Monday, March27, 2017 L-36.com


Marine Weather and Tides
Chicago, IL

Version 3.4
What's New / NOTES
5/19/2016 - There were issues with the 3 day airport observation history. I switched to another data source. Let me know if you see any issues with the data feeds.
3/12/2015 - Added section for Gulf current for users in the GMZ marine zones.
This was requested by a user. If you have requests, please let me know.

Sunrise 6:38AMSunset 7:12PM Monday March 27, 2017 9:36 AM CDT (14:36 UTC) Moonrise 6:38AMMoonset 6:52PM Illumination 0% Phase: New Moon; Moon at 0 days in cycle
NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.
Marine Forecasts
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LMZ742 Winthrop Harbor To Wilmette Harbor- Wilmette Harbor To Northerly Island- Northerly Island To Calumet Harbor- 657 Am Cdt Mon Mar 27 2017
.dense fog advisory in effect until 1 pm cdt this afternoon...
Today..Variable winds less than 10 kt becoming northeast in the late morning and early afternoon, then increasing to 10 to 15 kt late in the afternoon. Areas of dense fog in the morning. Chance of showers in the afternoon. Waves around 1 ft building to 1 to 3 ft late in the afternoon.
Tonight..North winds 10 to 20 kt increasing to 20 to 25 kt after midnight. Chance of showers through the night. Waves 3 to 5 ft occasionally to 7 ft building to 4 to 6 ft occasionally to 8 ft after midnight. A small craft advisory will likely be needed.
Tuesday..North winds 15 to 20 kt. Partly Sunny. Waves 3 to 6 ft occasionally to 8 ft subsiding to 3 to 5 ft occasionally to 7 ft in the afternoon. A small craft advisory will likely be needed.
Tuesday night..North winds 15 to 20 kt becoming northeast after midnight. Partly cloudy. Waves 3 to 6 ft occasionally to 8 ft subsiding to 3 to 5 ft occasionally to 7 ft after midnight. A small craft advisory will likely be needed.
LMZ742 Expires:201703271515;;155574 FZUS53 KLOT 271157 NSHLOT NEARSHORE MARINE FORECAST NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 657 AM CDT MON MAR 27 2017 FOR WATERS WITHIN FIVE NAUTICAL MILES OF SHORE ON LAKE MICHIGAN WAVES ARE PROVIDED AS A RANGE OF SIGNIFICANT WAVE HEIGHTS, WHICH IS THE AVERAGE OF THE HIGHEST 1/3 OF THE WAVES, ALONG WITH THE AVERAGE HEIGHT OF THE HIGHEST 10 PERCENT OF THE WAVES WHICH WILL OCCASIONALLY BE ENCOUNTERED. LMZ740>742-271515-

7 Day Forecast for Marine Location Near Chicago, IL
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location: 41.85, -87.6     debug


Area Discussion for - Chicago, IL
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Fxus63 klot 271302 aaa
afdlot
area forecast discussion... Updated
national weather service chicago/romeoville, il
802 am cdt Mon mar 27 2017

Update
800 am cdt
residual moisture and nearly calm winds continues to support dense
fog over lake michigan, and per webcam imagery this is along
immediate shoreline locations, including lakeside areas of
chicago. The city of chicago has indicated the stratus cloud is
only about 30 ft off the ground. Webcam imagery has shown a
decline in visibility since daybreak including in far northwest
indiana (michigan city).

Nearly calm synoptic winds will continue this morning and given
the already warmer land temperatures than water, a mesoscale
northeast wind is favored along the lakefront this morning. This
may drag the dense fog inland, likely only less than a mile
inland, but still could have notable impacts. Would expect this to
ease gradually into the afternoon, but may get worse through 10
a.M. Or so.

Have updated the forecast and issued an sps and graphical nowcast
and will continue to monitor closely for an advisory issuance.

