Friday, August18, 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 6:02AMSunset 7:47PM Friday August 18, 2017 11:09 AM CDT (16:09 UTC) Moonrise 2:30AMMoonset 5:31PM Illumination 14% Phase: Waning Crescent; Moon at 26 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-calumet Harbor To Gary- 908 Am Cdt Fri Aug 18 2017
Rest of today..West winds 15 to 25 kt diminishing to 10 to 20 kt early this afternoon. Partly cloudy this morning then becoming mostly Sunny. Waves 2 to 4 ft subsiding to 1 to 3 ft during the afternoon.
Tonight..West winds 10 to 15 kt becoming northwest 5 to 10 kt overnight. Chance of showers and slight chance of Thunderstorms late this evening and overnight. Waves around 1 ft.
Saturday..Northwest winds 5 to 10 kt becoming northeast by noon, and then east around 10 kt in the early afternoon. Sunny. Waves around 1 ft.
Saturday night..Southeast winds 5 to 10 kt becoming southwest after midnight. Mostly clear. Waves 1 ft or less.
LMZ741 Expires:201708182145;;573447 FZUS53 KLOT 181408 NSHLOT NEARSHORE MARINE FORECAST National Weather Service Chicago/Romeoville IL 908 AM CDT Fri Aug 18 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>743-182145-

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 181556
afdlot
area forecast discussion
national weather service chicago romeoville, il
1056 am cdt Fri aug 18 2017

Update
1056 am cdt
minor updates this morning for lingering cloud cover across
northeast il and northwest in, and associated slower temp rise.

Surface low pressure was just north of lake huron late this
morning, with a region of slightly cyclonic west-northwest low
level flow extending across the western great lakes region. An
extensive stratocu field was evident in GOES visible imagery over
much of eastern wi and northeast il northwest in, while generally
mostly sunny conditions were in place west of the chicago area.

Modest height rises reflect large scale subsidence, evident at the
surface in weak high pressure ridge moving across the mississippi
river with 1-2 mb rises. Subsidence, combined with diurnal warming
of the boundary layer, should continue to raise cloud bases and
scatter out cloud cover across the northeast CWA into early
afternoon. Have held forecast maxes about the same, though slowed
the warmup over mostly cloudy locations in hourly temp forecast.

Increasing clouds and developing showers expected this evening, as
a pair of mid-level short waves approach the area. Initial warm
advection precip with the initial wave has had a difficult time
holding together across ia per regional radar mosaic. While a few
showers from mid-level deck could spread in to the western parts
of the fa around 00z, high-res guidance indicates decent agreement
in the focus for heavier showers thunderstorms developing out of
southeast ia and spreading across areas especially south of i-80
later in the evening.

Ratzer

Short term
248 am cdt
through Saturday night...

as an upper low and associated sfc system lift out to the northeast,
short wave ridging aloft and a weak ridge of high pressure at the
surface will build across the region. This will set up a mostly
cloudy with seasonable conditions with highs in the low 80s and
dewpoints in the low 60s. West winds should be strong enough to
keep any lake cooling at bay, so the low 80s temperatures should
reach up to the lakefront. The quiet weather will be relatively
brief as a pair of northern stream short waves dropping out of the
northern plains will cross the region late this afternoon and
tonight. The lead wave should take a more northerly track, across
wisconsin late this afternoon and this evening. The strongest
forcing with this wave should remain well to the north, and the main
impact from this wave should be some increasing cloud cover this
afternoon for the northern portions of the cwa. The trailing wave
is expected to take a more southerly track, moving across northern
il late tonight and pushing into the eastern great lakes by tomorrow
afternoon. This system should bring some showers and thunderstorms
to the area, possibly reaching the rockford area during the early
evening hours and the chicago metro area overnight. Some lingering
showers should end across nwrn indiana in the early morning hours.

Surface high pressure will build across the region again on
Saturday, bringing mostly sunny skies and light winds. Temps should
once again, reach the lower 80s, but the weak pressure gradient and
wind field should allow a lake breeze to develop by early afternoon,
turning winds onshore. Lakefront locations, including downtown
chicago should see highs only in the mid 70s. Quiet conditions
should continue Saturday night with mostly clear skies, light winds
and lows in the upper 50s to lower 60s for much of the area. The
urbanized areas of the chicago metro area should see temps only drop
into the middle to upper 60s.

Long term
248 am cdt
Sunday through Thursday...

for Sunday, the sfc high will gradually build to the east, centered
over the ohio valley Sunday and then moving off the mid atlantic
coast on Monday. A system moving through central canada will drag a
cold front across the upper mississippi valley on Sunday with weak
toughing setting up through the central plains. This will lead to
winds turning more southerly and a return flow of low and mid level
moisture. Even with the center of the high moving off the mid
atlantic coast, general ridging will persist over the sern conus.

