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Marine Weather and Tides
Version 3.4 |
10/9/2019 Updated the Marine Zones. 9/4/2019 Fixed the weather maps due to NOAA moving them. 7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports. 6/2/2019. Many thanks to a user for reporting an error on one of the Edit pages. The switch to PHP 7.2 caused many pages that previously worked to quit working. I fixed many but I still depend on users to report ones I missed. Please report errors HERE or send an email to me at L-36.com. Allen |
Sunrise 7:07AM | Sunset 4:20PM | Thursday December 12, 2019 1:54 PM CST (19:54 UTC) | Moonrise 5:57PM | Moonset 8:27AM | Illumination 99% | ![]() |
LMZ741 Expires:201912122230;;242601 Fzus53 Klot 121517 Nshlot Nearshore Marine Forecast National Weather Service Chicago/romeoville Il 917 Am Cst Thu Dec 12 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>742-122230- Winthrop Harbor To Wilmette Harbor- Wilmette Harbor To Northerly Island- Northerly Island To Calumet Harbor- 917 Am Cst Thu Dec 12 2019
.small craft advisory in effect until 9 pm cst this evening...
Rest of today..South winds to 30 kt. Mostly cloudy. Waves 4 to 7 ft occasionally to 9 ft.
Tonight..Southwest winds to 30 kt diminishing to 15 to 20 kt after midnight. Cloudy. Waves 4 to 7 ft occasionally to 9 ft subsiding to 2 to 4 ft after midnight.
Friday..Southwest winds 10 to 15 kt. Cloudy. Waves 1 to 3 ft subsiding to 1 ft or less in the afternoon.
Friday night..Southwest winds 10 to 15 kt becoming west 5 to 10 kt after midnight. Slight chance of rain in the evening, then slight chance of drizzle and snow after midnight. Waves 1 ft or less.
.small craft advisory in effect until 9 pm cst this evening...
Rest of today..South winds to 30 kt. Mostly cloudy. Waves 4 to 7 ft occasionally to 9 ft.
Tonight..Southwest winds to 30 kt diminishing to 15 to 20 kt after midnight. Cloudy. Waves 4 to 7 ft occasionally to 9 ft subsiding to 2 to 4 ft after midnight.
Friday..Southwest winds 10 to 15 kt. Cloudy. Waves 1 to 3 ft subsiding to 1 ft or less in the afternoon.
Friday night..Southwest winds 10 to 15 kt becoming west 5 to 10 kt after midnight. Slight chance of rain in the evening, then slight chance of drizzle and snow after midnight. Waves 1 ft or less.
LMZ741
7 Day Forecast for Marine Location Near Evanston, IL
Hourly EDIT Helplocation: 42.03, -87.69 debug
Area Discussion for - Chicago, IL
  (on/off)  Help NOTE: mouseover dotted underlined text for definitionFXUS63 KLOT 121814 AFDLOT
Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 1214 PM CST Thu Dec 12 2019
SHORT TERM. 300 AM CST
Through Friday .
Today will find temperatures jump 15 to 20 degrees from yesterday thanks to gusty southerly winds expected to sporadically peak near 35 mph. Apart from a chance of sprinkles/spotty light rain in the far north, through the day Friday looks dry for most if not all of northern Illinois and northwest Indiana.
Early morning satellite water vapor imagery reveals a mid-level circulation across the Dakotas headed quickly east-southeast. This will pivot more due east in southern Minnesota into Wisconsin as it rounds the larger scale long wave trough across the eastern half of Canada. With this feature impinging quickly on the modified arctic air mass, this has limited time for any moistening in its warm sector, and that's why any afternoon/early evening brief light rain or sprinkles should be confined to near the Wisconsin state line associated with a 60+ kt low-level jet. It's this return flow that will be the story for the area, with sustained southerly winds near 20 mph thanks to a large surface isallobaric component. Given the unlikely scenario of any lower base clouds, would expect the boundary layer while shallow to still be able to mix gusts occasionally to the top of the mixing channel of 35 mph shown by the RAP and GFS.
