Gale Watch 7, NWS Chicago, IL

622 
WHUS73 KLOT 261506
MWWLOT

URGENT - MARINE WEATHER MESSAGE
National Weather Service Chicago IL
1006 AM CDT Wed May 26 2021

LMZ740>745-262315-
/O.EXT.KLOT.GL.A.0007.210528T0200Z-210528T2000Z/
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-
1006 AM CDT Wed May 26 2021

...GALE WATCH NOW IN EFFECT FROM THURSDAY EVENING THROUGH FRIDAY
AFTERNOON...

* WHAT...Northeast gales to 35 kt and waves 8 to 11 ft possible,
  especially along the Illinois nearshore.

* WHERE...Illinois and Indiana nearshore waters of Lake Michigan.

* WHEN...From Thursday evening through Friday 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.

&&

$$

RC

956 
WHUS73 KLOT 262047
MWWLOT

URGENT - MARINE WEATHER MESSAGE
National Weather Service Chicago IL
347 PM CDT Wed May 26 2021

LMZ740>742-270500-
/O.NEW.KLOT.SC.Y.0046.210527T0800Z-210528T0200Z/
/O.EXT.KLOT.GL.A.0007.210528T0200Z-210529T0000Z/
Winthrop Harbor to Wilmette Harbor IL-
Wilmette Harbor to Northerly Island IL-
Northerly Island to Calumet Harbor IL-
347 PM CDT Wed May 26 2021

...SMALL CRAFT ADVISORY IN EFFECT FROM 3 AM TO 9 PM CDT
THURSDAY...
...GALE WATCH NOW IN EFFECT FROM THURSDAY EVENING THROUGH FRIDAY
EVENING...

* WHAT...For the Small Craft Advisory, northeast winds to 25 kt to
  30 kt, significant waves up to 8 ft and occasional waves up to 
  10 ft. For the Gale Watch, northeast gales to 35 kt possible, 
  with significant waves up to 11 ft and occasional waves up to 14
  ft.

* WHERE...Winthrop Harbor to Wilmette Harbor IL, Wilmette Harbor 
  to Northerly Island IL and Northerly Island to Calumet Harbor 
  IL.

* WHEN...For the Small Craft Advisory, from 3 AM to 9 PM CDT 
  Thursday. For the Gale Watch, from Thursday evening through 
  Friday evening.

* 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.

&&

$$

LMZ743>745-270500-
/O.NEW.KLOT.SC.Y.0046.210527T0800Z-210528T0200Z/
/O.EXT.KLOT.GL.A.0007.210528T0200Z-210529T0000Z/
Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN-
Burns Harbor to Michigan City IN-
347 PM CDT Wed May 26 2021

...SMALL CRAFT ADVISORY IN EFFECT FROM 3 AM TO 9 PM CDT
THURSDAY...
...GALE WATCH NOW IN EFFECT FROM THURSDAY EVENING THROUGH FRIDAY
EVENING...

* WHAT...For the Small Craft Advisory, northeast winds to 25 kt,
  with significant waves up to 6 ft and occasional waves up to 8
  ft. For the Gale Watch, northeast winds to 30 kt with 35 kt gale
  force gusts possible, significant waves up to 8 ft and
  occasional waves up to 10 ft.

* WHERE...Calumet Harbor IL to Gary IN, Gary to Burns Harbor IN 
  and Burns Harbor to Michigan City IN.

* WHEN...For the Small Craft Advisory, from 3 AM to 9 PM CDT 
  Thursday. For the Gale Watch, from Thursday evening through 
  Friday evening.

* 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.

&&

$$

RC

702 
WHUS73 KLOT 270230
MWWLOT

URGENT - MARINE WEATHER MESSAGE
National Weather Service Chicago IL
930 PM CDT Wed May 26 2021

LMZ740>742-271100-
/O.CON.KLOT.SC.Y.0046.210527T0800Z-210528T0200Z/
/O.CON.KLOT.GL.A.0007.210528T0200Z-210529T0000Z/
Winthrop Harbor to Wilmette Harbor IL-
Wilmette Harbor to Northerly Island IL-
Northerly Island to Calumet Harbor IL-
930 PM CDT Wed May 26 2021

...SMALL CRAFT ADVISORY REMAINS IN EFFECT FROM 3 AM TO 9 PM CDT
THURSDAY...
...GALE WATCH REMAINS IN EFFECT FROM THURSDAY EVENING THROUGH
FRIDAY EVENING...

