temperature

April 30, 2012

April Colder Than March – A Rare Case

The statewide average temperature for April 2012 was 54.1 degrees, based on available data. The statewide average temperature for March was 55.0 degrees, based on the latest numbers from NOAA. That means that April was almost a degree cooler than March. What makes this even more impressive was that the April temperatures are still 2.4 degrees above normal!
By the way, the statewide normal monthly temperature is 40.7 degrees for March and 51.7 degrees for April, an eleven degree rise.
How rare is it for April to be colder than March? In the statewide records that extend back to 1895, it happened only in 1907 when the March temperature was 47.0 degrees and the April temperature was 43.2 degrees. In all the other cases between 1895 to 2011, April was always warmer.
The highest temperature reported in the state for April was 92 degrees at Kaskaskia on April 2 and at Jacksonville and Pana on April 3. The coldest temperature reported was 23 degrees at Jerseyville on April 17.

Precipitation

The statewide average precipitation was 3.32 inches. That is about 0.5 inches below normal. The rainfall over the weekend was fairly widespread and helped much of the state. In general, the heaviest rains of 5 inches or more fell east of St. Louis. Meanwhile, rainfall amounts of 2 inches or less fell in far southern Illinois, far northwestern Illinois, and a large swath between Peoria and Kankakee. Those areas were 1 to 3 inches below normal for the month (second map).
The highest monthly rainfall total reported in Illinois for April was a CoCoRaHS observer near Belleville (IL-SC-3) with 8.64 inches. Some of the lowest monthly rainfall totals in the state were in Kankakee and Will Counties. For example, Grant Park (IL-KK-19) in Kankakee County reported all 30 days and only received 0.83 inches for the month.

april-radar — April rainfall totals, based on a radar product developed by the National Weather Service. Click to enlarge.

april-radar-dep — April rainfall departure from normal, based on a radar products developed by the National Weather Service. Click to enlarge.

April 23, 2012

April Colder Than March So Far

I realized this morning that I was wearing short-sleeve shirts in March and long-sleeve shirts (and a light jacket) in April. It’s like that movie Freaky Friday about the mother and daughter switching bodies, only in this case March and April have switched.
[updated April 25] The statewide average temperature for April 1-24 is 53.7 degrees. The statewide average temperature for March was 55.0 degrees, based on the latest numbers from NOAA. That means that April was more than a degree cooler than March. What makes this even more freaky is that the April temperatures are still 2.6 degrees above normal!
BTW, the statewide normal monthly temperature is 40.7 degrees for March and 51.7 degrees for April, an eleven degree rise.
How rare is it for April to be colder than March? In the statewide records that extend back to 1895, it happened only in 1907 when the March temperature was 47.0 degrees and the April temperature was 43.2 degrees. In all the other cases between 1895 to 2011, April was always warmer.
Will this strange situation continue through the end of April? The forecast is for warmer temperatures Wednesday but then a return to cooler conditions afterwards. So we have a good shot at maintaining this record.

April 16, 2012

April Showers Finally Arrive

Temperature

Some much-needed rain arrived in Illinois over the weekend. As the first map below shows, the rains were widespread across the state. The heaviest amounts of two inches or more fell in the area from around St. Louis eastward and another band across northern Illinois.
However, rainfall in some key agriculture areas of the state remains below normal for April (second map). A band through north-central Illinois is running about 1 to 2 inches below normal for the month. Another area of dry conditions can be seen in southern Illinois in the counties along the Ohio River. This area of dryness is connected to a larger region in southeast MO, western KY, and southern IN.

Precipitation

The statewide average temperature for the first half of April is 54.5 degrees, 5.7 degrees above normal. As noted in earlier posts, despite the warm weather we have had several days with below freezing temperatures. Considering that many plants in the landscape are about 3 to 4 weeks ahead of schedule, the freezing temperatures did cause some damage. In my yard, the list of damage included some hostas, a smoke bush, and the tips of some rose bushes and yews – all cosmetic.

Severe Weather

At least Illinois has avoided the severe weather so far in April. No tornadoes were reported as of April 16, unlike the states to our west. The tornado count in Illinois for 2012 is 2 for January, 4 for February, and 8 for March.

april16-prcp — Seven-day precipitation for Illinois, ending April 16, based on radar data from the NWS.

april-prcp-dep — Precipitation departures from normal for April 2012, based on radar data from NWS.

April 6, 2012

World View of March Temperatures

One of the advantages of using satellites to measure temperatures is that you can get a world view, even over the oceans. The University of Alabama-Huntsville produced this map of temperature departures around the globe for March 2012. The temperature departures are in degrees Celsius, so if you double them you can get a ballpark idea of the temperature departures in degree F.
The area of much above normal temperatures are clearly seen in much of the U.S. and Canada. Warmer than normal temperatures were also found in western Europe and the north-central Pacific Ocean. Meanwhile, colder than normal temperatures were seen in Alaska and parts of eastern Europe and northern Asia. The Southern Hemisphere was much quieter.
On a monthly time scale, it is very common when certain areas are experiencing unusual conditions that other areas are experiencing the exact opposite. The global temperature departures for March 2012 from the satellite data was calculated at +0.11 degrees Celsius (+0.2 degrees F).