Good News on Soil Moisture

The Illinois Weather and Crops report was released today by the USDA. As of March 24, the statewide topsoil moisture looked great with 81 percent “adequate” and 11 percent “surplus”. There was some lingering dryness across central Illinois. However, that was before Sunday’s storm that dropped a lot of snow whose water content ranged from 0.5 to 1.5 inches in that region.

Subsoil soil moisture was a little more pessimistic. Statewide numbers included 11 percent “very short”, 26 percent “short”, 58 percent “adequate”, and only 5 percent “surplus”. Some of the lowest numbers were in the northern and western part of the state. Subsoil moisture is not critical in the spring but provides a useful reserve, or cushion, during periods of dry weather in the summer.

The Illinois Weather and Crops is coming off it’s typical winter schedule of once per month to it’s growing season schedule of once a week. The reports can be found here. You can get the reports automatically by subscribing here.

Table from the USDA report, click to enlarge. 

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Guidelines on soil moisture (USDA)

Topsoil is defined as the top six inches. Subsoil is defined as the area from six inches below the surface to a depth of three to four feet.

Very Short – Soil moisture supplies are significantly less than what is required for normal plant development. Growth has been stopped or nearly so and plants are showing visible signs of moisture stress. Under these conditions, plants will quickly suffer irreparable damage.

Short – Soil dry. Seed germination and/or normal crop growth and development would be curtailed.

Adequate – Soil moist. Seed germination and/or crop growth and development would be normal or unhindered.

Surplus – Soil wet. Fields may be muddy and will generally be unable to absorb additional moisture. Young developing crops may be yellowing from excess moisture.

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Snowfall Map from the March 24-25 Snowstorm

Here is a great product from the NWS (www.srh.noaa.gov/ridge2/snow/) showing the snowfall totals of the last two days. I chose the last two days since some snow from the event fell before 7 am on Sunday. The heaviest amounts were concentrated over central Illinois, including 18.5 inches at Springfield. It was very impressive for a late season snowfall. NWS Lincoln has a listing of the snowfall totals from the storm.

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Semi-official snowfall total for Champaign-Urbana

I measured 12.7 inches of snow at my house, which is 3 miles west of the official site for Champaign-Urbana (on the corner of 1st and Windsor). Until I can get into work, that will be the semi-official snowfall total for C-U.

[Update] I took measurements at the official site this morning at 10 am and we ended up with 11.5 inches of snow. That brings our monthly snowfall total up to 16.4 inches. Amazingly, that is not the snowiest March on record for C-U. The snowiest was 1906 with 32.0 inches. The second snowiest was 1960 with 20.9 inches.

Also, this brings our season snowfall total to 23.2 inches, which is right at the 1981-2010 average.

Jim Angel

Illinois Drought Free

According to the US Drought Monitor, Illinois is now drought free for the first time since April 3, 2012. Most areas in Illinois have seen positive responses in soil moisture, stream flows, lake levels, and groundwater levels since the fall. A small area of northwest Illinois remains as abnormally dry due to some lingering concerns about subsoil moisture and groundwater levels in that area.

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Illinois Soil Temperatures – Then and Now

You can find 4 and 8-inch soil temperatures for Illinois on the Water Survey’s web site at www.isws.illinois.edu/warm/soiltemp.asp. These data are from a network of 19 sites around Illinois that is maintained by the Survey.

Below are the maps of what the 4-inch soil temperatures looked like on Wednesday and a year ago on the same date. This year the soil temperatures are barely above freezing in northern Illinois and barely above 40 degrees in southern Illinois. On the same date in 2012, the 4-inch soil temperatures were in the upper 50s and lower 60s across the state.

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Cold March

I dropped my car off at the shop for some brake work this morning here in Champaign and decided to walk to work. The air temperature was 21 degrees and the wind chill was 4 degrees. That was an uncomfortable stroll even with a winter coat, hat, and gloves. A year ago this morning (March 20, 2012), the air temperature was 63 degrees and well on its way up to a high of 82 degrees, a record high for this date.

So far this year, the statewide March temperature is 33.3 degrees. A year ago through this date, the statewide temperature was 51.1 degrees. That’s a whopping 17.8 degree difference. March went on to become the warmest March on record at 55.3 degrees, 14.2 degrees above the long-term average monthly March temperature of 41.1 degrees.

The rest of March does not look promising. The 1-5 day forecast shows temperature 10 to 14 degrees below average for Illinois. The 6-10 and 8-14 day forecast show widespread cold weather across Illinois and the central US. Figures below.

The long-term average temperatures for March were calculated from the 1981-2010 period.

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March Off to Cold, Wet Start

So far, March has been both colder than average across all of Illinois and wetter than average across western and northern Illinois. The statewide temperature for March 1-14 was 32.5 degrees, 5.4 degrees below average. That stands in stark contrast to last March when the statewide temperature for March 1-14 was 45.2 degrees, 7.3 degrees above average. That is a 12.7 degree difference between the two periods.

Precipitation through the morning of March 15 (Figure 1) ranged from less than an inch in southern Illinois to over 2 inches in western Illinois. Precipitation was below average in southern and eastern Illinois (Figure 2) and above average in western and northern Illinois. The dryness in southern and eastern Illinois is not a major concern at this point because of wet conditions in those areas in January and February.

The latest NWS forecasts show that rains of 1 to 2 inches or more could fall in the southern third of Illinois over the next five days (Figure 3). Also their 6-10 day and 8-14 days forecast show that colder and wetter than average conditions will prevail for the rest of March. Because of recent rains and melting snow, the NWS has issued flood warnings today on portions of the Mississippi, Illinois, and Wabash Rivers (Figure 4).

Figure 1.
Figure 1.
Figure 2.
Figure 2.
Figure 3.
Figure 3. Five-day precipitation forecast. Source: http://www.hpc.ncep.noaa.gov/medr/medr_mean.shtml
Figure 4.
Figure 4. Flood warnings in Illinois. http://water.weather.gov/ahps/region_forecast.php?state=il#