Tuesday, September17, 2019 L-36.com


Marine Weather and Tides
Chicago, IL

Version 3.4
NOTICE
9/4/2019 Fixed the weather maps due to NOAA moving them.
7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports.
6/2/2019. Many thanks to a user for reporting an error on one of the Edit pages. The switch to PHP 7.2 caused many pages that previously worked to quit working. I fixed many but I still depend on users to report ones I missed. Please report errors HERE or send an email to me at L-36.com. Allen

Sunrise 6:31AMSunset 6:58PM Tuesday September 17, 2019 3:40 PM CDT (20:40 UTC) Moonrise 8:57PMMoonset 9:39AM Illumination 86% Phase: Waning Gibbous; Moon at 18 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 Expires:201909180315;;938475 Fzus53 Klot 171954 Nshlot Nearshore Marine Forecast National Weather Service Chicago/romeoville Il 254 Pm Cdt Tue Sep 17 2019 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>742-180315- Winthrop Harbor To Wilmette Harbor- Wilmette Harbor To Northerly Island- Northerly Island To Calumet Harbor- 254 Pm Cdt Tue Sep 17 2019
Tonight..East winds 5 to 10 kt becoming southeast 10 to 15 kt after midnight. Patchy fog. Waves 1 to 3 ft.
Wednesday..Southeast winds 10 to 15 kt. Patchy fog in the morning. Waves 1 to 3 ft subsiding to 1 ft or less in the afternoon.
Wednesday night..Southeast winds 10 to 15 kt. Partly cloudy. Waves 1 to 3 ft.
Thursday..South winds 5 to 10 kt becoming southeast in the afternoon. Mostly Sunny. Waves 1 to 3 ft subsiding to 1 ft or less in the afternoon.
LMZ742


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 171933
afdlot
area forecast discussion
national weather service chicago romeoville, il
233 pm cdt Tue sep 17 2019

Short term
231 pm cdt
through Wednesday night...

upper ridging is overhead while surface high pressure is off to
the east this afternoon, though a weak ridge axis extends westward
across the area. Main concern for tonight will be fog development
which looks to be less extensive than recent nights. Will carry
patchy fog for mainly northern areas and along the lakeshore from
chicago north. Upper ridging will remain across the region
Wednesday keeping warm air in place once again. Expect highs in
the low to mid 80s. A lake breeze may set up and work inland,
especially across the northern chicago suburbs, keeping lakefront
areas of illinois in the 70s. An upper trough will move northeast
across the northern plains Wednesday shunting the ridge eastward
while a weak cool front approaches from the northwest. Should see
an influx of cloud cover across north-central illinois Wednesday
night with chances for rain likely holding off to the northwest of
the forecast area.

Mdb

Long term
231 pm cdt
Thursday through Tuesday...

the main weather story for the later half of the week will be the
very warm temperatures expected across the area, followed by what
looks to be a period of inclement weather over the weekend.

The period will start on the warm side for both Thursday and
Friday as a large mid-level ridge axis remains centered across the
region. Temperatures over the area both days still look likely to
top out well into the 80s, which is about 10 degrees above average
for this time of year. Active weather, with showers and
thunderstorms, is likely remain confined to the west-
northwestern periphery of the mid-level ridge through this
period. This would favor the plains and upper midwest to our west-
northwest. I cannot totally rule out the possibility for a few
weakening storms moving into far northern il Friday morning, but
at this time, this potential looks low.

A potent upper trough over the western CONUS is expected to
transition eastward over the central and northern plains by
Saturday. As it does so, strong height falls will overspread the
upper midwest and western great lakes, essentially resulting in a
break down of the mid-level ridge across the area. This should
act to focus active weather into our region this weekend. A
surface cold front is expected to move across the area sometime
Sunday or Sunday night. However, prior to its passage, it appears
possible that some tropical moisture associated with the remnants
of imelda could shift northeastward over our area. This could
thus set the stage for a period or two of thunderstorms with heavy
rainfall, especially Saturday night into Sunday.

It appears that the orientation of the surface front could remain
somewhat parallel to the southwesterly flow pattern aloft, which
would favor a slow eastward movement across the area. For this
reason this pattern could become favorable to support a couple
periods of training thunderstorms later in the weekend. However,
given this is still several days away, and timing differences in
the frontal arrival are apparent in forecast guidance, confidence
on the specific areas favorable for heavy rain remains low at this
time. This will certainly be a period to keep an eye on though,
especially with the ongoing flooding across northern il.

Following this active period of weather, it appears things could
quiet down for a couple of days early next week before more active
weather returns later in the week.

Kjb

Aviation
For the 18z tafs...

surface high pressure is off to the east of the terminals this
afternoon. Low cloud cover has mostly eroded, though day time
heating has triggered some stratocu in the 2000-3000 ft range but
this should remain few to scattered in coverage. East to
southeast winds have set up in the 5 to 10 kt range and will
continue through the afternoon and diminish to 5 kt or less
overnight. Not expecting much in the way of fog or stratus
development over land tonight with high pressure well to the east.

Some patchy shallow fog could develop at rfd dpa. South to
southeast winds develop for Wednesday withVFR expected.

Mdb

Lot watches warnings advisories
Il... None.

In... None.

Lm... Dense fog advisory... Il nearshore waters until 4 pm Tuesday.

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
CNII2 1 mi40 min NNE 4.1 G 6 71°F 65°F
CHII2 - Chicago, IL 5 mi50 min NE 9.9 G 9.9 69°F 67°F
JAKI2 5 mi100 min ENE 2.9 G 7 70°F
CMTI2 - 9087044 - Calumet, IL 9 mi52 min NNE 7 G 9.9 70°F 1020.2 hPa67°F
45174 20 mi30 min E 3.9 G 5.8 67°F1 ft1019.1 hPa
BHRI3 - Burns Harbor, IN 28 mi40 min NNE 2.9 G 5.1 69°F 1021 hPa (-1.7)
45170 34 mi30 min NNE 7.8 G 9.7 69°F 69°F1 ft67°F
45186 37 mi40 min ESE 1.9 G 3.9 71°F 66°F
MCYI3 - Michigan City, IN 37 mi50 min NNE 9.9 G 9.9 70°F 66°F

Wind History for Calumet Harbor, IL
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago, Chicago Midway Airport, IL9 mi47 minE 89.00 miMostly Cloudy78°F66°F67%1019.4 hPa
Chicago, Chicago-O'Hare International Airport, IL18 mi49 minENE 910.00 miMostly Cloudy78°F64°F62%1019.8 hPa
Gary Regional Airport, IN19 mi55 minENE 76.00 miFog/Mist75°F62°F65%1021 hPa
Lansing Municipal Airport, IL22 mi45 minNE 710.00 miMostly Cloudy78°F68°F71%1020.3 hPa
Chicago / Wheeling, Pal-Waukee Airport, IL24 mi48 minE 710.00 miFair75°F64°F71%1020.7 hPa

Link to 5 minute data for KMDW

Wind History from MDW (wind in knots)
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Last 24hrNE5----NE7NE7--E10------E7--E4E5E6E5NE6--E6E546SE7E8
1 day agoS10S5S4S5S4--------CalmCalmCalm----N6N7N8--N6N5N5N8NE9N7
2 days agoW11
G19
SW11SW9SW5S6----------------SW14
G22
S12S9----S13
G21
SW12SW12
G18
SW9S11SW11
G20

Tide / Current Tables for
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Weather Map
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GEOS Local Image of Midwest    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
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Wind Forecast for Chicago, IL (16,3,4,5)
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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.