* WHAT...For the Small Craft Advisory, northeast winds to 25 kt 
  to 30 kt, significant waves up to 8 ft and occasional waves up 
  to 10 ft. For the Gale Watch, northeast gales to 35 kt 
  possible, with significant waves up to 11 ft and occasional 
  waves up to 14 ft.

* WHERE...Winthrop Harbor to Wilmette Harbor IL, Wilmette Harbor 
  to Northerly Island IL and Northerly Island to Calumet Harbor 
  IL.

* WHEN...For the Small Craft Advisory, from 3 AM to 9 PM CDT 
  Thursday. For the Gale Watch, from Thursday evening through 
  Friday evening.

* 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.

&&

$$

LMZ743>745-271100-
/O.CON.KLOT.SC.Y.0046.210527T0800Z-210528T0200Z/
/O.CON.KLOT.GL.A.0007.210528T0200Z-210529T0000Z/
Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN-
Burns Harbor to Michigan City IN-
930 PM CDT Wed May 26 2021

...SMALL CRAFT ADVISORY REMAINS IN EFFECT FROM 3 AM TO 9 PM CDT
THURSDAY...
...GALE WATCH REMAINS IN EFFECT FROM THURSDAY EVENING THROUGH
FRIDAY EVENING...

* WHAT...For the Small Craft Advisory, northeast winds to 25 kt, 
  with significant waves up to 6 ft and occasional waves up to 8 
  ft. For the Gale Watch, northeast winds to 30 kt with 35 kt 
  gale force gusts possible, significant waves up to 8 ft and 
  occasional waves up to 10 ft.

* WHERE...Calumet Harbor IL to Gary IN, Gary to Burns Harbor IN 
  and Burns Harbor to Michigan City IN.

* WHEN...For the Small Craft Advisory, from 3 AM to 9 PM CDT 
  Thursday. For the Gale Watch, from Thursday evening through 
  Friday evening.

* 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.

&&

$$

Carlaw

309 
WHUS73 KLOT 270854
MWWLOT

URGENT - MARINE WEATHER MESSAGE
National Weather Service Chicago IL
354 AM CDT Thu May 27 2021

LMZ740>742-271700-
/O.EXT.KLOT.SC.Y.0046.000000T0000Z-210527T2100Z/
/O.UPG.KLOT.GL.A.0007.210528T0200Z-210529T0000Z/
/O.NEW.KLOT.GL.W.0012.210527T2100Z-210529T0000Z/
Winthrop Harbor to Wilmette Harbor IL-
Wilmette Harbor to Northerly Island IL-
Northerly Island to Calumet Harbor IL-
354 AM CDT Thu May 27 2021

...SMALL CRAFT ADVISORY NOW IN EFFECT UNTIL 4 PM CDT THIS
AFTERNOON...
...GALE WARNING IN EFFECT FROM 4 PM THIS AFTERNOON TO 7 PM CDT
FRIDAY...

* WHAT...For the Small Craft Advisory, northeast winds to 30 kt
  with significant waves to 7 feet and occasional waves to 9 feet
  expected. For the Gale Warning, northeasterly gales to 40 kt
  with significant waves to 12 feet and occasional waves to 16 
  feet expected. 

* WHERE...Winthrop Harbor to Wilmette Harbor IL, Wilmette Harbor 
  to Northerly Island IL and Northerly Island to Calumet Harbor 
  IL.

* WHEN...For the Small Craft Advisory, until 4 PM CDT this 
  afternoon. For the Gale Warning, from 4 PM this afternoon to 7 
  PM CDT Friday.

