Sunday, August20, 2017 L-36.com


Marine Weather and Tides
Woodstock, 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 6:06AMSunset 7:47PM Sunday August 20, 2017 10:14 AM CDT (15:14 UTC) Moonrise 4:42AMMoonset 7:12PM Illumination 3% Phase: Waning Crescent; Moon at 28 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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LMZ740 Winthrop Harbor To Wilmette Harbor- Wilmette Harbor To Northerly Island- Northerly Island To Calumet Harbor- 953 Am Cdt Sun Aug 20 2017
Rest of today..Southeast winds 10 to 15 kt. Mostly Sunny becoming partly Sunny. Isolated showers late this afternoon. Waves 1 to 2 ft.
Tonight..South winds 10 to 15 kt. Slight chance of showers after midnight. Waves 1 to 2 ft.
Monday..South winds 10 to 15 kt. Chance of showers and slight chance of Thunderstorms. Waves 1 to 2 ft.
Monday night..Southwest winds 10 to 15 kt increasing to 10 to 20 kt. Showers likely and a chance of Thunderstorms. Waves 1 to 2 ft.
LMZ740 Expires:201708202115;;677231 FZUS53 KLOT 201453 AAA NSHLOT NEARSHORE MARINE FORECAST...UPDATED National Weather Service Chicago/Romeoville IL 953 AM CDT Sun Aug 20 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>742-202115-

7 Day Forecast for Marine Location Near Woodstock, IL
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location: 42.32, -88.45     debug


Area Discussion for - Chicago, IL
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Fxus63 klot 201140
afdlot
area forecast discussion
national weather service chicago romeoville, il
640 am cdt Sun aug 20 2017

Short term
414 am cdt
through tonight...

quiet weather is on tap for the short term forecast period, with the
primary concern being timing of lake breeze development and the
impact on temperatures along the lakefront.

The center of a large area of sfc high pressure is slowly sliding to
the east though weak ridging will still extend west across the
region. Also, low pressure moving across central canada is dragging
a cold front across the upper mississippi while another low is
developing over the central plains. The high will limit the
eastward progression of the frontal system, with the northern
portion of the front pushing east across the upper great lakes, and
then extending southwest across northern wisconsin and then into the
upper missouri valley. More broad scale warm advection will set up
across the midwest, with 925mb temps of 24-25c, supporting temps
approaching 90 f. A couple factors may limit warming a little
today, cirrus blow-off from the MCS over iowa and NRN mo, and a mid
level shortwave crossing NRN cntrl il this afternoon may generate
some CU or a few showers. However, have maintained a dry forecast
since the warm advection aloft should keep the area capped and there
is no sfc forcing to help break the cap. So, have gone with temps
in the upper 80s over much of the cwa, through an isolated 90 f is
not out of the question if the cirrus is thin enough. The exception
will be the illinois lakefront. A lake breeze should develop, but
the orientation of the boundary should be oriented more northwest to
southeast, reflective of the southerly synoptic flow and with wind
speeds arnd 10 mph this afternoon, the boundary should not penetrate
inland very far. Locations north of downtown chicago to the
wisconsin border should see highs only in the middle 70s. The cold
front should see some sewd progression overnight tonight as the sfc
high center moves to the mid atlantic coast. Cloud cover and pcpn
chances will be in the increase overnight as the front progresses to
the southeast.

Long term
414 am cdt
Monday through Saturday...

multiple concerns are shaping up for the longer term forecast
period, most of which will be confined to a very unsettled period
from Monday through Tuesday afternoon. Upper level flow is trending
to more zonal aloft with fast westerly mid and upper level flow
setting up across the region. As this happens, the sfc cold front
will begin to lay out into a more west-east orientation. A series
of shortwaves rippling through the fast wly flow aloft will help
keep tsra shra chances going through the period. While the daytime
hours on Monday look to be somewhat unsettled with some chances for
shra tsra, most guidance suggests that activity should be scattered,
and periods of broken sky cover may be limited. Sky cover will
likely not be very conducive to direct observation of the much
anticipated eclipse. With little progression to the larger scale
pattern, temperatures on Monday should be very similar to Sunday,
with highs in the upper 80s likely for much of the area. Increasing
cloud cover and slightly higher pcpn chances could keep ncntrl il a
little cooler. Some isolated 90 f reading may be possible again in
areas that experience some breaks in the cloud cover in the
afternoon.