By advection alone, temperatures will climb into the 40s with high confidence for most of the CWA, apart from toward Rockford where readings may stay just shy of that due to the thickest mid-level clouds. The question is just how far into the 40s. Some limited snow cover in the Illinois and Vermilion River Valleys should sublimate fairly quickly today and there is some guidance indication that the southeast CWA sees some thinning of high-mid cloud cover offering some sun. For now have gone primarily mid 40s, trying to balance the fact that the day after a heart of an arctic mass often can run a little cooler than guidance, though those often have widespread snow cover.
The clipper's associated low-level trough/cold front will move into the CWA late tonight and gradually weaken through Friday. Clouds should start to thicken and gradually lower Friday in a slowly moistening mid to low levels, but forcing for precipitation looks limited. In the absence of any advection and with clouds, high temperatures look to peak upper 30s to 40.
MTF
LONG TERM. 325 AM CST
Friday night through Wednesday .
An unsettled pattern will be in place Friday night through Monday, with Monday having some signal for accumulating snow maybe more so along/south of I-80, but that is with low confidence. For the beginning of this time (Fri night into Sat), the precipitation intensity looks light and coverage potentially limited, so impacts look to be small. The one main caveat to that is that there is a limited chance of freezing drizzle later Friday night and early Saturday morning.
A pseudo-split flow regime Friday night into Saturday will see multiple slow-moving short waves in the region, with guidance favoring the southern stream jet to drive some phasing of this activity east of the region into Saturday night. This presents limited deeper upper jet support in the region, as well as minimized areas of focus/convergence/baroclinicity in the lower to mid levels. On Friday night, any precipitation looks light and associated with either very weak isentropic upglide or pockets of ascent ahead of/within any of the mid-level impulses. Profiles show some marginal saturation of the heterogeneous ice nucleation layer, but also have doubts there will be precipitation actually occurring in such a profile. So while drizzle/freezing drizzle is possible it is again low confidence. Equally if not slightly more likely if any precipitation occurs is that it may be patchy very light snow/flurries. Lows on Friday night/Saturday morning have consistently looked like they would be right around freezing.
With the strengthening low expected to the east into Saturday p.m., cold advection will gradually strengthen over the area with still some impulses rotating through. So some potential for light snow Saturday and depending on how temperatures fall out, could see some very light accumulation. Anything higher than that is a diminishing forecast outcome at this point. The shot of cold advection will bring wind chills into the single digits during Saturday evening persisting into Sunday morning.
A continued quasi-split flow pattern rides into the start of next week. Guidance is in sound agreement on a southern stream system anchored along the subtropical jet and amplifying somewhere in the eastern half of the country on Monday. The ECMWF has been consistently south with this while the GFS has been frequently further north over a larger part of the CWA on its solutions. The GFS ensemble does have some more members that have trended north this past 24 hours, and a majority of them are producing some snow in the southeast forecast area as the system matures. For now have only inched up blend-provided chances in the southeast CWA, but tough to stray much from the consistent ECMWF solution at this medium range distance. Will be a period to watch as a swath of accumulating snow is certainly possible somewhere in the Ohio Valley to southern Great Lakes region.
Beyond looks somewhat quiet as northwest flow aloft takes back over for at least a multi-day period. Temperatures should be slightly below normal, though if any snow cover materializes that would likely tilt the forecast colder.
MTF
AVIATION. For the 18Z TAFs .
Low pressure across northern IA will shift into Wisconsin this afternoon and will continue the gusty south winds across the terminals. A strong inversion will limit the strength of gusts at the surface but lower 30 kt gusts have been observed and should remain the case this afternoon. Cannot rule out stray gust to 35 kt which would impinge on the ORD cross runway threshold, otherwise expect LLWS through the afternoon with 50-55 kt at 2000 ft. Speeds will taper off this evening as will the magnitude of the LLWS.
Lower VFR or some MVFR ceilings may impinge on the area this evening and overnight, with a bit higher confidence toward RFD and to the the west of ORD/MDW Friday morning.
KMD
LOT WATCHES/WARNINGS/ADVISORIES. IL . None. IN . None. LM . Small Craft Advisory . IN nearshore waters until midnight Friday.
Small Craft Advisory . IL nearshore waters until 9 PM Thursday.
