Saturday, March25, 2017 L-36.com


Marine Weather and Tides
Woodstock, IL

Version 3.4
What's New / NOTES
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.
3/12/2015 - Added section for Gulf current for users in the GMZ marine zones.
This was requested by a user. If you have requests, please let me know.

Sunrise 6:44AMSunset 7:14PM Saturday March 25, 2017 6:31 PM CDT (23:31 UTC) Moonrise 5:33AMMoonset 4:37PM 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- 311 Pm Cdt Sat Mar 25 2017
.dense fog advisory in effect until 10 am cdt Sunday...
.small craft advisory in effect through Sunday afternoon...
Tonight..Northeast winds 15 to 25 kt becoming east overnight. Areas of dense fog. Periods of showers and slight chance of Thunderstorms. Waves 5 to 8 ft occasionally to 10 ft subsiding to 4 to 6 ft occasionally to 8 ft late.
Sunday..Southeast winds 15 to 20 kt becoming south 10 to 20 kt in the afternoon. Areas of fog in the morning, then patchy fog in the afternoon. Showers likely and slight chance of Thunderstorms in the morning, then rain likely in the afternoon. Waves 3 to 6 ft occasionally to 8 ft subsiding to 2 to 4 ft in the afternoon.
Sunday night..Southwest winds 10 to 20 kt becoming west 10 to 15 kt after midnight. Patchy fog in the evening. Slight chance of rain in the evening. Waves 1 to 3 ft subsiding to around 1 ft after midnight.
Monday..North winds around 5 kt becoming northeast 10 to 15 kt in the afternoon. Chance of rain. Waves around 1 ft.
LMZ740 Expires:201703260330;;071459 FZUS53 KLOT 252011 NSHLOT NEARSHORE MARINE FORECAST NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 311 PM CDT SAT MAR 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>742-260330-

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 252001
afdlot
area forecast discussion
national weather service chicago/romeoville, il
301 pm cdt Sat mar 25 2017

Short term
300 pm cdt
through tonight...

expansive, stacked upper low center is sprawled across missouri
this mid-afternoon with a plume of 1-1.25 inch precipitable waters
nosed ahead of this feature into our area. This moisture has
helped to fill back in the thicker clouds. There are some areas
of thinning and agitated cumuliform clouds across west central
illinois, but in and immediately upstream of the cwa, any showers
are rooted aloft. The earlier slight concern of some storms moving
over the boundary and possibly becoming a bit feisty is even less
of a concern in our CWA given the thickened cloud cover impeding
any low-level instability.

In response to a small scale disturbance lifting northward near
st. Louis on satellite water vapor imagery, would expect showers
to continue to show an uptick across central illinois and moving
into the CWA during the rest of the afternoon into early evening.

While the northward-oriented upper jet ahead of the low does
weaken some tonight, it still should support lift atop continued
moisture transport for showers to develop. Convective-allowing
model solutions support this, with clusters of showers and some
hints of isolated thunder moving over at times throughout the
night. Most unstable CAPE values of a few hundred j/kg look
probable, especially in the south late this afternoon into
tonight. Sometimes with closed upper lows at night too, it seems
like there can be a holding steady of isolated thunder when
otherwise it would dissipate.

The surface boundary extends from near lacon to kankakee and to
near valparaiso. This should not move much further north this
evening. Temperatures may inch up a few degrees north of the
boundary, while will slowly fall south of the boundary, so all in
all not much of a change for tonight. The northeast flow north of
the boundary may drag some thicker fog into northeast illinois,
including chicago. Confidence on this is low though, and if the
boundary does inch a little further northward, it may increase the
potential for dense fog. Also apart from marine fog, there could
be some fog development areawide near and north of the boundary,
but with stratus already present that will likely be dominant over
dense fog.

Mtf

Long term
252 pm cdt
Sunday through Saturday...

main forecast concerns for the longer term forecast period will
continue to be timing of a series of systems bringing periodic
chances for pcpn to the region as well as temperature trends.

The latest guidance continues to indicate a series of southern
stream systems lifting out of the swrn CONUS and tracking across the
region. The models remain relatively consistent on this trend,
though some differences in the track remain, with the gfs
trending a little south of the nam/ecmwf, the general idea of the
associated sfc low lifting tracking from the middle mississippi
valley and across NRN il/srn wi tomorrow remains consistent with
previous runs. As the low tracks slowly to the northeast, an
associated warm that is pushing nwd through il/in today will be
north of the cwa, the warmer air overspreading the region today
will remain in place through the day on Sunday, allowing
temperatures to rebound back into the lower 60s. Instability will
be on the increase in advance of the system and at least some
partial clearing along with forcing from the sfc low and mid-level
shortwave will keep some chance for thunderstorms over portions
of the area through the day tomorrow. Generally expect the greater
chances for TS to be near the greater forcing of the sfc low/mid-
level shortwave. For timing, expect that the most favorable window
of opportunity for TS will be through late morning or early
afternoon, with the system lifting to the northeast durg the
afternoon hours. There should be a grief lull in pcpn Sunday
night as weak shortwave ridging crosses the region in advance of
the next system. The models are in a little better agreement on
the track and timing of the next system. With strong high pressure
building out of central canada and into the NRN plains/upper
mississippi valley, the track of this system should be more to the
south, through SRN il/in and the ohio valley. The most widespread
pcpn with this system Monday into Monday night should be over
portions of the area south of the i-80 corridor, but there should
still be some light rain over the NRN portions of the CWA as well.

Temperatures on Monday should still trend higher than normal,
with much of the area seeing temps in the upper 50s to lower 60s,
but winds on Monday should trend toward nely through the day,
which would keep the far NRN portions of the CWA and the lakefront
a bit cooler, as flow turns off of the cool lake michigan waters.

