A Look Back at 2012 in Central and Southeast Illinois

 

2012 was warmer and drier than normal across central and southeast Illinois.  Some of the highlights included the warmest March on record, and a summer which was one of the hottest in recent memory.  Drought conditions rapidly developed during the late spring and summer, and severely impacted area crops and lawns.  While much of the area saw some easing of the drought during September, areas northwest of the Illinois River saw drought conditions persist the remainder of the year.  Severe weather occurrences were lower than normal due to the dry conditions, with 14 tornadoes observed this year; the normal total for the 35-county Lincoln NWS coverage area is 16.  Nine of the 14 tornadoes occurred on August 31 and September 1, as the remnants of Hurricane Isaac passed through the area.

 

Season by Season Highlights:
 


Winter Season (December 1, 2011 through February 29, 2012):

Seasonal snowfall totals through the end of February 2012.  Click image to enlarge.  
Snowfall for the 2011-12 winter season as of February 29, with amounts generally less than 50% of normal.  Image courtesy of the Illinois State Climatologist Office.  Click image to enlarge.

Seasonal Averages:

  • Temperatures -- Above normal
  • Precipitation -- Below normal in central Illinois, and near to slightly above normal in southeast Illinois

TEMPERATURES -- The unusually mild weather during the winter was the main highlight.  With the polar jet stream typically remaining well north in Canada, Arctic outbreaks of cold weather were few and far between.  Through the winter, temperatures averaged 4 to 6 degrees above normal across central and southeast Illinois.  In fact, many areas saw temperatures remain at or above zero the entire winter.  Springfield had its first winter in nearly 30 years (since the winter of 1982-83) where temperatures failed to fall to zero, with the coldest temperature of 6 degrees on January 13-14, and Peoria saw its coldest temperature of 5 degrees on January 19-20, its first winter without sub-zero temperatures since 1997-98.   However, areas north of I-74 did see more days with temperatures at least near zero, and Chenoa and Minonk fell to 3 below zero on January 20.

WEATHER -- With the milder than normal temperatures, snowfall was also fairly hard to come by at times.  It took until January 12 before many areas saw more than one inch of snow fall at one time.  This resulted in approximately 320 days passing between 1" snowfalls in areas west of a Bloomington to Springfield line, with Galesburg and Normal ranking in 5th place for longest elapsed time between 1" snowfalls.  On January 12-13, 2 to 5 inches of snow were common in areas north of the I-72 corridor, with the higher amounts generally around Peoria and Galesburg northward, with an inch of snow common south of a Jacksonville to Paris line.  Amounts of 1 to 3 inches were also common on Feburary 13-14, focused along a St. Louis to Paris line.  However, overall snow totals for the winter were less than 10 inches in many areas.  Springfield only saw 5.4 inches of snow fall by the end of February, its second lowest total on record for the December through February period.  Typically, when it did snow, it only lasted a couple days before melting.


Spring Season (March 1 through May 31):

Departure from normal of average high temperatures from March 14-20.  Image courtesy of Midwestern Regional Climate Center.
Departure from normal of average high temperatures from March 14-20, with dark purple shades at least 25 degrees above normal.  Image courtesy of Midwestern Regional Climate Center. Click image to enlarge.

Seasonal Averages:

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

TEMPERATURES -- It was the warmest March on record in much of central and southeast Illinois, and across the Midwest in general.  Average temperatures for the month were 12 to 15 degrees above normal.  The period from March 15-21 was especially warm, with high temperatures frequently reaching the lower to mid 80s.  Some highlights of the warm weather:

  • Urbana, Normal, and Galesburg all reached 80 degrees on the earliest day on record in those locations. 
  • Charleston, Danville, Decatur, Jacksonville, Peoria, Springfield, and Windsor all saw their warmest March nights on record during this period, with lows in the lower to mid 60s. 
  • March record high temperatures were tied at Chenoa, Danville, Morrisonville, and Normal. 

Temperatures at the start of April remained quite warm, with Pana recording a high of 92 degrees on the 3rd, setting its April record high.  However, a cold snap occurred a week later, with widespread sub-freezing temperatures in the 20s on the 11th and 12th.  Because of the warm weather the previous several weeks, many crops and plants were growing well ahead of schedule by this point, and were significantly damaged by the freezing temperatures.  While temperatures in April still averaged above normal, the month as a whole was actually cooler than March.  This had only happened once before at Peoria (1907), and twice at Springfield (1907 and 1918). 

May averaged 5 to 6 degrees above normal as well, and unseasonably hot temperatures in the 90s occurred Memorial Day weekend.  This warm May contributed to the warmest spring on record at Danville, Flora, Galesburg, Lincoln, Normal, Peoria, Springfield, and Urbana. 