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Weather Reporting Stations
EDIT (on/off)  Help NOTE: Click on distance to see the station location on a mapStations | Dist | Age | Wind | Air Temp | Water Temp | Waves | Pressure | DewPt |
CHII2 - Chicago, IL | 10 mi | 35 min | SSW 29 G 32 | 43°F | 28°F | |||
CNII2 | 13 mi | 25 min | S 17 G 24 | 43°F | 25°F | |||
CMTI2 - 9087044 - Calumet, IL | 22 mi | 55 min | S 13 G 23 | 42°F | 1020.4 hPa (-4.4) | 28°F | ||
KNSW3 - Kenosha, WI | 39 mi | 55 min | SSW 15 G 20 | 43°F | 1018.6 hPa (-4.4) | |||
MCYI3 - Michigan City, IN | 46 mi | 35 min | S 20 G 26 | 41°F | 26°F |
Wind History for Calumet Harbor, IL
(wind in knots) EDIT (on/off)  Help2 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 | 6 AM | 7 AM | 8 AM | 9 AM | 10 AM | 11 AM | 12 PM | 1 PM | |
Last 24hr | W G8 | NW | SW | SW | SW | SW | SE | S | SE | SE | SE G10 | SE G10 | SE G13 | SE G12 | SE G13 | SE G11 | SE G12 | S G15 | S G18 | S G22 | S G19 | S G20 | S G23 | S G23 |
1 day ago | SW G14 | SW G14 | SW G13 | SW G12 | SW G16 | SW G12 | SW G10 | SW G13 | SW G12 | SW G11 | SW G9 | SW G12 | W G13 | SW G12 | SW G14 | SW G11 | SW G11 | SW G12 | SW G10 | W G12 | W G11 | SW G10 | SW G10 | SW G11 |
2 days ago | SW G16 | SW G12 | SW G14 | SW G19 | SW G24 | SW G19 | W G24 | SW G16 | W G14 | W G15 | W G17 | W G16 | W G14 | SW G17 | SW G16 | SW G16 | W G16 | SW G13 | SW G14 | SW G14 | W G12 | W G15 | W G16 | W G14 |
Airport Reports
EDIT (on/off)  Help Click EDIT to display multiple airports. Follow links for more data.Airport | Dist | Age | Wind kt | Visibility | Sky/Weather | Temp | DewPt | Humidity | Pressure |
Chicago / Wheeling, Pal-Waukee Airport, IL | 12 mi | 63 min | S 20 G 31 | 10.00 mi | Overcast and Breezy | 44°F | 24°F | 45% | 1020.7 hPa |
Chicago, Chicago-O'Hare International Airport, IL | 12 mi | 64 min | SSW 13 G 27 | 10.00 mi | Overcast | 42°F | 26°F | 53% | 1020.5 hPa |
Chicago, Chicago Midway Airport, IL | 17 mi | 62 min | SSW 14 G 27 | 10.00 mi | Overcast | 43°F | 27°F | 53% | 1021.9 hPa |
Link to 5 minute data for KPWK
Wind History from PWK (wind in knots)
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 | 6 AM | 7 AM | 8 AM | 9 AM | 10 AM | 11 AM | 12 PM | 1 PM | |
Last 24hr | W | W | Calm | Calm | Calm | Calm | Calm | Calm | Calm | Calm | SE | S | SE | SE | SE | SE | S | S | S G19 | S | S G22 | S G27 | S G31 | |
1 day ago | W G19 | W G17 | W | W G17 | W | SW | W | W G17 | W | W | W G17 | W G18 | W G19 | W G17 | W | W | SW | W | W | W | W G19 | W | W | W G16 |
2 days ago | SW | W G20 | W G16 | W G30 | W G28 | W G32 | W G27 | W G21 | W G22 | W G20 | W | W G23 | W G21 | W G24 | W G19 | W G21 | W G18 | W | W | W | W G17 | W G19 | W G17 | W G18 |
Tide / Current Tables for
EDIT Weekend mode (on/off) (on/off)  HelpTide / Current Tables for
EDIT (on/off)  HelpWeather Map
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GEOS 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 (14,3,4,5)
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Ground Weather Radar Station Chicago, IL
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