Sunday, September19, 2021
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Marine Weather and Tides
Winnetka, IL

Version 3.4
NOTICE
3/30/2021 -- ANZ330 has been split into ANZ331 and ANZ332. Click EDIT in Marine Forecast and select your new zone.
1/26/2021 -- The West Coast Satellite images havd been updated. They now use GEOS-17.
1/1/2021 -- The 7 day forecast are now working well. Thank you NOAA for your support.

Sunrise 6:34AMSunset 6:54PM Sunday September 19, 2021 8:56 AM CDT (13:56 UTC) Moonrise 6:46PMMoonset 4:50AM Illumination 96% 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
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LMZ740 Winthrop Harbor To Wilmette Harbor- Wilmette Harbor To Northerly Island- Northerly Island To Calumet Harbor- 327 Am Cdt Sun Sep 19 2021
Today..Southeast winds 10 to 15 kt becoming east in the afternoon. Sunny. Waves 1 to 3 ft.
Tonight..Southeast winds 10 to 15 kt becoming south after midnight. Slight chance of showers and Thunderstorms after midnight. Waves 1 to 3 ft.
Monday..South winds 15 to 25 kt. Showers likely and a chance of Thunderstorms, especially in the morning. Waves 3 to 5 ft.
Monday night..South winds 15 to 25 kt. Chance of showers and Thunderstorms, mainly late at night. Waves 3 to 5 ft.
LMZ740 Expires:202109191515;;844321 FZUS53 KLOT 190827 NSHLOT NEARSHORE MARINE FORECAST National Weather Service Chicago/Romeoville IL 327 AM CDT Sun Sep 19 2021 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>742-191515-


7 Day Forecast for Marine Location Near Winnetka, IL
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location: 42.11, -87.74     debug


Area Discussion for - Chicago, IL
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FXUS63 KLOT 191124 AFDLOT

Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 624 AM CDT Sun Sep 19 2021

SHORT TERM. 308 AM CDT

Through this Evening .

The main forecast message for today is a mostly sunny to partly cloudy and hot last Sunday of astronomical summer. Highs will reach the upper 80s to around 90/lower 90s for inland areas, about 15-20F above normal highs for the date. Shallow nature of the moisture will be prone to mixing out dew points into the upper 50s-low/mid 60s during the afternoon, keeping apparent temps close to forecast highs. Southeasterly synoptic winds due to high pressure ridge axis extending back across Lake Michigan will support early lake breeze development. This will shift winds to easterly near the Illinois shore and northeasterly near the northwest Indiana shore. Nature's AC will limit highs to the upper 70s to lower 80s along the immediate shoreline, with mid 80s several miles inland followed by gradual later day cooling. Lighter winds will make for much calmer conditions for boaters and late season beachgoers.

High and then mid clouds from the weak mid-upper low lifting north from the Arklatex will spread northward during the afternoon, along with Cu development. Plentiful mid-level dry air, capping, and lack of trigger this afternoon is expected to inhibit convective development. Lead isolated showers may push into areas primarily near and south of US-24 toward midnight. For the remainder of the discussion of shower and isolated thunderstorm trends into Monday, see the long term section below.

Castro

LONG TERM. 319 AM CDT

Late tonight through Saturday .

Weak upper low currently evident on water vapor imagery near the TX/LA Gulf Coast is still progged to open up and lift quickly toward the area today. The deep southerly flow that's going to advect this shearing out wave north is also progged to draw an unseasonably moist air mass into the area late tonight into Monday. Precipitable water values are progged to approach 2 inches (around 200% of normal) by later tonight into Monday morning as mid 60F to near 70F dewpoints advect into the area. While forcing with the approaching wave isn't expected to be particularly impressive, it shouldn't take much for showers to develop given the very moist airmass. Weak lapse rates should limit instability, but with a few hundred j/kg of MUCAPE present would be surprised if there weren't at least some isolated thunderstorms. While any storms that do form will be very efficient heavy rain producers, the weak forcing and expected disorganized nature of the convection should limit any widespread/organized heavy rain/flash flood threat.

Will likely see a decrease in coverage of precipitation Monday afternoon in the wake of the wave as forcing from this wave lifts north of the area. Assuming skies clear out sufficiently for temps to climb to around 80F Monday afternoon, the 65-70F Tds would be enough to support MLCAPE CAPE of 500-1250 j/kg Monday afternoon. Forecast soundings do show some weak to moderate convective inhibition, which given the excepted lack of forcing doesn't bode well for convection. However, given the instability, maintained shower/t-storm chances into the afternoon Monday.

