoon, expect most areas to remain
precipitation free the remainder of the day.

Dry weather will persist tonight, but with low-level moisture
remaining elevated and winds likely to be rather light (less
than 5 mph), some patchy dense fog could develop across parts of
the area overnight. While some shallow ground fog could develop
in most areas outside the urban areas in this airmass
overnight, I suspect the better chances for any more
substantial fog will be across my southern areas, where slightly
higher dewpoints will reside. Accordingly, I did not stray from
the previous forecast that mentions patchy fog late tonight
for areas near and south of I-80. Any fog that manages to
develop will dissipate quickly after sunrise Thursday morning.

On Thursday, the center of the upper low will slide eastward
into the Great Lakes as another notable mid-level impulse digs
south-southeastward along its western periphery into the lower
Missouri Valley. Ultimately, this digging disturbance will drive
an area of surface low pressure eastward from the Ozarks into
the Ohio Valley Thursday into Thursday night. The track of this
system is expected to keep much of the more widespread rainfall
south of our area Thursday afternoon and night. However, with
some breaks in the cloud cover across our area likely to push
temperatures into the lower 70s Thursday afternoon, some
isolated to widely scattered showers may develop into our area
during the afternoon. However, with the rather small footprint
of these diurnal showers, most areas will remain dry. It also
appears the threat for thunder will remain very low (<10% chance)
with these showers as equilibrium levels largely remain below
the -10C level.

KJB


Thursday Night through Wednesday:

An upper level trough is expected to descend out of Canada`s
Hudson Bay and phase with the remnant upper level low over the
western Great Lakes on Friday. A surface cold front is expected
to accompany the northern trough as it tracks southward toward
the area in the afternoon/evening. How the troughs interact with
each other will impact timing and coverage of storm chances. An
afternoon arrival would potentially lead to more widely
scattered thunderstorm development, with lower shower and storm
coverage expected if it arrives later in the evening.

The NBM has started picking up on the later arrival of the cold
front suggesting low to mid 70s are possible closer to the
shoreline on Friday. While there is confidence for interior
locations to reach the mid to upper 70s on Friday, there is a
chance forecast high temperatures near the lake are too warm
should the front`s progress be quicker than currently
anticipated. As north to northeast winds develop behind the
front over the weekend, areas closer to Lake Michigan will be in
the 60s through the weekend, with 70s farther inland with dry
conditions.

A pattern change is then expected across the eastern half of
the CONUS next week as the mean upper-level troughing over the
northeastern quadrant of the CONUS is pushed eastward and
replaced by an amplified upper-level ridge. As the ridge sets up
over the region, a warmup to more summer-like temperatures with
highs solidly in the 80s and possibly even in the 90s appears
likely to occur early next week. Early on in the week, surface
high pressure should help keep our area devoid of any
precipitation, but as the ridge slides eastward later on in the
week, stormier conditions may return to the region.

DK

&&

.AVIATION /06Z TAFS THROUGH 12Z FRIDAY/...
Issued at 120 AM CDT Thu May 29 2025

Key Messages:

- Low stratus and/or fog will affect the terminals through early
  to mid-morning, though confidence is low in overall trends.

- Northeasterly/easterly wind shift expected this afternoon at
  GYY, ORD, and MDW behind a lake breeze.

- Isolated showers possible this afternoon, particularly near
  the lake breeze.


A ragged IFR/MVFR stratus deck is located over the Chicago metro
terminals at press time. Confidence in how it will evolve over
the remainder of the night/early morning is low, but at least
MVFR ceilings appear likely to persist here through the early to
mid-morning hours, with forecast guidance indicating that the
stratus could build down to as low as LIFR in some locations.
Fog development is also likely tonight, especially in areas away
from the influence of the stratus deck. Didn`t quite have the
confidence to go lower than IFR on the visibility reductions
this morning with the 06Z TAF package, but observational trends
will be monitored, and amendments to include lower visibilities
may ultimately be warranted.

A lake breeze is expected to develop today and should push
inland this afternoon, causing a northeasterly/easterly wind
shift behind it. The timing of its arrival at GYY, ORD, and MDW
remains uncertain owing to uncertainties over how much clouds
will clear out this morning, which will, in turn, affect air
temperature differentials between the lake and inland locations.
If the lower, more opaque clouds hang around for longer, then
the lake breeze may not reach ORD and MDW until late this
afternoon or early this evening, by which point, it may get
washed out. Either way, flow on either side of the lake breeze
should largely tend to remain at or under 10 kts.

Lastly, there is some potential for isolated showers to develop
this afternoon, particularly along the lake breeze, where low-
level convergence will be maximized. Confidence in this
occurring at/near any particular TAF site was still too low to
warrant a formal mention of this potential in the TAFs, but if
confidence increases in the lower clouds clearing out fairly
quickly this morning, then may need to give stronger
consideration to adding a VCSH or SHRA mention to at least of
some of our Chicago metro TAFs. If showers were to develop, the
probability of lightning occurring would be very low (under
10%).

Ogorek

&&

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

&&

$$

Visit us at weather.gov/chicago