A Look Back at 2011 in Central and Southeast Illinois

 

Season by Season Highlights:


Winter Season (December 1, 2010 through February 28, 2011):

3-day snowfall ending February 3.  Click image to enlarge.  
3-day snowfall ending February 3, following the Groundhog Blizzard.  Click image to enlarge.

Seasonal Averages:

  • Temperatures -- Below normal
  • Precipitation -- Below normal south of I-70, and above normal north of I-70

TEMPERATURES -- After December ended with unseasonably mild temperatures in the 50s and 60s on the 30th and 31st, January temperatures were colder than normal.  January 7-13th, and January 20-24th, saw extended periods of cold weather, with the worst conditions on the morning of January 21, when lows around 10 below zero were reported near Springfield, Champaign, and Mattoon.  In February, bitter cold accompanied a major snowstorm as the month began, and the deep snowcover allowed temperatures to fall to as low as 17 below zero near Galesburg on the 10th.  However, rapid snowmelt followed, as temperatures reached as high as the lower 70s on the 17th and 18th.

WEATHER -- 2010 ended with an EF-3 tornado affecting the Lake Petersburg area of Menard County on December 31.  2011 started with more typical winter weather, with 4-6 inch totals reported on January 11th (from Galesburg to Peoria) and the 19-20th (along and south of I-70).

A widespread and unusually powerful snowstorm affected a large part of the nation as February began.  Excessive snowfall totals of a foot were common in a large area from Oklahoma northeast to Michigan, before the storm went on to affect New England.  Across central Illinois, most areas west of I-55 received at least a foot of snow on February 1-2, with totals in excess of 18 inches over parts of the Illinois River valley.  Storm total snowfall included 19.3 inches at St. David (Fulton County), 18.5 inches at Avon (Fulton County), and 18 inches at Winchester (Scott County).  Several locations broke all-time records for most snowfall in 24 hours.  Winds gusting from 50 to 70 mph caused widespread blizzard conditions.  Areas east of I-55 saw more of a mixture of freezing rain, sleet and snow, while southeast Illinois saw freezing rain accumulate to as much as 3/4 inch thick.  Damage from the snow and ice over central and southeast Illinois was estimated at $10 million, with snow removal costs estimated at $4.4 million.  

Due to the blizzard, February snowfall was unusually significant in several areas, especially west of I-55.  Peoria had its second snowiest February on record with 20.9 inches falling; the December through February total of 52.5 inches was the most on record for that period.  Springfield had its 4th snowiest February (16.5 inches) and Lincoln 7th snowiest.

By the end of the month, severe thunderstorms began to affect the area.  Hail ranging from dime to golfball size hail was reported on the 27th, from Rushville to near Bloomington, with 60 mph wind gusts reported as far southeast as Effingham.


Spring Season (March 1 through May 31):

Observed rainfall for April 2011.  Click image to enlarge.
Observed rainfall during April.  Pink shades are in excess of 10 inches.   Click image to enlarge.

Seasonal Averages:

  • Temperatures -- Near normal
  • Precipitation -- Above normal

TEMPERATURES -- While March averaged near normal, a substantial period of warmer weather occurred from the 15-23rd.  Several days during this period saw highs in the 70s, and approached 80 degrees south of I-70 and in west central Illinois near Jacksonville.  On the warmest days, observed low temperatures were warmer than the normal highs.  The first half of April was warmer than normal, with temperatures reaching as high as 88 degrees at Springfield and Jacksonville on the 10th, but the second half of the month was much cooler.   While May started out quite cool, 90 degree temperatures arrived by the 11th.  However, significantly cooler conditions followed shortly afterward, from the 14-17th.

WEATHER -- A strong storm system affected much of the area on March 4-5th, producing a large amount of the observed precipitation for the month.  Rainfall totals of over an inch were widespread from the Illinois River southeastward, with the heaviest totals generally along and south of I-70.  An area of 2 to 2.5 inches occurred near the Illinois/Indiana border from Casey to Hutsonville, and 2.13 inches was also reported in west central Illinois near Winchester.  These rainfall totals caused minor flooding on some area rivers.

