Sleepy Hollow, IL Marine Weather and Tide Forecast
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Marine Weather and Tide Forecast for Sleepy Hollow, IL

June 20, 2024 2:30 PM CDT (19:30 UTC) Change Location
Sunrise 5:15 AM   Sunset 8:34 PM
Moonrise 7:51 PM   Moonset 3:37 AM 
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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 Il- Wilmette Harbor To Northerly Island Il- Northerly Island To Calumet Harbor Il- 1145 Am Cdt Thu Jun 20 2024

.dense fog advisory in effect until 10 pm cdt this evening - .

Rest of today - North winds 10 to 15 kt. Areas of dense fog. Slight chance of showers and Thunderstorms in the afternoon. Waves 1 to 3 ft.

Tonight - North winds 10 to 15 kt diminishing to 5 to 10 kt. Areas of dense fog in the evening. Slight chance of showers and Thunderstorms in the evening. Waves 1 to 3 ft.

Friday - North winds 5 to 10 kt becoming east in the afternoon. Slight chance of showers and Thunderstorms. Waves 1 to 2 ft.

Friday night - East winds 10 to 15 kt becoming south 5 to 10 kt overnight. Partly cloudy. Waves around 1 ft.

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7 Day Forecast for Marine Location Near Sleepy Hollow, IL
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Area Discussion for - Chicago, IL
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Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 1244 PM CDT Thu Jun 20 2024


- Isolated to scattered storms this afternoon into early evening. Locally gusty winds and torrential downpours possible with these storms, but organized severe weather is not expected.

- Hot and muggy conditions will prevail through Saturday, although cooler conditions are expected near Lake Michigan today and on Friday.

- Periodic chances for thunderstorms will continue, though most hours will remain dry.

Issued at 1105 AM CDT Thu Jun 20 2024

The threat of widely scattered thunderstorms continues to be the primary focus this afternoon into early this evening. This will particularly be the case to the south/southeast of the area of cloud cover currently draped from eastern IA northeastward across far northwestern IL into southern WI. Diurnal heating of a very moist low-level airmass (dew points near 70) in this region is expected to weaken surface convective inhibition this afternoon as a short wave impulse moves eastward into northern IL. This is thus expected to foster at least some widely scattered thunderstorm development after about 2 pm this afternoon. While isolated storms will be possible across most of northern IL into northwestern IN later today, most of the activity may tend to become more focused in close proximately to a sharpening west-to-east oriented surface frontal boundary near the I-80 to I-88 corridors, and west of a lake breeze boundary.

Widespread severe weather is not anticipated with these storms this afternoon, owing to the overall weak deep layer shear.
However, the potential exists for some wet microbursts, which could thus result in some isolated instances of strong gusty winds with any of the stronger storms. A very moist airmass (featuring near 2" PWATs) will also support torrential downpours with these storms this afternoon. The threat of storms will then diminish through the evening.


Issued at 337 AM CDT Thu Jun 20 2024

Through Friday:

A cold front has moved into the CWA and brought light northerly winds to the northwest half of the area. Through the morning hours this front will retreat back to the north, setting up along the IL/WI state line. A backdoor cold front is also expected to advance down Lake Michigan and approach the area this morning. The backdoor front/lake breeze will likely be held up just inland, but will surge southward across northwest IL and northern IN early this afternoon into this evening.
Temperatures behind the backdoor front/lake breeze are much cooler than out ahead of it, so the timing of the front could impact high temperatures today. Areas that are unaffected by the backdoor front/lake breeze through roughly 18Z will see temperatures climb into the low 90s, bringing maximum heat indices into the mid 90s.

Behind the backdoor front/lake breeze, conditions appear favorable for marine fog to form this morning. This will decrease visibility over the lake and may seep slightly inland through the morning, but is not expected to persist inland into the afternoon.

The presence of both of these fronts brings a chance of showers and storms across the area this afternoon. Highest coverage will likely be along and north of I-80 where a band of 1000-1500 J/kg of MLCAPE is expected to build. Where all of these boundaries converge may also serve as a prime location for convective development. Any storms that are able to form here will likely move into the Metro area. Organized severe weather is not expected, although some storms may be able to produce gusty downburst winds. Coverage will be highest through the afternoon with some storms lingering into the evening hours, however, the overnight hours are expected to be dry.

Friday looks to be a fairly quiet day. A shortwave will move across Wisconsin bringing a chance of showers and storms into the far northern portion of the CWA, however, most areas should remain dry. Temperatures will return to the low-to-mid 90s except along the lakeshore where a lake breeze will keep things cooler. This will create heat indices in the mid-to-upper 90s away from the lake.


Friday Night through Wednesday:

A developing surface low to our west/northwest on Saturday will yield a tighter surface pressure gradient across the region.
This will afford us breezy southwesterly winds that will help facilitate warm air advection and push the warmth all the way up to the lakeshore for the first time in a few days. Saturday's highs are currently pegged to top out in the low to mid 90s across the area, and with dew points generally expected to span from the mid 60s to near 70F, this will translate to another day of heat indices peaking in the 95-100 degree range at most locations.

