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.
I was driving back from a meeting yesterday and saw creeks that were bank full and water standing in fields. That’s the first time I’ve seen those sights in a while, maybe over a year ago in this part of Illinois (Champaign County).
In the last 7 days, widespread rainfall amounts of 1 to 3 inches have been reported across the state. See the map below. This is a National Weather Service product that combines high-resolution radar estimates calibrated with rain gauge measurements (see map below). The heaviest rains fell in northern Illinois, an area considered to have been in some stage of drought earlier this week. Because some of the rain fell after the cutoff for this week’s Drought Monitor, I would expect to see the effects of these rains in next week’s map.
Another bit of good news is that the soils appeared to be unfrozen across most of the state during this rain event, thanks to the warm temperatures early in the week. See the second map below from our network of 19 soil temperature sites across Illinois. As a result, much of this rain should have had a chance to soak in and recharge the soil moisture profile.
Finally, the abundant and widespread rainfall across the state has increased the flow in streams and rivers across the state. Many stream gauges report levels that are in the upper 90th percentile for this time of year. In fact, the National Weather Service has reported some minor flooding along the Kaskaskia and Little Wabash Rivers. The result is that much more water is flowing into the critically low Mississippi River. The Mississippi River stage at Chester Illinois (below St. Louis) has risen seven feet and is expected to rise another four feet in the next day or two (last figure).
While the recent rains should provide some temporary relief for barge traffic on the Mississippi River, levels are expected to start dropping again in a few days. The larger problem is that about 80 percent of the Missouri River and Upper Mississippi River basins are in some stage of drought, according to the U.S. Drought Monitor. Until those two basins are in better shape, concerns with Mississippi River flows will remain for some time.
The year 2012 will long be remembered for the drought and the exceptionally warm temperatures. While the data for December is still preliminary, it was the second warmest and tenth driest year on record for Illinois.
The statewide average temperature for 2012 was 55.5 degrees, 3.3 degrees above normal and the second warmest year on record for Illinois. The warmest year was 1921 with 55.6 degrees. Temperatures were much warmer than normal in January-May, July, and December (figure below). For some places in Illinois it was the warmest year on record, including Chicago and Rockford (see story here).
The statewide average precipitation for 2012 was 30.37 inches. That was 9.83 inches below normal and the 10th driest year on record in Illinois. The normal annual precipitation in Illinois is 40.20 inches. Precipitation was much drier than normal in May-July and November (figure below). Here is how 2012 compared with other dry years:
1901 – 26.34″
1930 – 27.88″
1963 – 28.00″
1953 – 28.05″
1914 – 28.58″
1976 – 28.84
1940 – 29.33″
1988 – 29.71″
1936 – 30.24″
2012 – 30.37″
The map of the precipitation departures from normal across the state (below), as of December 31, 2012, shows large areas of the state with deficits in the range of 8 to 16 inches below normal (the darker tan and bright red colors) for 2012.
Unfortunately, winter is our driest time of year in Illinois. The normal precipitation for January and February is 2.11 and 2.12 inches, respectively. Even March is not much wetter at 2.98 inches. That adds up to 7.21 inches for those three months combined. It would take something close to record precipitation in January (6.92 inches), February (4.46 inches), and March (7.53 inches), for a total of 18.91 inches, to erase the deficits accumulated in 2012.
The statewide average precipitation for December 2012 was 2.34 inches, just 0.4 inches below normal.
The statewide average temperature for December 2012 was 35.8 degrees, 5.9 degrees above normal and the 13th warmest December on record. The warmest December on record was 1923 with 39.7 degrees.
The Climate Prediction Center of the NWS has released their latest forecast for January and for the series of 3-month periods starting with January-March. The forecast for January (first map, top panels) in Illinois is non-committal with “equal chances” of above, below, and near-normal temperature and precipitation across the state. We are sandwiched between wetter than normal areas to the north and south of us.
The forecast is a little more interesting for the 3-month period starting in January (first map, bottom panels) with much of the southern two-thirds of Illinois in an increased chance of above normal precipitation. Far southern Illinois has an increased chance of above normal temperatures.
