Wednesday, December12, 2018 L-36.com


Marine Weather and Tides
Chicago, IL

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 7:07AMSunset 4:21PM Wednesday December 12, 2018 5:37 AM CST (11:37 UTC) Moonrise 12:02PMMoonset 10:19PM Illumination 24% Phase: Waxing Crescent; Moon at 5 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
    EDIT      (on/off)   Help
LMZ742 Northerly Island To Calumet Harbor-calumet Harbor To Gary- Gary To Burns Harbor-burns Harbor To Michigan City- 330 Am Cst Wed Dec 12 2018
Today..Southeast winds 15 to 25 kt becoming southwest in the afternoon. Slight chance of rain in the morning. Waves 2 to 4 ft.
Tonight..West winds 10 to 20 kt becoming southwest 5 to 10 kt after midnight. Mostly cloudy. Waves 2 to 4 ft subsiding to 1 to 3 ft after midnight.
Thursday..Southeast winds 10 to 15 kt. Slight chance of rain in the afternoon. Waves 1 ft or less.
Thursday night..Southeast winds 10 to 15 kt. Light freezing rain likely in the evening. Rain through the night. Waves 1 ft or less.
LMZ742 Expires:201812121615;;671429 FZUS53 KLOT 120930 NSHLOT NEARSHORE MARINE FORECAST National Weather Service Chicago/Romeoville IL 330 AM CST Wed Dec 12 2018 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. LMZ742>745-121615-


7 Day Forecast for Marine Location Near Chicago, IL
   Hourly   EDIT   Help
location: 41.85, -87.6     debug


Area Discussion for - Chicago, IL
      (on/off)   Help   NOTE: mouseover dotted underlined text for definition
Fxus63 klot 121107
afdlot
area forecast discussion
national weather service chicago romeoville, il
507 am cst Wed dec 12 2018

Short term
330 am cst
through tonight...

have decided to cancel the winter weather advisory that had been
in effect for this morning. The previous concern for mixed
precipitation and an icy glaze coinciding with the commute is
becoming increasingly unlikely to materialize. Overnight aircraft
soundings from rfd have shown a very dry profile, matching up with
current observation of overcast skies with a cloud base height of
15kft. Looking along just west of the ms river, minimum ceiling
heights are 5-7kft. The rap and hrrr have been consistent since
Tuesday afternoon in indicating that there will not be sufficient
saturation for the brief narrow warm advection band of precip to
form and move across northern illinois. The 3km namnest and a few
other cams still hold onto the possibility of a narrow band of
precip right ahead of the system dry slot. Therefore, greatly
backed off on pops but still held onto chance pops along north of
i-88 through mid morning, highest near wi border, with slight
chances down to around i-80.

Looking at current surface obs, most temperatures are at to a few
degrees above freezing. Thus, if any brief precip occurs, can't
rule out a wintry mix with the marginal thermal profile, but with
temps likely to remain at or above freezing through mid morning,
do not anticipate roadway impacts for most of the area that had
been in an advisory, with *maybe* an outside chance for a very
brief period of light rain with temps around 32. A perhaps
*slightly* better chance of frozen precipitation may arrive in the
mid to late morning in portions of north central and northwest
illinois.

As the cold pocket of the vigorous clipper hybrid overspreads the
area, temps may dip to near or locally just below freezing.

Surface obs do show <1000 ft ceilings back across iowa under the
system cold pocket, so if any drizzle falls out of this deck in
mid- late am across northwest cwa, can't rule out some very
spotty patchy freezing drizzle. Confidence in occurrence and
coverage is low and with temps at worst being at to 1-2 degrees
below 32f after spending the earlier morning above freezing, road
temps may not respond in time to enable any localized icing.

Finally, as the clipper low tracks across southern wi, in response
west-southwest winds will pick up and gust to around 25 mph,
which also is not a favorable set-up for ice accretion. For
reference, the freezing drizzle event this past january over parts
the chicago area had 500ft or less ceilings and light calm winds
along with temps in the 20s where the worst impacts occurred.

