When do Chicago fireflies arrive?

Dear Tom,
When do fireflies (lightning bugs) start to come out in Chicago? I understand it has to do with warmth.

—Donna Morris

Dear Donna,
“One of the most enchanting sights of the season is the delicate light of fireflies blinking in the night. … These graceful little stars put on a magical show that would make even Tinkerbell jealous! … They don’t sting, bite, attack or carry disease, they’re not poisonous, and they don’t even fly very fast. What’s not to like about fireflies?” –Signs of Spring Magazine.
Firefly larvae hatch from eggs deposited in damp soil in the summer. They live one or two years underground, develop into pupae in late spring and emerge as adults in early summer. In the Chicago area, fireflies begin to appear in June and remain active through August. Their life cycle changes are apparently genetically controlled, rather than determined by temperatures.

Tim's Weather World: Location, Location, Location

Not all carbon dioxide is created equally…

A new study by Stanford University indicates that carbon dioxide’s affects people living in cities with more harm than people living in rural areas.   According to the study, carbon dioxide “domes” over cities increase the local temperatures there, which then eventually increases the amount of local pollutants such as ground-level ozone and soot.


chicagosmog.jpgMark Jacobson, director of Stanford’s Atmosphere/ Energy Program, estimates that urban CO 2 caused 50 to 100 excess deaths per year in California and 300 to 1000 excess deaths across the United States each year.

This is one of the first studies to look at the local effects from increased levels of CO 2.  If their findings are correct, the authors of the study say, “this result contradicts the basis for air pollution regulations worldwide, none of which considers controlling local CO2 based on its local health impacts.”




Often stormy March should remain quiet

March is proverbially a blustery month in Chicago. Its weather, more often than not, is especially unsettled as warm and cold air masses jostle for supremacy. And following a winter that delivered colder temperatures and considerably more snow than normal, most Chicagoans are anxiously anticipating the arrival of spring.

To date, this March has not been a disappointment: Its weather has been uncharacteristically quiet and storm-free — Saturday’s snow notwithstanding. The month’s temperatures have averaged 5.6 degrees above normal and severe thunderstorms, often an increasing threat in northern Illinois in March, have so far not entered the picture.

The quiet pattern, at least by March standards, is set to continue a few more days. Temperatures will take a nice upward bump today and Tuesday and a few showers are possible midweek, then more showers are possible next weekend.

– By Richard Koeneman, WGN Weather Center Meteorologist

Frost despite lows in the 40s?

Dear Tom,
Why do we have frost when low temperatures at night are in the 40s? Golfers are made to wait until the frost melts before they can tee off.

– Tom Mezyk

Dear Tom,
The National Weather Service, following international standards, measures air temperatures at a height of four to five feet above the ground. On clear, calm and dry nights when heat radiates strongly away from the ground (so-called “radiative cooling”), air temperatures right at ground level sometimes drop 5 to 8 degrees lower than readings at thermometer height. In addition, surfaces such as blades of grass chill even more quickly than the ground-level air in which they are immersed. One result of this localized cooling is frosty grass even though “official” air temperatures are 5 to 10 degrees above freezing. Frost that forms on such nights disappears quickly in direct sunlight or when a morning breeze begins to stir.

Up to 5" of snow reported in Chicago's north suburbs, 8" in Miami (Oklahoma that is)

Up to a foot of snow fell over 4 different southern states last night and today.  Locally, Chicago’s northern suburbs were hit the hardest from the weekend storm.

For the very latest, including a complete listing of snowfall totals, follow the link below to the WGN Severe Weather Blog     http://weblogs.wgntv.com/chicago-weather/severe-weather/


Below:  Snow, still falling at a good clip in Howe, Texas at 8:15AM Sunday. 

03 21 2010 0815_howe tx.jpg 


Weekend snowfall totals

The first snow of the entire month of March is just about over.   A few flurries or sprinkles are still possible through the afternoon, but the bulk of the precipitation is over.

Here are a few storm totals from across the Chicago area

5.0″  Lake Forest

4.2″  Gurnee

3.9″  Elk Grove Village

3.5″  De Kalb

2.2″  Batavia

2.1″  Downers Grove

2.0″  Chicago- Wrigley Field

1.8″  Chicago- O’Hare

1.0″  Yorkville

0.5″  Romeoville

Below:  The snow is already starting to melt this morning in north suburban Wadsworth. 

03 21 2010 0950_s wadsworth.jpg