Rip Current in Indiana, July 29, 2023

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1247 PM CDT Sat Jul 29 2023

.UPDATE...
Issued at 1120 AM CDT Sat Jul 29 2023

Expanded the Beach Hazards Statement to include the Illinois shore
earlier this morning due to steadily increasing wave heights to
over 5 ft just offshore at the Wilmette Buoy and web cams of high
waves at some area beaches. This will be in effect through the
rest of the afternoon for both the Illinois and Indiana Lake
Michigan beaches. Stay dry when the waves are high!

Otherwise the low stratus/strato-cumulus deck has been slower to
erode than expected which has slowed the amount of warming so far
this morning and may linger into at least the first half of the
afternoon. Accordingly, have nudged the high temperatures down a
smidge, though it looks like lower 80s are still possible inland
away from the lake, with 70s still expected near the IL shore and
further into NW IN.

Petr

&&

.SHORT TERM...
Issued at 320 AM CDT Sat Jul 29 2023

Through Sunday night...

Today will mark the start of a relatively quiet period as upper-
level troughing becomes established across the Upper Great Lakes and
the effective warm front modulated by convective outflow continues
moving southward toward the Ohio River Valley. Owing to recent
rainfall (48-hour totals pushing 3-5" in some locations) and only
weak north to northeasterly flow across the western Great Lakes,
humidity levels will be slow to drop throughout the day.
However, surface temperatures today will be much cooler than the
past few days with highs expected to top off in the mid 80s.

Waves of 3-6' are being observed along the southern tip of Lake
Michigan, apparently kicked up by impressively strong sustained
winds of 40+ mph along the backside of the thunderstorm complex
earlier this morning. Even as the convective winds continue to
subside this morning, high resolution model guidance (HRRR, NAM3,
RAP) depict another area of 15-20 mph sustained winds working down
the western shore of Lake Michigan through daybreak which seems
supported by observations near Door County Peninsula at press time.
For this reason, it seems possible the observed 3-6' waves may
continue through at least 10 am or even noon. For this reason, opted
to issue a Beach Hazards Statement for Lake and Porter counties in
Indiana through 1 PM.

Upper-level water vapor imagery depicts a pair of upper-level
shortwaves propagating along the US/Canadian border which are poised
to move southeast over the Great Lakes over the next 48 hours. The
first wave is on track to arrive this evening, while the second will
arrive tomorrow afternoon. Even with lingering low-level moisture,
forecast soundings this afternoon depicting a deep warm nose from
800-600 mb should limit the ability for what may end up a healthy
cumulus deck from growing into showers or storms. By the time the
second wave arrives tomorrow, low-level moisture values should be
comparatively lower limiting the opportunity for showers or storms.
So, chances for rain today and tomorrow appear slim (<15%).

With upper-level troughing more established by Sunday, highs should
be a hair cooler than today and near the 80 degree mark. Onshore
flow both today and Sunday will hold lakeshore locations to the mid
to upper 70s. Tonight, clearing skies and light winds should allow
for efficient radiational cooling with overnight lows in the mid 50s
(the coolest lows since July 19).

Borchardt

&&

.LONG TERM...
Issued at 320 AM CDT Sat Jul 29 2023

Monday through Friday...

Upper-level troughing is expected to only gradually drift eastward
Monday and Tuesday leading to a continuation of pleasant summertime
conditions. Highs each day should be a degree or two warmer than the
last and in the low to mid 80s. Daily lake breezes (or just onshore
flow) will keep lakeshore locations in the 70s.

Toward the middle of the week, ensemble model guidance depicts the
eastward-drift of the central-US mid-level ridge supporting
gradually rising temperatures and humidity levels. Thursday appears
poised to be the warmest/most humid day of the week, though at this
point the heat doesn't look comparable to the past few days
(forecast heat index values currently climb into the 90s).
Deterministic and ensemble model guidance depict a reasonable signal
for an upper-level shortwave to move through the Great Lakes
sometime in the Thursday to Friday time period which should present
the next opportunity for showers and thunderstorms.

Borchardt

&&

.AVIATION...
For the 18Z TAFs...

The BKN MVFR strato-cu deck will continue to diminish in coverage
and drift to the south through the rest of the daylight hours.

Winds will be somewhat variable through the period though a weak
lake breeze will keep winds more persistently northeast at ORD/MDW
and N at GYY this afternoon. Directions overnight will again be
quite variable though may favor a northerly direction between
330-030. The lake breeze will move inland again early Sunday
afternoon.

Dry conditions are forecast through a stray shower or sprinkle
can't be fully ruled out.

