Even before today’s rain, the statewide average rainfall for June in Illinois is 7.11 inches. That makes it the 5th wettest June on record. And June is not over. Here are the top ten wettest June totals on record and where we stand:
- 1902 with 8.27 inches
- 2010 with 7.71 inches
- 1998 with 7.64 inches
- 2000 with 7.34 inches
- 2015 with 7.11 inches (as of 6/21/2015)
- 1928 with 6.93 inches
- 1993 with 6.85 inches
- 1924 with 6.80 inches
- 2014 with 6.77 inches
- 2011 with 6.69 inches
Notice anything unusual about that list? Five out of the 10 wettest June totals have occurred since 2000. Our statewide records go back to 1895.
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Due to the heavy rains of June, we first saw flooding on the smaller rivers and streams in Illinois. Now the larger rivers are responding to the wet conditions. The NWS can keep you posted on the latest flooding issues at www.weather.gov
The post from this morning documented the above-average rainfall received so far in June across Illinois. On top of that, the latest NWS forecasts indicate that wetter-than-average conditions are expected for the rest of June as well as July in Illinois.
The first map shows the 6-10 day forecast with Illinois and most of the Corn Belt having an increased chance of wetter-than-average conditions. The second map shows the 8-14 day forecast with the same wet pattern.
The third map shows the month of July with an increased chance of wetter-than-average conditions across all of Illinois. The fourth map shows the three-month forecast for July-September. At that point, the chance for wetter-than-average conditions is confined to western Illinois.
6-10 Day Forecast. Areas in green have an increased chance of above-average precipitation. Click to enlarge.
June 2015 has been wet across the Midwest and we still have 12 more days in the month. Wet conditions extend from Kansas/Nebraska and eastward through Missouri, Iowa, Illinois, Indiana, and Ohio. Amounts in those areas are in the 4 to 8 inch range.
Monthly totals from a few stations are in the 10 inch range, including 10.44 inches at Lacon, IL (north of Peoria) and 10.41 inches in Stockton, IL (in the northwest corner).
While this is very preliminary, the statewide average precipitation is 5.3 inches for June. The monthly average is 4.2 inches, so we would already have an above-average month if it stopped raining today. The record for June is 8.27 inches set in 1902.
Rainfall across Illinois and the central US has been substantial for June so far. This map represents the June rainfall through this morning. Large portions of the Missouri and Upper Mississippi River Basins have seen between 2 to 5 inches (yellows and oranges), while some spots in Illinois, Missouri, Nebraska, and Kansas have received 5 or more inches (red).
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Zooming in on Illinois, the map below shows how far above average the wet areas have become. The areas in blue are 2 to 4 inches above average while the areas in green are 0.5 to 2 inches above average. Only small areas northwest of Chicago and south of Carbondale are below-average on rainfall.
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The potential rainfall amounts over the next week are significant. The 7-day precipitation forecast from the National Weather Service shows that central Illinois could see between 4 and 6 inches of rain, while the northern third of the state could see 2 to 4 inches. The southern third of Illinois could see 1 to 3 inches. Since much of this rain will come from thunderstorms, local amounts could be much higher or lower.
The reason for this rain is that a somewhat stationary front is sitting over Illinois and will remain so over the next week. Rain will continue to develop along and south of that front as warm, moist air flows northward.
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Reported rainfall amounts from the July 1996 storm in northern Illinois. This storm caused widespread damage across the region. See the report for details. Click to enlarge.
The current record for the heaviest 24-hour rainfall total in Illinois is 16.94 inches at the NWS cooperative observer gauge in Aurora on July 17-18, 1996. An entire Water Survey report was written on the storm that produced this record.
The previous record 24-hour rainfall was 16.54 inches set on June 14-15, 1957, near Millstadt in St. Clair County (near East St. Louis), according to a Water Survey report. While the 1996 event occurred over 24 hours, the 1957 storm lasted only 12 hours – essentially producing the same amount of rain in less than half the time.
But here is the next interesting fact. Before the 1957 storm, the previous record 24-hour rainfall was 10.48 inches on October 1, 1954 set at Aurora, IL.
So Aurora held the statewide record 24-hour rainfall for about three years until it lost out in 1957 only to regained the crown in 1996, where the record remains to this day. I’m not sure if they deserve the golden rain gauge or the golden sump pump award for this honor.
Severe weather, including tornadoes, heavy rains, high winds, hail, and flooding occurred across parts of Illinois yesterday and last night.
Here is the radar estimated precipitation with areas in green indicating 1 to 2.5 inches an areas in yellow and orange indicating 2.5 to 4 inches.
Below are reports of storm damage across the US for the 24 hours ending on the morning of June 8, 2015. The two tornadoes in Illinois occurred near Petersburg and Seymour. Neither one cause much damage and no injuries. There were a few reports of 1-inch hail and many reports of wind damage in Illinois from these storms. Data obtained from the NOAA Storm Prediction Center storm damage page. Continue reading
The NWS Climate Prediction Center released their updated outlook for June, 2015. The new June outlook shows northern Illinois, including the Chicago area, with an increased chance of warmer and drier than average conditions.
Much of central and southern Illinois has equal chances (EC) of above, below, and near-average temperature and precipitation. This is different from the previous outlook for June that was released mid-May. That one had central and southern Illinois with an increased chance of wetter than average conditions.
While these outlooks cover the entire month, most of the model forecast skill is in the first 10 days. So the features of warmer and drier conditions in northern Illinois may be more in line with what’s expected in the first week or two and less with the entire month. More useful information can be obtained from the NWS 6-10 and 8-14 day forecasts which are updated daily.
Temperature forecast for June. Click to enlarge.
Precipitation forecast for June. Click to enlarge.