Lakefront locations should should see temperatures only in the
upper 40s to lower 50s. High pressure will then spread east across
the upper mississippi valley and the great lakes region through
midweek, keeping generally northerly winds in place through much
of next week. The temperature trend through next week should be
for warmer conditions inland and cooler near the lake. As high
dominates the region through midweek, conditions should generally
be dry. The next significant chance for pcpn will not come until
late next week as another SRN stream system lifts out of the swrn
conus.

Aviation
For the 18z tafs...

the concerns with the chicago area tafs are:
- northeast winds through tonight with sporadic gusts this
afternoon.

- isolated shra early this afternoon gradually upticking in
coverage by late day into the evening, with potential for
isolated tsra.

- 400-700 ft CIGS probable to continue through tonight, with
potential overnight and Sunday morning to dip just below this,
but confidence in that occurring and for how long is low.

- potential for more showers on Sunday with winds veering to
south, though low-medium confidence in when that shift occurs.

Low pressure across missouri this afternoon will move to far
western illinois by daybreak Sunday and to near/just north of
chicago by mid-afternoon Sunday. The warm front with this remains
south of the TAF sites this afternoon, with northeast flow locking
in lower clouds. Webcams and observations indicate 400-600 ft
cigs from ord and mdw back to the lake, so do not see these
changing much. Would think the better potential to dip a tad lower
is tonight, especially in-between any showers overnight. Cannot
rule out 200 ft given the synoptic scenario and bases already at
400 ft, but feel it is a low chance right now.

As for showers, isolated to scattered activity is expected to
develop this afternoon and pass over northeast illinois, though
the highest coverage is not expected until late day into the
evening. Some of this may contain thunder, though the instability
is quite limited, so did not have confidence enough to include in
the tafs. Confidence in shower coverage overnight into Sunday is
lower, though at least isolated should be present.

There is uncertainty on how far north the warm front will reach
tonight, which is key because south of this boundary conditions
are likely to beVFR. The front reaching gyy is a real
possibility, even by late afternoon. As for mdw and ord, it may
get pretty close, but feel that winds should continue out of the
northeast/east and maintain the low clouds and occasionally MVFR
to ifr visibility.

Mtf

Marine
300 pm cdt
winds are trending to easterly today with speeds up to 30 kt over
much of the lake as low pressure over missouri slowly moves
across the mid mississippi valley tonight. Hazardous conditions
for small craft will persist through tonight, mainly for the
illinois nearshore waters in the persistent east flow. As the low
then tracks north through illinois on Sunday and central lake
michigan Sunday night, anticipate that speeds will diminish to
the 10 to 20 kt range. High pressure is expected to build across
the upper great lakes region Tuesday through Thursday setting up
generally north to northeast winds over the lake with more
moderate wind speeds.

Lot watches/warnings/advisories
Il... None.

In... None.

Lm... Small craft advisory... Il nearshore waters until 5 pm Sunday.

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WHRI2 - Waukegan Harbor, IL 34 mi52 min NNE 16 G 19
KNSW3 - Kenosha, WI 39 mi32 min NNE 16 G 17 38°F 1017.3 hPa (-0.6)
FSTI2 49 mi92 min NNW 20
CHII2 - Chicago, IL 54 mi42 min NNW 13 G 14

Wind History for Calumet Harbor, IL
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Last
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NW19
G26
NW15
G20
N10
G17
NW11
G14
NW12
G23
N14
NW11
G16
NW12
G18
NW11
G17
NW10
G16
NW11
G17
N10
G15
N11
G17
N9
G13
N9
G13
NW9
G13
NW12
G15
NW10
G13
N7
NW7
NW7
NW11
G16
NW14
G18
1 day
ago
SE12
G17
SE9
G15
SE9
G13
S9
G14
S7
G11
S5
G8
S4
G7
SE5
S4
S4
G7
S7
G10
S10
G13
S15
G20
S12
G19
S12
G18
S8
G18
S18
G24
S18
G25
SW18
G30
SW10
G23
SW14
G25
SW12
G23
S14
G21
NW25
G32
2 days
ago
NE7
NE7
NE7
G10
NE6
E7
G11
E8
SE8
G11
SE4
G9
SE8
G12
SE12
G16
SE6
SE9
G13
SE7
G14
SE10
G15
SE11
G15
SE7
G10
S10
G16
SE11
G15
SE11
G16
SE11
G17
SE14
G17
S13
G21
SE13
G16
SE11
G18

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Burlington Municipal Airport, WI27 mi37 minENE 83.00 miUnknown Precip42°F41°F100%1016.9 hPa

Wind History from BUU (wind in knots)
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Last 24hrNE10NE11NE8
G14
N5NE10NE11NE8NE9
G15
NE8NE7NE9NE9
G14
NE12
G15
NE12
G15
NE11
G21
E11
G18
NE13
G23
E12
G18
E15
G19
E10
G15
NE10
G18
E11
G16
NE8NE9
G15
1 day agoS11
G14
CalmSE6SE9S6S11
G14
S11
G17
S12
G17
S14
G17
SW10
G14
S13
G16
S11SW6E3S4SW10SW13
G18
SW11
G16
SW19
G23
W12
G20
CalmNE11
G14
NE14NE10
2 days agoE9SE6SE6CalmCalmCalmCalmCalmCalmCalmS3SE5SE6SE6SE6SE9
G17
SE11
G16
SE10
G18
SE11
G17
S9
G17
S11
G15
S11SE8SE9

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 (19,4,5,8)
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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.