Friday, December15, 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 7:11AMSunset 4:23PM Friday December 15, 2017 9:21 PM CST (03:21 UTC) Moonrise 5:32AMMoonset 4:05PM Illumination 5% Phase: Waning Crescent; Moon at 27 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- 905 Pm Cst Fri Dec 15 2017
Rest of tonight..Southwest winds 10 to 20 kt. Scattered flurries. Waves 1 to 3 ft.
Saturday..Southwest winds 10 to 15 kt becoming south in the afternoon. Mostly Sunny. Waves 1 ft or less.
Saturday night..Southeast winds 10 to 15 kt. Partly cloudy. Waves 1 ft or less building to 1 to 3 ft after midnight.
Sunday..South winds 10 to 15 kt. Chance of rain through the day. Waves 1 to 3 ft.
LMZ741 Expires:201712161000;;957626 FZUS53 KLOT 160305 NSHLOT NEARSHORE MARINE FORECAST National Weather Service Chicago/Romeoville IL 905 PM CST Fri Dec 15 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>743-161000-

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 160232
afdlot
area forecast discussion
national weather service chicago romeoville, il
832 pm cst Fri dec 15 2017

Update
817 pm cst
latest radar imagery depicting blossoming snow across far
northeast illinois, but primarily over the lake and areas
eastward. Locations in far northeast illinois and even portions
of northwest indiana may see the western edge of this development
for the next hour or so before this focuses more to the east.

However, am monitoring upstream development over southeast mn to
western wi where additional snow development is occurring. This is
in response to isentropic ascent moving east southeast across the
region, with short term guidance fairly consistent with this
forcing reaching far northeast illinois in the 4-6z time frame.

This would allow another period of either flurries or light snow
across the area during that time, mainly for locations along and
northeast of a roscoe to skokie il line. Given upstream trends,
it's quite possible for more light snow to be observed, and have
included low chance pops to the forecast. If this were to occur,
it could be possible for isolated areas to observe a light
dusting. Expect any snow chances to end just after the midnight
time frame tonight.

Did increase low temps tonight to around 30, as waa, cloud cover,
and steady winds should keep temps steadier. Locations that could
still drop more into the upper 20s would be the southwest cwa
where low stratus is departing. However upstream mid clouds should
soon fill any clearing skies.

Rodriguez

Short term
1202 pm cst
through Saturday...

there are several short lived periods for snow chances
today, first with a weak disturbance moving through early this
afternoon. Flurries have been reported fora few hours or less at
any one location upstream in northeast iowa. This evening a bit
stronger NW flow disturbance will interact with a a northward
moving warm frontal feature. Isentropic lift over this front will
lead to some snow or more likely flurries, mainly northeast of a
rfd-mdw-vpz line during the 0z-5z time frame, or mid to late
evening. This would also be brief, only a few hours or so. After
this, the final push with this clipper will come overnight, but by
this point the forcing will have shifted north of the wisconsin
border. Some guidance tries to break out snow farther south, but
at this point the main frontal boundary will have shifted into
wisconsin and the air temperatures in the cloud layer will be less
than optimal for snow production.

The story for Saturday will be the milder air mass that will advect
into the area from the southwest as we at least temporarily break
the cycle of northwest flow aloft. There is a closed positively
tilted trough well south into the baja peninsula. Surface high
pressure to our south will also shift into the southeast on
Saturday, which will promote deep layer southwesterly flow. With the
front to the north, we will be in the dry and largely cloud free
warm sector. The surface front may not actually get north of the
wisconsin border, so cooler southeast winds will keep readings
closer to 40 in these areas, where across central illinois highs
will approach 50. The gulf moisture is still far enough away to
make for a pleasant and not too breezy day than typically occurs
when we get into southerly winds in the winter time.

Kmd

Long term
215 pm cst
Saturday night through Friday...

main concern for the long term forecast period remains precipitation
type Sunday morning.

The upper level pattern is trending toward a higher amplitude,
slowly progressive longwave pattern. By Saturday night, broad upper
ridging will build over the ERN 2 3 CONUS with deep troughing over
the rockies, with upper ridging building onto the west coast. This
will shift the pattern from cooler nwly flow aloft to more moderate
swly flow. Southern stream shortwave energy will be the primary
weather driving systems for the long term period. In general,
temperatures for the long term forecast period will trend toward
above normal for much of next week as the area remains under upper
ridging, with highs in the upper 30s to upper 40s with more
seasonable lows generally in the mid 20s to mid 30s until late next
week.

