Sunday, February17, 2019 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 6:41AMSunset 5:27PM Sunday February 17, 2019 10:30 PM CST (04:30 UTC) Moonrise 4:09PMMoonset 6:19AM Illumination 98% Phase: Waxing Gibbous; Moon at 13 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 Expires:201902181000;;106769 Fzus53 Klot 180309 Nshlot Nearshore Marine Forecast National Weather Service Chicago/romeoville Il 909 Pm Cst Sun Feb 17 2019 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>743-181000- Winthrop Harbor To Wilmette Harbor- Wilmette Harbor To Northerly Island- Northerly Island To Calumet Harbor-calumet Harbor To Gary- 909 Pm Cst Sun Feb 17 2019
.small craft advisory in effect through Monday morning...
Rest of tonight..Northeast winds 10 to 20 kt. Snow. Waves 3 to 5 ft.
Monday..North winds 20 to 25 kt diminishing to 10 to 20 kt in the afternoon. Snow showers likely in the morning, then slight chance of snow showers in the afternoon. Waves 3 to 5 ft.
Monday night..Northwest winds 10 to 15 kt. Mostly cloudy. Waves 2 to 4 ft subsiding to 1 to 3 ft after midnight.
Tuesday..North winds 5 to 10 kt becoming east in the afternoon. Partly Sunny. Waves 1 to 3 ft subsiding to 1 ft or less in the afternoon. Wave forecast is for ice free areas
LMZ742


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 180124 aaa
afdlot
area forecast discussion... Updated
national weather service chicago romeoville, il
724 pm cst Sun feb 17 2019

Update
724 pm cst
wintry precipitation continues across the area with a line just
south of i-80 being a fairly solid dividing one between snow to
the north and primarily freezing drizzle, at times a mix, to the
south. The heaviest snow accumulations thus far have been in north
central and far northern illinois, so the winter weather advisory
continues there for cumulative impacts. An advisory is now also
in effect for southern locations where freezing drizzle has been
the dominant precipitation type since mid-afternoon and should
continue to for the evening. In-between including the heart of the
chicago metro area, moderate snow will continue through 10 pm
with totals of around two inches favored and impacts a little
below that of a winter weather advisory. Bottom line for the cwa
is at the least patchy slick roads and to allow extra travel time
and have heightened caution.

Early evening satellite imagery and 00z soundings depict the
broad, slow-moving upper low across the western great lakes,
centered to the immediate north-northwest of the cwa. An
impressive 185 kt 250 mb jet was sampled at ilx this evening and
captures the stout jet streak that has maintained strength of
this closed low and resulted in the blossomed area of lift and
snow across northern illinois. This upper forcing will shift east-
northeast by late evening early overnight, but until then,
moderate snow is expected along north of i-80 with one to two
inches through 10 pm or so. South of i-80, which is further from
the deeper ascent, saturation will remain marginal in the ice
nucleation layer and radar, satellite, and observations all
support this trend continuing for at least a few hours. In
talking with a few law enforcement dispatches in the southern cwa,
the ice conditions reported there were worthy of an advisory,
especially considering expectations through the remainder of the
evening.

Behind the aforementioned strong upper forcing, the shearing but
still defined upper trough will hang back over the area with
saturation better aligning in the -12c to -18c layer. This should
allow for periodic light snow during the overnight, including in
the far southern CWA as low-mid level cold advection eases its way
southward transitioning any freezing drizzle. Additional
accumulation overnight looks to be under one inch area wide.

Confidence in this is medium to high.

For Monday, lake effect snow shower likelihood remains for the
morning and could continue into northeast illinois far northwest
indiana through the afternoon. This is not an ideal setup due to
low inversion heights from minimal cold advection, but the cloud
layer is forecast to intersect the snow growth layer and a
convergent axis is part of this setup. Thus light to possibly
brief moderate snow showers look like a fair bet for at least a
period. Further refinement of the best placement and duration will
be made into the overnight as confidence is low on those key
characteristics at this time, but for now some minor snow
accumulation (primarily <1.5 inches) will likely be seen in some
parts of far northeast illinois during the day Monday and possibly
even into early evening depending on the persistence of the
convergence.

