Gale Watch 9, NWS Chicago, IL

485 
WHUS73 KLOT 061401
MWWLOT

URGENT - MARINE WEATHER MESSAGE
National Weather Service Chicago IL
901 AM CDT Mon Sep 6 2021

LMZ740>745-062215-
/O.CON.KLOT.GL.A.0009.210907T1200Z-210907T2300Z/
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-
901 AM CDT Mon Sep 6 2021

...GALE WATCH REMAINS IN EFFECT FROM TUESDAY MORNING THROUGH
TUESDAY AFTERNOON...

* WHAT...Southwest gales of 35 kt possible.

* WHERE...Portions of Lake Michigan.

* WHEN...From Tuesday morning through Tuesday afternoon.

* IMPACTS...Strong winds can cause hazardous waves which could 
  capsize or damage vessels and reduce visibility.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Mariners should consider altering plans to avoid possible
hazardous conditions.  Remain in port, seek safe harbor, alter
course, and/or secure the vessel for severe wind and waves.

&&

$$

670 
WHUS73 KLOT 061951
MWWLOT

URGENT - MARINE WEATHER MESSAGE
National Weather Service Chicago IL
251 PM CDT Mon Sep 6 2021

LMZ740>745-070400-
/O.CON.KLOT.GL.A.0009.210907T1200Z-210907T2300Z/
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-
251 PM CDT Mon Sep 6 2021

...GALE WATCH REMAINS IN EFFECT FROM TUESDAY MORNING THROUGH
TUESDAY AFTERNOON...

* WHAT...Southwest gales of 35 kt possible.

* WHERE...Portions of Lake Michigan.

* WHEN...From Tuesday morning through Tuesday afternoon.

* IMPACTS...Strong winds can cause hazardous waves which could 
  capsize or damage vessels and reduce visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Mariners should consider altering plans to avoid possible
hazardous conditions.  Remain in port, seek safe harbor, alter
course, and/or secure the vessel for severe wind and waves.

&&

$$

442 
WHUS73 KLOT 070229
MWWLOT

URGENT - MARINE WEATHER MESSAGE
National Weather Service Chicago IL
929 PM CDT Mon Sep 6 2021

LMZ743>745-071030-
/O.UPG.KLOT.GL.A.0009.210907T1200Z-210907T2300Z/
/O.NEW.KLOT.SC.Y.0069.210907T1400Z-210908T0300Z/
Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN-
Burns Harbor to Michigan City IN-
929 PM CDT Mon Sep 6 2021

...SMALL CRAFT ADVISORY IN EFFECT FROM 9 AM TO 10 PM CDT
TUESDAY...

* WHAT...Southwest winds to 30 kt with occasional gale force
  gusts.

* WHERE...Indiana nearshore waters.

* WHEN...From 9 AM to 10 PM CDT Tuesday.

* IMPACTS...Conditions will be hazardous to small craft.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Inexperienced mariners, especially those operating smaller
vessels, should avoid navigating in hazardous conditions.

&&

$$

LMZ740>742-071030-
/O.UPG.KLOT.GL.A.0009.210907T1200Z-210907T2300Z/
/O.NEW.KLOT.SC.Y.0069.210907T1400Z-210908T0000Z/
Winthrop Harbor to Wilmette Harbor IL-
Wilmette Harbor to Northerly Island IL-
Northerly Island to Calumet Harbor IL-
929 PM CDT Mon Sep 6 2021

...SMALL CRAFT ADVISORY IN EFFECT FROM 9 AM TO 7 PM CDT TUESDAY...

* WHAT...Southwest winds to 30 kt with occasional gale force
  gusts.

* WHERE...Illinois nearshore waters.

* WHEN...From 9 AM to 7 PM CDT Tuesday.

* IMPACTS...Conditions will be hazardous to small craft.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Inexperienced mariners, especially those operating smaller
vessels, should avoid navigating in hazardous conditions.

&&

$$

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
237 AM CDT Mon Sep 6 2021

.SHORT TERM...
142 PM CDT

Through Monday night...