The cold front associated with the aforementioned surface low will press southeastward on Saturday as the low center approaches Lake Superior, and thunderstorms will likely develop along it as it does so. These storms will enter our forecast area from the northwest as early as the mid-late afternoon, but more likely during the evening, and continue southeastward into the night, likely weakening and diminishing in coverage with time as diurnal instability is lost. Deep-layer shear will be better than it has been the past several days given the presence of enhanced flow through the tropospheric column on the southeastern periphery of the deepening low pressure system, and with pre-frontal MLCAPE potentially pushing 2000-2500 J/kg, the overall kinematic and thermodynamic parameter space will likely allow for some of the frontal convection to become severe.
Whether any severe thunderstorms occur in our forecast area will largely hinge on the timing of the cold frontal passage.
An earlier frontal passage while diurnal instability is still plentiful would be more favorable for severe weather prospects here, while a later frontal passage would see convection arrive as the boundary layer stabilizes and our supply of instability has been depleted to some degree, thus keeping the potential for severe weather minimal. The Marginal (level 1/5) Risk introduced into the northwest half or so of our CWA in SPC's Day 3 Convective Outlook seems appropriate for now given the current distribution of frontal passage timing in the latest available deterministic and ensemble guidance.

A slow frontal passage could also see showers linger around into Sunday morning in our southeastern counties, but otherwise, no additional precipitation is expected on both Sunday and Monday as surface high pressure and a drier post-frontal air mass settle into the region. Averaged across our forecast area, both days should generally be cooler and less humid than the past few days, but high temperatures on both days still look like they'll end up being slightly above normal for late June.
Towards mid-week, a flattened ridge should build back into the southern Great Lakes and allow for 90+ degree air temperatures to make a return to the area on Tuesday. The presence of a baroclinic zone in the region could also present us an additional opportunity or two to see showers and storms mid-week next week.


Issued at 1242 PM CDT Thu Jun 20 2024

The primary aviation weather concerns through the 18Z TAF period include:

* Isolated to widely scattered thunderstorms this afternoon and evening

Light NE winds will continue through the remainder of today.
Isolated to widely scattered showers and thunderstorms are expected to begin developing during the mid-late afternoon and continue into the evening. While storms aren't expected to be overly aggressive, brief heavy downpours and localized gusty winds will be possible.
Thunderstorm chances drop considerably following 00Z, although pockets of showers may persist late into the evening. Barring any downpours overhead, conditions look to remain VFR through the event.

Winds overnight will be light and predominantly NE, variable at times. There is a modest, but growing, signal for MVFR cigs and possibly even some fog to move inland off the lake and over the Chicago sites overnight. With the majority of model guidance holding onto VFR, kept the TAFs as such. A much stronger and consistent signal exists over GYY for MVFR, or even IFR, cigs tonight into Friday morning. Friday should see easterly winds over Chicagoland, southerly to southwesterly over RFD, near and under 10 kt.


Issued at 337 AM CDT Wed Jun 19 2024

After breaking a couple of temperature records this week, the high and warmest low temperature records for both today and Friday are unlikely to be broken, though Saturday's temperature records for both Chicago and Rockford could potentially be threatened.

Here are the daily high and warmest low temperature records for Chicago and Rockford for each day through Saturday, June 22nd:

Chicago ----------------------------- Day: 6/20 6/21 6/22 ----------------------------- Record High: 104 101 97 Record Warm Low: 78 74 76

Rockford ----------------------------- Day: 6/20 6/21 6/22 ----------------------------- Record High: 101 100 97 Record Warm Low: 73 71 73


IN...Air Quality Alert until midnight CDT Friday night for INZ001- INZ002-INZ010-INZ011.

Air Quality Alert until midnight EDT Friday night for INZ019.

LM...Dense Fog Advisory until 10 PM CDT this evening for the IL and IN nearshore waters.

Weather Reporting Stations
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Stations Dist Age Wind AirWater WavesinHgDewPt
45186 32 mi30 minSW 14G19 62°F 64°F3 ft
45174 34 mi30 minNW 9.7G14 63°F 66°F3 ft30.2563°F
45187 38 mi20 minN 14G19 60°F 61°F3 ft
OKSI2 38 mi90 minNNE 4.1G6 66°F
CHII2 - Chicago, IL 40 mi30 minN 13G14 68°F 68°F
CNII2 40 mi15 minN 7G13 69°F 63°F
45198 41 mi30 minNNE 12G14 65°F 67°F2 ft30.32
KNSW3 - Kenosha, WI 42 mi30 minNNE 9.9G12 59°F 30.28
CMTI2 - 9087044 - Calumet, IL 47 mi42 minNNW 7G12 68°F 30.2466°F

Wind History for Calumet Harbor, IL
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Airport Reports
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AirportDistAgeWind ktVisSkyWeatherAirDewPtRHinHg
KDPA DUPAGE,IL 13 sm38 minvar 0510 smMostly Cloudy90°F68°F49%30.24
KPWK CHICAGO EXECUTIVE,IL 21 sm38 minNE 0910 smClear77°F64°F65%30.29
KORD CHICAGO O'HARE INTL,IL 22 sm39 minNE 0810 smA Few Clouds82°F66°F58%30.26
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Wind History graph: DPA
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GEOS Local Image of great lakes   

Chicago, IL,

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