The longer range models continue to come into a little better
agreement on the timing of the closed upper closed low located over
the southern end of the sea of cortez Saturday morning lifting
northeast through the lower missouri valley Sunday morning. The
longer term model consensus is a little better in both timing and
strength of the system as it opens up into an open wave, with timing
that is trending slightly slower than yesterday's guidance. By
Sunday morning, expect that there will still be sub-freezing surface
temperatures over NRN il in as far south as the southern tier
counties from livingston to benton counties. The mid-level pattern
will be transitioning to strong warm advection, with the warmer air
overrunning the colder surface air. For example, the 925mb
temperatures indicated by the ECMWF will be above 0 c by Saturday
evening and climbing through the night as sfc temperatures drop below
32 f, with persistent easterly flow locked in over NRN il in srn
lake michigan by strong high pressure parked sern canada and the ern
great lakes. The warm front, induced by the SRN stream shortwave is
expected to still be just south of the CWA Sunday morning as
associated pcpn begins to spread in from the southwest. GFS is
advertising a relatively similar solution, but is trending a little
faster in lifting the warm front to the north, likely due to a
slightly faster progression of the associated shortwave. At this
point, would tend to favor the slower solution which is supported by
the nam, gem and SREF guidance. So, while the faster timing
indicated by the GFS may only be on the order of 3 to 6 hours, this
would have a significant impact on precipitation type. With the sfc
colder air more likely to be scoured out by the warm advection
aloft. Thermal profiles should be a shallow sub-freezing layer at
the surface with the warmer air aloft. The shallow cold air would
be more supportive of freezing rain, and have carried that scenario
for early Sunday morning. While there is still a chance that the
warm air aloft could mix down to the surface, setting up a rain
scenario, there is also a chance that the initial pcpn could also
generate some evaporative cooling near the surface, delaying sfc
temperatures from rising above freezing. So, to make a short story
long, will carry a short period of freezing rain. Possibly reaching
as far north as the i-88 corridor. However, the window of
opportunity for freezing rain will be relatively brief, quickly
changing over to rain as the warmer air spread north. Given that
pcpn amounts are likely to be light and the period of freezing rain
brief, any glazing of surfaces should be brief.

Otherwise, have made little change to the going forecast for the
remainder of the period. The relatively mild should continue
through much of next week. The longer term models are still
advertising another pattern shift by late next week with an upper
trough carving out over the upper mississippi valley and great lakes
regions as a series of northern stream shortwaves break down the
upper ridging and bringing a return to more seasonable
temperatures.

Aviation
For the 00z tafs...

522 pm... A weak upper wave will move across southern wi and far
northern il this evening. A band of light snow is expected to
develop with this wave... But remain just north of the terminals as
it moves east northeast. Scattered flurries will be possible this
evening... Then dry conditions are expected for the rest of the
period. High MVFR CIGS extend from rfd to ord and should be
scattering to a 3-5kft cig early this evening... Which will then
lift to a mid deck overnight... Which will scatter out Saturday
morning leaving few sct high mid clouds for the rest of the
period. West southwest winds 10-15kts this evening will turn more
southerly overnight with speeds diminishing under 10kts. Wind
directions will turn more south southeast Saturday afternoon. Cms

Marine
215 pm cst
a relatively quiet period of weather is setting up for lake
michigan for the next several days as a series of weak clipper-
type lows track across the upper great lakes region. The next
chance for impactful weather and gale force winds will not be
until early next week when the passage of a cold front. There is
still some uncertainty as to the timing of the cold front passage,
but the latest model guidance continues to suggest Monday night
or early Tuesday for the frontal passage, with west to northwest
gales for Tuesday into Wednesday. The active pattern looks to
persist late next week with another system bringing another round
of strong winds to the lake.

Lot watches warnings advisories
Il... None.

In... None.

Lm... Small craft advisory... Gary to michigan city in until 9 pm Friday.

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
OKSI2 17 mi142 min W 4.1 37°F
FSTI2 17 mi142 min SSW 15 35°F
CNII2 18 mi22 min SSW 7 G 9.9 35°F 20°F
CHII2 - Chicago, IL 20 mi32 min SW 15 G 16 36°F 23°F
JAKI2 21 mi142 min WSW 8 36°F
CMTI2 - 9087044 - Calumet, IL 24 mi52 min SSW 7 G 9.9 34°F 1012.7 hPa22°F
WHRI2 - Waukegan Harbor, IL 33 mi42 min SSW 8 G 9.9 33°F
BHRI3 - Burns Harbor, IN 45 mi42 min SSW 12 G 16 35°F 1013.9 hPa
KNSW3 - Kenosha, WI 49 mi82 min SW 7 G 8.9 32°F 1012.2 hPa (+0.3)

Wind History for Calumet Harbor, IL
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Last
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago, Chicago-O'Hare International Airport, IL7 mi31 minSSW 810.00 miOvercast34°F21°F59%1013 hPa
Chicago, Chicago Midway Airport, IL12 mi29 minSW 1010.00 miOvercast35°F21°F59%1014.1 hPa
Chicago / Wheeling, Pal-Waukee Airport, IL15 mi30 minSSW 610.00 miOvercast35°F23°F61%1013.4 hPa
Chicago / West Chicago, Dupage Airport, IL17 mi30 minSSW 1110.00 miOvercast33°F21°F64%1013 hPa
Lewis University Airport, IL21 mi47 minSW 810.00 miOvercast35°F22°F61%1013.2 hPa

Wind History from ORD (wind in knots)
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Last 24hrSW3SW4SW5SW5SW6SW6SW10SW8W14
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W8SW7SW9SW6SW6SW8
1 day agoN19
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N14N13N10N12NW10NW10NW11N11N11N9N7NW6NW4NW5NW3SW4W4W4W3SW3W3
2 days agoW4SW5SW4S4S7S8S9S10S10S10S15S19S14
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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 (22,6,7,8)
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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.