Mtf

Short term
235 pm cst
through tonight...

after a period of moderate to briefly heavy snow this morning across
the NW half of the cwa, deeper moisture has briefly departed ahead
of an approaching upper-low. Weak low-level WAA and the loss of some
ice aloft has allowed light snow to mix with or change over to
freezing drizzle generally south of i-88 early this afternoon. As
the upper low over ia nears over the next few hours, thermo profiles
will once again become supportive of all snow. Radar imagery
depicts this transition zone across the western cwa, with arrival
time of 3:30-4:30pm for the chicago metro. Light snow will then
continue into the mid-evening before the upper-low begins to exit
to the east while slowly weakening and becoming more sheared. This
should allow snow to end for nearly the entire area away from
lake mi by around midnight, though very light snow may linger into
the overnight as the western extent of the sheared-out trough
slowly shifts east. Snow totals mid-afternoon through this evening
should range from less than a 0.5" south to up 2" north of i-88.

Near lake michigan, embedded lake enhancement across primarily
lake county(il) will support higher snow totals this evening, with
amounts up to 3" there. Thermo profiles will remain marginally
supportive of les across lake county into cook county overnight
into Monday morning, with an additional 1" possible for these
locations. The set-up looks favorable for a ragged band of les
showers slowly transitioning southward overnight into Monday
morning, with any location seeing about a 1-2 hr window of
moderate snow showers.

The only headline adjustment was to move up the end time of the
mchenry county advisory from 12z to 06z tonight as much of the les
activity overnight should remain confined to lake county. The
advisories away from lake county continue until midnight, but
could be canceled early if light snow diminishes quick enough this
evening.

Kluber

Long term
338 pm cst
Monday through Sunday...

main forecast concerns challenges are with continued potential
for lake effect snow showers on Monday, and then with increasing
chances for accumulating snow and possible wintry mix by mid week.

Surface low trough will continue to pull away at the start of the
period, with low level flow veering to more of a northerly
direction. As this occurs, expect chances for lake effect snow to
increase across portions of far northeast il and northwest in
Monday morning. Although lake effect snow may already be ongoing
across parts of lake il county, expect greater focus with possibly
higher intensity snow to swing down the lake and across locations
right near the shore. Guidance is showing some increase to the
inversion heights and delta TS late tonight into Monday. This
trend with the thermal profiles over the lake and with the
upstream low level convergent axis to shift down the lake Monday
morning, feel confident for a progressive area of lake effect snow
to impact areas adjacent to the shore. Confidence not overly high
with amounts but given the anticipated thermal profiles and
limited residence time of this, don't think amounts will be too
high. No real change from the previous forecast with additional
snowfall amounts, with additional amounts around an inch expected.

Some additional flurries may occur across northwest in in the
afternoon, but expect the bulk of this snow to end during this
time. High pressure expected to build across the region late
Monday into Tuesday, with dry weather likely.

Still monitoring the next system to provide another round of
winter weather to the region by mid week. Upper level trough and
attendant surface low trough expected to move through the central
conus Tuesday into Tuesday night. Out ahead of these features,
strong WAA will assist for an expanding precip shield to move
across the CWA late Tuesday night through Wednesday morning. At
this time, have high confidence of precip occurring and for this
to be all snow late Tuesday night. However, confidence lowers with
precip type Wednesday morning through midday. Guidance varying to
the northward extent of the warm nose and with the duration of
deeper moisture. It is appearing though that this snow could
transition over to freezing rain Wednesday morning for areas south
of i80. Some guidance showing this potential into the i-88
corridor, but have lower confidence with this potential. Did trend
the forecast this way though given latest guidance, bringing
chances for freezing rain further north. Stronger forcing should
depart Wednesday afternoon, with precip chances quickly ending. A
period to continue to monitor, as accumulating snow is appearing
likely across the region, along with the potential for ice
accumulation.

Rodriguez

Aviation
For the 06z tafs...

608 pm... Forecast concerns include light snow through tonight and
lake effect snow showers Monday morning.

Precipitation has switched back to mainly light snow across
northern il with light freezing drizzle still possible across
northwest il and for areas south of interstate 80 this evening.

The light snow is expected to persist though late evening and
likely into the overnight hours. The low levels currently are
expected to stay cool enough to support mainly light snow or
flurries overnight at the terminals. However... Some patchy
freezing drizzle can not be completely ruled out but the chance
currently looks small enough to keep out of this forecast.

Lake effect snow showers are expected to develop during the early
morning hours and the best timing for these to affect ord mdw
would be just before around daybreak. Lake effect snow showers
into northeast il are often challenging and can sometimes occur
just east of ord mdw. Guidance has not changed much so maintained
current tempo mention and its possible that any changes may not be
made until these lake effect snow showers actually develop later
tonight. These snow showers should shift into northwest indiana by
mid morning affecting gyy.

