Oak Park, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

186
FXUS63 KLOT 022335
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
635 PM CDT Wed Apr 2 2025

.KEY MESSAGES...

- The threat for severe weather continues through early this
  evening, roughly south of a Streator IL to Gary IN line, and
  particularly from southwest Ford County to far southeast
  Porter County IN and points south and southeast. Severe
  threats will include damaging wind gusts, tornadoes, and
  at least isolated instances of large hail.

- For locations off to the north and northwest, the severe
  weather threat is lower, with a localized flooding threat
  into the Chicago metro.

- Strong south winds late this afternoon through early evening,
  especially south of I-80 where gusts in excess of 45 mph are
  probable.

- Periods of rain, possibly heavy, late Friday afternoon into
  Saturday morning, with possible localized flooding south of
  I-80.

&&

.MESOSCALE...
Issued at 635 PM CDT Wed Apr 2 2025

Near Term Storm Trends through 7pm:

The severe threat in Benton and southeastern Jasper Counties
will be ending soon (before 7pm CDT). This will likely be the
final mesoscale update of the evening.

Shortly after the previous update was posted, rotation quickly
strengthened just east of Rensselaer, prompting a tornado
warning issuance, though this rotation (and possible tornado)
has already pushed well into the WFO IWX CWA. Farther south
into eastern Benton County and southeast Jasper County, the
damaging wind threat will be exiting those areas shortly. We`re
planning on clearing all counties except Jasper and Benton from
the watch shortly, and Jasper and Benton just after 7pm CDT.

Ahead of the cold front, isolated convection (mainly showers)
will likely continue to struggle, with any stronger storms thus
far in southern Wisconsin.

Castro

PREVIOUS MESOSCALE UPDATES...

Near Term Storm Trends:

Issued at 600 PM CDT Wed Apr 2 2025

Storm mode has become increasingly messy from east central
Illinois across into northwest Indiana. With the entire area
rain-wrapped, weaker low-level lapse rates and depleted low-
level CAPE are likely translating to fairly transient rotational
signatures that hadn`t been long-lived enough to produce any
reported damaging tornadoes. The main rotational signatures of
note recently have been over southern Newton and Jasper
Counties. While there will be some tornado threat in the area
generally south of a Roselawn to Wheatfield line, the lack of
longer lived, stronger rotation precluded the issuance of a
tornado warning. A new Severe Thunderstorm Warning with a
tornado possible tag was issued and we will continue to closely
monitor radar trends for any signs of tightening low-level
rotation.

Issued at 450 PM CDT Wed Apr 2 2025

Supercell over southern Ford County/Champaign County border has
shown occasional signs of tightening rotation, especially
aloft, but has struggled to become more organized at the lowest
levels thus far. We will continue to monitor for a potential
tornado threat with this storm across extreme southern Ford
County (generally near and south of Elliot to Paxton to
Clarence) through 5:15 PM and then far southern Iroquois County
through about 5:40pm. North of the mesocyclone, the main threat
will be large hail up to ping pong ball size.

The small line segment north of the supercell (Ford panhandle
and western Iroquois as of this writing) will pose a threat for
strong winds as it pushes northeast. However, the less favorable
environment northeast of there and lack of recent reports from
within the severe warned area suggest a lessening threat for
severe winds and associated damage.

Castro

&&

.DISCUSSION...
Issued at 319 PM CDT Wed Apr 2 2025

Through Friday Afternoon:

The threat of showers and thunderstorms will come to an end
from west to east following a cold frontal passage this evening.
For more on the ongoing threat for severe thunderstorms,
reference the meso discussions above.

Meanwhile, the threat of strong southerly wind gusts up to 45
mph will continue in the going wind advisory through early this
evening. Accordingly, no changes are planned to the wind
advisory headline. The ongoing convection has acted to slow the
northward progression of the warm front for the last few hours,
and hence has kept the stronger southerly winds largely south of
the area. This should change within the next couple of hours,
however, as the warm front begins to surge northward in response
to the parent surface low quickly shifting northward into the
Upper Midwest. As it does so, expect the strong gusty southerly
winds to develop across the advisory area. There could even end
up being a short hour or two period early this evening where
winds gust 40-45 mph in areas north of the going advisory
(including the Chicago metro area) before the cold front shifts
across the area. Also, expect temperatures to jump up into the
60s across much of northern IL for a period early this evening
following the warm frontal passage.