* IMPACTS...Strong winds and hazardous waves may capsize or 
  damage vessels and reduce visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

$$

LMZ743>745-271700-
/O.CON.KLOT.SC.Y.0046.000000T0000Z-210528T0200Z/
/O.CON.KLOT.GL.A.0007.210528T0200Z-210529T0000Z/
Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN-
Burns Harbor to Michigan City IN-
354 AM CDT Thu May 27 2021

...SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL 9 PM CDT THIS
EVENING...
...GALE WATCH REMAINS IN EFFECT FROM THIS EVENING THROUGH FRIDAY
EVENING...

* WHAT...For the Small Craft Advisory, northeast winds of 15 to 25
  kt with significant waves to 7 feet and occasional waves to 9 
  feet. For the Gale Watch, northeasterly gales to 35 kt with 
  significant waves to 10 feet and occasional waves to 13 feet 
  possible. 

* WHERE...Gary to Burns Harbor IN, Burns Harbor to Michigan City 
  IN and Calumet Harbor IL to Gary IN.

* WHEN...For the Small Craft Advisory, until 9 PM CDT this 
  evening. For the Gale Watch, from this evening through Friday 
  evening.

* IMPACTS...Strong winds and hazardous waves may 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.

&&

$$

Borchardt

744 
WHUS73 KLOT 271449
MWWLOT

URGENT - MARINE WEATHER MESSAGE
National Weather Service Chicago IL
949 AM CDT Thu May 27 2021

LMZ740>742-272300-
/O.CON.KLOT.SC.Y.0046.000000T0000Z-210527T2100Z/
/O.CON.KLOT.GL.W.0012.210527T2100Z-210529T0000Z/
Winthrop Harbor to Wilmette Harbor IL-
Wilmette Harbor to Northerly Island IL-
Northerly Island to Calumet Harbor IL-
949 AM CDT Thu May 27 2021

...SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL 4 PM CDT THIS
AFTERNOON...
...GALE WARNING REMAINS IN EFFECT FROM 4 PM THIS AFTERNOON TO
7 PM CDT FRIDAY...

* WHAT...For the Small Craft Advisory, northeast winds to 30 kt 
  with significant waves to 7 feet and occasional waves to 9 
  feet expected. For the Gale Warning, northeasterly gales to 40 
  kt with significant waves to 12 feet and occasional waves to 
  16 feet expected.

* WHERE...Winthrop Harbor to Wilmette Harbor IL, Wilmette Harbor 
  to Northerly Island IL and Northerly Island to Calumet Harbor 
  IL.

* WHEN...For the Small Craft Advisory, until 4 PM CDT this 
  afternoon. For the Gale Warning, from 4 PM this afternoon to 7 
  PM CDT Friday.

* IMPACTS...Strong winds and hazardous waves may capsize or 
  damage vessels and reduce visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

$$

LMZ743>745-272300-
/O.CON.KLOT.SC.Y.0046.000000T0000Z-210528T0200Z/
/O.CON.KLOT.GL.A.0007.210528T0200Z-210529T0000Z/
Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN-
Burns Harbor to Michigan City IN-
949 AM CDT Thu May 27 2021

...SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL 9 PM CDT THIS
EVENING...
...GALE WATCH REMAINS IN EFFECT FROM 9 PM CDT THIS EVENING
THROUGH FRIDAY EVENING...

* WHAT...For the Small Craft Advisory, northeast winds of 15 to 25
  kt with significant waves to 6 feet and occasional waves to 8 
  feet. For the Gale Watch, northeasterly gales to 35 kt with 
  significant waves to 10 feet and occasional waves to 13 feet 
  possible.

* WHERE...Gary to Burns Harbor IN, Burns Harbor to Michigan City 
  IN and Calumet Harbor IL to Gary IN.

* WHEN...For the Small Craft Advisory, until 9 PM CDT this 
  evening. For the Gale Watch, from this evening through Friday 
  evening.

* IMPACTS...Strong winds and hazardous waves may 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.

