Wednesday, October17, 2018 L-36.com


Marine Weather and Tides
Chicago, IL

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 7:04AMSunset 6:06PM Wednesday October 17, 2018 4:14 AM CDT (09:14 UTC) Moonrise 2:52PMMoonset 12:00AM Illumination 54% Phase: First Quarter Moon; Moon at 8 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- 300 Am Cdt Wed Oct 17 2018
.small craft advisory in effect through early this evening...
Today..Northwest winds to 30 kt diminishing to 20 to 25 kt early this afternoon. Partly cloudy then becoming mostly Sunny. Waves 3 to 5 ft subsiding to 2 to 4 ft in the afternoon.
Tonight..Northwest winds 10 to 20 kt diminishing to 10 to 15 kt after midnight. Mostly clear. Waves 2 to 4 ft subsiding to 1 to 3 ft.
Thursday..West winds 10 to 15 kt becoming southwest 10 to 20 kt in the afternoon. Sunny. Waves 1 to 3 ft.
Thursday night..Southwest winds 10 to 20 kt. Clear. Waves 1 to 3 ft.
LMZ742 Expires:201810171515;;309709 FZUS53 KLOT 170800 NSHLOT NEARSHORE MARINE FORECAST National Weather Service Chicago/Romeoville IL 300 AM CDT Wed Oct 17 2018 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>742-171515-


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 170814
afdlot
area forecast discussion
national weather service chicago romeoville, il
314 am cdt Wed oct 17 2018

Short term
225 am cdt
through tonight...

another breezy day will unfold today though not as gusty as
yesterday. The advection regime flips back to cold air, so highs
today drop back to 12 to 15 degrees below mid-october normals.

North american water vapor imagery reveals a massive upper trough
across eastern canada into the northeast quarter of the u.S., with
a strong jet streak rounding its base digging the trough just a
tad further into the great lakes. The surface cold front was
actually visible earlier in infrared satellite as it was
progressing down the lake. This front is moving through the area
early this morning and will provide cold air advection and
associated steepened lapse rates just after daybreak. In tandem
with this are surface pressure rises of 4mb per 3hr spreading
across. This should all result in sustained northwest winds of 15
to 18 mph and wind gusts of 25 mph or just a bit over through
early afternoon.

A solid area of stratocumulus is rotating southeast across
wisconsin within the strongest 850-925 mb cold advection.

Projections of relative humidity at that level from the rap and
nam indicate northeast illinois and far northwest indiana should
get into at least scattered clouds later this morning. Still some
decent uncertainty on how solid this will be as their often can be
with cold advection stratocu, as well as if scattered clouds
develop elsewhere. Lake effect clouds are probable into porter
county in northwest indiana this afternoon and this evening.

With 925mb temperatures dropping to slightly below 0c, highs are
favored in the upper 40s, with some degree of spread depending on
cloud coverage. The surface high of 1034 mb will move over the
area later this evening and persist into Thursday morning. Lows
look to be subfreezing across much of the area, with some of the
favored cool spots likely dipping into the mid 20s.

Mtf

Long term
314 am cdt
Thursday through Tuesday...

for the longer term forecast period, general weather trends are
expected to be relatively quiet and mainly dry with below normal
temperatures. The one deviation from this trend may a chance for
some light rain for Friday and Saturday.

For Thursday, conditions will be and cool as broad upper ridge
builds east across the mississippi valley and upper midwest and
great lakes regions. A strong shortwave is expected to over-top the
ridge and drop across the upper midwest on Friday while both
flattening the upper level pattern and pushing a cold front across
the area. In advance of the approaching sfc cold front, as
strengthening swly pressure gradient and daytime mixing will help
tap into 35-40 kt winds at the top of the mixed layer. Expect that
Friday will be a rather windy day, however, increasing cloud cover
in the broad isentropic lift of the warm sector may help limit the
max potential mixing, with gusts to arnd 30-35 mph possible through
the day. There is a chance for some scattered showers, mainly
diurnally driven during the daytime hours. However, forecast
soundings indicate quiet a bit of dry air in the lower levels, so
any pcpn will likely be light and patchy.

Strong cold air advection will set up across the region on Friday
night into Saturday following the passage of the cold front. Strong
cold advection and strong pressure rises between the exiting frontal
trough and high pressure building into the central plains will
result in another windy day. Forecast soundings continue to show
winds at the top of the mixed layer of around 40kt and suggest
another day with the potential for wind gusts in excess of 30 mph,
but from the northwest. Meanwhile, a second and weaker shortwave is
expected to digs across the area on Saturday and may produce another
wave of scattered diurnally-driven showers as the region sits under
cyclonic flow aloft. High pressure should build over the region
Sunday through Monday, ending the pcpn chances. Another cold front
is expected to pass over the area Monday night into Tuesday, but the
latest long range guidance suggests that this will be a dry FROPA as
sfc ridging extending from the mid-atlantic region through the lower
mississippi valley should keep the local area shut off from any
significant moisture influx.

