National Climate Assessment for Illinois

Earlier this year the National Climate Assessment for Illinois was released, tracking the historical changes in temperatures and precipitation in Illinois. You can find the full report for Illinois and other states at the State Climate Summaries website.

Here is Key Message #1

Average annual temperature has increased by about 1°F since the beginning of the 20th century. There has been seasonal variation in this warming, with average spring temperature increasing by about 2°F and average summer
temperature increasing very little. Under a higher emissions pathway, historically unprecedented warming is projected by the end of the 21st century.

Key Message #2

Precipitation in spring and summer has generally been above average over the past two decades, affecting agriculture in both positive (adequate soil moisture) and negative (delays in spring planting) ways. Precipitation in winter and spring is projected to increase, which poses a continuing risk of spring planting delays.

Key Message #3

Severe flooding and drought have occurred periodically in recent years. Future increases in extreme precipitation events and in evaporation rates may increase the intensity of both floods and droughts.

You may notice that two out of the three messages relate to increases in precipitation and especially heavy rainfall events. The graphic I found most compelling was this one for the increasing number of 2-inch rain events with time. The caption explains how this graph was created. The increased frequency in 2-inch rain events seen since the early 1980s lines up very well with my experience and research over the years in Illinois.

il_obs-number-extreme-precip_v1_2
Figure 5: The observed number of days with extreme precipitation events (annual number of days with precipitation greater than 2 inches) for 1900–2014, averaged over 5-year periods; these values are averages from 43 available long-term reporting stations. A typical station experiences 1–2 such events each year. The number of extreme precipitation events has been above average since the 1990s. During the most recent 5-year period (2010–2014), Illinois experienced a record high number of events when stations averaged more than 2 events annually. The dark horizontal line is the long-term average (1900–2014) of 1.62 days per year. Source: CICS-NC and NOAA NCEI.

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Volcanoes and Climate in Illinois

When I give talks on climate and climate change, I often get questions about volcanoes and their impact on our climate. The Washington Post had a recent article on the subject, mentioning the famous eruption of Tambora in 1815, which in 1816 led to the year without a summer in the eastern US. It probably had impacts on Illinois but we had no widespread observations in place at the time.

http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2015/04/24/the-epic-volcano-eruption-that-led-to-the-year-without-a-summer/

The one I remember the best was Mount Pinatubo. The following summer after that eruption was exceptionally cool across the US and around the world.

summer1992
Summer 1992 temperature departures from average for the lower 48 states. Shades of green indicate level of coolness. Click to enlarge.

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2014 – Warmest on Record for World, 6th Coldest for Illinois. Wait, What?

I could see this one coming. While Illinois had its 6th coldest year on record, three major groups (Japan, NASA, and NOAA) have noted that 2014 was the warmest year on record. Check out this map from NOAA of the temperature departures for 2014 (red is warmer, blue is cooler). The area from the Great Lakes and southward to the Gulf of Mexico was the only place over land that was colder than average. All the other land masses and most of the ocean surface was warmer than average. In other words, relatively speaking, Illinois was one of the coldest places on earth in 2014.  Continue reading

Illinois and Global Temperatures for June-August

Based on the latest updates from the National Climatic Data Center, this summer in Illinois was the 29th coolest. Daytime highs were much cooler than average while the nighttime lows were near-average.

The average maximum temperature in Illinois was 82.3 degrees Fahrenheit, 2.6 degrees below the 1900-2000 base period and the 14th coolest on record.

illinois-max

The average minimum temperature in Illinois was 62.3 degrees F, 0.3 degrees above the 1900-2000 based period.

illinois-min

GLOBAL

In contrast to the cool summer in the central US, most of the globe was warmer than average this summer (June-August), according to the National Climatic Data Center. In fact, even in the US, temperatures were significantly warmer in the West than the East.

201406-201408

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New U.S. National Climate Assessment Released

CS_Net_Change_in_annual_Precip_12909_v9
Observed Precipitation Changes in the US. The colors on the map show annual total precipitation changes for 1991-2012 compared to the 1901-1960 average, and show wetter conditions in most areas. The bars on the graphs show average precipitation differences by decade for 1901-2012 (relative to the 1901-1960 average) for each region. The far right bar in each graph is for 2001-2012. (Figure source: adapted from Peterson et al. 20131). Click to enlarge.

The third U.S. National Climate Assessment was released today, including state-specific fact sheets like this one for Illinois.  I’ll post some Illinois specific comments in the near future.

The assessments are mandated by law with the intent of providing the latest report of climate change and it’s impacts on the United States.

Here are the key findings for the Midwest (the Midwest report is located here):

  • In the next few decades, longer growing seasons and rising carbon dioxide levels will increase yields of some crops, though those benefits will be progressively offset by extreme weather events. Though adaptation options can reduce some of the detrimental effects, in the long term, the combined stresses associated with climate change are expected to decrease agricultural productivity.
  • The composition of the region’s forests is expected to change as rising temperatures drive habitats for many tree species northward. The role of the region’s forests as a net absorber of carbon is at risk from disruptions to forest ecosystems, in part due to climate change.
  • Increased heat wave intensity and frequency, increased humidity, degraded air quality, and reduced water quality will increase public health risks.
  • The Midwest has a highly energy-intensive economy with per capita emissions of greenhouse gases more than 20% higher than the national average. The region also has a large and increasingly utilized potential to reduce emissions that cause climate change.
  • Extreme rainfall events and flooding have increased during the last century, and these trends are expected to continue, causing erosion, declining water quality, and negative impacts on transportation, agriculture, human health, and infrastructure.
  • Climate change will exacerbate a range of risks to the Great Lakes, including changes in the range and distribution of certain fish species, increased invasive species and harmful blooms of algae, and declining beach health. Ice cover declines will lengthen the commercial navigation season [this winter was the exception to the rule – Jim].