Given all the above considerations, opted to make the difficult
decision of cancelling the headline before any precip arrived.

Early afternoon highs will be in the upper 30s to lower 40s from
chicago to lasalle county and points southeast, with earlier highs
northwest of there in the mid 30s cooling to the low 30s as the
cold pocket arrives. Some partial clearing for a time tonight and
very weak pressure gradient should enable temps to dip into the
mid to upper 20s to around 30 in chicago.

Castro

Long term
223 am cst
Thursday through Tuesday...

our next weather maker is across the pacific northwest early this
morning. The energy associated with this system will be split
across a broad trough axis spanning the country, with a more open
wave across the northern great lakes, while strong upper jet on
the back side of the trough will allow the southern stream to
develop a closed low. Model agreement with the track of this low
was not great to this point, but the 0z global runs are in a bit
better agreement with digging this low well south of the region,
reaching the ARKLATEX region Thursday evening. Regardless,
warm moist southwest flow advection will feed 1"+ precipitable
water values into the approaching system. While those values may
not get this far north, a decent inverted surface trough will
setup. Therefore, expect a blossoming shield of precipitation
Thursday night. Model thermal progs suggests the column will be
warm enough for all liquid precipitation.

As mentioned above, mid range models now are in better agreement
with the track the ECMWF has been showing for a few days, where
the bulk of the system will continue east of the area but along
and south of the ohio valley. The low will be close enough that
we will need to watch how quickly it exits our region and if any
rain bands will continue to pinwheel around the low, therefore
some chances for rain continue into Friday, and maybe into
Saturday with the GFS ensemble NAM hanging the low a bit farther
west. Still, confidence has increased maybe a little bit,
suggesting a farther south track and less impacts from this system
after Thursday night into Friday and is reflected in lower precip
chances after the initial surge and no snow.

One area of concern will be with the back edge of the
precipitationshield across north central illinois where some
guidance does try to advect some colder low level temperatures in.

This would bring some icing potential. Have low confidence in
this occurring given the model discrepancies, and given the lack
of a significant cooling behind this system.

Outside of a cold front on Sunday, upper level heights will be on
the rise Saturday and again early next week, suggesting a
transition to a milder pattern, and one that at least for now is
still largely dry.

Kmd

Aviation
For the 12z tafs...

concerns center around lowering ceilings later this morning and
afternoon, and whether there will be any drizzle this afternoon.

Wind gusts to 25 kt are also possible this afternoon.

Other than some virga, most areas will remain dry through mid
morning. As the center of low pressure shifts in mid to late
morning, there could still be a brief window of light
rain drizzle. Only period of concern for freezing drizzle may be
toward rfd in the afternoon. Expect MVFR ceilings to reach rfd
mid morning, then toward the chicago terminals toward 18z, with
ceilings to lift mid to late evening. Could get close to ifr at
rfd.

Low pressure will track from northwest il and then on across
southern wisconsin. Winds will start off the period
southeasterly, but then shift to southwesterly as the continues
toward sheboygan wisconsin late in the day. Gusts may approach 25
kt this afternoon after winds have shifted to southwest. Winds
will become more light and variable tonight as they back toward
southeast for Thursday.

Kmd

Lot watches warnings advisories
Il... None.

In... None.

Lm... Small craft advisory... Winthrop harbor to northerly is. Until noon Wednesday.

