879
FXUS63 KLOT 070721
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
221 AM CDT Fri Jun 7 2024

.KEY MESSAGES...

- West/northwest winds will gust to 35-40 mph today.

- Chance (40%) for showers Saturday with small chance (20%) for
  a few thunderstorms.

- Hot and humid conditions return toward the end of next week.

&&

.DISCUSSION...
Issued at 220 AM CDT Fri Jun 7 2024

Through Saturday:

Westerly winds are expected to quickly increase just after
sunrise and will peak in the 35-40 mph range this morning. Winds
will turn more to the northwest by early afternoon with gusts
slowly diminishing into the 30-35 mph range. Speeds and gusts
will rapidly diminish with sunset this evening. Mainly sunny
skies this morning should allow temps to quickly warm into the
mid/upper 70s with a few locations possibly tagging 80 for highs
this afternoon. Increasing high clouds are expected by late
afternoon and into the early evening.

There will be a chance of showers Saturday morning, mainly
across the southern cwa as an upper wave moves across central
IL. Its possible that most of the area will remain dry through
midday. A cold front will then move south into northern IL late
Saturday afternoon into Saturday evening. There will be chances
for showers along/ahead of this front Saturday afternoon, mainly
across the northern cwa. Instability is rather limited, but an
isolated thunderstorm is possible. High temps on Saturday will
be tricky. If the cloud cover is thick enough, that may hold
temps in the upper 60s/lower 70s, regardless of precip
coverage. Though sunshine for just a few hours may push temps in
the mid, possibly upper 70s. cms


Saturday Night through Thursday:

As mentioned above a few showers may linger into Saturday
evening as the cold front gradually makes its way across the
area. In spite of the frontal passage and continued northwest
surface winds through the day on Sunday, the combination of
deep mixing and ample sunshine should allow for temperatures to
warm back into the mid-upper 70s for areas inland from the
immediate lakeshore.

Generally cooler conditions are then on tap for the start of the
workweek with highs in the low-mid 70s as an expansive surface
high moves over the region beneath a southward sagging upper jet.
There continues to be variability in the evolution of the upper
level pattern and the handling of a potential cut-off upper
low and subsequent embedded shortwaves. This variability as
well as the broader influence of the surface high have resulted
in reduced precipitation chances with this update, less than
20% for any given 6 hourly period through midweek. A stray
shower certainly can`t be ruled out at times though most areas
could remain dry.

Ensemble guidance for late next week continues to point toward a
return toward summer-like conditions as the western CONUS ridge
begins to build east toward the region with highs back into the
upper 80s to even lower 90s.

Petr

&&

.AVIATION /06Z TAFS THROUGH 12Z SATURDAY/...
Issued at 1215 AM CDT Fri Jun 7 2024

Key Messages:

- Gusty WNW winds to around 30kt develop after daybreak and
  ease mid to late afternoon

Sporadically gusty winds to 20-25kt may continue at times
overnight mainly at the Chicago terminals due to occasional
mixing into the low-level jet overhead. Elsewhere expect gusts
to be less frequent overnight. After daybreak winds will
steadily pick back up with gusts in the lower 30kt range
expected by 13-14Z. Gusts will be highest through early
afternoon then ease as the low-level jet weakens and high clouds
begin to expand in coverage across the area. Winds then become
light and variable overnight. VFR and dry conditions are
forecast through the period.

Petr

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 7 PM CDT this evening for the IL
     nearshore waters.

     Small Craft Advisory until 3 PM CDT this afternoon for the IN
     nearshore waters.

&&

$$

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