Lombard, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

731
FXUS63 KLOT 051118
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
618 AM CDT Sun Apr 5 2026

.KEY MESSAGES...

- Chance for showers tonight, though better coverage is expected
  north of the Wisconsin state line

- Slight chance for a rain/snow mix Tuesday night

- Cooler temperatures early in the week before more mild
  temperatures late in the week

- Periods of showers and storms are possible late in the week
  into next weekend.

&&

.DISCUSSION...
Issued at 233 AM CDT Sun Apr 5 2026

Weak returns are still visible on KLOT radar at the time this
discussion was published, but finding obs reporting rain is
becoming more challenging. Isolated sprinkles are still possible
until sunrise, but with drier conditions upstream and the radar
returns moving east the expectation is for most of the area to
remain dry. Winds are out of the west-northwest and still
gusting around 30 mph presently. While the overall trend for
gusts is to diminish through the day today, breezy gusts 20 to
25 mph can still be expected through the afternoon. As cloud
cover decreases, temperatures are expected to slowly warm into
the low 50s with upper 40s along the Indiana lake shoreline.

A mid level trough and a reflected surface cold front is
projected to descend southward over Wisconsin late this
afternoon and swing east toward Detroit overnight. The moisture
profile is not as robust as recent systems. But with modest
forcing along the front, sprinkles or even light rain showers
are possible overnight. However, there is lower confidence in
the coverage of showery activity. Some models have a deeper
trough allowing for the front to stretch out to even Lee and
Ogle counties, where other models have either a weaker trough
or quicker movement eastward taking any showers out over Lake
Michigan limiting chances west of the Fox Valley. For now,
maintained the slight chance for rain for areas near and north
of Interstate 80, but the better confidence is toward far
northeast Illinois and along the Wisconsin state line.

Cold air will continue to filter in behind the front through the
early part of the week. Morning low temperatures on Monday
morning are expected in the low to mid 30s and Tuesday morning
is projected to be even colder with lows in the 20s (coldest
north of Interstate 88). An upper level ridge begins to grow
west of the area and a surface area of high pressure will slowly
slide eastward overnight Monday into Tuesday morning. Some
models are showing a very weak wave embedded in the long wave
trough earlier Monday night before being shunted east as the
ridge builds. Model uncertainty creates lower confidence in any
rain or even rain/snow mix overnight, so only "silent PoPs"
(less than 15 percent chance) near the lake shoreline were
maintained in the forecast.

The surface high is projected to continue to move east toward
the Atlantic through Tuesday as the next mid to upper level
trough descends out of Canada over the northern Plains. A weak
shortwave out ahead of this parent trough is expected to pass
over the area, but will be forced northward over the mid level
ridge to the east. This wave can provide another quick shot of
some precipitation for some of the area. The uncertainty for
coverage lies in the strength of the ridge. Models with a
stronger ridge keep most of the precipitation north of the area,
where models with weaker ridges bring the precip down toward
Interstate 88. The other question is precipitation type. Colder
temperatures aloft can lead to potentially snow being the
primary type with this wave. But as surface winds switch to the
south allowing for better warm air advection, rain or a
rain/snow mix (maybe briefly sleet?) is possible Tuesday night
into Wednesday.

Better warm air advection is expected on Wednesday and remain
through the weekend allowing high temperatures to climb back
into the 50s and 60s and, at times, some low 70s. However, the
previously mentioned trough that starts moving through the
northern Plains Tuesday night (arriving late Wednesday) is only
the first wave to approach and eventually pass over the area
through the weekend. There will be breaks at times but it looks
like the forecast area is in store for another busy stretch as
periods of showers and storms starting Wednesday night through
next weekend appears likely.

DK

&&

.AVIATION /12Z TAFS THROUGH 18Z MONDAY/...
Issued at 618 AM CDT Sun Apr 5 2026

Aviation forecast concerns for the 12Z TAFs:

- Brief period of MVFR ceilings this morning.

- Breezy WNW-NW winds today, with gusts 20-25 kts.

- Chance (30-40%) of scattered SHRA late this evening/overnight,
  with potential for MVFR ceilings in precip.

Surface low pressure continues to pull slowly away from the
region into western Quebec early this morning. Breezy west-
northwest surface winds linger in its wake, and will persist
today with gusts 20-25 kts likely. Winds should diminish quickly
with sunset this evening, and back west-southwest to southwest.

Broken stratus deck remains in place across the terminals this
morning, though the back edge has moved into northwest
IL/western WI and should continue to make eastward progress
through midday. Patchy MVFR ceilings across northwest IL and
southwest WI within the trailing portion of this deck may
result in some patchy MVFR bases 2500-3000 ft this morning
before giving way to decreasing VFR cloud cover.

Another mid-level disturbance will transit the upper Midwest and
western Great Lakes region tonight, accompanied by a reinforcing
cold front which is forecast to pass through the terminals
roughly between 05-09Z. A chance of showers (30-40%) and a
period of patchy MVFR ceilings are expected, along with a wind
shift to the northwest and gusts near/above 20 kts behind the
front. Breezy northwest winds will persist into Monday morning.

Ratzer

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 10 AM CDT this morning for the IL
     and IN nearshore waters.

&&

$$

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