WEATHER --  Portions of central and southeast Illinois were on the fringes of a large severe weather outbreak on March 2, which affected areas from Illinois and Indiana southward to the Gulf Coast.  Most of the reports in our area were hail from dime to quarter size, with hail up to golfball size near Neoga (Cumberland County).  As the parent low pressure system exited the area, winds (not associated with thunderstorms) gusted around 50 mph near the Indiana border, and around 40 mph as far west as I-55.  Rain around Galesburg and Peoria mixed with sleet, snow and hail at times, and over an inch of snow occurred in northern parts of Knox and Stark Counties.  After this system exited the area, a fast moving storm system raced southeast on March 4, and deposited 2 to 4 inches of snow in a corridor from Macomb through Springfield to Lawrenceville, in what was the last measurable snowfall of the season over most of the area. 

While some severe weather occurred in April and May, it was not as frequent as typically occurs.  Storms on April 28 in southeast Illinois produced hail of quarter to golfball size in several areas.  On May 1, four tornadoes occurred over Piatt, Champaign and Vermilion Counties, including one that came within 2 miles of Willard Airport near Savoy.  Another tornado occurred just southwest of Hoopeston on May 6, and was accompanied by tennis ball size hail and 3 inches of rain that fell in just 90 minutes.


Summer Season (June 1 through August 31):

Coverage of drought on August 12, with most of central and southeast Illinois in extreme drought conditions.
Drought coverage as of August 12, with most of central and southeast Illinois in extreme drought conditions.  Click image to enlarge.

Seasonal Averages:

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

TEMPERATURES -- Unusually hot weather was the main highlight during the summer, with the most brutal periods from about the last third of June, through all of July, into the first few days of August.  The drought that developed allowed for an unusually high number of 100 degree days for this part of the country.  Olney and Palestine each had 15 days with highs of 100 or higher, with 14 days at Charleston, 12 days at Normal, and 11 days at Springfield.  The highest temperature reported was 109 degrees at Hidalgo (Jasper County) on July 7, with 108 degrees reported at Effingham on that day, and at the Lawrenceville Airport on June 28.  Average high temperatures for the entire month of July were in the mid to upper 90s in most areas.  One side benefit of the drought was that humidity levels were much lower than normal, so heat index values frequently were near or just a couple degrees higher than the actual temperature.

WEATHER -- The intensifying drought was the main highlight during the summer.  Rainfall totals for the season ranged from 5 to 10 inches below normal, including 3-month totals of only 3.41 inches at Lincoln, 3.78 inches at Charleston, and 3.88 inches at Lawrenceville.  Severe drought conditions had developed by mid-June from about the Illinois River southeast to Decatur and Monticello, as well as south of I-70.  By mid July, severe drought was observed over nearly all of Illinois, and the extreme drought across the far south parts of the state overspread much of the central parts of Illinois by late month.  Burn bans were becoming widespread by Independence Day, with some locations cancelling fireworks displays due to the dry weather.  A wildfire near Rochester (Sangamon County) on July 27 burned 350 acres and caused $25,000 damage.  Water restrictions were implemented around Decatur, Mattoon, Springfield, Taylorville, and Jacksonville by the end of July.  Crop conditions were so poor that in some cases, farmers began harvesting the crop in July for use as silage.

As a large thunderstorm complex rolled across northeast Illinois and northwest Indiana on June 29, it clipped the northeast part of Vermilion County, producing hail of 2 to 3 inches in diamater around Danville and Bismarck.

During a severe thunderstorm outbreak on August 9, downburst winds of 70 to 80 mph produced a wide swath of damage from Danvers to Bloomington.  159 homes in the Apollo Acres subdivision were damaged.  Damage to the homes was estimated around $1 million, while $2.5 million damage occurred to 30 businesses along the path.  Other storms also produced widespread wind damage in Champaign and Edgar Counties.  Another severe weather outbreak on August 16 produced extensive damage in Windsor (Shelby County), where hundreds of trees were uprooted, and about 200 homes sustained roof damage; around $3 million damage was reported.


Autumn Season (September 1 through November 30):

Rainfall totals from Hurricane Isaac's remnants
7-day rainfall totals ending September 3, mainly comprised of the rains from the remnants of Hurricane Isaac.  Click image to enlarge.