Northeast winds 10-12kts will slowly turn more northerly overnight
and then to the north northwest Monday morning though only medium
confidence for timing these shifts. MVFR CIGS expected to continue
through the period withVFR CIGS possible at rfd by Monday
afternoon. Cms

Lot watches warnings advisories
Il... Winter weather advisory... Ilz003-ilz004-ilz005-ilz008-ilz010-
ilz011-ilz019-ilz023-ilz032-ilz033-ilz039 until midnight
Monday.

Winter weather advisory... Ilz006 until 6 am Monday.

In... Winter weather advisory... Inz010-inz011-inz019 until midnight
Monday.

Lm... Small craft advisory... Winthrop harbor to gary in until noon
Monday.

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 mi15 min NE 4.1 G 6 26°F 24°F
CHII2 - Chicago, IL 5 mi30 min NE 8.9 G 9.9 28°F 27°F
JAKI2 5 mi90 min E 5.1 G 8 28°F
CMTI2 - 9087044 - Calumet, IL 9 mi30 min ENE 8.9 G 9.9 27°F 1012.5 hPa (+1.4)26°F
FSTI2 9 mi90 min NE 17 27°F
BHRI3 - Burns Harbor, IN 28 mi50 min E 6 G 7 26°F 1013.2 hPa
MCYI3 - Michigan City, IN 37 mi30 min NE 8 G 8.9 26°F 24°F
WHRI2 - Waukegan Harbor, IL 37 mi50 min ENE 8.9 G 11 27°F

Wind History for Calumet Harbor, IL
(wind in knots)    EDIT      (on/off)   Help
10
PM
11
PM
12
AM
1
AM
2
AM
3
AM
4
AM
5
AM
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
Last
24hr
E12
G16
E11
G18
E14
G18
E8
G13
E11
E10
G13
E10
G13
E8
G13
E12
G15
E11
G15
E10
G14
E14
E13
E11
G14
NE9
G13
NE11
G14
NE8
G11
NE8
G11
NE8
G11
NE8
G11
NE9
G13
NE10
E5
G8
NE8
G11
1 day
ago
W4
G7
W5
G8
W4
G7
W5
G9
W5
G8
W5
G8
W3
G7
NW4
W3
W3
NW2
NW5
G10
NW8
G11
N5
G8
NE8
G11
NE8
G12
NE11
G16
NE10
G15
NE11
G16
NE5
G10
NE8
G11
NE8
G11
NE10
G14
NE13
G17
2 days
ago
W6
G13
W10
G18
W10
G19
W10
G17
W9
G16
SW12
G20
W7
G18
W9
G13
W7
G15
W7
G14
W8
G14
SW8
G13
SW9
G15
SW9
G16
W7
G14
W10
G16
W7
G11
SW5
G8
W5
G9
W4
G8
W3
NW5
NW6
G9

Airport Reports
    EDIT      (on/off)   Help   Click EDIT to display multiple airports
AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago, Chicago Midway Airport, IL9 mi37 minNE 61.00 miLight Snow Fog/Mist27°F25°F92%1014.2 hPa
Chicago, Chicago-O'Hare International Airport, IL18 mi39 minN 92.50 miLight Snow Fog/Mist25°F24°F96%1013.8 hPa
Gary Regional Airport, IN19 mi45 minN 02.00 miLight Snow Fog/Mist28°F26°F93%1012.9 hPa
Lansing Municipal Airport, IL22 mi35 minN 02.50 miLight Snow27°F25°F95%1012.9 hPa
Chicago / Wheeling, Pal-Waukee Airport, IL24 mi38 minNNE 41.75 miLight Snow Fog/Mist27°F23°F85%1014.6 hPa

Wind History from MDW (wind in knots)
11
PM
12
AM
1
AM
2
AM
3
AM
4
AM
5
AM
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
Last 24hrE13E13
G22
E9E10E11E11E11E12E12E9E12E15
G20
E13E11E10E10NE8E10NE11NE10NE8NE7N4NE6
1 day agoNW8NW5NW8NW7NW6NW5NW7NW5NW5N5N7NW6N7N6NE9E12NE9E10E12
G19
E13NE11E9E12E11
2 days agoW16
G25
W16
G27
W19
G26
W20
G31
W13
G21
W15
G21
W16
G24
W15
G21
W12W14
G21
W13
G22
W13
G20
W12
G19
W14W12W15
G21
W13W9NW8NW7NW5NW10NW8NW8

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    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 (23,6,7,8)
      (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.