April Colder Than March – A Rare Case

Temperature

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 rainfall totals, based on a radar product developed by the National Weather Service. Click to enlarge.
April rainfall departure from normal, based on a radar products developed by the National Weather Service. Click to enlarge.
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Latest Soil Moisture and Drought Monitor for Illinois

Observed Soil Moisture

The Illinois State Water Survey has been monitoring the soil moisture at 19 sites around the state. The soil moisture is measured with probes set at specific depths at each site. It is reported as the fraction of water in the soil by volume. Most of the non-sandy soils in Illinois can hold up to 30-40 percent water by volume in the spaces between the soil particles.

Current observations in the driest areas of the state show significant declines at 2, 4, and 8 inches since early March. At the Peoria site, in the heart of the dry area, the fraction of water in the soil is only 15 percent at 2 inches, 18 percent at 4 inches, and 22 percent at 8 inches. The 20-inch depth has remained unchanged at 32 percent. By comparison at the end of April of last year, the fraction of water in the soil at those depths were all in the 35-40 percent range.

We are in the process of getting these data online in the next few weeks. Stay tuned.

U.S. Drought Monitor

The latest U.S. Drought Monitor map for Illinois shows an expanded area of D0 “abnormally dry” weather across the central part of the state between Interstates 70 and 80. A small area of D1 “moderate drought” is located in the area centered on Logan County. Another small area of D0 is in southeastern Illinois.

Here is what the U.S. Drought Monitor says for Illinois. Click to enlarge. Link to original (updated weekly). Released on April 26, 2012.

Dry Weather Across the Eastern Corn Belt

If you look at the Corn Belt this spring you see two different stories. Much of the western Corn Belt has enjoyed above normal rainfall if you look at the last 30 and 90 days (first two maps below). However, below normal rainfall was common across much of Illinois, and parts of Indiana, Ohio, Kentucky and southeastern MO. Those areas have widespread rainfall departures of 2 to 4 inches in the last 90 days.  A few isolated spots scattered across Illinois have departures of 4 to 6 inches.  A particularly dry spot in southeastern Illinois, southwestern Indiana, and western Kentucky has rainfall departures of 6 to 8 inches at 90 days.

This has definitely had an effect on streamflows (third map) and soil moisture (fourth map). Keep in mind that while the streamflows are low for this time of year, it is relative to the normally high streamflow in spring. The same would be true of soil moisture.

The last map shows the U.S. Drought Monitor depiction for Illinois as of April 17 with a large swath of “abnormally dry” conditions across central and southeastern Illinois.

There are some opportunities for rainfall between now and Saturday but the expected amounts are modest at 0.5 to 1.0 inches total. In the past few weeks, the forecasts have been overly optimistic about rainfall amounts. This is likely the result of the soils drying out, cutting off the local source of atmospheric moisture (humidity).

The 90-day precipitation departure for the Midwest, ending on April 24, 2012. Click to enlarge.
The 30-day precipitation departure for the Midwest, ending on April 24, 2012. Click to enlarge.
The 7-day average streamflow showing areas with very low flows for this time of year, USGS. The areas in the lightest tan are in the 10-24 percentile class and classified as "below normal" by USGS. The next shade darker is at the 6-9 percentile class, and is classified as "moderate hydrologic drought". The darker shade of brown is at the less than 5 percentile class and is classified as "severe hydrologic drought". Click to enlarge. Link to original (updated daily).
University of Washington's soil moisture model run for April 23, 2012. Click to enlarge. Link to original (updated daily).
Here is what the U.S. Drought Monitor says for Illinois. Click to enlarge. Link to original (updated weekly).

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.

Frost Damage to Corn

There is an excellent article in the integrated pest management Bulletin at the University of Illinois by Emerson Nafziger about the damage of frost to corn this April and it’s impact on yield. You can read the full article at http://bulletin.ipm.illinois.edu/article.php?id=1619 

Here are the low temperatures reported last week, sorted from coldest to not so coldest. 