The seasonal temperature forecast for April-June (second map) shows an increased chance of above-normal temperatures across Illinois and much of the US. Their seasonal precipitation forecast for April-June (not shown) calls for equal chances of above, below, and near-normal precipitation. The seasonal temperature and precipitation forecast for July-September are non-committal with equal chances of above, below, and near-normal conditions during that period.
The seasonal forecast for drought shows expected improvement in drought in northern Illinois (third map). They expect drought to continue in western Illinois with only limited improvement in the next three months. They expect drought to continue to the west of Illinois with limited improvements in parts of Missouri, Iowa, and Minnesota.
You can see all the Climate Prediction Center forecasts on their website: http://www.cpc.ncep.noaa.gov/
On Saturday, the US Corps of Engineers began releasing water from Lake Carlyle (east of St. Louis), which flows down the Kaskaskia River into the Mississippi River near Thebes. They kept the water level higher than usual on Lake Carlyle this fall, in anticipation of this move. As the article below states, it’s a short-term measure.
And for you drought history buffs, during the 1988 drought Governor Thompson (Illinois) suggested increasing flow out of Lake Michigan and down the Illinois River to aid in navigation on the Mississippi River. Stan Changnon discussed this in an article on the 1988 drought and it’s impacts on the barge and railroad industries. The abstract of that article summarizes the situation:
The drought of 1988 rated as one of the nation’s worst in the past 100 years, resulting in a myriad of impacts and responses. A notable, largely unexpected impact involved stoppages of barge traffic on the lower Mississippi River during June and July, a result of shallow areas produced by record low flows and shoaling. The barge industry hauls 45% of all bulk commodities (grains, coal, petroleum) shipped in the central United States. The low flows were a result of the unusually large areas extent of drought conditions across most of the Mississippi Basin, which comprises 40% of the continental United States. Most 1987 months had been relatively warm and dry, minimizing moisture in the soils and shallow ground water. Then deficient snowmelt (due to low winter snow-falls) and record low spring 1988 precipitation combined to produce the record low flows along much of the Mississippi River.
Most responses to the drought came in a crisis mode and included concentrated dredging to open channels, government enforced reductions in barge loads and in numbers of barges per tow, tripled barge shipping rates, and shifts in transportation modes. The barge industry suffered a 20% income loss. The total losses to the barge industry coupled with higher costs for shipping were $1 billion. The Illinois Central Railroad, which parallels the major blocked waterways, used a climate prediction to anticipate the low flows 3 months in advance. They leased additional cars to help handle the increased shipments transferred from barges and made a sizable profit. A response proposed by Illinois and shippers—a temporary increase in the water diverted from lake Michigan to raise the levels on the lower Mississippi River—was met with strong objections by other lake states and Canada. The federal government declined the proposal, but the sizable controversy it engendered reflects the growing sensitivity to water resources issues in the Great Lakes Basin and is also illustrative of problems to be expected from a drier future climate (as hypothesized by certain global climate models as a result of ever-increasing trace gases in the atmosphere). This case study illustrates the value of using seasonal climate predictions of limited skill, and the need for better near real-time climatic data, including information about physical impacts of current climatic conditions.
There has been much concern with the low river stages on the Mississippi River between St. Louis and Cairo, IL, and what that means for barge traffic, for example here and here.
How bad is it? The first graph shows the river stage at Chester, IL, from January 2011 to present. The river was actually above flood stage for much of May-July 2011. It dropped from almost 40 feet during that time to 5 feet in November 2011. Then it fluctuated between 5 and 25 feet, until this summer when it dropped below 5 feet and into negative numbers in late September. The latest forecast from the NWS has the river stage reaching -2 feet by December 10 (second figure). By the way, you can get negative river gauge heights because the reference point on the gauge (zero) may not always be the bottom of the river.
The reason for the low river stages in the stretch between St. Louis and Cairo is that much of the Upper Mississippi River basin and the entire Missouri River basin are in some stage of drought, according to the U.S. Drought Monitor (last figure). For the Missouri River basin, 90 percent of the basin is either abnormally dry or in some stage of drought. In fact, 41 percent of the basin is in D3 or D4, the two worst categories of drought.