Several periods of severe weather occurred during April.  The most significant ones were on the 15th and 19th.  Three tornadoes were reported on the 15th in Mason and Menard Counties, while hail of 1.75 to 2 inches in diameter occurred at Springfield and Waverly.  On the 19th, there was an early morning severe weather outbreak, then one again late afternoon into the evening, due to a sharp warm front (the high in Peoria was only 46 degrees, while the high at Springfield, about 60 miles south, reached 80 degrees).  A total of 6 tornadoes were reported, in Christian, Edgar, and Vermilion Counties.

A persistent frontal boundary over the Ohio Valley produced copious rainfall from April 22-27th in southeast Illinois.  Totals of 6-8 inches were common south of I-70 during that period, with Olney reporting 9 inches.   This contributed to April monthly record rainfall totals in several locations, including Hutsonville (13.74 inches), Olney (13.31 inches), and Lawrenceville (12.56 inches).  Additional rainfall into early May contributed to serious river flooding on the Wabash and Embarras Rivers.  The Embarras River crested at Lawrenceville nearly 11 feet above flood stage (40.82 feet on April 30), while the Wabash River at Hutsonville crested over 11 feet above flood stage on May 2, at 27.40 feet (10th highest crest on record).  Three breeches occurred in the Cross Levee in Lawrence County on May 3rd, resulting in extensive flash flooding. 

Another active severe weather day was May 25, when two outbreaks occurred (before dawn, and during the late afternoon and evening).  Eight tornadoes occurred during the later outbreak.

 


Summer Season (June 1 through August 31):

Observed dewpoints and heat index values at 6 pm July 19.  Click image to enlarge.
Observed dewpoints and heat index values at 6 pm July 19.  Click image to enlarge.

Seasonal Averages:

  • Temperatures -- Above normal
  • Precipitation -- Below normal (except near normal west of Jacksonville)

TEMPERATURES --  While temperatures the first 10 days of June averaged well above normal, the remainder of the month was cooler than normal.  The hottest day was on the 4th, when highs in the mid to upper 90s were common, with 100 degrees reported at Hutsonville, and 98 degrees at Champaign.

Excessive heat and humidity plagued the area during July.  The worst conditions were from the 17-24th, when an Excessive Heat Warning was in effect.  Heat index values reached as high as 115 degrees.  Urbana reported its first 100 degree occurrence since 1995, and Springfield had 14 straight days with highs of at least 90 degrees, the first such occurrence since 1955.  While August was not as brutally hot, several 90+ degree days were observed, as many as 13 days at Springfield.   Jacksonville and Springfield reached 99 degrees on August 24, and 100 degrees was observed at Winchester on the 31st.

WEATHER -- Copious rainfall occurred over portions of Morgan and western Sangamon Counties on June 17-18, along an outflow boundary.  Rainfall totals of 6 to 10 inches occurred from Jacksonville east to near New Berlin and Loami, with some unofficial totals near 12 inches.  This rainfall caused tremendous flash flooding in Jacksonville, which shut down the water treatment plant for over a week.  The runoff from the flooding resulted in a levee breech in Scott County near Oxville on the 19th.  One person was killed near Loami after being swept off a flooded road.

While not weather related, portions of central Illinois were affected by a magnitude 3.9 earthquake on June 7, which was centered about 50 miles southwest of St. Louis. 

The significant heat during July, and a persistent dome of high pressure which steered storm tracks to the north, resulted in rapid drying of the soils.  Rainfall during July was generally a quarter to half of what normally occurs, although extreme southeast Illinois from Flora to Lawrenceville saw above normal rainfall.  The drying trend continued into August, with monthly rainfall as low as 0.07 inch at Jacksonville (2% of normal), 0.14 inch at Havana (4%), 0.15 inch at Decatur (4%) and 0.25 inch at Springfield (7%).  This resulted in rapid development of moderate to severe drought conditions, with areas between the I-72 and I-74 corridors most impacted.

On August 13, numerous reports of hail were received during the mid to late afternoon, mainly along and north of a Jacksonville to Danville line, as a strong upper disturbance moved across the area.  The largest hail fell across southern Logan County at around 4:30 PM, when a weather observer from Mt. Pulaski noted tennis ball-sized stones (2.5" diameter). Several cars suffered damage due to the hail.  Other large hail was noted across portions of Morgan County, where golf ball-sized stones (1.75" diameter) created significant crop damage near the town of Pisgah and across southern Peoria County, where ping pong ball-sized hail (1.5" diameter) caused car and shingle damage just north of Mapleton.