Strong cold front still expected to move across the area late Monday night into Tuesday morning. The air mass in advance of this front will remain unseasonably moist and with stronger/deeper forcing expected with this front and associated upper trough there's a high chance of rain with the frontal passage. Deep moisture will help keep low-mid level lapse rates fairly weak, so even with unseasonably high boundary layer moisture, only expected weak instability to be present ahead of the front. Given the forcing with the front, seems quite plausible that there will be at least some scattered thunderstorms embedded with the band of showers accompanying the front.

Cooler and drier air will filter into the region behind the front during the day Tuesday and into Tuesday night. By Wednesday, look for high temps to hold in the 60s across the area with breezy northerly winds adding to the "chill" to the air (at least compared to temps experienced so far this autumn).

The 00z operational runs of the GEM and ECMWF both still want close off mid-upper level low at the base of this trough Wednesday night into Thursday. Though these runs are farther east than last night which would keep the rain chances to our east Wed night into Thursday. Given the tendency for models to often struggle with closing off mid-upper level lows and with GFS not on board with the closed low solution, it seems likely that subsequent model runs over the next day or two could continue to show a fair degree of variability. So confidence in the details of the forecast are lower than average Wed into Thur and while current guidance would support dry conditions, the blended model slight chance pops in the grids are reasonable and worth maintaining in case subsequent runs flop back west with the closing off mid-upper low.

Will also need to keep an eye on potential for some lake effect showers mid-week, though current forecast soundings show fairly low inversion heights, even the deeper ECMWF. There is also a fair amount of model spread with respect to the exact direction of the low-mid level flow and where any potential lake effect would even end up.

This trough is progged to quickly move east, followed by ridging and a period of strong warm air advection and rebound in temps by Friday before the next cold front knocks temps down next weekend.

- Izzi

AVIATION. For the 12Z TAFs .

Lake breeze expected at GYY by early/mid afternoon and at ORD/MDW very late afternoon or early evening with a wind shift to more easterly. Winds should settle back to southerly during the evening. System approaching from the south will result in SHRA spreading north into the terminals late tonight with gradually lowering CIGS and potentially reduced VSBY. Will probably be some ISOLD TSRA in the area very late tonight into Monday morning, though coverage and confidence too low for inclusion in TAFs at this time. Through 12z Monday, expect the better chance of rain to remain east and south of RFD.

- Izzi

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
45174 5 mi26 min SE 7.8 G 9.7 70°F2 ft1019.6 hPa
OKSI2 15 mi116 min ESE 2.9 G 5.1 72°F
45186 18 mi26 min 3.9 G 5.8 72°F 69°F1 ft
45198 18 mi26 min ESE 5.8 G 5.8 71°F 70°F2 ft65°F
WHRI2 - Waukegan Harbor, IL 18 mi116 min SSE 4.1 69°F
CNII2 19 mi26 min E 2.9 G 6 72°F 61°F
JAKI2 24 mi116 min Calm G 1 71°F
45187 26 mi26 min S 5.8 G 7.8 71°F 68°F1 ft
CMTI2 - 9087044 - Calumet, IL 28 mi56 min SE 4.1 G 7 1019.8 hPa (+0.4)
KNSW3 - Kenosha, WI 33 mi56 min SE 2.9 G 4.1 69°F 1020.7 hPa (+0.7)
BHRI3 - Burns Harbor, IN 45 mi76 min SE 7 G 9.9 68°F 1020.7 hPa
45170 48 mi26 min SE 12 G 14 70°F 1 ft64°F

Wind History for Calumet Harbor, IL
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N9
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S6
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NE8
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G9
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago / Wheeling, Pal-Waukee Airport, IL8 mi64 minN 010.00 miFair67°F62°F84%1020.7 hPa
Chicago, Chicago-O'Hare International Airport, IL12 mi65 minSE 310.00 miFair69°F63°F81%1020 hPa
Chicago, Chicago Midway Airport, IL22 mi63 minESE 510.00 miFair70°F59°F68%1019.6 hPa
Chicago/Waukegan Regional Airport, IL23 mi61 minN 09.00 miFair69°F66°F90%1019.8 hPa

Link to 5 minute data for KPWK

Wind History from PWK (wind in knots)
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Last 24hrNE12
G20
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G17
E7NE11NE8NE8NE8NE8NE5NE9NE5N3CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalm
1 day agoSW6SW7W10W9SW9SW7
G17
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G19
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G15
S6S3W8CalmN3N11NE5NE9N9N8N6N6N6N5NE6NE11
2 days agoSE3S9S10S7SE7
G16
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G17
E7SE6E6SE4SE4SE3CalmCalmCalmCalmS4S4CalmCalmCalmS3

Tide / Current Tables for
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NOTE: This section has been updated as of 1/26/2021. If the image you are expecting is not showing, please let me know. You may use the EDIT function to update your location.
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