&&

$$

709 
WHUS73 KLOT 271959
MWWLOT

URGENT - MARINE WEATHER MESSAGE
National Weather Service Chicago IL
259 PM CDT Thu May 27 2021

LMZ740>742-280400-
/O.CON.KLOT.SC.Y.0046.000000T0000Z-210527T2100Z/
/O.CON.KLOT.GL.W.0012.210527T2100Z-210529T0000Z/
Winthrop Harbor to Wilmette Harbor IL-
Wilmette Harbor to Northerly Island IL-
Northerly Island to Calumet Harbor IL-
259 PM CDT Thu May 27 2021

...SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL 4 PM CDT THIS
AFTERNOON...
...GALE WARNING REMAINS IN EFFECT UNTIL 7 PM CDT FRIDAY...

* WHAT...For the Small Craft Advisory, northeast winds to 30 kt 
  with significant waves to 7 feet and occasional waves to 9 
  feet expected. For the Gale Warning, northeasterly gales to 40 
  kt with significant waves to 12 feet and occasional waves to 
  16 feet expected.

* WHERE...Winthrop Harbor to Wilmette Harbor IL, Wilmette Harbor 
  to Northerly Island IL and Northerly Island to Calumet Harbor 
  IL.

* WHEN...For the Small Craft Advisory, until 4 PM CDT this 
  afternoon. For the Gale Warning, from 4 PM this afternoon to 7 
  PM CDT Friday.

* IMPACTS...Strong winds and hazardous waves may capsize or 
  damage vessels and reduce visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

$$

LMZ743>745-280400-
/O.CON.KLOT.SC.Y.0046.000000T0000Z-210528T0200Z/
/O.CON.KLOT.GL.A.0007.210528T0200Z-210529T0000Z/
Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN-
Burns Harbor to Michigan City IN-
259 PM CDT Thu May 27 2021

...SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL 9 PM CDT THIS
EVENING...
...GALE WATCH REMAINS IN EFFECT FROM 9 PM CDT THIS EVENING
THROUGH FRIDAY EVENING...

* WHAT...For the Small Craft Advisory, northeast winds of 15 to 
  25 kt with significant waves to 6 feet and occasional waves to 
  8 feet. For the Gale Watch, northeasterly gales to 35 kt with 
  significant waves to 10 feet and occasional waves to 13 feet 
  possible.

* WHERE...Gary to Burns Harbor IN, Burns Harbor to Michigan City 
  IN and Calumet Harbor IL to Gary IN.

* WHEN...For the Small Craft Advisory, until 9 PM CDT this 
  evening. For the Gale Watch, from this evening through Friday 
  evening.

* IMPACTS...Strong winds and hazardous waves may 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.

&&

$$

767 
WHUS73 KLOT 272050 CCA
MWWLOT

URGENT - MARINE WEATHER MESSAGE...CORRECTED
National Weather Service Chicago IL
350 PM CDT Thu May 27 2021

LMZ740>742-280400-
/O.CON.KLOT.SC.Y.0046.000000T0000Z-210527T2100Z/
/O.CON.KLOT.GL.W.0012.210527T2100Z-210529T0000Z/
Winthrop Harbor to Wilmette Harbor IL-
Wilmette Harbor to Northerly Island IL-
Northerly Island to Calumet Harbor IL-
350 PM CDT Thu May 27 2021

...SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL 4 PM CDT THIS
AFTERNOON...
...GALE WARNING REMAINS IN EFFECT UNTIL 7 PM CDT FRIDAY...

* WHAT...For the Small Craft Advisory, northeast winds to 30 kt 
  with significant waves to 7 feet and occasional waves to 9 
  feet expected. For the Gale Warning, northeasterly gales to 40 
  kt with significant waves to 12 feet and occasional waves to 
  16 feet expected.

* WHERE...Winthrop Harbor to Wilmette Harbor IL, Wilmette Harbor 
  to Northerly Island IL and Northerly Island to Calumet Harbor 
  IL.

* WHEN...For the Small Craft Advisory, until 4 PM CDT this 
  afternoon. For the Gale Warning, from 4 PM this afternoon to 7 
  PM CDT Friday.