Aviation
For the 06z tafs...

gusty northwest winds and a chance for a morning period of broken
3000-4000 ft clouds are the two items of note for the tafs.

A cold front will move across northern illinois and northwest
indiana prior to daybreak, turning winds more 300-310 degrees.

Mixing should be quick to ensue with cold advection and
occasional gusts in the mid 20s kt are expected during mid to late
morning and possibly early afternoon. Confidence in forecast wind
direction is high, while is medium in gust magnitude.

A solid area of 3000-4000 ft stratocumulus across northern and
central wisconsin will continue to move southeast. This likely
will graze the area and may spread over ord and mdw between 13z-
17z.

Winds will drop sharply this evening as high pressure envelops the
region.

Mtf

Lot watches warnings advisories
Il... None.

In... None.

Lm... Small craft advisory... In nearshore waters until 4 am Thursday.

Small craft advisory... Il nearshore waters until 7 pm Wednesday.

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
CNII2 1 mi29 min SW 5.1 G 8.9 47°F 33°F
JAKI2 5 mi134 min W 6 G 13 48°F
CHII2 - Chicago, IL 5 mi44 min W 18 G 21 50°F 35°F
FSTI2 9 mi134 min W 2.9 47°F
CMTI2 - 9087044 - Calumet, IL 9 mi44 min WSW 5.1 G 8 47°F 1018.5 hPa35°F
45174 20 mi34 min W 14 G 19 49°F 58°F2 ft39°F
BHRI3 - Burns Harbor, IN 28 mi34 min WSW 8.9 G 11 51°F 1019 hPa
45170 34 mi34 min WNW 19 G 25 53°F 59°F6 ft42°F
WHRI2 - Waukegan Harbor, IL 37 mi34 min WNW 9.9 G 14 46°F
MCYI3 - Michigan City, IN 37 mi44 min WSW 27 G 29 53°F 39°F
45186 37 mi34 min WNW 12 48°F 56°F1 ft
45187 45 mi34 min 47°F 53°F1 ft

Wind History for Calumet Harbor, IL
(wind in knots)    EDIT      (on/off)   Help
4
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5
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-12
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-12
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Last
24hr
SW5
G10
SW5
G8
S7
S7
SW6
G10
SW8
G13
SW12
G17
SW8
G19
SW13
G23
SW12
G20
SW9
G16
SW11
G14
SW4
G11
SW6
G9
SW5
G10
SW6
G9
SW6
G11
SW8
G13
SW6
G11
SW5
G9
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SW4
G9
1 day
ago
W6
G12
W8
G15
W5
G12
NW7
G12
W6
G12
W8
G13
W7
G13
W8
G14
W5
G13
SW6
G10
W6
G11
W7
G14
SW8
G13
W6
G12
W1
G4
SW4
SW4
S5
SW4
SW4
SW3
SW4
SW4
G7
2 days
ago
S1
S1
S3
SE3
S3
S7
G10
SE7
G11
S6
G12
S7
G10
SW3
G6
SW5
G11
SW4
G8
--
W3
G6
W3
NW4
NW5
G9
W3
G6
NW3
W2
NW3
G7
W2
G7
W2
G5

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago, Chicago Midway Airport, IL9 mi21 minW 1110.00 miFair47°F32°F56%1019.4 hPa
Chicago, Chicago-O'Hare International Airport, IL18 mi23 minW 1010.00 miFair45°F33°F63%1018.9 hPa
Gary Regional Airport, IN19 mi19 minWSW 710.00 miFair46°F35°F65%1019.6 hPa
Lansing Municipal Airport, IL22 mi19 minW 610.00 miFair41°F34°F79%1019.6 hPa
Chicago / Wheeling, Pal-Waukee Airport, IL24 mi22 minW 710.00 miFair46°F30°F56%1019.4 hPa

Wind History from MDW (wind in knots)
5
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Last 24hrSW6SW6SW8SW7SW10SW16
G24
SW16
G30
SW21
G29
SW14
G28
W16
G28
W15
G25
W15
G23
W16
G25
SW11
G23
SW8SW8SW10SW12W11--W8SW6W10W11
1 day agoNW11NW11
G20
NW9NW13NW9NW14NW13NW10W15
G21
W16
G24
W12
G21
W14
G20
W15
G21
W11W7W6W6W5SW5W7W6SW6SW8SW7
2 days agoCalmSE3SE3CalmS4S5S11SW7S8
G15
SW8
G14
SW4SW10W8W9W6NW8NW10NW7NW3NW5NW5W7NW11
G18
NW12

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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wmap_A
GOES 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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Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for Chicago, IL (5,6,7,8)
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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.