The main focus through Monday night will be the passage of a cool
front tonight. Gusty afternoon winds will ease this evening. The
cool front across southern Minnesota and central Wisconsin this
afternoon will reach the IL/WI border by midnight then continue
south across the remainder of the forecast area overnight. Winds
will turn northerly with the passage of the front. Should see a
modest increase in clouds with the front and perhaps a sprinkle or
isolated shower but am thinking those chances are pretty minimal
so will carry a dry forecast. Overnight lows will fall into the
mid to upper 50s most areas and around 60 in the Chicago metro.

High pressure will move across the area Monday resulting in a
pleasant day with highs in the lower 80s for most areas. The
exception will be areas within a few miles of Lake Michigan which
will be held into the mid to upper 70s thanks to a lake breeze.
Winds will turn southerly Monday night allowing for warn advection
to commence. This will lead to milder overnight lows in the lower
60s.

MDB

&&

.LONG TERM...
237 AM CDT

Tuesday night through Sunday...

In the wake of the cold front and scattered thunderstorms Tuesday
night, breezy northwest winds will prevail through Wednesday
evening. Cooling mid-level temperatures will also support the
blossoming of diurnal cumulus clouds, which when paired with
forecast highs in the mid 70s will paint a decidedly early-fall
scene. Wednesday night, the coolest 850 mb temperatures and trough
axis will pass overhead allowing inversion heights over Lake
Michigan to grow to 20kft+. At the very least, a steady stream of
lake effect clouds will flow off Lake Michigan and into northwestern
Indiana through Thursday morning, though an introduction of
scattered showers into our forecast may not be far off. Overnight
lows will drop into the low to mid 50s, except near 60 beneath the
aforementioned lake effect clouds.

As the trough axis shifts east and the upper-level pattern becomes
zonal, Thursday through the weekend will feature gradually warming
temperatures with highs in the upper 70s to lower 80s and lows in
the upper 50s to lower 60s. Occasional chances for showers and
thunderstorms may return from the weekend onward (moreso next week),
each tied to subtle ripples in the zonal flow aloft. Ensemble model
guidance offers no coherent signal on timing or magnitude of each
wave, outside a general "splattering" of QPF. So, the message is to
expect a warming trend with a return of occasional shower and
thunderstorm chances as we head into the middle of September.

Borchardt

&&

.AVIATION...
For the 06Z TAFs...

Initially southwest winds this morning will shift northwesterly
over the next few hours as a weak cold front moves through
northern Illinois and northwest Indiana. The frontal passage is
expected to be dry, though a very brief (<10 minute) shower with
no visibility or ceiling restriction cannot be ruled out,
particularly near ORD at 07Z. Winds will then remain
northwesterly through early afternoon before a lake breeze shifts
winds northeasterly at GYY/ORD/MDW and eventually DPA this
afternoon. With a weak surface pressure pattern expected to be in
place, the lake breeze may arrive quicker than forecast model
guidance indicates (and the winds may flop northeasterly before
the boundary itself). For now, opted to modestly shift the timing
of the lake breeze back by one hour at ORD/MDW to 20Z. Winds will
then adopt a southerly component toward the end of the TAF period.

Borchardt

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Gale Watch...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...7 AM
     Tuesday to 6 PM Tuesday.

&&

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Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
252 AM CDT Mon Sep 6 2021

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-070800-
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-
252 AM CDT Mon Sep 6 2021 /352 AM EDT Mon Sep 6 2021/

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

.DAY ONE...Today and Tonight.

  No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Tuesday...
  Limited Severe Thunderstorm Risk.
  Limited Non Thunderstorm Wind Risk.

DISCUSSION:

There is a conditional threat for severe thunderstorms with
damaging winds and hail Tuesday afternoon. In other words, if
thunderstorms develop, they will likely be severe. The highest
threat is across far northeastern Illinois and into northwestern
Indiana.

Gusty southwest winds are expected Tuesday ahead of a cold front
which will move through the area during the afternoon and early
evening hours.

.SPOTTER INFORMATION STATEMENT...

  Spotter activation will not be necessary through tonight.

LMZ740>745-070800-
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-
252 AM CDT Mon Sep 6 2021

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.

  No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Tuesday...
  Gale force winds and or very hazardous waves are likely.
  Limited Severe Thunderstorm Risk.

Borchardt

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