Winds will turn westerly this evening following the quick
eastward passage of the cold front. While wind speeds tonight in
the wake of the cold front will not be nearly as strong as the
southerly winds ahead of the front, gusty westerly winds up to
around 30 mph are expected at times overnight into Thursday
morning before gusts ease Thursday afternoon. Expect a
seasonably mild day under mostly cloudy skies Thursday, with
highs ranging from the upper 50s to the lower 60s.

The surface cold front that shifts across our area this evening
will stall out across the Ohio Valley on Thursday into early
Friday. This front will become the primary focus for several
additional rounds of heavy rain producing showers and
thunderstorms Thursday through Friday as deep Gulf moisture
continually feeds into this frontal zone. Fortunately, a
majority of this heavy rain is expected to fall south of our
area across southern parts of IL and IN through Friday morning.
Accordingly, most of our area is likely to remain dry Thursday
through at least early Friday afternoon. The only exception
being a low chance (20-30%) for a few light showers well south
of I-80 Thursday afternoon and evening.

KJB

Friday Afternoon through Wednesday:

The threat for rain (and even some storms) will return to our
area late Friday through Saturday. This as several low amplitude
impulses begin to eject northeastward out of a potent
mid/upper-level trough/low shifting across the Desert
Southwest. Each impulse is expected to drive a wave of surface
low pressure northeastward along the remnant frontal boundary to
our south through the weekend. The first such wave will track
into central parts of IN Friday night into early Saturday
morning. As it does, it will aid in the northward push of
moisture over the surface frontal boundary, thus supporting
increasing rain (and perhaps a few embedded thunderstorms)
chances across much of our area Friday afternoon into Saturday.
Rain chances will peak in the 80 to 100% range areawide Friday
night, though the heaviest rainfall (1"+) is currently favored
to fall south of I-80 into Saturday morning.

Our next wave of low pressure is expected to track farther to
our southeast late Saturday into early Sunday morning. It
appears this wave may remain far enough to our southeast to keep
the threat for the next wave of rain south and east of our area
late Saturday into early Sunday. Accordingly, aside from some
low chance PoPs into Sunday morning (mainly south of I-80),
drier weather is favored for the end of the weekend.

Temperatures through the weekend will cool down as northerly
flow dominates. Daytime highs will generally be in the lower
50s, though even cooler conditions in the lower to mid 40s can
be expected near the lake due to the onshore wind component. A
period of even colder (below average) weather is then likely to
shift into the area for Monday as a stout northern stream trough
digs in over the Great Lakes. High temperatures will likely
remain in the lower 40s for Monday, and the potential exists for
periods of snow showers during the day. Conditions should then
gradually moderate into the middle of next week following the
eastward passage of a surface high.

KJB

&&

.AVIATION /00Z TAFS THROUGH 06Z FRIDAY/...
Issued at 630 PM CDT Wed Apr 2 2025

The storm threat has ended across the terminals, with the
continued severe thunderstorm threat now southeast of the area.
Only a few lingering isolated showers are possible across the
area for the next hour or so.

A short period of strong gusty south winds (briefly up to around
35 kt) is expected across the eastern terminals just in advance
of a quickly approaching cold front. Otherwise, winds will turn
west-southwesterly this evening as the cold front shifts
eastward across northern IL. Winds will likely remain gusty (up
to 30 kt at times) in the wake of the front tonight into
Thursday morning. However, expect the winds to ease Thursday
afternoon as the pressure gradient relaxes. Otherwise, no
significant weather concerns are expected through Thursday
evening.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Wind Advisory until 7 PM CDT this evening for ILZ019-ILZ021-
     ILZ023-ILZ032-ILZ033-ILZ039.

IN...Wind Advisory until 7 PM CDT /8 PM EDT/ this evening for
     INZ010-INZ019.

LM...Gale Warning until 7 PM CDT this evening for the IL and IN
     nearshore waters.

&&

$$

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