Mtf

Short term
243 am cdt
through tonight...

early this morning, foggy conditions are in place as a weak
surface trough moves across the area resulting in weak flow. To
our southwest, water vapor imagery shows an upper low spinning
over eastern ks while a surface low is analyzed over far
southeastern ks. As the low moves east across missouri today, a
col area will move over northern illinois and northwest indiana
resulting in light and variable or calm winds through much of the
morning over the CWA which will delay or slow improvement of
visibility possibly into the afternoon for some areas. This
afternoon, surface low is progged to move east across the mid
mississippi valley into far downstate illinois with a
northeasterly gradient developing over northern illinois. Onshore
flow and fog over lake michigan will suppress temperatures near
the lake front. Expect high temperatures in the mid to upper 50s
with a few spots south of i-80 tagging 60. Near the lake,
temperatures are expected to top out in the mid to upper 40s.

Precipitation out ahead of the low is expected to begin
overspreading the CWA south of i-80 by late morning or early
afternoon, then overspread the i-88 to i-90 corridor mid
afternoon. Models have trended slightly farther south, and it
now appears the northern tier and possibly two tiers of counties
in illinois could stay dry with precipitation most likely across
the south half of the cwa. Very weak instability only clips the
far southern counties in the CWA so have kept thunder mention
along and south of the kankakee river valley.

Deubelbeiss

Long term
243 am cdt
Tuesday through Sunday...

a sprawling area of high pressure will spread south from the
canadian prairies into the upper midwest and western great lakes
region Tuesday and Wednesday bringing dry conditions and some
peeks of sunshine. North to northeast flow and persistent onshore
flow will keep temperatures lower near the lake front. Local
climate data indicates that downtown chicago struggles to reach
the mid 40s in lake august on days with persistent onshore flow.

Have undercut some of the guidance near the lake front keeping
temperatures in the low 40s immediately along the shore while
inland temperatures should be able to warm into the low to mid
50s.

Models continue to come into better agreement on area of low
pressure lifting across the region late in the week. While timing
differences remain moderately large, models are now honing in on
a low track from near st louis to northern indiana. Despite
falling on the cold side of the low track, forecast soundings from
the GFS indicate the column will be warm enough for all rain.

Models remain in reasonably good agreement through Saturday
building high pressure across the midwest, but begin to diverge
thereafter on handling a cutoff low that develops over the western
states late this week into the weekend.

Deubelbeiss

Aviation
For the 12z tafs...

main forecast concerns are with ifr/lifr ceilings, reduced vis
this morning, wind shift to the northeast this morning.

Weak surface trough is pushing through northeast illinois at this
time, and is allowing for some drizzle or light rain to develop.

This precip will remain light and likely last only for the next
couple of hours. However, do think this will assist with keeping
vis lower, in the 1-2sm range. Ifr and lifr ceilings in place this
morning and at this time, do think there will be some slight
improvement. This may not occur quite as soon though as am
monitoring really low ceilings and vis in dense fog right along
the nearshore waters of lake michigan. As this trough pushes
through over the next couple of hours, winds will turn to the
northeast. Although speeds will initially stay low, this may allow
for these lower conditions to move inland and help keep
conditions lower. Confidence is low with regards to the inland
extent of these lower conditions, but will need to monitor this
morning for possible lower conditions than currently forecast.

Still have a slow improvement in ceilings later today, but once
again, lower ceilings may still linger. Trends would suggest that
the bulk of the precip expected later today may stay just to the
south of the terminals. With these trends, have trended away from
this precip in the tafs, but have not yet removed completely. At
this time, gyy has the highest chance to observe these showers.

Rodriguez

Marine
317 am cdt
low pressure over the central great lakes is departing to the
northeast this morning, while west to northwest winds are in
place. Expect a trend towards the northwest for much of the lake
this morning, and then more northerly throughout today. However,
speeds don't appear to be too strong for much of today. Very moist
conditions still in place over much of the lake, with dense fog
likely being observed over the entire lake with the exception of
the indiana nearshore. Have the dense fog advisory in place
through later this morning and do think this end time still seems
reasonable. Will need to monitor for fog to possibly linger longer
over portions of the lake today though, especially over the
southern end of the lake. High pressure to the northwest and low
pressure tracking through the region just south of the lake
tonight into Tuesday will allow northerly winds to increase.

Expect speeds of 15 to 25 kt with some gusts up to 30 kt over much
of the lake tonight, with these speeds and direction likely
continuing into Tuesday. These stronger winds and building waves
will likely provide conditions hazardous to small craft by late
tonight and especially into Tuesday. These stronger northerly
winds will persist through midweek.

