Thursday, May25, 2017 L-36.com


Marine Weather and Tides
Chicago, IL

Version 3.4
What's New / NOTES
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 5:19AMSunset 8:15PM Thursday May 25, 2017 3:09 PM CDT (20:09 UTC) Moonrise 5:34AMMoonset 8:06PM 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- 251 Pm Cdt Thu May 25 2017
.small craft advisory in effect until 4 pm cdt this afternoon...
Tonight..Northwest winds 10 to 15 kt. Partly cloudy in the evening then becoming mostly cloudy. Waves 3 to 5 ft occasionally to 7 ft subsiding to 2 to 4 ft in the late evening and overnight.
Friday..East winds 10 to 15 kt. Chance of showers and slight chance of Thunderstorms in the afternoon. Waves 1 to 3 ft.
Friday night..East winds 10 to 15 kt becoming north after midnight. Chance of Thunderstorms in the evening. Chance of showers through the night. Waves 1 to 3 ft.
Saturday..North winds around 10 kt becoming northeast in the afternoon. Mostly Sunny. Waves around 1 ft.
LMZ742 Expires:201705260315;;196335 FZUS53 KLOT 251951 NSHLOT NEARSHORE MARINE FORECAST NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 251 PM CDT THU MAY 25 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>742-260315-

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 251957
afdlot
area forecast discussion
national weather service chicago romeoville, il
257 pm cdt Thu may 25 2017

Short term
238 pm cdt
through Friday...

the 19z experimental goes-r imagery shows clearing skies
associated with a lake breeze across the wi il in shorelines of
lake michigan this afternoon. Thickness of the cloud cover is also
decreasing as the bases lift. Some peeks of sunshine will then be
likely through the evening with a scattering trend of the clouds.

Clouds are also taking on a more cumulus-nature as compared to
the stratus observed across the area earlier today. Churning low
pressure over the ohio valley will push further east through the
evening, allowing weak high pressure to influence the region. This
will bring lighter winds as the pressure gradient relaxes.

Moisture content remains quite low, but there will still be a
small chance for patchy fog in outlying rural areas tonight. This
is dependent on current cloud cover clearing out to allow for
radiational cooling and fog formation.

The 500mb pattern shows a departing trough in the eastern conus
as a ridge builds in from the central plains. This will allow for
warming temperatures the next couple days, and the flow will
become zonal for Friday. Satellite imagery is showing a southern
pacific jet that continues to pump in moisture to the southwest
us. A weak embedded wave near nm tx will quickly shoot northeast
to help spark some showers for Friday. This wave will work in
association with developing low pressure and a warm front. There
is a marked increase in h85 theta-e and total totals index as
warmer and unstable air works into the region from the southwest.

While model guidance is quite variable with the probabilities for
convection or rain showers Friday, there remains a chance for
development from afternoon through evening.

Mm

Long term
253 pm cdt
Friday night through Thursday...

zonal flow aloft early in the weekend will gradually become more
meridional through the period with longwave troughing expected to
result in active and seasonably cool weather much of the upcoming
week.

Low amplitude shortwave and weak surface reflection will shift east
of the CWA after midnight Friday night with precipitation ending
behind the wave as mid level height rises overspread the region.

Most of the day Saturday should be dry under the influence of a
transient ridge building across the region. Northeast flow will keep
temperatures cooler along the lake front, in the upper 50s and low
60s, but inland expect the warmest day of the upcoming week with
highs in the upper 70s to around 80.

Attention will turn to the west later in the day as another
shortwave begins to carve out an increasingly amplified upper
trough over the northern great plains. At the surface, low
pressure will move across northern missouri into central illinois
Saturday evening. Showers and thunderstorms will increase in
advance of the low with the greatest focus along the warm front
which is expected to be draped across central illinois. There
remains some uncertainty in the northward extent of precipitation
which may become cut off from the better moisture feed due to
ongoing convection to our south and for now have confined likely
pops to areas south of i-80 with just chance pops north.

There should be a lull in any precipitation starting Sunday morning
as the main 500mb vort passes overhead. Cold air advection into the
region will help steepen low level lapse rates during the day Sunday
which will help set the stage for isolated diurnal showers and
possibly a thunderstorm. Forcing on Sunday is fairly negligible
though there continue to be mid level height falls as an upper low
gradually meanders from the canadian prairies into the upper
midwest. Lack of any appreciable forcing or focus for ascent will
keep any precip coverage low on Sunday.

Upper low trough axis will gradually shift east across the great
lakes early through the middle of next week which will keep the
local area under cooler northwest flow aloft. There will be periodic
chances for showers and possibly a thunderstorm or two as several
low amplitude waves rotate over the area. Steep low level lapse rate
and fairly minimal CIN will persist through the middle of next week
and precipitation will be diurnally favored.

