Monday, September28, 2020
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Marine Weather and Tides
Sleepy Hollow, IL

Version 3.4
NOTICE
8/26/2020 The 7 day forecast is taking about 5 seconds to load but it will eventually load. NOAA is still working on it.
8/18/2020 NOAA continues to have trouble. Wind guest will occasionally be left off graphs. I am working with NOAA to resolve the issue.
12/16/2019 NOAA is having trouble with requests that include wind gusts. I am posting graphs without wind gusts until it gets fixed.
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.

Sunrise 6:46AMSunset 6:40PM Monday September 28, 2020 10:13 PM CDT (03:13 UTC) Moonrise 5:45PMMoonset 3:19AM Illumination 90% Phase: Waxing Gibbous; Moon at 12 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- 841 Pm Cdt Mon Sep 28 2020
Rest of tonight..West winds 15 to 20 kt. Mostly clear. Waves 1 to 3 ft.
Tuesday..West winds 10 to 20 kt. Mostly Sunny. Waves 1 to 3 ft.
Tuesday night..West winds 15 to 20 kt. Slight chance of showers in the evening. Waves 1 to 3 ft.
Wednesday..West winds 15 to 25 kt. Chance of showers through the day. Waves 1 to 3 ft building to 2 to 4 ft in the afternoon.
LMZ740 Expires:202009290915;;520825 FZUS53 KLOT 290141 NSHLOT NEARSHORE MARINE FORECAST National Weather Service Chicago/Romeoville IL 841 PM CDT Mon Sep 28 2020 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>742-290915-


7 Day Forecast for Marine Location Near Sleepy Hollow, IL
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location: 42.1, -88.29     debug


Area Discussion for - Chicago, IL
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FXUS63 KLOT 290005 AFDLOT

Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 705 PM CDT Mon Sep 28 2020

SHORT TERM. 239 PM CDT

Through Tuesday night .

Quite a fall look to satellite and radar this afternoon with scattered showers with closed cell low-topped convection across much of the area. The widespread stratus from this morning has advected out of the area or scatted out, with the subsequent increase in heating combined with an upper trough to the northwest driving the shower activity. Tops of most showers are under 15 kft, but an isolated shower may grow deep enough to produce a rogue lightning strike. Either way, primarily warm rain processes will result in short-lived moderate to heavy downpours. This activity will quickly diminish with both the loss of daytime heating and passage of the upper trough early this evening.

Skies should generally clear tonight with some straggling pockets of stratus possible, though a rather compact vort max nearing Minneapolis will track southward along the Mississippi River tonight and may bring some enhanced cloud cover across the western CWA. Low- level gradient flow should remain just high enough to preclude fog development for much of the area, especially with some drying today after last night's steady rainfall. With that said, any typically fog-prone locations (e.g. river valleys or localized low points) may decouple enough to allow for shallow fog to develop toward sunrise. Otherwise, with temps already starting off at only around 60 late this afternoon, decent cooling tonight will allow temps to drop into the low 40s outside of the core of Chicago metro to the upper 40s in Chicago proper.

Daytime mixing combined with lingering low-level moisture will allow a broken stratocumulus deck to develop by Tuesday afternoon. The low- level thermo profile will be similar if not a touch colder than today, so max temps will likely be a within a couple degrees on either side of 60F. Another trough axis quickly digging southeast out of northern Saskatchewan this afternoon will pivot across southern Wisconsin Tuesday afternoon and evening and may interact with the lingering low-level moisture to produce some isolated showers generally north of I-80 late in the afternoon through much of the evening.

Kluber

LONG TERM. 252 PM CDT

Wednesday through Monday .

A cool and occasionally unsettled weather pattern will persist for the remainder of the week.

Another cold upper low will drop south out of northern Canada mid week, and this will carve out a another/reinforce the existing long wave trough across the northern and eastern tier of the United States. The leading edge of the second in a series of cold frontal surges will come with a vort maximum/nose of the upper jet Wednesday morning which will reinvigorate shower activity across Wisconsin and into portions of northeast Illinois and northwest Indiana, lingering to some degree into the afternoon. The main trough will shift south of the region Wednesday night, with a secondary surge of cold advection knocking on our doorstep after a "milder" day on Wednesday for locations south of I-88/I-80. Temperatures will fall back well into the 40s with a break in the clouds.

Additional shortwave energy will continue to rotate through the area on Thursday. This coupled with some fairly cold air aloft for early October and steep low level lapse rates should again lead to a round of moderate rain showers on Thursday, especially in the afternoon. Breezy northwesterly winds on Thursday will continue to usher in a colder airmass through the day as an upper trough sets up shop over the Great Lakes. This will result in high temperatures holding in the 50s during the day. These showers could continue into Friday as these steep lapse rates will be favorable for lake effect showers into parts of northwest Indiana.

