Here are the June 2010 rainfall totals for sites in Illinois, ranked from highest to lowest. The numbers are impressive with 35 sites scattered throughout northern and central Illinois reporting 10 or more inches of rain.
These numbers are preliminary and have not been quality-controlled. In some cases data may be missing that could lead to totals that are too low. Due to the localized nature of some of the heavier storms, one may see large differences over short distances. These sites are part of the NWS cooperative observer program – volunteers with standard equipment and observing practices.
Illinois has experienced the 2nd wettest June on record, based on preliminary records through June 30. The statewide average rainfall was 7.8 inches, 3.7 inches above normal. The wettest June on record was 1902 with 8.37 inches. The rains over the weekend, especially north of I-80 and along I-70 caused this June to move up from fourth to second wettest June on record. Statewide records extend back to 1895. This number is provisional and may change slightly as more data comes in.
The larger rainfall totals occurred in the northern two-thirds of the state where amounts of 7 to 12 inches were common. Meanwhile far southern Illinois remains closer to normal with amounts ranging from 3 to 6 inches.
Right now the statewide precipitation average of 7.20 inches makes this the 4th wettest June on record. Statewide records go back to 1895. Here are the top 5 …
8.37 inches in 1902
7.68 inches in 1998
7.31 inches in 1928
7.20 inches in 2010 (as of June 25)
7.13 inches in 2000
With rain in the NWS forecast for the weekend, it is possible to move up to third or perhaps even second place. However, it would take widespread heavy rains to beat 1902. By the way, normal statewide June rainfall is 4.1 inches.
Of the ten wettest Junes, in 7 out of 10 cases rainfall returned to within an inch of normal conditions in July and August. Only in 1993 did the wet conditions persist into July and August. Only in 1945 and 1947 did we experience much drier conditions in July and August.
Meanwhile temperatures have been above normal for June so far. The statewide average temperature of 74.9 degrees is 3.6 degrees above normal. This is now the tenth warmest June on record (as of June 25). The warmest June on record for Illinois is 1934 with 78.5 degrees. The only recent year in the top 10 list is 2005 with 74.8 degrees.
The National Weather Service just posted the message below. As noted in an earlier posting Galesburg has already experienced its wettest June on record with 11.25 inches.
RECORD EVENT REPORT
NATIONAL WEATHER SERVICE LINCOLN IL
1055 PM CDT TUE JUN 22 2010
...RECORD DAILY MAXIMUM RAINFALL 2.46 INCHES IN LINCOLN IL JUNE 22...
...WETTEST JUNE ON RECORD IN LINCOLN WITH 9.85 INCHES SO FAR THIS
A RECORD RAINFALL OF 2.46 INCHES WAS SET AT LINCOLN IL TODAY WITH
2.42 INCHES FALLING IN LESS THAN 6 HOURS THIS MORNING. THIS BREAKS
THE OLD RECORD OF 2.33 INCHES SET IN 1924.
SO FAR THIS MONTH 9.85 INCHES OF RAIN HAS FALLEN IN LINCOLN THROUGH
JUNE 22ND AND THIS BECOMES THE WETTEST JUNE ON RECORD...JUST BEATING
THE 9.83 INCHES SET IN 1947. THERE ARE STILL EIGHT MORE DAYS IN THE
MONTH TO GET MORE PRECIPITATION...AND MORE HEAVY RAINS ARE STILL
POSSIBLE THROUGH WEDNESDAY NIGHT.
The wetter and warmer than normal weather continued in Illinois this week. For the period of June 16-22, the state average temperature was 76.8 degrees, 3.6 degrees above normal. Meanwhile the statewide average precipitation was 2.46 inches, 1.55 inches above normal.
Illinois already experienced above normal temperature and precipitation in the first half of June. Combined with this week’s weather, the statewide average temperature for June so far is 74.5 degrees, 3.4 degrees above normal. The statewide average precipitation at this point is 6.35 inches, 3.37 inches above normal.
If you are thinking that we must be closing in on a record, you are correct. Statewide this is already the 10th wettest June on record. The wettest June on record is 1902 with 8.37 inches. Several individual station records will be set as well. For example, Galesburg has already received 11.25 inches this month. This handily beat the old June record of 9.97 inches set in 1974. This is impressive given that their records go back to 1927.
The wettest areas of the state are western Illinois and east-central Illinois. Based on radar estimates and reports from weather observers, monthly totals of 9 inches or more were common in these areas. The wettest spot so far is Warsaw (Hancock County CoCoRaHS observer) which has reported 11.38 inches through today (June 22) with more rain falling after the regular reporting time.
Here are the precipitation and precipitation departure maps for June 1-22, 2010, for Illinois.
Based on preliminary data, the statewide average temperature for the first half of June was 73.4 degrees, 3.3 degrees above normal.
The statewide average rainfall for the first half of June was 3.85 inches, 1.78 inches above normal. Much of the southern and northern thirds of the state were near normal while central Illinois was much above normal.
The wettest areas are in a region between Quincy and the Quad Cities (again) and in east-central Illinois. For June 1-15, the following rainfall totals were reported: Moline with 4.35 inches, Quincy with 4.78 inches, Springfield with 3.85 inches, Champaign with 4.88 inches , and a CoCoRaHS observer in Sidney (SE of Champaign) with 7.84 inches.
The National Weather Service provides a high-resolution precipitation product that combines both rain gauge and radar data. It can be found at http://water.weather.gov/precip/. Here is the rainfall departure map for June 1-15, 2010, clearly showing the heavy rain areas in western and east-central Illinois.
More rains are falling in Illinois while this is being written on the afternoon of June 15.
A large tornado outbreak occurred in Illinois on June 5. The NOAA Storm Prediction Center has 31 preliminary damage reports for the state (see below). In some cases a single tornado generated multiple damage reports as it moves cross-country. At this time there appears to have been 15 confirmed tornadoes involved.
NWS offices conducted extensive damage surveys in central and northern Illinois the next day. Here are their findings:
Based on preliminary data, the statewide average temperature for spring in Illinois was 55.3 degrees, 3.3 degrees above normal and the fourth warmest spring on record. Warmer than normal conditions prevailed in the spring months of March (+2.5 degrees), April (+6.2 degrees), and May (+1.3 degrees).
The statewide average precipitation for spring was 11.97 inches, just 0.7 inches above normal. This is notably less than the 15.83 inches that fell in the spring of 2009 and the 14.21 inches that fell in the spring of 2008.
Climatologists and meteorologists tend to use the calendar months of March-May to define spring and not the astronomical definition from the vernal equinox (usually March 20) to the summer solstice (usually June 21). The calendar months better match the climate of Illinois. Our winter weather usually diminishes by early to mid March across much of Illinois and summer weather usually arrives long before June 21.
For Illinois, the preliminary statewide average temperature was 64.1 degrees, 1.3 degrees above normal. Basically the first 17 days of the month ran on the cool side (1.4 degrees below normal) while the rest of the month ran on the warm side (4.8 degrees above normal). The map below shows the temperature departures.
The statewide average rainfall was 5.68 inches, 1.42 inches above normal or 133% of normal. The heaviest amounts for the month were in western Illinois between Quincy and the Quad Cities. Dallas City, along the Mississippi River, reported 9.07 inches for the month.