Sunday’s 70s to bring warmest Easter in 4 years

By Meteorologist Steve Kahn

High temperatures are forecast to climb  into the 70s Sunday as  south winds and ample sunshine deliver holiday warmth. Winds cutting in off chilly Lake Michigan, however, will keep areas along the north lakeshore a bit cooler.  It should be the city’s warmest Easter in four years since a 76-degree high on April  4, 2010.

 A cool-down will follow the passage of a cold front Monday, which will be accompanied by showers and thunderstorms. Despite the Chicago area’s very snowy winter, precipitation since March 1 is running  about 1.5 inches below normal.  A return to cooler weather is expected Tuesday and Wednesday before another round of showers and thunderstorms arrives Thursday setting the stage for a chilly weekend with temperatures forecast to only reach the lower 50s Saturday.

ASK TOM: Chicago’s biggest Easter snow

Dear Tom, 

What was Chicago’s biggest Easter snow?

— Bob Johnson,

Buffalo Grove

Dear Bob,

By the nature of Easter’s movable date, which can be as early as March 22 or as late as April 25, the weather on the holiday has greatly varied, ranging from wintry to summerlike. Since 1885 snow has fallen on 21 Easters, most recently in 2007. Most of the snowfalls have been minor events, but the holiday has hosted two major snowstorms.

On April 4, 1920, the city was hit by 6.4 inches of snow, but the biggest snowfall occurred March 29, 1964, when 7.1 inches fell. The snow began just before sunrise and lasted until about 5 p.m. Winds gusting to nearly 40 mph created near-blizzard conditions, with visibility dropping to less than one-quarter of a mile. An inch of snow also fell that Saturday.

Temps headed to 60-degrees Thursday for the 9th time in 2014

By Meteorologist Tom Skilling

More seasonable temperatures return to Chicago Thursday building on Wednesday’s 52-degree high.

Coincident with the arrival of the city’s first day with a normal temp of 60-degrees, Thursday afternoon’s peak reading is also to hit 60. It marks only the 9th time this year that Chicago’s temperature has been as warm or warmer.

Late season Midwest snowstorm hits the North Woods hard; accumulations have topped 1ft.

The storm responsible for the gusty southerly winds which began raking the Chicago area Wednesday have helped propel milder air into this  area while fueling the latest snowstorm burying sections of the upper Midwest.

What’s interesting is that part of the area being lambasted by wind and snow across northern Wisconsin,  Minnesota and Upper Michigan, may, in a matter of just days, warm areas to within striking distance of 60-degrees later this coming Easter weekend.

Snow totals reported late Wednesday—with snow still coming down—had reached 13.5” Grantsburg, WI; 12.3” Spooner, WI; 10.5” Hinckley, MN; 10” Hayward and New Post, Wisconsin.

April 2014′s has had its share of cool days—but the month’s running 1.6-degrees ahead of last year

April, 2014’s has generated its share of cool temperatures. But, the month’s average temperature has moved into positive territory. It’s the first time that’s happened in any months since last October. Thus, while subtle, the road to the warmer temps of late spring and summer is clearly underway—an effort which can be expected to yield warmth with increasing frequency in the weeks and months to come—-but area residents shouldn’t be fooled. Lake Michigan is still cold and a wind shift off the chilly waters can— and will—generate cool temperatures until water temperatures warm.

ASK TOM: Bright green streak falling star.

Dear Tom,

In late March I saw a bright green streak, a falling star. What accounts for that color? Air pollution?

— Frank Dezio

Dear Frank,

Meteoroids, orbiting the sun in huge numbers, are believed to be debris left over from the formation of the solar system.

They are occasionally captured by the Earth’s gravitational pull and, plunging at speeds up to150,000 mph, glow to incandescence because of friction with the atmosphere.

A brief streak of light, usually whitish, is the familiar result.

But astronomer Dan Joyce of Triton College tells us that a distinct green color is not rare.

The color of the streak has nothing to do with the atmosphere, he says.

The composition of the meteoroid is probably a reason for the color, and he suspects it is likely chromium.

Yesterday's showers produced some impressive shafts of rain out of the base of the clouds--like this group of showers photographed by Amanda Rauch in DeKalb. Photo courtesy of Amanda Rauch, DeKalb, IL

Yesterday’s showers produced some impressive shafts of rain out of the base of the clouds–like this group of showers photographed by Amanda Rauch in DeKalb. Photo courtesy of Amanda Rauch, DeKalb, IL

Photographer Lorraine Mahoney sends us this lunar eclipse time sequence--you see it on the right side of this photo as the moon transitions to its orange and red hued Blood Moon-state----near the Fabyan Windmill out in the Fox Valley in Geneva. Photo courtesy of Lorraine Mahoney, Fabyan Windmill-Geneva, IL

Photographer Lorraine Mahoney sends us this lunar eclipse time sequence–you see it on the right side of this photo as the moon transitions to its orange and red hued Blood Moon-state—-near the Fabyan Windmill out in the Fox Valley in Geneva. Photo courtesy of Lorraine Mahoney, Fabyan Windmill-Geneva, IL

HERE'S David Spearman's shot of Tuesday morning's Blood Moon as photographed from Chicago. Photo courtesy of David Spearman, Chicago

HERE’S David Spearman’s shot of Tuesday morning’s Blood Moon as photographed from Chicago. Photo courtesy of David Spearman, Chicago

You can see how little ice remains on southern Lake Michigan in this shot. This ice floe was floating out on Lake Michigan and was photographed by Kyle Anderson near Holland, Michigan as Kyle was flying eastbound at the 5,500 ft. level.  It's a testament to how much of the once record level of ice has melted.  This ice is floating there in open water. Photo courtesy of Kyle Anderson, Near Holland Michigan

