923
FXUS63 KLOT 102324
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
624 PM CDT Thu Apr 10 2025

.KEY MESSAGES...

- The upcoming weekend will feature warmer temperatures and
  otherwise pleasant springtime conditions.

&&

.DISCUSSION...
Issued at 227 PM CDT Thu Apr 10 2025

Through Saturday:

Surface high pressure will dominate across the western Great Lakes
region for Friday into Saturday. Accordingly, a period of
tranquil weather is expected both days. Temperatures both days
will remain the coolest near the Lake Michigan shore (highs in the
40s) due to persistent onshore flow. However, inland portions of
northern IL and northwestern IN will experience warmer
temperatures. Readings are expected to top out in the low to mid
50s Friday afternoon, albeit under partly cloudy/partly sunny
skies resulting from a developing diurnal cumulus deck. Even
warmer temperatures are then slatted for Saturday as the surface
flow turns southerly along the western periphery of the exiting
surface high. This will allow for readings to top out into the
lower 60s across inland sections of northern IL.

KJB

Saturday Night through Thursday:

Warm air advection is expected to kick up across the region
Saturday night into Sunday along an increasing southwesterly low-
level jet developing in advance of low pressure setting up over
the central Plains. Ultimately, this will set the stage for a
breezy and mild day across our area on Sunday as a low-level
thermal ridge advects overhead. While there does look to be a
decent amount of cloud cover around during the day Sunday,
temperatures in this air mass should have no problem warming
into the mid to upper 60s. Slightly cooler conditions could
persist right along the the far northeastern IL lakeshore,
however, especially if wind directions are slow to shift to an
offshore component.

The threat of rain Saturday night into Sunday overall looks low.
Nevertheless, there is the potential (about 20% chance at this
point) for a few showers (maybe even a storm or two given some
steeper mid-level lapse rates) late Saturday night into Sunday
morning as the nose of the low-level jet and better moisture
transport shifts overhead. While this activity could linger into
early Sunday morning, most areas and much of the day looks to
be rain free at this point.

On Monday as the central Plains low tracks northeastward into the
Upper Great Lakes, in advance of the parent mid/upper trough, an
accompanying cold front will shift southeastward across our area
during the early portion of the day. Given the potential early day
passage of this front, and most of the low-level moisture looking
to quickly be shunted off to our southeast, much of the shower
and storm threat with the front may end up largely across eastern
sections of IL into IN. As such, our chances for showers and
storms remain low for much of northern IL (~20%). Otherwise,
expect winds to turn west-northwesterly and become quite gusty
(35+ mph) in the wake of the cold frontal passage Monday
afternoon.

A period of cooler weather (highs in the 50s) is likely Tuesday
into Wednesday of next week as a surface high briefly settles
across the region.

KJB

&&

.AVIATION /00Z TAFS THROUGH 06Z FRIDAY/...
Issued at 624 PM CDT Thu Apr 10 2025

Forecast concerns for the terminals...

- MVFR ceilings this evening

A couple of shortwave disturbances will continue to pivot
through northern IL and northwest IN this evening allowing BKN
to OVC MVFR ceilings to prevail especially near Lake Michigan.
While there has also been some scattered showers across southern
WI with these disturbances, recent radar trends do show the
showers weakening and moving away from the terminals. Therefore,
no precipitation is expected tonight.

Once the disturbance pivot through after midnight, clouds should
gradually rise to the 3500-4000 ft level and scatter out
through Friday morning. However, some SCT to BKN diurnal VFR cumulus
are expected Friday afternoon. Otherwise, expect winds to
remain out of the northeast through Friday evening with speeds
generally in the 6-12 kt range. Wind directions will become more
westerly behind a frontal boundary late Friday evening (after
03z) with speeds easing to around 5 kts to close out the
forecast period.

Yack

&&

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

&&

$$

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