Forecast concerns will shift to more significant weather Monday
night into Tuesday morning. There should be significant moisture
pooling along the front, with pwats reaching or slightly exceeding 2
inches. With flow aloft still zonal into Monday night, the swd
progression of the front should be relatively slow. The combination
of high levels of deep layer moisture, slow progression of the front
and upper level flow generally parallel to the front all point to
the potential for widespread heavy rain across the area. Latest
guidance suggest that the highest rainfall amounts should be over
portions of the CWA north of the i-80 corridor where areal average
qpf in excess of 1 inch is likely and locally higher amounts
possible. There may be flooding potential, especially for
ncntrl nwrn il where the heaviest rainfall is expected. There will
also be a severe thunderstorm threat Monday night. The latest
guidance remains consistent on indicating that the environment will
be especially moist and unstable, with steep mid level lapse rates,
cape values arnd 2000 j kg and mid-level flow of 30-40 kt. So,
thunderstorms will not only have the potential to produce very heavy
rainfall, strong, damaging winds may be possible as well. Given
these factors, SPC has highlighted NRN il in a slight risk severe wx
area and wpc has highlighted nwrn il with a slight risk for
excessive rainfall. The remainder of the CWA are highlighted with
marginal risk for severe and excessive rainfall.

By Tuesday morning, high pressure building out of canada and
spreading across the upper mississippi valley along with increasing
amplitude to the upper level pattern will help accelerate the front,
pushing it more quickly south and east of the CWA by mid-day
Tuesday, bringing an end to both pcpn and the warm humid conditions.

Much quieter weather is expected for Tuesday afternoon through the
end of the period as the upper level pattern transitions to high
amplitude, slow progression with a deep upper low setting up over
sern canada and upper ridging building over the rockies. Northwest
flow aloft and sfc high pressure will cover the area through Friday,
with the longer range guidance suggesting that the pattern will
break down and become more progressive by Friday or Saturday. Until
then, dry weather and below normal temperatures will prevail, with
highs in the upper 60s to low 70s along the lakefront and middle to
upper 70s inland. The next chance for any pcpn will likely not be
until next weekend.

Aviation
For the 12z tafs...

for the chicago TAF sites today and tonight, concerns are south-
southwest winds approaching 10 kt during the afternoon, a chance
for isolated showers late this afternoon and evening, and then a
chance of storms late tonight into Monday.

Light south-southeast winds will become south-southwest by mid to
late morning. Speeds will increase with 9-10 kt expected at ord
and mdw by 19z-20z. A few gusts in the mid teens are possible
mid- late afternoon. Winds will drop in speed near sunset and back
slightly to due south or a little east of south. Confidence in
winds for this TAF is medium-high.

The convective complex across central iowa early this morning will
continue to move east-southeast with a gradual weakening likely
to continue. The upper level disturbance supporting the activity
will continue to move east and will drift over the area this
afternoon early evening. Isolated showers are possible with this,
and cannot 100% rule out a storm or two. This window of
opportunity for showers will be near rfd from 18z-21z and ord mdw
from 21z-02z. Confidence on the showers occurring is low.

For overnight into early Monday morning, the next upper
disturbance will likely trigger storms across iowa and possibly
further north northeast. This convection should slowly progress
southeast and may impact rfd as early as overnight and its
possible the chicago TAF sites see this during Monday morning.

However, confidence on evolution of storms tonight into Monday
morning is very low. It is possible the most robust Monday
morning convective activity passes to the southwest of local area
airports.

Mtf

Marine
159 am cdt
as high pressure moves east today, winds will turn southerly
across the lake. The exception will be in the illinois nearshore,
where southeast to possibly due east onshore winds will be seen
in the afternoon. The highest speeds over the lake today will be
across the northern part, with the far north seeing gusts of
20-25 kt late today into this evening.

Low pressure will take shape across northern lake michigan by
daybreak Tuesday, and accelerate and deepen as it tracks eastward
during the day Tuesday. Given the pressure gradient in its wake,
northwest winds will increase with 20-25 kt gusts likely. The
northwest direction on Tuesday would favor small craft advisory
winds and waves across the indiana nearshore and possibly the
illinois one due to winds.

Mtf

Lot watches warnings advisories
Il... None.

In... None.

Lm... None.

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WHRI2 - Waukegan Harbor, IL 34 mi35 min SSE 7 G 8 75°F
KNSW3 - Kenosha, WI 39 mi75 min S 7 G 9.9 71°F 1017.3 hPa (+0.7)
45174 44 mi25 min SSE 7.8 G 9.7 73°F 73°F1 ft67°F
FSTI2 49 mi135 min S 8 75°F
CHII2 - Chicago, IL 54 mi25 min SSE 8 G 9.9 75°F 64°F

Wind History for Calumet Harbor, IL
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Burlington Municipal Airport, WI27 mi40 minN 010.00 miFair72°F67°F85%1017.3 hPa

Wind History from BUU (wind in knots)
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Last 24hrCalmW5CalmNW4SW3CalmCalmNW4CalmSW3CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalm
1 day agoNW11
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NW8W6W8W9W8W6W6W7W5NW4CalmSW3SW3CalmNW3CalmCalmCalmW3CalmCalmCalmNW3
2 days agoSW9SW10
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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
wmap_A
IR Satellite Image from GEOS
east_satellite

GOES Local Image of Midwest    EDIT
Geos

Wind Forecast for Chicago, IL (11,2,3,4)
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Ground Weather Radar Station Milwaukee, WI
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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.