Marine Forecasts

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7 Day Forecast for Marine Location Near Joliet, IL

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Area Discussion for - Chicago, IL

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FXUS63 KLOT 251154 AFDLOT

Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 554 AM CST Sat Jan 25 2020

SHORT TERM. 311 AM CST

Through Sunday .

The center of the upper low, that has been impacting the weather across the region for the past couple of days, is now east of KVPZ. Expect this storm system shift east-northward across southern Lower Michigan through the day and over New England by Sunday afternoon.

Bands of moderate to, at times, heavy snow have been ongoing across mainly western sections of the area around the I-39 corridor over the past several hours within a corridor of enhanced deformation centered near the track of the 700 mb low. This has effectively resulted in a narrow corridor of strong forced ascent through the dendritic growth zone, and within a region of steeper mid-level lapse rates. Rockford airport (KRFD) reported 1 inch per hour rates from about 10 pm through around 1 am within this band of heavier snow. This band of deformation is likely to shift eastward over parts of northeastern IL early this morning, so a period of moderate snow is likely to shift in over the Chicago metro area over the next couple of hours.

While snowfall rates will not be as impressive today, it still appears that accumulating snow will occur in a north-northwest to south-southeast corridor across northeastern IL and into northwestern IN today. Isentropic upglide on the western periphery of this large upper low is likely to continue for much of the day, so periods of snow will be a good bet across the Chicago metro area, and points to the south-southeast, especially through the morning hours and into the early afternoon. During this period the another 1 to 2 inches could occur. The snow should begin to gradually wind down later this afternoon and into the evening, with little to no additional accumulation thereafter.

We will have to monitor a small potential for drizzle or freezing drizzle later this evening. Model soundings indicate that drier air will shift in over the area aloft, while we maintain low cloud cover. This could result in the possibly of any lingering light precipitation falling as drizzle/freezing drizzle. I do not have a high amount of confidence that precipitation will still be occurring later this evening, so the potential for this freezing drizzle remains low, but I felt that a small chance mention in the forecast was warranted.

As for the ongoing winter weather advisory, I am not planning any changes to the end time due the possibly of freezing drizzle this evening. However, as previous discussions noted, it is possible that the advisory could be ended for the area later today, prior to its expiration tonight.

Quieter weather is expected over the area on Sunday. However, expect the low cloud cover to continue through the day. Highs should be in the low 30s.

KJB

LONG TERM. 221 AM CST

Sunday night through Friday .

Fairly benign pattern for the long term period. Weak long wave troughiness over the Great Lakes expected to persist much of the upcoming work week with mainly just some weak clipper-like systems potentially affecting the area with some light precip chances at times. Looks to be a fairly cloudy period with continued above average temps, largely due to above average nighttime lows. Will probably be a bit larger of a temp gradient across the CWA between the deeper snow pack left behind from this current system, but until we have a better idea where the snow pack will lay out, didn't make any adjustments to temps.

- Izzi

AVIATION. For the 12Z TAFs .

Light snow is expected to persist this morning and probably linger into the afternoon at the Chicago terminals. Best chance for IFR VSBY due to snow is this morning, but some potential for at least ocnl IFR in snow this afternoon. By later this afternoon will probably see a transition to possibly light snow/drizzle mix or just plain drizzle. Also possible that precipitation could just end later this afternoon with little or no drizzle. Temperatures will likely inch above freezing this morning and remain just a bit above freezing into this evening, so not anticipating much snow accumulation today. IFR CIGS expected to persist into this evening and possible through the overnight hours as well, though guidance does suggest a gradual improvement to MVFR by Sunday morning.

- Izzi

LOT WATCHES/WARNINGS/ADVISORIES. IL . Winter Weather Advisory . ILZ003-ILZ004-ILZ005-ILZ006-ILZ008- ILZ010-ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021- ILZ022 until midnight Sunday.

IN . None. LM . None.

Visit us at weather.gov/chicago

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Weather Reporting Stations

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Stations	Dist	Age	Wind	Air Temp	Water Temp	Waves	Pressure	DewPt
CMTI2 - 9087044 - Calumet, IL	36 mi	53 min	SW 6 G 8.9	33°F			1008.3 hPa	33°F
CNII2	37 mi	23 min	SW 5.1 G 8.9	34°F				32°F
CHII2 - Chicago, IL	41 mi	33 min	W 11 G 12	34°F				34°F

Wind History for Calumet Harbor, IL

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Airport Reports

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Airport	Dist	Age	Wind kt	Visibility	Sky/Weather	Temp	DewPt	Humidity	Pressure
Joliet Regional Airport, IL	1 mi	48 min	W 5	2.00 mi	Light Snow	34°F	33°F	97%	1009.8 hPa
Lewis University Airport, IL	7 mi	48 min	W 8	3.00 mi	Light Snow	32°F	32°F	100%	1009.5 hPa
Morris Muni-James R Washburn Field Airport, IL	15 mi	28 min	W 10	3.00 mi	Light Snow	33°F	32°F	99%	1010.2 hPa
Aurora Municipal Airport, IL	24 mi	31 min	W 9	2.50 mi	Light Snow Fog/Mist	33°F	30°F	92%	1009.9 hPa

Link to 5 minute data for KJOT

Wind History from JOT (wind in knots)

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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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Wind Forecast for Chicago, IL (8,2,3,4)

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Ground Weather Radar Station Chicago, IL

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