Station Name Low Temp(°F) Month/Day
PAXTON 20 11-Apr
CHAMPAIGN 9 SW 21 11-Apr
PAW PAW  23 11-Apr
JERSEYVILLE 2 SW 23 17-Apr
MT CARROLL 24 11-Apr
SIDELL 5 NW  24 11-Apr
WATSEKA 2 NW 24 11-Apr
LISLE-MORTON ARBORETUM 25 11-Apr
SHABBONA 5 NNE 25 10-Apr
ALTONA 25 11-Apr
MONMOUTH 4 NW  25 11-Apr
NORMAL 4NE 25 11-Apr
CONGERVILLE 2 NW 25 11-Apr
NORMAL 4NE 25 11-Apr
PERRY 6 NW 25 12-Apr
GALENA 26 11-Apr
STOCKTON 3 NNE 26 11-Apr
MARSEILLES LOCK  26 11-Apr
LA HARPE 26 11-Apr
PRINCEVILLE 2W 26 11-Apr
DWIGHT 26 11-Apr
HOOPESTON 1 NE 26 11-Apr
NEOGA 4NW  26 11-Apr
SULLIVAN 26 11-Apr
ELIZABETH  27 11-Apr
KEWANEE 1 E  27 12-Apr
ROCKFORD GTR ROCKFORD AP 27 11-Apr
DE KALB  27 11-Apr
MCHENRY STRATTON L&D 27 11-Apr
MUNDELEIN 4 WSW  27 11-Apr
BENTLEY  27 12-Apr
GALESBURG  27 11-Apr
PRAIRIE CITY 2S  27 11-Apr
CHENOA 27 11-Apr
DANVILLE 27 11-Apr
EFFINGHAM  27 11-Apr
NEWTON 27 11-Apr
PARIS WTR WKS  27 11-Apr
TUSCOLA  27 11-Apr
WINDSOR  27 12-Apr
FREEPORT WWP 28 11-Apr
HENNEPIN 28 12-Apr
MOLINE QUAD CITY INTL AP 28 12-Apr
ROCHELLE 28 11-Apr
ROCHELLE 28 11-Apr
BARRINGTON 3 SW  28 11-Apr
ELGIN  28 11-Apr
MARENGO  28 11-Apr
MORRIS 28 11-Apr
KNOXVILLE  28 11-Apr
BLOOMINGTON 5W 28 11-Apr
DECATUR  28 11-Apr
MINONK 28 11-Apr
OGDEN  28 12-Apr
PONTIAC  28 11-Apr
CARLINVILLE  28 11-Apr
MORRISONVILLE  28 11-Apr
SPRINGFIELD CAPITAL AP 28 11-Apr
CHARLESTON 28 11-Apr
PALESTINE 2W 28 11-Apr
RAMSEY 28 11-Apr
ROBINSON 28 11-Apr
SHELBYVILLE DAM  28 11-Apr
ALEDO  29 11-Apr
CHICAGO BOTANICAL GARDEN 29 11-Apr
OTTAWA 29 11-Apr
ROMEOVILLE LEWIS UNIV AP 29 11-Apr
QUINCY RGNL AP 29 11-Apr
RUSHVILLE  29 11-Apr
URBANA 29 11-Apr
GRIGGSVILLE  29 13-Apr
PITTSFIELD #2  29 12-Apr
SPRINGFIELD #2 29 11-Apr
WHITE HALL 1 E 29 12-Apr
WINCHESTER 29 11-Apr
HIDALGO 3SW  29 11-Apr
PANA 29 11-Apr
MT VERNON 3 NE 29 12-Apr
GENESEO  30 11-Apr
NEW BOSTON DAM 17  30 13-Apr
AURORA 30 11-Apr
JOLIET BRANDON RD DM 30 11-Apr
LITTLE RED SCHOOL HSE  30 11-Apr
PARK FOREST  30 11-Apr
PEORIA GTR PEORIA AP 30 11-Apr
FISHER 30 11-Apr
RANTOUL  30 11-Apr
JACKSONVILLE 2 E 30 12-Apr
OLNEY 2S 30 11-Apr
TRIMBLE 1E 30 11-Apr
VANDALIA 30 11-Apr
CARBONDALE SEWAGE PLT  30 12-Apr
SPARTA 30 11-Apr
FAIRFIELD RADIO WFIW 30 12-Apr
ILLINOIS CITY DAM 16 31 12-Apr
CHANNAHON DRESDEN ISLAND 31 12-Apr
CHICAGO MIDWAY AP  31 11-Apr
CHICAGO MIDWAY AP 3 SW 31 11-Apr
KANKAKEE METRO WWTP  31 11-Apr
FLORA  31 12-Apr
IUKA 31 11-Apr
BELLEVILLE SIU RSRCH 31 12-Apr
DU QUOIN 4 SE  31 12-Apr
ROCK ISLAND L&D 15 32 11-Apr
ROCK ISLAND L&D 15 32 11-Apr
CHICAGO OHARE INTL AP  32 11-Apr
QUINCY DAM 21  32 12-Apr
STREATOR 32 11-Apr
JACKSONVILLE 2 32 11-Apr
CARLYLE RSVR 32 11-Apr
KASKASKIA RIV NAV LO 32 12-Apr
LEBANON  32 12-Apr
SMITHLAND L&D  32 12-Apr
MORRISON 33 17-Apr
GLADSTONE DAM 18 33 11-Apr
BIRDS 2E 33 11-Apr
LAWRENCEVILLE  33 11-Apr
SALEM  33 11-Apr
NASHVILLE 1 E  33 12-Apr
CAIRO 3 N  34 12-Apr
GRAND CHAIN DAM 53 34 12-Apr
BROOKPORT DAM 52 34 12-Apr
ALTON MELVIN PRICE 41 10-Apr
GRAYVILLE  44 10-Apr