Seasonal Averages:

  • Temperatures -- Below normal
  • Precipitation -- Above normal, except below normal northwest of the Illinois River

TEMPERATURES --  The heat finally broke in early September after a few more days with highs in the 90's, and average temperatures for the months of September and October were 1 to 2 degrees below normal.  A few areas saw below-freezing temperatures as early as September 24th, especially northwest of Peoria, and several locations set record lows on the 24th and 25th.  However, most of the area saw its first freeze on October 6th, and highs on the 6th and 7th set records for the coldest values for the period (generally in the 40s to around 50).  In November, average temperatures were near normal west of I-55, and below normal further east.  However, unseasonably warm weather occurred from the 9-11th, 20-22nd, and again to close the month.  Record highs in the 70s occurred on the 10th and 11th, and lows in the 50s also set some records for warm low temperatures.

WEATHER -- The remnants of Hurricane Isaac affected central and southeast Illinois on Labor Day Weekend.  This brought widespread rainfall of 2 to 6 inches over drought-stricken areas of central and southeast Illinois.  In addition, 9 tornadoes were reported over the area from this system, two on August 31 in Morgan County, and the others on September 1 in Woodford, Marshall, and Stark Counties.  Most of these tornadoes were weak and did no damage, but one did some structural damage near Franklin (Morgan County).

The Isaac rainfall was the start of an unusually wet September over most of the area, especially south of the I-70 corridor.  Amounts in excess of 6 inches were common over east central and southeast Illinois. The highest rainfall totals for the month were in Clay County, and included 14.37 inches near Clay City, and 14.20 inches at Flora.  This rainfall, along with above normal rainfall in October, led to significant easing of the drought conditions.  However, areas along and northwest of the Illinois River recovered at a slower rate and were still rated as being in a moderate drought at the end of November, as rainfall during that month was generally less than 50 percent of normal.

The remnants of Hurricane Sandy, which came ashore in New Jersey at the end of October, impacted areas as far west as Illinois.  Wind gusts in east central Illinois were as high as 40 mph on October 30.


Winter season to date (December 1-31):

Snowfall in southeast Illinois from the winter storm of December 26.  Click image to enlarge.
Snowfall totals from the December 26 winter storm in southeast Illinois.  Click image to enlarge.

Averages:

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

TEMPERATURES -- December started with unseasonably mild weather, with temperatures in the 60s and 70s on the 1st through the 3rd.  The high of 74 degrees at Springfield on the 3rd tied the December record high.  While temperatures moderated somewhat by the 10th, average temperatures for the first half of the month ranged from 8 to 13 degrees above normal.  A significant cooling trend set up for the second half of the month, with high temperatures frequently near or below normal for the 21st onward.

WEATHER --  Dry conditions affected a good portion of the area during the first half of the month, especially northwest of I-55.  However, a narrow strip from Pana to Paris saw above normal precipitation during the period, as well as locations near and just north of Springfield.  Snowfall had largely been limited to flurries, and most of the area had not seen measurable snowfall since March 5 (a period of 286 days as of December 15). 

The second half of the month started seeing more frequent winter weather conditions.  Two significant storms occurred during the period.  The first was on December 20, when areas along and west of I-55 saw widespread blizzard conditions with the passage of an intense low pressure area.  The highest amounts of 3 to 5 inches occurred west of the Illinois River, and many areas saw wind gusts of 50 to 60 mph or higher.  The following week, blizzard conditions occurred in southeast Illinois on the 26th, as part of a storm system that produced widespread heavy snow across the western Ohio Valley northeast into Indiana.  Snowfall amounts were close to a foot around Lawrenceville.  However, there was a very sharp cutoff to the snow, with only around an inch near Effingham, and very little snow west of an Effingham to Champaign line in general.  Another 7 inches occurred near Lawrenceville on the 28th, and there were 16 inches on the ground there the next morning, the highest snow depth on record in Lawrenceville.


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

  • Highest Temperature:  109 degrees at Hidalgo on July 7
  • Lowest Temperature:   3 degrees below zero at Altona on January 14, and at Chenoa and Minonk on January 20 
  • Most Rain in 24 Hours:  4.95 inches at Clay City 6SSE on September 2 
  • Most Snow in 24 Hours:  11.5 inches at Lawrenceville on December 26-27 
  • Most Rain in 1 Month:   14.37 inches at Clay City 6SSE in September 
  • Most Snow in 1 Month:   18.5 inches at Lawrenceville in December 
  • Reported Tornadoes:  14.  By EF-Scale intensity:  EF0=12, EF1=2.  By county:  Stark 3, Woodford 3, Champaign 2, Marshall 2, Morgan 2, Vermilion 2, Piatt 1.  (Total is greater than 14 due to border crossers.)

 
Specific climate statistics for area cities will be issued on January 1, 2013.

 


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