Lake effect parameters still appear rather impressive, with a strong 850 to lake surface differential, lake induced equilibrium levels pushing 20kft or more and 500-1000 J/KG of lake induced CAPE. Water spouts may also develop in this thermodynamic environment but remain offshore. While initially the low level flow will point the heavier shower activity toward eastern Lake Michigan, there are some hints of localized wind convergence or possibly some meso-low development which could steer some enhancement toward the northwest Indiana shoreline also. Thunder chances over/near the IN lakeshore are also nonzero given this thermodynamic setup.

The back edge of the upper trough will rotate through the area on Friday, thus the main precipitation shield would over the lake and then moving eastward. The core of cold air will be overhead per 850 mb temps of -2C to -4C on Friday, keeping chilly highs in the low to mid 50s common.

Still some mixed signals as to how cold temperatures will fall Friday night. The surface ridge will shift overhead, and with the cool start point readings may fall fairly quickly. The uncertainty lies in how quickly clouds may advect back in (or linger) around the area, especially with active west-northwest flow in place aloft, and low level warm advection. If things come together right, expect some areas of frost.

The unseasonably chilly weather looks to continue into next weekend as the upper trough remains in place. Saturday will only reach the mid to upper 50s after the chilly start to the day. There remains a signal that another disturbance and associated surface low shifting through the large scale trough could result in another chance for rain for the later half of the weekend. There is a decent signal for this on the GFS/ECM/CMC and per ensembles, which could make for a raw day Sunday if the slower/deeper guidance pans out.

KMD

AVIATION. For the 00Z TAFs .

Scattered showers have mostly dissipated this evening with only a few light showers remaining that are quickly weakening. The gusty winds have also eased this evening, with mostly light west northwesterly winds expected overnight.

Scattered to broken mid-level clouds are expected to continue overnight. Do note the MVFR stratus currently up in Minnesota this evening on the northwest side of a southward moving disturbance. This is expected to remain off to our west but there is some potential for the MVFR cigs to approach our area toward daybreak. Current expectation is for this to remain just to our northwest, perhaps with the best chances at RFD. Will keep an eye on this potential with later TAF updates.

West to southwesterly winds will increase during the day tomorrow with scattered showers possible toward the late afternoon and early evening. Have added a VCSH mention from 23 to 01Z when the greatest certainty and coverage is expected. There could also be occasionally stronger gusts that mix down with any showers that move through the area.

Petr

LOT WATCHES/WARNINGS/ADVISORIES. IL . None. IN . Beach Hazards Statement . INZ002 until 4 AM Tuesday.

LM . Small Craft Advisory . IN nearshore waters until 4 AM Tuesday.



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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WHRI2 - Waukegan Harbor, IL 31 mi73 min W 8 G 11
45174 34 mi23 min W 12 G 14 55°F 61°F1 ft1009.8 hPa49°F
FSTI2 35 mi133 min SSW 6 55°F
45187 38 mi33 min W 7.8 G 12 52°F 47°F
OKSI2 38 mi133 min NNW 1.9 G 2.9 57°F
CHII2 - Chicago, IL 40 mi43 min W 15 G 18 56°F 50°F
CNII2 40 mi28 min W 4.1 G 12 55°F 46°F
KNSW3 - Kenosha, WI 42 mi73 min W 9.9 G 13 54°F 1009.5 hPa (+1.7)
CMTI2 - 9087044 - Calumet, IL 47 mi55 min W 1.9 G 7 55°F 1009.9 hPa48°F

Wind History for Calumet Harbor, IL
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago / West Chicago, Dupage Airport, IL12 mi21 minW 510.00 miFair50°F43°F77%1010.6 hPa
Chicago / Wheeling, Pal-Waukee Airport, IL21 mi21 minW 610.00 miMostly Cloudy54°F48°F80%1010.4 hPa
Chicago, Chicago-O'Hare International Airport, IL22 mi22 minW 610.00 miA Few Clouds54°F46°F75%1010.1 hPa

Link to 5 minute data for KDPA

Wind History from DPA (wind in knots)
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Last 24hrNW7W5W6W7W5SW3SW4SW7SW6W6W8SW8SW9SW8SW11
G18
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NW11W9W9W6W7W5
1 day agoS14
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S10S11
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SW12SW11SW9SW9SW10SW5SW5SW4W11NW11NW15
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2 days agoS10S12SW11S9S7S9S8S9S10S12S9
G18
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Tide / Current Tables for
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Tide / Current Tables for
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Weather Map
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GEOS 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.
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Ground Weather Radar Station Chicago, IL
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