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Dangerous Fire Weather Threat Continues in Southern California; Winter Weather from the Mid-Mississippi Valley to the Mid-Atlantic

Critical fire weather conditions continue for portions of Southern California. Conditions should improve somewhat by Thursday, and at least an elevated fire weather threat is expected to continue. A storm system is expected to bring heavy rain with a river/flash flooding threat to the Southeast, and accumulating snow and ice from the Mid-Mississippi Valley to the interior Mid-Atlantic. Read More >

May 2018 was either very wet or very dry, depending on your location. While a generally active pattern brought several opportunities for precipitation, Aberdeen recorded their 7th driest May on record with just 0.52” of moisture (1900 holds the record at 0.25”). This is 0.13” less than was recorded in May 2017. However, 2017 was drier than 2018 from January 1st to May 31st in Aberdeen by 0.58” (3.76” below normal vs 3.18” below normal respectively). On the contrary, an exceptionally heavy rainfall event took place across portions of north central South Dakota on May 17th. Training thunderstorms, those which develop and pass over the same areas over extended periods of time, led to extreme rainfall reports including 13.15” four miles northwest of Long Lake, SD. These measurements are being vetted to determine if they meet standards necessary to qualify as South Dakota’s state 24 hour precipitation record (currently held by Groton, SD with 8.74” recorded on May 6th, 2007). This heavy rainfall contributed to the failure of the Hiddenwood Lake Dam about 4 miles north of Selby, SD on the morning of May 18th. Several area roadways were submerged as a result. More information on the May 17th event can be found here: https://www.weather.gov/abr/2018May17_18_severe_flooding

 May 2018 was very warm across the board, May 24-27th in particular. The following were record daily high temperatures: Watertown reached 96° on the 27th, Sisseton reached 90° on the 24th, 93° on the 25th, and 95° on the 26th, and Aberdeen reached 94° on the 25th, 97° on the 26th and 101° on the 27th. This is only the 4th year on record in Aberdeen when a May day reached at least 100° (once in 2018, 1959 and 1931, and 7 times in 1934). This was the 3rd warmest May on record in Aberdeen (64.5° average temperature vs 1st place 69° in 1934), the 3rd warmest May on record in Sisseton (64.3° average temperature vs 1st place 70.3° in 1934), the 3rd warmest May on record in Wheaton (64.8° vs 1st place 67.1° in 1977, the 4th warmest in Timber Lake, 7th in Pierre and Watertown, and 8th warmest in Kennebec. This is an abrupt turn-around from just a month ago. Amazingly, Aberdeen recorded their 2nd coldest April on record this year, and both Sisseton and Wheaton recorded their 3rd coldest April on record this year. “Normal” weather is just the average of extremes in the Northern Plains after all.

 

MAY 2018

       

Temperature Data

Aberdeen

Sisseton

Wheaton

Watertown

Warmest Temperature / Date

101 / 27th

97 / 27th

94 / 27th

96 / 27th

Coldest Temperature / Date

29 / 2nd

33 / 2nd

35 / 2nd

35 / 2nd

Average High / Departure from Normal

80.1 / +11.4

78.7 / +9.3

77.7 / +9.2

74.8 / +7.2

Average Low / Departure from Normal

49.0 / +4.9

51.7 / +6.6

51.9 / +6.2

49.9 / +5.3

Monthly Average / Departure from Normal

64.5 / +8.1

65.2 / +7.9

64.8 / +7.1

62.4 / +6.3

Precipitation Data

 

 

 

 

Monthly Precipitation / Departure from Normal

0.52 / -2.59

1.80 / -0.92

1.44 / -1.24

1.67 / -0.97

Most Precipitation in 24 hours / Date

0.33 / 14th

0.78 / 27th

0.39 / 27th

1.00 / 8th

         

Temperature Data

Pierre

Kennebec

Mobridge

Timber Lake

Warmest Temperature / Date

91 / 26th

94 / 27th

93 / 31st

91 / 26th

Coldest Temperature / Date

35 / 2nd

36 / 2nd

36 / 2nd

38 / 20th

Average High / Departure from Normal

76.5 / +6.3

78.9 / +6.0

77.4 / +9.0

75.4 / +5.7

Average Low / Departure from Normal

51.0 / +5.3

50.9 / +5.0

50.7 / +6.8

48.9 / +4.9

Monthly Average / Departure from Normal

63.8 / +5.9

64.9 / +5.5

64.0 / +7.8

62.2 / +5.3

Precipitation Data

 

 

 

 

Monthly Precipitation / Departure from Normal

2.78 / -0.37

3.74 / +0.17

3.33 / +0.51

2.77 / -0.07

Most Precipitation in 24 hours / Date

1.26 / 17th

0.86 / 11th

2.09 / 17th

2.3 / 18th

 

 

Total precipitation accumulation in May 2018, courtesy of the Midwestern Regional Climate Center

 

Precipitation departures in May 2018, courtesy of the Midwestern Regional Climate Center

 

A wider view of precipitation totals (first) and departures (second) during May 2018 across the Northern Plains for perspective, from https://water.weather.gov/ahps/ 

 

 

Temperature departures in May 2018, courtesy of the Midwestern Regional Climate Center