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


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



Up to a foot of snow buries Oklahoma, Arkansas, Kansas and Texas

Chicago escaped the latest spring storm rather unscathed compared to some of our neighbors to the south.   Up to a foot of new snowfall is being reported this Sunday morning across portions of four southern states   The snow extended as far south as north Texas where some suburban residents of Dallas awoke to over a half foot of snow. 

Here are some of the storm totals                                    Below:  Fayetteville, Arkansas at 8:15 this AM

03 21 2010 0815_s fayetteville ar.jpg12.0″  Fayetteville, AR

12.0″  Fort Scott, KS

12.0″  Jerico Springs, MO

12.0″  Siloan Springs, OK

11.5″  Westville, OK

 8.3″   Carbondale, KS

 8.0″   Plano, TX

 8.0″   Miami, OK

 8.0″   Sadalaia, MO

 5.6″   McKinney, TX


Below:  Winter Storm Warnings are still in effect this Sunday morning from Kansas City, Missouri to Dallas, TX 




Snow should disappear in the Chicago area as temperatures rebound quickly

After a mostly cloudy cool day Sunday, astronomical spring will shift
in gear Monday and with winds shifting to the southwest temperatures
are expected to return to the 60-degree level by Tuesday afternoon.
This means the thin layer of snow deposited over much of the area
Saturday–greatest amounts were between 2 and 3 inches–will probably
be gone, perhaps as soon as Monday.

Heavy snows to the south

a strong low pressure system tracks east out of the southern plains,
Winter Storm Warnings were posted for eastern Oklahoma, southeast
Kansas, Southwest Missouri and northwestern Arkansas where
Saturday-Sunday snowstorm totals of 6 to 12 inches were forecast. The
cold air was to moderate, with primarily rain expected as the low
center tracks east reaching the mid-Atlantic coast Tuesday.

Warmup next weekend

through Friday northeastern Illinois temperatures are expected to
average a little above seasonal norms with 60-degree readings marking
the return of strong southerly winds the start of next weekend.