The Tale of Two Winters – One Dry, One Wet

We have had a remarkable contrast in the last two winters in terms of precipitation. While both winters have been relatively quiet in terms of snow (at least up until the last week), this winter has made up for it in rainfall.

Here are the January 1 to February 25 precipitation departure maps for 2012 (first figure) and 2013 (second figure) for the Midwest. Precipitation is the combination of rainfall and the water content of any snow/sleet/freezing rain events.

Areas in shades of yellow show below-average precipitation while areas in shades of green show above-average precipitation. As you can see, the widespread yellow in 2012 was replaced with widespread green in 2013. This is good news for Illinois and for the Midwest.

First two months of 2012.

First two months of 2013.

Advertisements

New Climate Prediction Center Outlooks

On February 20, the NWS Climate Prediction Center released their new outlooks for March and beyond. Below are the maps for March, spring (March to May), and summer (June to August).

The overall theme for Illinois is an increased chance of above-average temperatures through August. We have an increased chance of above-average precipitation in the March-May period, followed by equal chances in the June-August period. If it pans out, above-average precipitation for this spring should help with low water levels on both the Great Lakes and Mississippi River as well as alleviate drought concerns in northern Illinois.

If you are wondering when was the last time we had a spring that was both warmer and wetter than average, you do not have to look very far. The springs of 2004, 2006, 2009, 2010, and 2011 all qualified as having both above average on precipitation and temperature. In fact, our spring temperatures in Illinois have been at or above average in all but 2 years since 1998 (last figure).

The Climate Prediction Center outlook for March and March-May. NOAA.
The Climate Prediction Center outlook for March and March-May. NOAA.
Climate Prediction Center outlook for summer (June-August).
Climate Prediction Center temperature outlook for summer (June-August).
Climate Prediction Center precipitation outlook for summer (June-August).
Climate Prediction Center precipitation outlook for summer (June-August).
Spring Temperatures in Illinois since 1895. Source: http://www.southernclimate.org/products/trends.php
Spring Temperatures in Illinois since 1895. The green dots are the spring temperatures each year. The shaded curve represents a 5-year running average with extended periods of cool temperatures shaded in blue and extended periods of warm temperatures shaded in red. Source: http://www.southernclimate.org/products/trends.php

Odds of Drought Years Repeating in Illinois

I am in the middle of my winter farm talk tour so I have not had much time to post on the blog. However, in coming days I will try to cover some recurring themes from my talks.

One of those themes is the odds of repeating drought in Illinois. Or in other words, does the drought of 2012 put us at increased risk for drought in 2013 in Illinois? If you look at the 10 driest years in Illinois since 1895, none of them were back to back to each other. That is comforting news.

A follow-up question I got from a farmer was: what does happen in the year after the big droughts? The table below shows the 10 driest years, their annual total, their departure from the 1981-2010 average, along with the next year, the annual total and departure. Since 2012 was in the list, we are left with nine cases. Of those nine, four cases were above and five were below average. However, being 1-3 inches below average would not be a big concern in my opinion. So we could say that about 6 out of 9 cases were close to average on precipitation.

However, the two pairs that stand out to me are 1963-64 and 1988-89. While the second year in both cases were not as severe in their precipitation deficits, and none of them made it into the top ten, the numbers are worrisome. In fact, 1964 ended up as the 14th driest and 1989 as the 16th driest on record. Meanwhile, the pair of 1953-54 was not as severe. However, it was followed by moderately dry conditions in 1955 (34.81 inches, down 5.14 inches) and more severe conditions in 1956 (30.76 inches, down 9.61 inches).

In conclusion, on one hand you could say that historically there has been a 44 percent chance  (4 out of 9 cases) of having above-average precipitation in the year after a “top ten” drought year. Or you could say that there has been a 67 percent chance (6 out of 9 cases) of being within 10 percent of the long-term average precipitation (39.95 inches) in the year after a “top ten” drought year.

On the other hand, you could say that there was a 33 percent chance (3 out of 9 cases) of having continued drought trouble in the second  year of a “top ten” drought year.

Year Annual Depart Next Year Annual Depart
1901 26.34 -13.61 1902 42.26 2.31
1930 27.88 -12.07 1931 38.17 -1.78
1963 28.00 -11.95 1964 31.94 -8.01
1953 28.05 -11.90 1954 35.44 -4.51
1914 28.58 -11.37 1915 42.28 2.33
1976 28.84 -11.11 1977 41.80 1.85
1940 29.33 -10.62 1941 40.64 0.69
1988 29.71 -10.24 1989 32.59 -7.36
1936 30.24 -9.71 1937 37.25 -2.70
2012 30.34 -9.61 ? ? ?

Note: this analysis was based on annual statewide precipitation for Illinois. The conclusions reflect overall conditions and may not pertain to a particular area of the state where more severe conditions may have occurred.

USDA Report Reflects Impact of Drought in Illinois

Last week the Illinois office of the National Agriculture Statistics Service released their report on crop yields in Illinois. The full report can be found here.

As expected, the Illinois corn yield for 2012 was only 105 bushels per acre, 52 bushels below last year. They noted that this was the lowest yield since 1988, when the average yield was only 73 bushels per acres. Because of the severe conditions of the corn crop, almost twice as many acres were harvested for silage in 2012 than in 2011.

Illinois soybean yield for 2012 was 43.0 bushels per acre, down 4.5 bushels from 2011. This was the lowest soybean yield since 2003, when the average yield was only 37.0 bushels per acre. While too late to do much good for corn, rains in the second half of August and the remains of Hurricane Isaac over Labor Day weekend may have provided some benefit to soybeans.

The one bright spot in the Illinois report was winter wheat production. The yield in 2012 was 63 bushels per acre, up 2 bushels from 2011. However, only 660,000 acres were seeded in the fall of 2011, which is down 140,000 acres from the previous fall. I suspect the decline was due in part to the already dry conditions experience in southern Illinois – the primary production area of the state.

January in Illinois – Wet Despite the Lack of Snow

The preliminary numbers are in and the statewide precipitation was 3.9 inches, 1.9 inches above average. Most of the state was in the 3 to 6 inch range except for some drier areas in central and western Illinois. It was wettest in southeastern Illinois with several sites with over 6 inches, including Smithland Lock and Dam on the Ohio River with 9.7 inches. By the way, the precipitation amount includes both rain events and the water equivalent of any snow.

Snowfall for January was below average and ranged from 6.5 inches in the northwest corner to zero in far southern Illinois (second map).

Even though January finished with below-average snowfall, it was offset with above-average rainfall in many areas. The impact of these rains were discussed in an earlier post.  As a result, the U.S. Drought Monitor has reduced the area in drought or abnormally dry conditions since January 1 (last figure) by 11 percent.

The statewide temperature for January was 28.7 degrees, four degrees above average. It was far short of the warmest January on record that was established in 2006 with 37.9 degrees and followed closely by 1933 with 37.7 degrees.

January precipitation (rain plus water content from snowfall).
January precipitation (rain plus water content from snowfall).
January Snowfall for Illinois.
January Snowfall for Illinois.
Change in the US Drought Monitor for Illinois through January 2013.
Change in the US Drought Monitor for Illinois through January 2013.