Visit us at http: weather.Gov chicago (all lowercase)
follow us on facebook... Twitter... And youtube at:


Weather Reporting Stations
   EDIT       (on/off)   Help   NOTE: Click on distance to see the station location on a map
Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
CNII2 1 mi23 min SSE 8 G 9.9 36°F 29°F
JAKI2 5 mi98 min S 11 G 17 38°F
CHII2 - Chicago, IL 5 mi38 min SSE 17 G 21 37°F 31°F
FSTI2 9 mi98 min SSE 19 35°F
CMTI2 - 9087044 - Calumet, IL 9 mi38 min SSE 8.9 G 13 36°F 1009 hPa (-3.5)30°F
BHRI3 - Burns Harbor, IN 28 mi58 min SSE 7 G 12 35°F 1011.2 hPa
WHRI2 - Waukegan Harbor, IL 37 mi58 min SSE 18 G 23 36°F
MCYI3 - Michigan City, IN 37 mi38 min SE 17 G 19 35°F 28°F

Wind History for Calumet Harbor, IL
(wind in knots)    EDIT      (on/off)   Help
6
AM
7
AM
8
AM
9
AM
10
AM
11
AM
12
PM
1
PM
2
PM
3
PM
4
PM
5
PM
6
PM
7
PM
8
PM
9
PM
10
PM
11
PM
12
AM
1
AM
2
AM
3
AM
4
AM
5
AM
Last
24hr
SW6
G10
SW6
G11
SW5
G8
SW8
G11
SW7
G12
SW6
G9
SW4
G7
SW3
G8
W4
G7
W5
W2
NE5
E4
E6
G9
E8
E5
E7
SE3
G6
SE6
G9
SE5
SE6
G10
SE8
G11
S11
G16
SE9
G13
1 day
ago
SW4
SW3
G6
SW5
G8
S4
SW4
G7
SW6
SW6
G9
SW8
G13
S8
G12
S9
S9
G14
S9
S10
S8
G12
SW6
G12
SW7
G12
S10
G13
SW9
G13
SW8
G12
SW9
SW8
G12
SW6
G11
SW7
2 days
ago
SW3
SW3
SW2
SW1
G4
SE1
NE4
N7
N7
N5
NE4
N3
N3
NW2
NW5
NW3
G6
W2
W2
W2
W2
SW2
SW2
SW3
SW3

Airport Reports
    EDIT      (on/off)   Help   Click EDIT to display multiple airports
AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago, Chicago Midway Airport, IL9 mi45 minSSE 88.00 miOvercast36°F28°F73%1010 hPa
Chicago, Chicago-O'Hare International Airport, IL18 mi47 minSSE 810.00 miOvercast34°F28°F82%1009.1 hPa
Gary Regional Airport, IN19 mi53 minESE 10 G 2010.00 miOvercast36°F30°F81%1010.5 hPa
Lansing Municipal Airport, IL22 mi43 minSSE 9 G 1610.00 miFair35°F28°F80%1010.2 hPa
Chicago / Wheeling, Pal-Waukee Airport, IL24 mi46 minSSE 910.00 miFair36°F28°F73%1009.4 hPa

Wind History from MDW (wind in knots)
6
AM
7
AM
8
AM
9
AM
10
AM
11
AM
12
PM
1
PM
2
PM
3
PM
4
PM
5
PM
6
PM
7
PM
8
PM
9
PM
10
PM
11
PM
12
AM
1
AM
2
AM
3
AM
4
AM
5
AM
Last 24hrSW8SW8SW8W9
G18
W10W9W6W6SW5W3CalmS3E7E6SE6SE7E5SE8SE8SE6SE8SE8S9S8
1 day agoCalmSW3SW4SW4W4SW5SW10SW10SW10SW9SW9SW11SW8SW8
G19
SW8
G19
SW7SW7SW6SW7SW7SW8SW9SW8SW12
2 days agoW3W3NW4NW3N3CalmNW5N5N4N3N4E4E4CalmNW6NW5NW6NW4W4W4NW3CalmW3W3

Tide / Current Tables for
   EDIT   RT Ports Option   Weekend mode (on/off)   (on/off)   Help
Tide / Current Tables for
   EDIT      (on/off)   Help
Weather Map and Satellite Images
       (on/off)   HelpWeather Map
wmap_A
GOES Local Image of Midwest    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
Link to Loop

Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for Chicago, IL (6,6,7,8)
      (on/off)   Help

Ground Weather Radar Station Chicago, IL
   (on/off)   Help
weather_mapweather_map weather_map

Ad by Google

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.