Thursday, March23, 2017 L-36.com


Marine Weather and Tides
Winthrop Harbor, 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 6:45AMSunset 7:09PM Thursday March 23, 2017 5:30 AM CDT (10:30 UTC) Moonrise 4:13AMMoonset 2:27PM Illumination 18% Phase: Waning Crescent; Moon at 25 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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LMZ646 Wind Point Wi To Winthrop Harbor Il- 303 Am Cdt Thu Mar 23 2017
.small craft advisory in effect from 10 am cdt this morning through this evening...
Today..Southeast wind 15 to 20 knots with gusts to around 25 knots. Mostly cloudy. Waves 3 to 4 feet.
Tonight..South wind 15 to 20 knots easing to 10 to 15 knots after midnight. Gusts up to 25 knots. Chance of showers and slight chance of Thunderstorms through around midnight. Waves 3 to 4 feet.
Friday..Southwest wind 10 to 15 knots rising to 15 to 20 knots in the late morning and early afternoon, then easing to 10 to 15 knots late in the afternoon. Slight chance of rain in the afternoon. Waves 1 to 3 feet.
Friday night..South wind 10 to 15 knots becoming northeast 5 to 10 knots in the late evening and overnight. Rain likely through around midnight, then rain after midnight. Waves 1 to 2 feet.
LMZ646 Expires:201703231630;;939740 FZUS53 KMKX 230803 NSHMKX NEARSHORE MARINE FORECAST NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 303 AM CDT THU MAR 23 2017 FOR WATERS WITHIN FIVE NAUTICAL MILES OF SHORE ON LAKE MICHIGAN LMZ646-231630-

7 Day Forecast for Marine Location Near Winthrop Harbor, IL
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location: 42.47, -87.82     debug


Area Discussion for - Chicago, IL
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Fxus63 klot 230830
afdlot
area forecast discussion
national weather service chicago/romeoville, il
330 am cdt Thu mar 23 2017

Short term
330 am cdt
through Friday...

lots to talk about this morning, in the short term, precip
chances, temps, and cloud cover are the biggest concerns.

Have continued the trend of lowering pops for today as low level
dry air and weakening of approaching shortwave both look to pose
impediments against more robust precip chances. Still concerned
that there could be a shower or sprinkle, but chances of anything
measurable this afternoon and evening appear low.

Extensive cloud cover upstream is moving into the area and
expected fairly cloudy skies today. Significant low level warm
air advection doesn't arrive until tonight, so with cloud cover
today have trended highs toward the lower side of guidance.

Developing warm front will lift north this evening, which should
shift the focus of nocturnal convective/precip chances well north
of our cwa. In addition, strengthening southerly winds should
begin to draw warmer and more moist air north into the area.

Evening lows could dip into the upper 30s/low 40s, but expect a
fairly significant rise in temps through the night with temps in
the 50s by sunrise Friday morning.

Temperature forecast is tricky Friday and bust potential is quite
high. There are essentially 2 different lines of reasoning, the
first being the domestic models (nam & gfs) which suggest low
stratus will blanket the area and the NAM keeps highs in the 50s
and GFS only in the 60s. Conversely, there is the foreign model
camp (ecmwf & gem) which keeps the area largely stratus free
Friday and sends temps soaring well into the 70s, even upper 70s
for chicago in the gem. The ECMWF has very strong support from its
50 member ensemble with very minimal spread.

Using backward trajectories in the models, the low levels (<1000m)
Friday afternoon originates from the carolinas, while slight
higher up the 1000-2000m parcels Fri pm are forecast to originate
over the nc/ne gulf coast. Both of these points of origin are dry
and void of stratus now. There is some patchy stratus beginning to
form over lower tx early this morning, but evening soundings
suggest this moisture is fairly shallow and would tend to advect
more to our west and southwest Friday afternoon. Given this, have
trended our sky grids and temperature grids toward the warmer
foreign model camp and bumped highs into the 70s. Given the strong
low level winds, higher late march Sun angle, the forecast
afternoon soundings from the GFS and NAM look suspicious under
mixed and cloudy. Obviously if the more stratusy solutions pan
out then highs Friday will be much cooler.

Izzi

Long term
330 am cdt
Friday night through Wednesday...

big upper low will work its way out into the central/southern
plains Friday afternoon with showers and thunderstorms likely to
break out along the associated surface cold front. This activity,
in a weakening phase, will begin to spread northeast into our cwa
Friday night. In addition, a strong canadian high will move east
into ontario Friday night and likely push the warm front to our
north back south as a back door cold front. Again, there are model
differences with foreign models more aggressive with the southward
movement of this backdoor front and the domestic models holding it
farther north. Climo this time of year and the very cold
lake/marine air mass make me think that the ecmwf/gem models
probably have the right idea with the farther south placement.

The impacts of this frontal position on temperatures is huge. The
blended model guidance with highs in the upper 50s to mid 60s is
likely substantially too warm north of the front, especially near
the lake. After collaboration with dvn/mkx, nudged temps downward
some north of i-80, especially near the lake, however if the
ecmwf/gem frontal positions are correct, then it will be much
colder Saturday north of the front. The operational 00z run of the
ecmwf has highs in the lower 40s at ord, mid 40 at rfd, and in the
upper 30s near the lake, with a sharp temp gradient and 60s south.