You can see how little ice remains on southern Lake Michigan in this shot. This ice floe was floating out on Lake Michigan and was photographed by Kyle Anderson near Holland, Michigan as Kyle was flying eastbound at the 5,500 ft. level. It’s a testament to how much of the once record level of ice has melted. This ice is floating there in open water. Photo courtesy of Kyle Anderson, Near Holland Michigan

HERE'S THE EASTER BUNNY---photographed by Bill Parkinson, a member of the Foresters Camera Club, amid Tuesday morning's snow. Photo courtesy of Bill Parkinson, Forester's Camera Club member

HERE’S THE EASTER BUNNY—photographed by Bill Parkinson, a member of the Foresters Camera Club, amid Tuesday morning’s snow. Photo courtesy of Bill Parkinson, Forester’s Camera Club member

Sue Stefanowicz headed out to feed the birds in the wake of Tuesday's ground covering snowfall. Here she's hand-feeding this Tufted Titmouse.  It's clear Sue has developed quite a rapport with this little fella. Photo courtesy of Sue Stefanowicz

Sue Stefanowicz headed out to feed the birds in the wake of Tuesday’s ground covering snowfall. Here she’s hand-feeding this Tufted Titmouse. It’s clear Sue has developed quite a rapport with this little fella. Photo courtesy of Sue Stefanowicz

John Tompkins sends us this shot of conditions earlier this evening in Osseo, MN ---a Minneapolis suburb.  John e-mailed “Chicagoans are actually lucky!!” Photo courtesy of John Tompkins, Osseo, MN

John Tompkins sends us this shot of conditions earlier this evening in Osseo, MN —a Minneapolis suburb.
John e-mailed “Chicagoans are actually lucky!!” Photo courtesy of John Tompkins, Osseo, MN

I received a flood of images of halos observed in Florida today.  These appeared to catch folks eyes—BIGTIME!! Photo courtesy of Bill Harris, Redington Shores, Florida

I received a flood of images of halos observed in Florida today. These appeared to catch folks eyes—BIGTIME!! Photo courtesy of Bill Harris, Redington Shores, Florida

This wider shot relayed to us from Adam Wlodarski in Siesta Key, Florida shows why this caught folks attention.  The halo dominated the sky. Photo courtesy of Adam Wlodarski, Siesta Key, Florida

This wider shot relayed to us from Adam Wlodarski in Siesta Key, Florida shows why this caught folks attention. The halo dominated the sky. Photo courtesy of Adam Wlodarski, Siesta Key, Florida

Tuesday’s 38-degree April 15 “Tax Day” temp the coldest here in 86 years; readings flirt with records and 21-degrees below normal

By Meteorologist Tom Skilling

Tuesday’s 38-degree Chicago high temperature would have been right at home in February. The reading equals the “normal” high here on Feb. 22.

But the frigid 38-degree reading, 21-degrees below normal, occurred on “Tax Day” and was the coldest April 15 which has been observed here in the 86 years since 1928!

Daytime highs were actually higher in much of Alaska than in Chicago and adjacent areas of Illinois, Wisconsin and Michigan—reaching levels close to 50-degrees at a number of locations across the 49th state.

Chicagoans didn’t shiver alone; records fell at a number of Upper Midwest locations; frost and freeze warnings issued for 24 states overnight

The abnormal chill wasn’t limited to Chicago Tuesday. Morning readings dipped to new records at International Falls, Minn.( 5 degrees), Sioux Falls, S.D. and Grand Forks, N.D. (11 degrees);  Watertown, S.D. (12 degrees) and at both Minneapolis, Minn. and Madison, Wisconsin (18 degrees).

Frost and freeze warnings were hoisted across 23 states south and east of Chicago—from eastern Oklahoma across much of the Deep South to New Jersey, Delaware and Maryland.

Tuesday highs averaged more than 20-degrees below normal south as far as Georgia, Alabama and Mississippi.

Only 4 other days beyond April 15 have generated daytime highs of 38-degrees or lower in over a half century at O’Hare 

Weather observations began at O’Hare in 1959. In all that time, temps of 38-degrees or lower have occurred beyond April 15 on only 4 other occasions.

Milder temps Wednesday and Thursday to yield to a chilly, new round of “NE” winds Friday

 Temps stage a modest recovery with the arrival of Wednesday’s powerful southerly winds. The “warming” may linger into a second day Thursday.  But a thermal downturn, prompted by the re-emergence of northeast winds Friday, is to render the “warming” short-lived.

Daytime highs Friday may remain in the 40s in areas close to Lake Michigan.

South winds Easter Sunday could send temps surging into the 60s

More significant warming is in the offing over the weekend—particularly Easter Sunday.  At that time, a new round of powerful southerly winds is to send temps back into the 60s.

ASK TOM: How are very abnormal temperatures figured into Chicago’s “normal” temps?

Dear Tom,

Over what period of time have Chicago’s daily normals been calculated? How are the very abnormal temperatures like our very cold winter figured into the normals?

— Tig White, Chicago

 

Dear Tig,

The National Weather Service’s National Climatic Data Center in Asheville, N.C., calculates the official normal daily high and low temperatures used in the U.S. By international agreement, normals are simple arithmetic averages of weather variables over 30 years, generally three consecutive decades, and they are recalculated each decade. Normals now in use cover the period 1981-2010.

Unusual temperatures are factored into the calculations just like any other readings.

Don’t overinterpret normal values. They don’t even represent what should happen; they are merely averages.