* IMPACTS...Strong winds and hazardous waves may capsize or 
  damage vessels and reduce visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

$$

LMZ743>745-280400-
/O.COR.KLOT.SC.Y.0046.000000T0000Z-210528T0200Z/
/O.COR.KLOT.GL.A.0007.210528T0200Z-210529T0000Z/
Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN-
Burns Harbor to Michigan City IN-
350 PM CDT Thu May 27 2021

...SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL 10 AM CDT FRIDAY
MORNING...
...GALE WATCH REMAINS IN EFFECT FROM 10 AM CDT FRIDAY MORNING 
THROUGH 9 PM CDT FRIDAY EVENING...

* WHAT...For the Small Craft Advisory, northeast winds of 15 to 
  25 kt with significant waves to 6 feet and occasional waves to 
  8 feet. For the Gale Watch, northeasterly gales to 35 kt with 
  significant waves to 10 feet and occasional waves to 13 feet 
  possible.

* WHERE...Gary to Burns Harbor IN, Burns Harbor to Michigan City 
  IN and Calumet Harbor IL to Gary IN.

* WHEN...For the Small Craft Advisory, until 10 AM CDT Friday
  morning. For the Gale Watch, from 10 AM CDT Friday morning 
  through 9 PM CDT Friday evening.

* IMPACTS...Strong winds and hazardous waves may 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.

&&

$$

949 
WHUS73 KLOT 280252
MWWLOT

URGENT - MARINE WEATHER MESSAGE
National Weather Service Chicago IL
952 PM CDT Thu May 27 2021

LMZ740>742-281100-
/O.CON.KLOT.GL.W.0012.000000T0000Z-210529T0000Z/
Winthrop Harbor to Wilmette Harbor IL-
Wilmette Harbor to Northerly Island IL-
Northerly Island to Calumet Harbor IL-
952 PM CDT Thu May 27 2021

...GALE WARNING REMAINS IN EFFECT UNTIL 7 PM CDT FRIDAY...

* WHAT...Northeasterly gales to 35 kt with significant waves to 11
  feet and occasional waves to 14 feet expected.

* WHERE...Northerly Island to Calumet Harbor IL, Winthrop Harbor 
  to Wilmette Harbor IL and Wilmette Harbor to Northerly Island 
  IL.

* WHEN...Until 7 PM CDT Friday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

$$

LMZ743>745-281100-
/O.UPG.KLOT.GL.A.0007.000000T0000Z-210529T0000Z/
/O.NEW.KLOT.SC.Y.0047.210528T0252Z-210528T1500Z/
/O.NEW.KLOT.GL.A.0008.210528T1500Z-210529T0200Z/
Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN-
Burns Harbor to Michigan City IN-
952 PM CDT Thu May 27 2021

...SMALL CRAFT ADVISORY IN EFFECT UNTIL 10 AM CDT FRIDAY...
...GALE WATCH IN EFFECT FROM FRIDAY MORNING THROUGH FRIDAY
EVENING...

* WHAT...For the Small Craft Advisory, northeast winds to 25 kt.
  Significant waves to 8 ft, occasionally to 10 ft late. For the
  Gale Watch, northeast gales to 35 kt possible. Significant waves
  to 10 ft, occasionally to 13 ft.

* WHERE...Calumet Harbor IL to Gary IN, Gary to Burns Harbor IN 
  and Burns Harbor to Michigan City IN.

* WHEN...For the Small Craft Advisory, until 10 AM CDT Friday. 
  For the Gale Watch, from Friday morning through Friday evening.

* 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.

&&

$$

Carlaw

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
312 AM CDT Wed May 26 2021

.SHORT TERM...
312 AM CDT

Through Thursday...

