Thursday, August17, 2017 L-36.com


Marine Weather and Tides
Elmhurst, IL

Version 3.4
What's New / NOTES
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.
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.

Sunrise 6:01AMSunset 7:49PM Thursday August 17, 2017 10:17 AM CDT (15:17 UTC) Moonrise 1:34AMMoonset 4:31PM Illumination 22% Phase: Waning Crescent; Moon at 25 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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LMZ741 Winthrop Harbor To Wilmette Harbor- Wilmette Harbor To Northerly Island- Northerly Island To Calumet Harbor- 905 Am Cdt Thu Aug 17 2017
.small craft advisory in effect through late tonight...
Rest of today..Southwest winds 20 to 25 kt. Slight chance of showers and Thunderstorms. Waves 1 to 3 ft.
Tonight..West winds 20 to 25 kt easing to 15 to 20 kt late. Mostly cloudy in the evening then becoming partly cloudy. Waves 1 to 3 ft.
Friday..West winds 15 to 25 kt. Mostly Sunny. Waves 1 to 3 ft.
Friday night..Northwest winds 10 to 15 kt. Chance of showers and slight chance of Thunderstorms after midnight. Waves 1 ft or less.
LMZ741 Expires:201708172200;;523121 FZUS53 KLOT 171405 NSHLOT NEARSHORE MARINE FORECAST National Weather Service Chicago/Romeoville IL 905 AM CDT Thu Aug 17 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>742-172200-

7 Day Forecast for Marine Location Near Elmhurst, IL
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location: 41.89, -87.94     debug


Area Discussion for - Chicago, IL
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Fxus63 klot 171057
afdlot
area forecast discussion
national weather service chicago romeoville, il
557 am cdt Thu aug 17 2017

Short term
339 am cdt
through tonight...

a potent area of low pressure (for august standards) over
southern mn, will shift northeastward over the upper great lakes
by tonight. As it does so, an associated cold front will shift
eastward across the area later this morning and into the
afternoon. Once this front passes, expect some gusty westerly
winds (up around 30 mph) to set up across the area this afternoon
and into the evening.

It appears that the main threat of any strong thunderstorm
development this afternoon ahead of the cold front may occur east
of the area in indiana and lower michigan. We are not out of the
woods yet for precipitation, however. There is still likely to be
another period of showers, and possibly a few thunderstorms early
this morning. While there is an area of widely scattered
showers thunderstorms over north central il at this time, there is
also another area of mainly showers shifting northeastward over
west central illinois. This activity appears to be associated with
a surge in the low-level jet being induced just ahead of the
approaching main upper trough. As this activity continues to shift
northeastward, it will overspread much of eastern il and
northwestern indiana early this morning. Additional widely
scattered activity is also likely to continue over far northern
illinois as well, at least through daybreak. All of this activity
should end by mid morning as it shifts out of the area. A few
scattered showers may redevelop over the area this afternoon,
especially over northern il, where cyclonic flow aloft will drive
another weak disturbance across southern wi.

Kjb

Long term
345 am cdt
Friday through Wednesday...

only two periods look favorable for any sort of active weather from
Friday through the middle of next week. The first would be Friday
night in association with a weak low center dropping out of the
northern plains, visible early this morning as a disturbance on ir
and WV satellite imagery moving from alberta into montana. The
likely timing of this appears to be overnight Friday into the
predawn hours of Saturday which hopefully should limit its impacts
on outdoor activities Friday evening and Saturday morning.

The second period of active weather appears to be in the Tuesday
timeframe as a cold front moves across the area. The ECMWF is
faster than the GFS with this feature by about 12 hours which
actually is not a vast disagreement five or six days out. To
address the differences in timing we will maintain a mention of
precip chances from Monday evening through Tuesday evening, though
the actual event likely would not be of that duration.

Beyond these two periods, the big focus for the extended period is
on the eclipse Monday. Assuming there is not a big acceleration in
the activity mentioned for Monday night or Tuesday, daytime Monday
appears to be dry and warm under the influence of southwesterly
flow. There are no strong signals yet to nudge sky cover forecasts
higher or lower, so will maintain fair weather partly cloudy
conditions for now.