There is more spread in the ECMWF ensembles for Saturday, so
confidence is lower supporting the small adjustment downward we
made in temps for now. Like Friday, temp forecast for Saturday has
a fairly high bust potential.

Behind the lake enhanced front, fog, possibly marine enhanced, is
a pretty good possibility and have introduced some fog into the
grids. The large, slow moving cyclone will become increasingly
vertically stacked/quasi-barotropic, so instability will be
decreasing with time, but some threat of thunder could linger into
Saturday, particularly if there are any breaks in the clouds
allowing for sfc heating. Otherwise, looks for showers to develop
and pinwheel around the low through the weekend. There will likely
be dry hours in between the rain bands, but overall the weekend
looks cloudy with several showery periods.

This upper low is expected to move east of the area by Sunday
night, but medium range models have another dampening southern
stream short wave moving into the confluent flow in its wake
Monday. This system could bring some showers, mainly to our
southern CWA and points south Monday. Should be a break in the
precip after that system heading into mid-week, but with winds off
the lake and probably some cloud cover sticking around not
expecting temps to get too terribly warm, even though the polar
jet will remain to our north holding back any real push of cold
air. Does look like there could be another big upper low moving
toward the area late next week.

Izzi

Aviation
For the 06z tafs...

a surface area of high pressure over the eastern great lakes will
shift eastward over the central atlantic coast by late afternoon.

As this occurs, expect the current light easterly winds to become
southeasterly 10 to 15 kt during the day. By late this evening, a
warm front, associated with low pressure developing over the
central high plains, is expected to shift northward over the area.

Prior to its passage, a period of MVFR CIGS and some scattered
showers will be possible, particularly during the evening.

However, once the front lifts north of the area, expect south-
southwesterly winds with the main precip chances and lower CIGS to
shift northward into wisconsin.

Low level wind sheer may also become an issue tonight as winds
1500-2000 ft agl increase to 50-55 kt. In spite of the fact that
surface winds could be up around 10 to 15 kt (with some slightly
higher gusts) late tonight with the passage of the warm front, the
actual magnitude of the winds off the surface are high enough to
justify a mention of such in the latest tafs.

Kjb

Marine
229 am cdt
surface high pressure over the eastern great lakes will shift
eastward to the central atlantic coast later today. As this occurs
winds over the lake will become south and be on the increase
today. Winds up to 30 kt are likely at times this afternoon and
tonight, especially over the northern half of the lake.

A cold front will then shift down the lake Friday before likely
becoming stalled near the southern end of the lake Friday night
into Saturday as surface high pressure builds eastward across
southern canada. An area of low pressure will then gradually shift
east-northeastward from the plains to southern lake michigan by
Sunday. Northeasterly winds up to 30 kt will set up over northern
lake michigan by Friday night following the cold frontal passage.

With time the winds will gradually veer easterly later Saturday
into Sunday. Over far southern lake michigan, however, expect
lighter and more variable wind directions, depending on where the
surface boundary stalls and if the surface low tracks overhead on
Sunday.

With the possibility of the frontal boundary stalling out over
southern lake michigan Friday night into Saturday, dense fog may
develop in this region. This fog may persist through late Sunday
as the surface low shifts over the southern end of the lake.

Kjb

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
KNSW3 - Kenosha, WI 8 mi31 min S 18 G 21 35°F 1029.8 hPa (-1.4)
WHRI2 - Waukegan Harbor, IL 8 mi51 min SSE 15 G 19 34°F
FSTI2 35 mi91 min SE 31 33°F
OKSI2 40 mi91 min ESE 6 34°F
MLWW3 - Milwaukee, WI 40 mi41 min S 15 G 19 35°F
CHII2 - Chicago, IL 40 mi41 min SSE 14 G 19 34°F 22°F
CNII2 44 mi31 min ESE 8 G 14 33°F
JAKI2 49 mi91 min S 8.9 33°F

Wind History for Calumet Harbor, IL
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Last
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G24
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SE10
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NW7
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G10

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago/Waukegan Regional Airport, IL4 mi36 minSSE 1110.00 miOvercast33°F23°F66%1031.2 hPa
Kenosha, Kenosha Regional Airport, WI10 mi38 minSSE 710.00 miOvercast31°F23°F72%1030.8 hPa
Racine, Batten International Airport, WI20 mi38 minSSE 1010.00 miOvercast34°F21°F61%1031.1 hPa

Wind History from UGN (wind in knots)
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Last 24hrNE10NE9NE5NE7NE11NE8E86NE8NE8E9NE8NE6NE6NE6CalmCalmCalmCalmE4E4SE7S6S11
1 day agoW4NW6NW6N8NW9N11
G19
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NE11NE10NE9NE9NE10
G17
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G23
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G18
2 days agoS8SE7S11S6S4N3N3CalmNE15
G21
N12
G19
NE15
G19
N13
G21
N10
G17
N10N4N3N5NW4NW4NW3NW4NW3W4W5

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
east_satellite

GOES Local Image of GreatLakes    EDIT
Geos

Wind Forecast for Chicago, IL (6,6,7,8)
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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.