Marine Forecasts

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7 Day Forecast for Marine Location Near Evanston, IL

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Area Discussion for - Chicago, IL

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FXUS63 KLOT 020915 AFDLOT

Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 415 AM CDT Thu Apr 2 2020

SHORT TERM. 355 AM CDT

Through Tonight .

Focus in the near term is on dense fog which has developed overnight near the lake and inland across parts of northwest Indiana and the southern Chicago metro area. Have expanded the dense fog advisory slightly to include areas south of the Kankakee River valley in northwest Indiana, and farther west across Will county in the south/southwest suburbs.

A combination of webcam imagery, surface obs and GOES IR satellite imagery indicates an area of low clouds and dense fog across far southern Lake Michigan and parts of adjacent northwest IN and southern Chicago metro early this morning. Fog appears to be pretty shallow in downtown cams with a view of the lake shore, with not much inland push into the heart of the city. High-res guidance has captured the fog threat fairly well, though it may be over-forecasting the inland push across the central portions of the metro area this morning. Low level east-southeast flow would support an expansion of fog across the city and west suburbs as depicted by RAP/HRRR and other guidance, though at this time fog appears to be shallow enough to be limited to the immediate surface wind field which is light/variable. Have updated to include more of Will county in the dense fog advisory, as well as Newton and Jasper counties in northwest Indiana were it fog has spread south of the Kankakee river, but with slower westward movement held off on central Cook/DuPage counties and will just have to monitor for any possible further expansion there. Shallow nature of the fog does suggest it will burn off fairly quickly this morning.

Otherwise, quiet weather is on deck for today with ridging aloft, and a gradual increase in southeast winds. After fog burns off this morning, expecting patchy mid/high clouds at times from a weak short wave west of the upper ridge axis. Partly sunny conditions should support temperatures warming to around 60/lower 60s west and south of the city, while southeast winds off the lake maintain cooler temps with upper 40s along the immediate shore.

Mid-level short wave west of the area today ripples overhead tonight, with a brief period of enhanced warm/moist advection and isentropic ascent which produces some mid-level saturation. Several models develop some light spotty QPF across parts of far northern IL, though dry low levels and relatively weak forcing suggests this should be limited to some scattered lighter showers and sprinkles overnight.

Ratzer

LONG TERM. 415 AM CDT

Friday through Wednesday .

Weak mid-level short wave which moves into the upper ridge across the area Thursday night will exit the area Friday morning, with the upper ridge strengthening downstream of deeper troughing advancing across the northern Plains. This will set the stage for a mainly dry day, with low level south-southeasterly flow providing a continued warm-up. Mid and high level cloud cover will remain in place in at least patchy fashion during the morning, and some sunshine will aid in warming temps into the low-mid 60s in most areas. A slight southeast component to surface winds will continue to keep the IL lake front cooler however. Scattered shower chances slowly increase from the west by late afternoon across northwest IL as a cold front drifts toward the Mississippi River from the west. A more substantial rain threat spreads east across the area Friday night, as the front pushes into the area. While better mid/upper level forcing passes north of the area, weak height falls do develop atop the low level frontal zone and narrow low-level moisture axis along and ahead of the front. In addition, a plume of steeper mid-level lapse rates (6.5-7.0 C/km) spreads across the area overnight, with some guidance depicting some modest 100-200 J/kg elevated CAPE for parcels originating above 800 mb. This may support a few embedded rumbles of thunder overnight especially across the western and southern parts of the cwa where the steep lapse rate plume is better established.

The cold front continues its slow east-southeastward trek across the forecast area Saturday, with rain gradually ending across north central IL by early afternoon and across all but areas generally east of I-55 by evening. Far southeastern parts of the cwa may see showers linger Saturday night as the front slows up. Surface high pressure builds across the area Sunday, and should provide a dry day to finish out the weekend.

Medium range guidance continues to develop a long wave trough along the west coast early next week, with a broad downstream upper ridge across the eastern CONUS. With quick southwesterly flow aloft, surface low pressure is progged to develop out of the Plains and progress northeast to the western Great Lakes region through mid-week. In the process, a warm front lifts across the region, bringing warmer (potentially 70+ degrees) and more humid air into the region. Shower and thunderstorm potential also increases, with a few periods of unsettled weather likely Monday into Wednesday.