This will limit the SRN progression of the cold front and low
pressure developing over the central plains, at the western extent
of the front will further limit the progression of the front, with
much of the guidance suggesting that the front should remain north
of the cwa. Sunday is shaping up to be warm and mostly sunny with
highs in the middle 80s. Into Monday, further warm advection is
expected with a persistent fetch of warm, moist air from the wrn
glfmex. Aloft, zonal flow will set up with an upper low over hudson
bay and ridging over the sern conus. This pattern will introduce
increasing uncertainty to the pcpn and cloud cover forecast for
early next week. Temperatures will likely continue the warming
trend, with highs on Monday in the middle to upper 80s, with the
increased moisture and heating bringing increased instability
through the day. Under zonal flow aloft, timing of individual waves
will be increasingly uncertain, so timing of possible showers or
thunderstorms will be a low confidence forecast. However, the
general trend looks to be for increasing pcpn chances through the
afternoon and into Monday night. The longer range models are
indicating that the pattern should become more progressive by
Tuesday, with broad longwave upper troughing moving into the region
forcing the frontal system across the region, bringing a more
organized area of showers and thunderstorms to the area on Tuesday
and Tuesday night. For the remainder of the period, conditions
should trend a bit cooler, as persistent nwly flow aloft sets up
across the region, temperatures should only be in the mid to upper
70s... And even cooler near the lake as northerly surface winds
develop.

Aviation
For the 12z tafs...

concerns with the chicago area tafs through Saturday morning are:
- possible period of MVFR ceilings between 13z and 16z
- chance for shra, less chance of tsra this evening into
overnight
- winds turning northeast of 10 kt or less at some point tonight
or Saturday morning, with some variability possible
scattered to broken 2500-3500 ft ceilings are rotating slightly
south of east over the area early this morning around a departing
low across the northern great lakes. These clouds should become
more cumulus by late morning, whenVFR ceilings are expected.

West to west-northwest winds will continue today, with some gusts
to around 20 kt likely by 14z or 15z. A couple mid-level
disturbances will move over the region during tonight. This will
likely bring scattered showers and possibly a few storms, though
the most favored area may remain west and south of the TAF sites.

The envelope of uncertainty certainly includes the airports
though, and felt it prudent to note a prob30 at the airports.

By daybreak Saturday light winds will either have or be trying to
turn north-northeast at chicago area airports, but confidence on
when the winds do finally shift to north-northeast is low.

Confidence is high though that the speed will be under 9 kt
after 02z tonight and through Saturday morning.

Mtf

Marine
151 am cdt
it will be a gusty Friday over the lake with an anomalously deep
low for summer over far eastern lake superior early this morning
slowly moving northeast. The strongest west-northwest winds to 30
kt will be primarily over both the open waters and the eastern
shores of the lake. For the illinois and indiana nearshore areas,
breezy west-northwest winds will prevail through midday before
gradually easing. Near small craft advisory conditions will be
seen this morning along the illinois shore while likely reaching
it along much of the indiana shore. Waves will be around 4 ft
along the porter county indiana shore, with lower wave heights
west along the illinois shore as wind direction will be offshore.

A weak high pressure ridge will move over the lake this weekend.

For Saturday in the illinois and indiana nearshores, winds will
turn onshore by late morning or so, mainly through a lake breeze.

For Sunday, a lake breeze cannot be ruled out, though direction
is likely to remain south around 10 kt.

After south-southwest winds early next week, a turn to north is
presently forecast during midweek. It is possible when this
occurs, that there is a period of small craft advisory along the
southern shores.

Mtf

Lot watches warnings advisories
Il... None.

In... None.

Lm... None.

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 mi129 min WNW 18 71°F
OKSI2 17 mi129 min NNW 1.9 73°F
45177 17 mi129 min 74°F
CHII2 - Chicago, IL 20 mi49 min W 12 G 14 71°F 62°F
JAKI2 21 mi129 min W 4.1 73°F
45174 23 mi39 min W 12 G 16 69°F 72°F2 ft62°F
CMTI2 - 9087044 - Calumet, IL 24 mi51 min WSW 2.9 G 8.9 74°F 1011.2 hPa64°F
WHRI2 - Waukegan Harbor, IL 33 mi49 min WNW 8.9 G 21 69°F
BHRI3 - Burns Harbor, IN 45 mi89 min W 12 G 14 70°F 1011.9 hPa
KNSW3 - Kenosha, WI 49 mi69 min NW 11 G 17 69°F 1010.5 hPa (+1.7)

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 mi78 minWNW 12 G 1910.00 miMostly Cloudy72°F61°F68%1011 hPa
Chicago, Chicago Midway Airport, IL12 mi76 minWNW 910.00 miMostly Cloudy73°F62°F69%1010.6 hPa
Chicago / Wheeling, Pal-Waukee Airport, IL15 mi77 minWNW 1110.00 miOvercast70°F62°F76%1011.5 hPa
Chicago / West Chicago, Dupage Airport, IL17 mi77 minNW 10 G 1710.00 miOvercast70°F63°F79%1011.5 hPa
Lewis University Airport, IL21 mi74 minNW 910.00 miOvercast71°F61°F72%1012.2 hPa

Wind History from ORD (wind in knots)
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W12W11W8W10W11W10W10W6W6W9W12NW11NW12
G19
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1 day agoSE56E7E11E14S16
G23
S10SE7SE6SE8S10S12
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S11S12--------SW11S10
G17
SW9S10S11SW8
2 days agoNE7NE7NE8NE12NE15NE11NE10NE9NE10E8NE4NE5NE5NE4NE5NE4NE5NE4N4NE5E8E8E7SE5

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
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GOES Local Image of Midwest    EDIT
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Wind Forecast for Chicago, IL (12,3,4,5)
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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.