Wednesday, July 2, 2014

Wet June Ends on Wild Note

The 30 days of June produced many days of rain and many inches of rain across a large part of the country. Rainfall was generally above normal from the mountains of Montana all the way into the lower Mississippi River Valley. In parts of the northern and central Plains and the Midwest June rainfall was five to six times normal. When all is said and done, this could end up being one of the wettest Junes on record in the corn and soybean belt, the area that extends from the Dakotas southeast into the Ohio Valley. Rain is good for the crops, but too much rain is not.

Percent of normal precipitation for June 2014.
Credit: NWS AHPS

In eastern South Dakota and western Iowa June precipitation records were shattered in many locations. Much of this area had been in a precipitation deficit for they year at the end of May, but no more. Sioux Falls, SD received 13.70 inches of rain in June, breaking the old record by more than 5 inches (8.43 inches in 1984). Sioux City, IA had 16.65 inches for June, breaking the old record by almost 8 inches (8.78 inches in 1967)! A number of other locations set records as well, including Canton, SD with 19.65 inches of rain for the month. This is a new state record  for the wettest month at any location in South Dakota. Canton has been an official National Weather Service Cooperative Observer location since 1896. Many locations received from 10 to 15 inches of rain.  The South Dakota CoCoRaHS observer at Beresford 0.2 E (SD-UN-5) measured 15.80 inches in June, and the observer at Garretson 6.9 W (SD-MH-56) measured 15.49 inches. One other observer reported more than 18 inches, which may be low since there were reports for only 7 days in the month. More on the heavy rain can be found on the NWS Sioux Falls, SD web site.

Compare the percent of normal map for this June with that of June 2013. Two significant features stand out. First, last June much of the country had below normal precipitation except for Montana, northern California,  and the eastern seaboard. The heavy rain along the eastern seaboard was largely due to Tropical Storm Andrea which moved up the coast the first week of the month.
Percent of normal precipitation for June 2013.
Credit: NWS AHPS
The other feature that probably caught your eye is the large blob of red in the southwestern U.S. Now, that area normally doesn't get a lot of rain during June, but they have received even less this month and most of the year to date. Drought conditions have overtaken all of California at the end of June, and the entire state is in Severe Drought, with 77 percent of the state in Extreme to Exceptional drought.

Drought status in California as of June 24, 2014.
Source: U.S. Drought Monitor

June closed out with some wild weather in the Midwest. Two derechoes tore through Iowa, northern Illinois, southern Wisconsin, and northern Indiana on Monday causing extensive amounts of straight-line wind damage. Power was still out in many areas as of Wednesday afternoon. Heavy rain with the storms caused widespread flash flooding, and  flood warnings are in effect for many rivers and streams in eastern Iowa and northwestern Illinois. Several smaller rivers have already reached record flood levels in Iowa.

Tracks of two derecho events in the Midwest on June 30.

 For more information on the derechoes, see the NWS Chicago web page on this event and this page for more on the severe weather that day.

 For information on the storm in Iowa, see the NWS Davenport/Quad Cities page on the severe weather.

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