Ratzer

AVIATION. For the 06Z TAFs .

1231 AM . Primary forecast concern is dense fog and low clouds through mid morning.

Dense fog across northwest IN and far northeast IL will slowly spread west/northwest through the overnight hours. Dense fog is likely at both ord and mdw and for now have only included in a tempo but as trends emerge its likely prevailing dense fog may be needed . especially at mdw. This fog appears to be fairly shallow and much of the guidance burns this fog off quickly after sunrise. Only medium confidence for this quick improvement so changes are possible with later updates Once the fog dissipates. just mid/ high clouds expected for the rest of the period. Fog may also persist over the lake into this afternoon.

Light easterly winds may become light and variable early this morning and then will become light southeasterly later this morning. A lake breeze may shift winds more easterly with speeds increasing to 10kts in the afternoon with light southeast winds tonight.

There may be a few light showers across northwest IL this evening and at rfd. Confidence is fairly low but may need to add some mention with later forecasts. cms

LOT WATCHES/WARNINGS/ADVISORIES. IL . Dense Fog Advisory . ILZ014-ILZ022-ILZ105-ILZ106-ILZ107-ILZ108 until 9 AM Thursday.

IN . Dense Fog Advisory . INZ001-INZ002-INZ010-INZ011 until 9 AM Thursday.

LM . Dense Fog Advisory . Wilmette Harbor to Michigan City IN until 10 AM Thursday.



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Weather Reporting Stations

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Stations	Dist	Age	Wind	Air Temp	Water Temp	Waves	Pressure	DewPt
OKSI2	9 mi	147 min	Calm G 1	38°F
CHII2 - Chicago, IL	10 mi	37 min	SE 1 G 1	32°F				32°F
CNII2	13 mi	42 min	Calm G 2.9	32°F				31°F
CMTI2 - 9087044 - Calumet, IL	22 mi	57 min	NNE 1 G 1.9	32°F			1020.5 hPa	32°F
KNSW3 - Kenosha, WI	39 mi	87 min	WNW 2.9 G 4.1	35°F			1021 hPa (+0.3)
MCYI3 - Michigan City, IN	46 mi	37 min	N 1 G 1	32°F				32°F

Wind History for Calumet Harbor, IL

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Last 24hr

NW8 G11

NW7 G10

N10 G13

NW9 G13

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NW8 G12

NW9 G12

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N12 G15

N9 G13

N6 G9

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N10 G16

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N10 G13

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N13 G18

N12 G16

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N10 G15

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NW9 G13

2 days ago

W5 G11

W8 G14

W7 G13

W8 G16

W9 G14

W11 G16

NW10 G14

NE4 G8

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NE5 G8

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SE4 G7

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NE6 G9

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N11 G14

N9 G12

N10 G13

NW10 G15

N10 G14

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Airport Reports

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Airport	Dist	Age	Wind kt	Visibility	Sky/Weather	Temp	DewPt	Humidity	Pressure
Chicago / Wheeling, Pal-Waukee Airport, IL	12 mi	35 min	N 0	10.00 mi	Fair	34°F	30°F	89%	1022 hPa
Chicago, Chicago-O'Hare International Airport, IL	12 mi	36 min	N 0	10.00 mi	Fair	36°F	32°F	86%	1021.1 hPa
Chicago, Chicago Midway Airport, IL	17 mi	34 min	S 3	10.00 mi	A Few Clouds	34°F	33°F	97%	1021.9 hPa

Link to 5 minute data for KPWK

Wind History from PWK (wind in knots)

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N6

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Calm

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1 day ago

N7

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NE10 G19

NE8 G18

NE10 G20

N12 G20

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NW12 G21

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NW13 G18

NW14 G20

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SE4

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N9 G17

N8

N5

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Tide / Current Tables for

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Weather 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.
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Wind Forecast for Chicago, IL (6,6,7,8)

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Ground Weather Radar Station Chicago, IL

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