Early morning surface analysis places 990 mb low pressure just west
of James Bay Ontario, with a cold front trailing southwest through
central WI and into eastern/northeast IA. Regional radar mosaic at
230 am depicts a linear band of showers and thunderstorms from just
south of Milwaukee, across northern IL to the Quad Cities area. A
contiguous area of rain and more isolated thunder was noted from
central IL into northern IN, where precipitation continues to fill
in ahead beneath the divergent right-rear entrance to an upper level
jet streak north-northeast of the forecast area. MRMS radar derived
rainfall estimation indicates some decent 0.50-0.75"+ amounts in
past several hours from Chicago north and westward, resulting from
veering low-mid level wind fields slowing cell propagation and
causing some training. Low-mid level winds are continuing to veer
with time this morning as the low level frontal zone makes its
approach, so not anticipating any significant flood concerns,
especially with the long-term dryness across the northern half of
the cwa. 35-40 kts of wind just above the boundary layer per
HRRR/RAP soundings will allow for sporadic wind gusts of 40+ mph
with some of the heavier showers, particularly between the I-88 and
I-80 corridors over the next few hours where deeper convective cells
will likely pass. Shower and thunderstorms will continue to push
east across the area early this morning ahead of the front, but will
end from northwest to southeast fairly quickly this morning.

With the front pushing southeast of the forecast area today, drier
air will spread into the region from the northwest and should allow
a good amount of sunshine across the area especially from mid-day
(clouds linger near the front south/southeast this morning) and
afternoon. Model soundings depict dry profiles and fairly deep
mixing in sunny areas by midday, with the HRRR particularly robust
with mixing to near 700 mb and potentially tapping 35-40 kt winds
near that level. Thus windy conditions are expected, with gusts in
the 35 mph range likely. Surface high pressure ridge then passes
north of the area heading into the evening, with winds turning
northeast along the lake perhaps prior to sunset with a lake
assisted synoptic wind shift. Drier air should preclude the low
cloud and fog which developed Sunday night. While somewhat cooler
air will filter in, sunshine and dry air mass should still support
above average temps today, from near 80 far north to the lower to
middle 80s south.

Surface low pressure is expected to develop across the Plains
tonight, and track to near the IA/IL/MO border region by Thursday
evening. The tightening of the gradient is expected to result in an
increase in east-northeast winds across the area especially mid-day
and beyond, with gusts increasing above 30-35 mph especially across
the northern half of the cwa. A warm front extending east from the
surface low may lift into the far southern tier or so of WFO LOT
counties during the afternoon, setting up a fairly large temperature
gradient across the forecast area with highs from the 50s and low
60s north, to the mid-upper 70s far south by late in the day. While
gusty easterly low level dry air may slow the eastward progress of
rain just a bit Thursday morning, strong return flow and
strengthening mid-level frontogenetic forcing is noted, with rain
and some thunderstorms developing from the west from mid-morning on.
Some strong to severe thunderstorm potential will exist across the
southern cwa and southward into central IL, in the vicinity of the
warm frontal boundary where low level convergence, instability and
shear will be juxtaposed. Forecast soundings depict steep mid-level
lapse rates north of the boundary above the elevated warm frontal
zone, so some thunder potential will exist some distance to the
north as well.

Ratzer

&&

.LONG TERM...
312 AM CDT

Thursday night through Tuesday...

As a surface low tracks through central Illinois Thursday evening
and Indiana Friday, widespread showers will encompass our area
making for a soggy 24 hours. While most areas will just see waves of
rain, a few thunderstorms can't be ruled out south of I-80 near an
elevated warm front. Total rainfall from Thursday night to Friday
night looks to range from 0.5 to 1", which when spread over a
relatively prolonged period should allow for prime soaking into the
ground. A tightening low-level pressure gradient along the northern
and then backside of the low will also lead to gusty northeast winds
off Lake Michigan Thursday night and Friday, with peak gusts near 40
mph along the immediate lakeshore Friday afternoon. Heavy clouds and
winds off the lake will hold highs only in the lower 50s with wind
chills in the low to mid 40s. Taken altogether, Friday looks
downright miserable. (Just a quick aside, our recent stretch of high
temperatures in the upper 80s fall into the warmest 10% of highs for
the last 1/3 of May at ORD. Yet, our forecast highs in the lower 50s
on Friday fall in the coldest 10%. So, we're going from one extreme
to the other in the span of a few days!)