Autumn Season (September 1 through November 30):

NASA satellite image of smoke from a Minnesota wildfire reaching Illinois on September 14.
NASA satellite image of smoke from a Minnesota wildfire reaching Illinois on September 14.  Click image to enlarge.

Seasonal Averages:

  • Temperatures -- Near normal
  • Precipitation -- Below normal west, above normal east

TEMPERATURES -- September started out  unseasonably hot, with highs of 100 degrees in many areas.  Springfield observed its first 100 degree temperatures since August 1995, and had 3 straight days of 100 degrees from September 1-3 (102 degrees on the 1st set a September record).  After that, temperatures trended below normal for the remainder of the month.  While October averaged fairly close to normal, highs in the 80s were common from the 4-11th, and some locations saw 80 degree temperatures as late as the 25th.  November was warmer than normal, with more pronounced warm periods during the second and fourth weeks of the month.

WEATHER -- Relief from the drought began spreading across southeast Illinois late in September, as a persistent upper low brought 1 to 3 inches of rain south of I-70.  Areal coverage of the drought shrank during October, with west central Illinois finally exiting the drought in mid November.

Smoky conditions were reported across east central Illinois on September 14.  The source of the smoke was a large wildfire in extreme northeast Minnesota; the smoke was carried across Wisconsin and eastern Illinois in the circulation after the passage of a cold front.  Visibility was lowered due to the smoke, and some reports of a smoky smell in the air were received as far southeast as Champaign.

Severe weather affected portions of the area on November 14.  Wind gusts as high as 76 mph were reported in the Champaign area, which downed some trees and power lines, and caused minor structural damage.  Reports of wind damage and large hail were also received in several locations near the Indiana border.


Winter season to date (December 1-31):

Averages:

  • Temperatures -- Above normal
  • Precipitation -- Above normal 

TEMPERATURES -- Temperatures fell into the single digits across most areas north of a Rushville to Bloomington line on the 9th and 10th, aided by some lingering snow cover from an earlier dusting of snow.  However, temperatures rapidly warmed up afterward, and by the 14th, highs in the 50s were observed over most of central and southeast Illinois, with a few 60s by the 15th.  The remainder of the month largely saw temperatures above normal.

WEATHER -- Some of the first measurable snowfall of the season occurred on December 8-9th, when a quarter to 1 inch of snow occurred north of a Rushville to Pontiac line, as well as around Champaign and Danville.  By the 13-14th, heavy rain was reported over some of these same areas.  Three inches of rain was observed around Galesburg, while amounts around 2.3 inches were reported in Bloomington.  Later in the month, 1 to 2 inches of snow fell late on the 26th into the morning hours of the 27th, generally in an area from about Taylorville to Rantoul, southeast to just south of I-70.  The highest totals included 3 inches at Hoopeston (Vermilion County), and 2.9 inches at Beecher City (Effingham County).  However, snowfall overall during the month was significantly lower than normal.


Preliminary statistics for the 35-county Lincoln NWS coverage area:

  • Highest Temperature:  104 degrees at Fisher and Hutsonville on July 23
  • Lowest Temperature:   17 degrees below zero at Knoxville on February 10
  • Most Rain in 24 Hours:  4.80 inches at Jacksonville on June 18 
  • Most Snow in 24 Hours:  18.0 inches at Winchester and St. David on February 1-2 
  • Most Rain in 1 Month:   13.74 inches at Hutsonville in April, and at Jacksonville in June 
  • Most Snow in 1 Month:   23.9 inches at St. David in February 
  • Reported Tornadoes:  21.  By EF-Scale intensity:  EF0=10, EF1=10, EF2=1.  By county:  Christian 3, Vermilion 3, Macon 2, Menard 2, McLean 2, Shelby 2.  One each in Champaign, Clay, Crawford, Edgar, Mason, Richland, and Schuyler.

 
Specific climate statistics for area cities will be issued on January 1, 2012.

 


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