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Heavy Rainfall and Flash Flood Threats Shift From Southern Plains to Lower Mississippi Valley; Elevated to Critical Fire Concerns Out West

Heavy to excessive rainfall with flash flood concerns will shift from the southern Plains into the Lower Mississippi Valley. Elevated to Critical Fire weather threats will linger through the weekend across the Great Basin and central Rockies. Finally, Major to Record river flooding will continue in portions of the Midwest and across parts of North and South Carolina this weekend. Read More >

Drought unfortunately not only continued but deepened over the course of the month for many across central South Dakota. While some locations in this area received one or more thunderstorm-induced bouts of heavy rain during the second half of the month, others unfortunately missed out. For instance thunderstorms on the 29th produced 1.6” of rain 2 miles south of Fort Pierre, but the Pierre airport picked up a mere 0.03”. Also, on the 30th, 1.93” of rain fell 3 miles west Sisseton while the airport received 0.01”. At the end of the month, Pierre had recorded just 0.17” of rainfall… the second driest July on record (surpassed only by the July of 1936 when 0.10” of rain fell). Sisseton received only 0.69” of rain: 5th driest on record. July featured several rounds of severe weather as well, including microbursts (http://www.weather.gov/abr/20170705_Microburst_Hail) , 3” hail (http://www.weather.gov/abr/20170711_WatertownHail) and a 100 mph straight-line wind gust (http://www.spc.noaa.gov/climo/reports/170719_rpts.html).

Temperatures reached record heights as a ridge of high pressure largely dominated the region from the 1st through the 17th. Temperatures ended above average overall across the area for the month, and several records were reached as well. While not a record for the day, Aberdeen’s 104 degree reading on the 17th was the warmest temperature since July 30th, 2006 and was their 5th 100+ degree day this year. Sisseton’s 101 degree reading on the 17th was similarly the warmest temperature since July 30th, 2006. Meanwhile, Pierre has reached 100 degrees 6 times this year, and Mobridge 7. The hottest temperature for July in our region was 109 degrees at Gann Valley on July 10th.

 

 JULY 2017

       

Temperature Data

Aberdeen

Sisseton

Wheaton

Watertown

Warmest Temperature / Date

104 / 17th

101 / 17th

98 / 17th

94 / 17th

Coldest Temperature / Date

46 / 1st

47 / 14th

52 / 14th

49 / 1st, 14th

Average High / Departure from Normal

88.3 / +4.8

86.5 / +3.6

82.4 / -0.1

83.8 / +1.2

Average Low / Departure from Normal

59.5 / +0.5

59.3 / -0.2

61.4 / +0.7

60.2 / +0.6

Monthly Average / Departure from Normal

73.9 / +2.6

72.9 / +1.7

71.9 / +0.3

72.0 / +0.9

Precipitation Data

       

Monthly Precipitation / Departure from Normal

2.05 / -0.97

0.69 / -2.89

0.98 / -2.22

3.21 / +0.19

Most Precipitation in 24 hours / Date

0.79 / 18th

0.30 / 19th

0.56 / 22nd

1.59 / 11th

         

Temperature Data

Pierre

Kennebec

Mobridge

Timber Lake

Warmest Temperature / Date

106 / 9th

107 / 9th

106 / 9th

101 / 3rd, 4th

Coldest Temperature / Date

49 / 1st

43 / 1st

51 / 1st

54 / 14th

Average High / Departure from Normal

94.1 / +5.3

97.4 / +7.7

92.2 / +6.4

92.5 / +6.5

Average Low / Departure from Normal

63.5 / +1.6

63.9 / +1.9

62.8 / +3.3

61.3 / +1.6

Monthly Average / Departure from Normal

78.8 / +3.4

80.6 / +4.7

77.5 / +4.9

76.9 / +4.1

Precipitation Data

       

Monthly Precipitation / Departure from Normal

0.17 / -2.44

2.79 / +0.30

2.97 / +0.27

1.16 / -1.46

Most Precipitation in 24 hours / Date

0.04 / 5th

1.50 / 26th

1.18 / 19th

0.39 / 18th

 

 

Animation of the U.S. Drought Monitor over the month of July. For those who are experiencing drought conditions/impacts and would like to submit a report on such, please visit http://droughtreporter.unl.edu/submitreport/

This photo, from Haakon county on July 26 just south of the Cheyenne River on State Highway 63, highlights how much of an impact such abnormally dry conditions have had on pastureland.

 

The following images are courtesy of the Midwestern Regional Climate Center and summarize July's precipitation and temperature in terms of observed values and departures from normal.