The official IL weather thread

[seastar311]

Wow, it's really raining! (South suburbs)

[Steve-o]

Was nice to have 2 sunny days in a row! LOL Been very unusally rainy this month!

[Avengerfire]

Originally Posted by Steve-o

...Been very unusally rainy this month!

You mean last month.

[Steve-o]

Yes, I forgot it was the 1st when I posted that.

Been nice the last few days! Supposed to get warm (low 70s) again this weekend.

[Avengerfire]

Originally Posted by Steve-o

...Supposed to get warm (low 70s) again this weekend.

Hmm. They only have said low to mid 60's for the city. Unless they updated it recently.

I would expect it to approach 70 near the lake at least. The lake is still relatively warm.

[Careless]

Originally Posted by Avengerfire

Hmm. They only have said low to mid 60's for the city. Unless they updated it recently.

I would expect it to approach 70 near the lake at least. The lake is still relatively warm.

Lake is about 55 now. It'll be cooler here

[Avengerfire]

Originally Posted by Careless

Lake is about 55 now. It'll be cooler here

The last few weeks the low at night by the lake has been 10 degrees warmer than in the far out burbs. It does not get colder by the lake until the end of December.

[Careless]

Originally Posted by Avengerfire

The last few weeks the low at night by the lake has been 10 degrees warmer than in the far out burbs. It does not get colder by the lake until the end of December.

The lake is physically incapable of warming 60 degree land when it is cooler than 60 degrees.
http://coastwatch.glerl.noaa.gov/cwdata/lct/glsea.png

[Avengerfire]

Originally Posted by Careless

The lake is physically incapable of warming 60 degree land when it is cooler than 60 degrees.

For example,why was it 56 in Lakeview about an hour ago,53 at Midway,52 at O'Hare and 48-50 in most of the western suburbs?

"Regional conditions
Location Conditions Temp.
Midway Airport Partly Cloudy 52°
O'Hare Airport Partly Cloudy 49°
DuPage Airport Clear 48°
Aurora Clear 43°
Gary Clear 55°
Joliet Clear 51°
Libertyville Clear 48°
Rockford Clear 51°
Waukegan Clear 48°"

http://weather.chicagotribune.com/US...RD.html?main=1

"Lakeview
52.4 °F
Partly Cloudy"

http://www.wunderground.com/US/IL/Chicago.html

[sandwalk]

Large bodies of water (Lake Michigan, for example) take longer to warm up and longer to cool down, whereas as land heats up quicker and cools down quicker (has to do with solar radiation reflection/retension). That, combined with the Urban Heat Island effect generally keeps the temperature a good 7-10 degree warmer in Chicago/Evanston/cities nearest the lake, at this time of year. The reverse occurs in the spring/early summer. The lake is still 45-55 degrees when the atmosphere can be 65-70; the cooler conditions over the lake allow the air to be cooler; cold air (high pressure) always sinks/flows toward the warmer air (lower pressure). That's how/when the "lake breeze" sets up and creates cooler conditions near the lakeshore in the spring/early summer.

It's a lot to take in; and there is more detail that I left out. But, that's generally how the lake effect works