On the bright side, Saturday onward (and indeed the holiday weekend)
look delightful with warming temperatures, light winds,
opportunities to see the sun, and low to no chances for additional
precipitation. Highs in the 60s Saturday will become the low to mid
70s Sunday and Monday, though daily lake breezes will keep lakeshore
locations cooler. Overnight lows will be in the low to mid 50s.
Applying the trusty "squint test" to ensemble forecast QPF fields
points toward the middle to end of next week for the next chance of
rain, though unsurprisingly the ensemble spread is vast. So, we'll
enjoy a beautiful holiday weekend without fear of impending
downpours.

Borchardt

&&

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

Showers and a few thunderstorms will increase in coverage over the
next few hours, warranting targeted TEMPO groups at all terminals
through daybreak. Opted to remove mention of northwesterly wind
gusts given upstream trends (e.g. no evidence of a robust cold
pool as was thought possible in earlier TAF packages). A moist
airmass will support soaking downpours with visibility below 3
miles in the heaviest cells. Showers and storms will exit toward
daybreak.

Breezy southwest winds will continue this evening before becoming
westerly behind showers and storms, and eventually northwesterly
by mid-Wednesday morning. Forecast wind profiles and mixing
heights suggest wind gusts may approach 30 kt at times through
Wednesday afternoon, so have increased explicit mention of gusts
in the outgoing TAF package. A lake-enhanced cold front will then
swing through all terminals from east to west Wednesday evening
switching winds to east-northeasterly. Toward the very end of the
TAF period, east winds will increase in magnitude as a surface low
pressure system approaches from the west (will provide more
detail with the 12Z TAF package).

Finally, the expectation is for VFR cigs through the entire TAF
package, though a brief period of MVFR cigs based near 2000 feet
can't be ruled out toward daybreak.

Borchardt

&&

.MARINE...
312 AM CDT

As a deepening low pressure system tracks through central Iowa,
Illinois, and Indiana, strong east to northeasterly gales may
develop over Lake Michigan as early as Thursday evening but most
likely from early Friday morning through Friday evening. A long
fetch over Lake Michigan combined with strong sustained winds will
also lead to building waves along the shoreline, with peak heights
above 8 feet probable Friday. After collaboration with NWS
Milwaukee, a Gale Watch has been issued for the entire Illinois and
northwestern Indiana Lake Michigan shoreline.

Borchardt

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory...nearshore waters
     until 4 AM Wednesday.

     Gale Watch...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...3 PM
     Thursday to 3 PM Friday.

&&

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Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
329 PM CDT Tue May 25 2021

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-262030-
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-
329 PM CDT Tue May 25 2021 /429 PM EDT Tue May 25 2021/

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

.DAY ONE...Tonight.

Weather hazards expected...

  Limited Thunderstorm Risk...with an associated:
     Limited damaging wind risk...up to 50 mph.
     Limited Flooding Risk.
  Limited Non thunderstorm wind Risk.

DISCUSSION...

Showers and thunderstorms are likely tonight. These storms
will produce locally heavy rainfall and gusty winds strong
enough to down small tree limbs.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Wednesday...
  Limited Early Morning Thunderstorm Risk.

Thursday...
  Limited Severe Thunderstorm Risk South.
  Limited Non Thunderstorm Wind Risk.
  High Swim Risk.
Friday...
  Limited Non Thunderstorm Wind Risk.
  High Swim Risk.

.SPOTTER INFORMATION STATEMENT...

  Spotter activation is not anticipated.

GENERAL STORM MOTION OF THE DAY:

  Moving toward the northeast at 35 mph.

LMZ740>745-262030-
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-
329 PM CDT Tue May 25 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...Tonight.

Weather hazards expected...

  Hazardous conditions for small craft.
  Limited Thunderstorm Risk...with an associated:
     Limited thunderstorm wind gust risk...up to 40 knots.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Wednesday...
  Hazardous conditions for small craft are likely.
  Limited Early AM Thunderstorm Risk.
Thursday...
  Gale force winds and or very hazardous waves are likely.
Friday and Saturday...
  Hazardous conditions for small craft are likely.

KJB

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