Deubelbeiss

Aviation
For the 18z tafs...

stratus clouds associated with low pressure over the in oh border
continue to slowly lift and scatter out through the afternoon today.

Visible satellite imagery shows decent clearing over lake michigan
which should expand over land east to west. Expect the trend ofVFR
to spread across the terminals in the next couple hours. There is a
weak lake breeze visible via surface observation as well as
terminal doppler radar. As a result, a slight shift to nne winds
near 10kt will occur 20-21z today. As low pressure departs further
to the east this evening, improving conditions will result. High
pressure overhead tonight will lead to variable winds, but there
is not much of a fog threat as dewpoint temps remain well below
surface temps. There is a small chance for rain or thunderstorms
Friday afternoon evening which will be updated in future
forecasts.

Mm

Marine
253 pm cdt
a moderate northerly gradient in place over lake michigan this
afternoon will gradually ease as low pressure over the upper ohio
valley departs towards new england Friday. As winds ease, the
small craft advisory will be allowed to expire this afternoon for
the illinois nearshore waters, but will continue a few more hours
into the evening as waves gradually diminish in the indiana zones.

A transient ridge will pass over the lake Friday which will allow
for generally light flow across the lake and for afternoon lake
breezes to develop. Flow should remain relatively light through
the remainder of the weekend as the western lakes fall between two
areas of low pressure -- one moving east across the canadian
prairies and another lifting from the southern plains to the
central great lakes. Fresh west flow will develop early next week
as these two lows merge over ontario and slowly lift to near james
bay.

Bmd

Lot watches warnings advisories
Il... Beach hazards statement... Ilz006-ilz014 until 7 pm Thursday.

In... Beach hazards statement... Inz001-inz002 until 10 pm Thursday.

Lm... Small craft advisory... Il nearshore waters until 4 pm Thursday.

Small craft advisory... In nearshore waters until 10 pm Thursday.

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
CNII2 1 mi40 min N 9.9 G 17 61°F
OKSI2 4 mi130 min NNE 8.9 56°F
CHII2 - Chicago, IL 5 mi50 min NNW 11 G 13 53°F 51°F
JAKI2 5 mi130 min N 8.9 57°F
FSTI2 9 mi130 min N 12 54°F
CMTI2 - 9087044 - Calumet, IL 9 mi52 min NNW 12 G 16 58°F 1003.7 hPa53°F
45174 20 mi30 min 12 G 16 51°F 52°F3 ft48°F
BHRI3 - Burns Harbor, IN 28 mi53 min NNW 8 G 15 50°F 1004.7 hPa
45170 34 mi30 min NW 12 G 16 48°F 51°F4 ft46°F
WHRI2 - Waukegan Harbor, IL 37 mi90 min NNE 18 G 19 53°F
MCYI3 - Michigan City, IN 37 mi50 min W 8.9 G 9.9 48°F 48°F

Wind History for Calumet Harbor, IL
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N13
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G15
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G20
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G21
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G19
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NW8
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NE4
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N1
N3
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G5
N8
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G12
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SW12
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G19
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SW10
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SW9
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G14
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G15
S7
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G12
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G11
SW7
G13
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G11
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G8
S4
S4
NE6
E6

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago, Chicago Midway Airport, IL9 mi77 minN 510.00 miMostly Cloudy66°F54°F65%1003.2 hPa
Chicago, Chicago-O'Hare International Airport, IL18 mi79 minNNW 710.00 miMostly Cloudy67°F53°F61%1003.2 hPa
Gary Regional Airport, IN19 mi85 minNNW 10 G 2015.00 miPartly Cloudy64°F53°F68%1003.7 hPa
Lansing Municipal Airport, IL22 mi75 minN 510.00 miMostly Cloudy64°F56°F78%1003.7 hPa
Chicago / Wheeling, Pal-Waukee Airport, IL24 mi78 minNNE 510.00 miOvercast65°F55°F70%1003.9 hPa

Wind History from MDW (wind in knots)
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Last 24hrN16N13N16N11N14N11N11N13N9N12N7N9N12N10N9N12NW10N11N12NW12NW12N9N5N8
1 day agoE6E6NE4E5CalmNE4E7NE3E4E7NE5NE8N8NE10N9N9NE10N11N13NE12NE17N12N14
G22
N13
2 days agoSW15
G26
SW19
G24
SW17
G22
SW11
G20
SW12
G20
SW18
G24
SW11S7SW9SW10SW9S7S8SW9SW11SW8SW9SW11
G20
W8SW6SW4SW3CalmSE4

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 (16,3,4,5)
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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.