Petr

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Beach Hazards Statement...ILZ006-ILZ103-ILZ104 until 7 PM
     Saturday.

IN...Beach Hazards Statement...INZ001-INZ002 until 7 PM Saturday.

LM...Small Craft Advisory...nearshore waters until 7 PM Saturday.

&&

Visit us at weather.gov/chicago

Follow us on Facebook, Twitter, and YouTube at:
www.facebook.com/NWSChicago
www.twitter.com/NWSChicago
www.youtube.com/NWSChicago

Hazardous Weather Outlook...UPDATED
National Weather Service Chicago/Romeoville IL
1031 AM CDT Sat Jul 29 2023

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-301545-
Winnebago-Boone-McHenry-Lake IL-Ogle-Lee-De Kalb-Kane-DuPage-
La Salle-Kendall-Grundy-Kankakee-Livingston-Iroquois-Ford-
Northern Cook-Central Cook-Southern Cook-Northern Will-
Southern Will-Eastern Will-Lake IN-Porter-Newton-Jasper-Benton-
1031 AM CDT Sat Jul 29 2023 /1131 AM EDT Sat Jul 29 2023/

This Hazardous Weather Outlook is for portions of North Central
Illinois...Northeast Illinois and Northwest Indiana.

.DAY ONE...Today and Tonight.

Weather hazards expected...

  High Swim Risk Lake Michigan Shore

DISCUSSION...

Dangerous swimming conditions and rip currents are expected at
Illinois and Indiana Lake Michigan beaches through this
afternoon.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Tuesday through Friday...
  Limited Thunderstorm Risk.

.SPOTTER INFORMATION STATEMENT...

  Spotter activation will not be necessary through tonight.

LMZ740>745-301545-
Winthrop Harbor to Wilmette Harbor IL-
Wilmette Harbor to Northerly Island IL-
Northerly Island to Calumet Harbor IL-
Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN-
Burns Harbor to Michigan City IN-
1031 AM CDT Sat Jul 29 2023

This Hazardous Weather Outlook is for portions of the Illinois
nearshore waters of Lake Michigan and the Indiana nearshore
waters of Lake Michigan.

.DAY ONE...Today and Tonight.

Weather hazards expected...

  Hazardous conditions for small craft.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Tuesday through Thursday...
  Limited Thunderstorm Risk.
Friday...
  Hazardous conditions for small craft are likely.
  Limited Thunderstorm Risk.

Petr

Visit us at www.weather.gov/chicago

Follow us on Facebook, Twitter, and Youtube at:
www.facebook.com/nwschicago
www.twitter.com/nwschicago
www.youtube.com/nwschicago

Preliminary Local Storm Report
National Weather Service Chicago IL
254 PM CDT Sat Jul 29 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1059 PM     Tstm Wnd Gst     Montrose Harbor         41.96N 87.63W
07/28/2023  M58 MPH          Cook               IL   Mesonet

            Mesonet station XMTB Montrose Beach Light.

1146 PM     Tstm Wnd Gst     1 NW East Chicago       41.65N 87.47W
07/28/2023  M57 MPH          Lake               IN   Mesonet

            Mesonet station XCAV Cline Avenue Bridge.

1150 PM     Tstm Wnd Gst     4 NE Town of Pines      41.73N 86.91W
07/28/2023  M47 MPH          LMZ745             IN   C-Man Station

            Station MCYI3 2 WNW Michigan City.

1244 AM     Non-Tstm Wnd Gst 1 NE Montrose Harbor    41.97N 87.63W
07/29/2023  M47 MPH          LMZ741             IL   Mesonet

            Winds observed well behind thunderstorms.
            Mesonet station XMTB Montrose Beach Light.

1256 AM     Non-Tstm Wnd Gst 4 NE Town of Pines      41.73N 86.91W
07/29/2023  M46 MPH          LMZ745             IN   C-Man Station

            Winds observed well behind thunderstorms.
            Station MCYI3 2 WNW Michigan City.

1226 AM     Non-Tstm Wnd Gst 3 NE Navy Pier          41.92N 87.57W
07/29/2023  M43 MPH          LMZ741             IL   C-Man Station

            Wind observed well behind storms. Station
            CHII2 Harrison-Dever Crib.

1118 PM     Tstm Wnd Gst     1 SE South Chicago      41.73N 87.54W
07/28/2023  M43 MPH          Cook               IL   C-Man Station

            Station CMTI2 Calumet Harbor.

1100 PM     Tstm Wnd Gst     4 NE Kenilworth         42.13N 87.66W
07/28/2023  M42 MPH          LMZ740             IL   Buoy

            Wilmette buoy station 45174.

&&