Conditions are just as bad on the Upper Mississippi with 96 percent of the basin either abnormally dry or in some stage of drought. However, only 17 percent of the basin is in D3 or D4 drought. So drought is a little more widespread but not as severe in the Upper Mississippi River basin as it is in the Missouri River basin. Unfortunately, the latest NWS drought outlook indicates that the drought is expected to continue across much of these two basins through this winter.
Table 1. Percent coverage by USDM drought stage for each basin as of November 20, 2012. Data courtesy of the National Drought Mitigation Center.
The latest US Drought Monitor map shows an expanded area in south-central Illinois that is completely drought-free at this point (7% of the state). In general, that area has received 8 to 16 inches of rain since August 1, which is about 4 to 8 inches above normal. The largest station total was 23.38 inches in Grayville, followed by Centralia IL with 20.01 inches.
Meanwhile, western and northern Illinois have not seen significant drought recovery so far this fall. Those areas have received only 2 to 6 inches of rain, where normal rainfall in that region is on the order of 8 inches.
Another thing that has helped recently with the drought situation in Illinois is that temperatures have run below normal since August. Most recently, October 1-10 has been 6 degrees below normal.
The statewide average temperature for September in Illinois was 64.6 degrees, 1.6 cooler-than-normal. This was the first cooler-than-normal month of 2012, and the first cooler-than-normal month since September of 2011. See graph below.
The statewide average precipitation for September was 4.9 inches, 1.7 inches wetter-than-normal. This is the first wetter-than-normal month in 2012. See second graph below.
Much of the September rainfall came from the remains of Hurricane Isaac that passed over Illinois on Labor Day weekend. Additional rains fell later, especially in south-central Illinois. In general, areas south of Interstate 80 had monthly totals in the 3 to 12 inch range. A few sites in that region reported over a foot of rain with the largest total at Centralia with 15.89 inches. See first map below.
Precipitation totals north of Interstate 80 were around 1-2 inches. One of the driest spots in the state was Elburn (Kane County IL-KN-30) with only 1.28 inches for the month. Chicago and Rockford were not far behind with O’Hare Airport reporting 1.76 inches while the Rockford airport reported only 1.74 inches for September.
By the end of September, drought conditions had eased somewhat according to the US Drought Monitor. Only 6.7 percent of the state was in the worst two categories of drought (D3 and D4). This compares to 70 percent of the state in the two worst categories at the end of August. Even so, 82 percent of the state still remained in some stage of drought at the end of September.
Even with a wet September, the January-September statewide precipitation total of 22.38 inches was 8.34 inches below normal and the fifth driest on record. Here are the top five:
1988 with 19.49″
1901 with 19.84″
1936 with 21.76″
1940 with 22.17″
2012 with 22.38″
Remarkably, the precipitation over the last two months has erased the precipitation deficit since January 1 in much of Fayette, Washington, Clinton, Bond, and Montgomery counties. Sizable deficits remain across much of Illinois, especially western and northern Illinois as well as far southern Illinois. See second map below.
The January-September statewide average temperature of 59.6 degrees was 4.1 degrees above normal. It was the second warmest January-September on record and just slightly cooler than the record of 59.7 degrees set in 1921.
Notes: “normal” refers to the 1981-2010 averages. Statewide temperature and precipitation records began in 1895.
NOAA’s Climate Prediction Center released their latest monthly and seasonal outlooks today (Thursday). In the figure below, the outlook for October in Illinois is for an increased risk of above-normal temperatures and below-normal precipitation. The 3-month outlook for October-December in Illinois is for an increased risk of above-normal temperatures. Their precipitation outlook is neutral at this time.
That’s not the best news for drought recovery but it might make it easier on farmers for fall harvest.
One factor that could come into play this winter is El Niño. In fact, the CPC says an El Niño event is likely to arrive some time in September, according to their latest advisory. However, in the last two winters the Arctic Oscillation has played a major role in our winter weather. Two winters ago it was in the negative phase and dumped lots of cold air into Illinois. Last winter it was in the positive phase and prevented a lot of cold air from reaching us. Unfortunately, we can only forecast the Arctic Oscillation out to 14 days.
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.