Rodriguez

Lot watches/warnings/advisories
Il... None.

In... None.

Lm... Dense fog advisory... Nearshore waters
until 1 pm Monday.

Dense fog advisory... Lmz777-lmz779 until 9 am Monday.

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
CNII2 1 mi36 min N 5.1 41°F
OKSI2 4 mi96 min Calm 43°F
CHII2 - Chicago, IL 5 mi46 min NE 6 G 6 40°F 40°F
JAKI2 5 mi96 min NNE 5.1 41°F
FSTI2 9 mi96 min N 12 40°F
CMTI2 - 9087044 - Calumet, IL 9 mi48 min NNW 4.1 G 5.1 43°F 1013.5 hPa42°F
BHRI3 - Burns Harbor, IN 28 mi36 min WNW 6 G 9.9 46°F 1014.2 hPa (+0.7)
WHRI2 - Waukegan Harbor, IL 37 mi56 min S 1.9 G 1.9 40°F
MCYI3 - Michigan City, IN 37 mi46 min N 6 G 6 43°F 43°F

Wind History for Calumet Harbor, IL
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Last
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SE8
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SW6
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N9
G13

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago, Chicago Midway Airport, IL9 mi43 minN 07.00 miOvercast50°F48°F93%1013.7 hPa
Chicago, Chicago-O'Hare International Airport, IL18 mi45 minENE 61.50 miLight Drizzle48°F45°F89%1013.7 hPa
Gary Regional Airport, IN19 mi51 minN 07.00 miOvercast52°F46°F82%1014.2 hPa
Lansing Municipal Airport, IL22 mi61 minN 07.00 miOvercast49°F49°F99%1013.9 hPa
Chicago / Wheeling, Pal-Waukee Airport, IL24 mi44 minNE 310.00 miOvercast47°F44°F90%1014.4 hPa

Wind History from MDW (wind in knots)
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Last 24hrS7S8SW6SW6SW9SW12SW11
G17
SW9SW7SW9SW8SW7SW8SW12W9SW11SW10SW8SW7SW8SW6SW6SW6Calm
1 day agoNE16
G20
N10N9N8N7NE9
G15
NE10NE9N11
G18
N9N6NE8--NE5N96565E5E8SE9SE8SE8
2 days agoSW16
G21
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NE8
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N9N11
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N9N9NE8
G18
NE10NE9
G18

Tide / Current Tables for
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Tide / Current Tables for
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Weather Map and Satellite Images
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Weather Map
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IR Satellite Image from GEOS
east_satellite

GOES Local Image of Midwest    EDIT
Geos

Wind Forecast for Chicago, IL (10,2,3,4)
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Ground Weather Radar Station Chicago, IL
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Disclaimer:
The information on this web site has not been checked for accuracy. It is for entertainment purposes only and should be independently verified before using for any other reason. There are five sources. 1) Documents and manuals from a variety of sources. These have not been checked for accuracy and in many cases have not even been read by anyone associated with L-36.com. I have no idea of they are useful or accurate, I leave that to the reader. 2) Articles others have written and submitted. If you have questions on these, please contact the author. 3) Articles that represent my personal opinions. These are intended to promote thought and for entertainment. These are not intended to be fact, they are my opinions. 4) Small programs that generate result presented on a web page. Like any computer program, these may and in some cases do have errors. Almost all of these also make simplifying assumptions so they are not totally accurate even if there are no errors. Please verify all results. 5) Weather information is from numerious of sources and is presented automatically. It is not checked for accuracy either by anyone at L-36.com or by the source which is typically the US Government. See the NOAA web site for their disclaimer. Finally, tide and current data on this site is from 2007 and 2008 data bases, which may contain even older data. Changes in harbors due to building or dredging change tides and currents and for that reason many of the locations presented are no longer supported by newer data bases. For example, there is very little tidal current data in newer data bases so current data is likely wrong to some extent. This data is NOT FOR NAVIGATION. See the XTide disclaimer for details. In addition, tide and current are influenced by storms, river flow, and other factors beyond the ability of any predictive program.