End of the Snow Drought in Illinois

With the looming winter storm expected to reach Illinois on Wednesday and Thursday, we should see the end of the 2012 snow drought in Illinois. Last winter’s snowfall season was cut short by warm and dry conditions in February and March. Meanwhile, the start of this winter’s snowfall was much delayed by the warm, dry conditions of the past several weeks. As a result, many sites in northern and central Illinois approached or set their records for the longest snow-free period.

Here is the map of total snowfall for this winter through December 17, how much we normally get through December 17, followed by reports on the remarkable snow-free season in Illinois. A few sites in western Illinois reported snowfall this morning.

dec17snow

Normal snowfall from November 1 to December 17 for the period 1981-2010.
Normal snowfall from November 1 to December 17 for the period 1981-2010.

Here is the report for Chicago. Here are additional reports for central Illinois and northwest Illinois.

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
1153 AM CST MON DEC 17 2012 /1253 PM EST MON DEC 17 2012/
...LATEST ON SNOWFALL RECORDS...
SUNDAY DECEMBER 16TH MARKED THE 287TH CONSECUTIVE DAY WITHOUT
MEASURABLE SNOWFALL AT ROCKFORD...BREAKING THE PREVIOUS
CONSECUTIVE DAY RECORD THAT HAD BEEN SET IN 1922. THIS IS NOW THE
LONGEST PERIOD OF TIME WITHOUT MEASURABLE SNOWFALL IN ROCKFORD ON
RECORD. THE LAST DAY WITH MEASURABLE SNOWFALL WAS MARCH 4TH.
CHICAGO HAS ALREADY BROKEN THEIR RECORD.
ROCKFORD
RANK # DAYS DATES W/O MEASURABLE SNOW
 1) 287 03/05/2012-12/16/2012+
 2) 286 03/03/1922-12/13/1922
 3) 284 02/26/1908-12/05/1908
 4) 282 03/31/1939-01/06/1940
 5) 270 03/06/2011-11/30/2011
 270 03/10/1999-12/04/1999
CHICAGO
RANK # DAYS DATES W/O MEASURABLE SNOW
 1) 287 03/05/2012-12/16/2012+
 2) 280 03/01/1994-12/05/1994
 3) 277 03/10/1946-12/11/1946
 4) 269 03/11/1999-12/04/1999

ON AVERAGE...CHICAGO HAS 226 DAYS IN A ROW WITHOUT MEASURABLE
SNOWFALL /SEVEN AND A HALF MONTHS/ AND ROCKFORD HAS 233 /ALMOST
EIGHT MONTHS/.
GIVEN THE CURRENT FORECAST...IT APPEARS BOTH LOCATIONS COULD HAVE
THEIR RECORD SNOW DROUGHT PERIODS COME TO AN END ON WEDNESDAY NIGHT
OR THURSDAY...WITH EVEN THE POSSIBILITY OF A BRIEF SNOW EARLIER ON
TUESDAY MORNING.
HERE ARE SOME STATISTICS REGARDING FIRST/LAST MEASURABLE SNOWFALLS...
CHICAGO ROCKFORD
 EARLIEST: 10/12/2006 10/12/1909
1ST AVERAGE: NOV 16 NOV 20
 LATEST ??/??/2012 01/07/1940
EARLIEST: 02/27/1997 02/06/1911
LAST AVERAGE: APR 4 APR 1
 LATEST 05/11/1966 05/11/1966
HERE ARE THE LATEST FIRST MEASURABLE SNOWFALLS FOR CHICAGO AND
ROCKFORD...
CHICAGO ROCKFORD
1) ??/??/2012 1) 01/07/1940
2) 12/16/1965 2) 12/21/1996
3) 12/14/2001 3) 12/19/2001
4) 12/12/1946 12/19/1948
5) 12/10/2003 5) ??/??/2012
6) 12/09/2011 6) 12/14/1922
 12/09/1948 7) 12/12/1916
8) 12/07/1914 8) 12/11/1924
9) 12/06/1994 9) 12/10/1970
10) 12/05/1999 12/10/1932
 12/05/1984 11) 12/08/1956
 12/05/1973 12/08/1927
 12/05/1909 12/08/1914

$$
MTF/RODRIGUEZ

First Half of September – Wet in Eastern and Southern Illinois

The statewide average precipitation for the first half of September was 3.77 inches, which is already above the monthly normal precipitation of 3.24 inches.

However, that precipitation was not distributed equally around the state. The figure below shows that large areas across eastern and southern Illinois received 3 to 6 inches of rain (shades of dark blue and green). Meanwhile, areas north of Interstate 80 and in western Illinois were much drier with amounts of less than 2 inches. Most of the heavy precipitation fell from the remnants of Hurricane Isaac that passed through Illinois on Labor Day weekend.

Reports from individual stations ranged from 8.08 inches for the CoCoRaHS station Bush (IL-WM-4) in southern Illinois to only 0.57 inches for the CoCoRaHS station Geneva (IL-KN-1) in northeast Illinois.

Precipitation totals for September, 2012, in Illinois through the morning of September 16. Click to enlarge.