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.

Seven-day precipitation for Illinois, ending April 16, based on radar data from the NWS.
Precipitation departures from normal for April 2012, based on radar data from NWS.

Lows for the Morning of April 11

After the record warmth in March left plants vulnerable to freezing temperatures, and with the average dates of the last freeze in mid April for most of Illinois, we were destined to get some damaging cold weather.

Here are the low temperatures reported for this morning from around the state (April 11):

Station Low
PAW PAW 23
MT CARROLL 24
WATSEKA 2 NW 24
NORMAL 4NE 25
MONMOUTH 4 NW 25
ALTONA 25
LISLE-MORTON ARBORETUM 25
LA HARPE 26
SULLIVAN 26
PRINCEVILLE 2W 26
MARSEILLES LOCK 26
GALENA 26
DWIGHT 26
NEOGA 4NW 26
PARIS WTR WKS 27
TUSCOLA 27
GALESBURG 27
DE KALB 27
MCHENRY STRATTON L&D 27
ELIZABETH 27
PERRY 6 NW 27
MUNDELEIN 4 WSW 27
PRAIRIE CITY 2S 27
EFFINGHAM 27
CARLINVILLE 28
MINONK 28
PONTIAC 28
WINDSOR 28
RAMSEY 28
MORRISONVILLE 28
BENTLEY 28
MORRIS 28
BARRINGTON 3 SW 28
FREEPORT WWP 28
BLOOMINGTON 5W 28
ROBINSON 28
ROCHELLE 28
ELGIN 28
ALEDO 29
OTTAWA 29
PANA 29
RUSHVILLE 29
KEWANEE 1 E 29
CHICAGO BOTANICAL GARDEN 29
WINCHESTER 29
OGDEN 29
SPRINGFIELD #2 29
AURORA 30
OLNEY 2S 30
SPARTA 30
PARK FOREST 30
JOLIET BRANDON RD DM 30
FISHER 30
GRIGGSVILLE 31
KANKAKEE METRO WWTP 31
IUKA 31
CHICAGO MIDWAY AP 3 SW 31
JACKSONVILLE 2 E 32
JERSEYVILLE 2 SW 32
PITTSFIELD #2 32
JACKSONVILLE 2 32
STREATOR 32
MT VERNON 3 NE 32
WHITE HALL 1 E 33
GLADSTONE DAM 18 33
NEW BOSTON DAM 17 33
CHANNAHON DRESDEN ISLAND 33
ILLINOIS CITY DAM 16 33
LAWRENCEVILLE 33
LEBANON 33
FLORA 33
SALEM 33
BIRDS 2E 33
NASHVILLE 1 E 36
QUINCY DAM 21 36
BROOKPORT DAM 52 37
SMITHLAND L&D 37
KASKASKIA RIV NAV LO 37
GRAND CHAIN DAM 53 40
CAIRO 3 N 42