Lenning

Aviation
For the 12z tafs...

seasonally strong surface low pressure centered near kmsp early
this morning will shift northeastward over the upper great lakes
by this evening. As it does so, an associated cold front will
shift eastward across northern il through the late morning, with
a gusty westerly wind expected to develop in its wake. Expect
gusts up around 26 kt this afternoon following the frontal
passage.

Scattered rain showers continue to fester across northeastern
illinois early this morning in association with disturbance
moving over the area. Expect a period of showers at the chicago
area terminals early this morning (through about 14z) before the
focus shifts to the east later this morning. While a lightning
strike or two cant be ruled out with this activity, it appears
that any such activity will be few and far between. The main
threat from these showers will be brief bursts of moderate to
heavy rain, which could result in MVFR to ifr visibilities. In
addition, a period of some lower MVFR CIGS will be possible over
the area this morning due to high lower-level moisture, but it
does appear likely that any lower CIGS will quickly improve
following the cold frontal passage by late morning.

Kjb

Marine
345 am cdt
the next two days will be fairly breezy over the lake with the
approach and passage of a cold front. Southerly flow will increase
today and prompt headlines for small craft but fortunately waves in
the il in nearshore will not grow too large with the offshore winds.

Passage of a cold front toward evening will turn winds westerly but
maintain a fairly tight pressure gradient, which with the cooler air
over warm water will sustain higher speeds into at least the late
evening to overnight hours. Weak high pressure moving over the lake
for the weekend will gradually reduce wind speeds through the day on
Friday.

Lenning

Lot watches warnings advisories
Il... None.

In... None.

Lm... Small craft advisory... Lmz740-lmz741-lmz742-lmz743-lmz744-
lmz745... 11 am Thursday to 3 am Friday.

Visit us at http: weather.Gov chicago (all lowercase)
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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
FSTI2 17 mi138 min SW 12 73°F
OKSI2 17 mi138 min WNW 2.9 74°F
45177 17 mi138 min 74°F
CHII2 - Chicago, IL 20 mi38 min SSW 18 G 23 74°F 70°F
JAKI2 21 mi138 min SSW 8 73°F
45174 23 mi28 min SSW 12 G 16 73°F 73°F2 ft71°F
CMTI2 - 9087044 - Calumet, IL 24 mi48 min S 7 G 14 74°F 1007.7 hPa71°F
WHRI2 - Waukegan Harbor, IL 33 mi38 min SW 13 G 17 74°F
BHRI3 - Burns Harbor, IN 45 mi38 min S 11 G 18 74°F 1009.1 hPa
KNSW3 - Kenosha, WI 49 mi78 min S 8 G 15 74°F 1006.8 hPa (-0.7)

Wind History for Calumet Harbor, IL
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago, Chicago-O'Hare International Airport, IL7 mi27 minSSW 1110.00 miOvercast74°F69°F85%1007 hPa
Chicago, Chicago Midway Airport, IL12 mi25 minSSW 12 G 1810.00 miOvercast74°F70°F88%1006.7 hPa
Chicago / Wheeling, Pal-Waukee Airport, IL15 mi26 minSSW 1010.00 miOvercast74°F71°F91%1007.3 hPa
Chicago / West Chicago, Dupage Airport, IL17 mi26 minSW 138.00 miOvercast73°F71°F94%1007.3 hPa
Lewis University Airport, IL21 mi43 minSW 910.00 miOvercast72°F68°F87%1008.5 hPa

Wind History from ORD (wind in knots)
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Last 24hrSE5SE56E7E11E14S16
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S11S12--------SW11S10
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1 day agoNE4NE7NE7NE8NE12NE15NE11NE10NE9NE10E8NE4NE5NE5NE4NE5NE4NE5NE4N4NE5E8E8E7
2 days agoSW74S4S10SW6SW12SW8W43SW3S4N4CalmS3S5SW4W6W4W4W4W3N5N7NE5

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
wmap_A
IR Satellite Image from GEOS
east_satellite

GOES Local Image of Midwest    EDIT
Geos

Wind Forecast for Chicago, IL (11,2,3,4)
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Ground Weather Radar Station Chicago, IL
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weather_mapweather_map weather_map

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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.