National Weather Service United States Department of Commerce

Florence Departs U.S. But Rivers Will Rise Further In Carolinas; Heavy Rain Continues In Midwest

Major-to-record river flooding will continue across the Carolinas for days to weeks to come as rainfall from Florence makes its way through area river systems. Meanwhile, a stationary front extending through the Midwest will be a focus for heavy rain with localized flash flooding across the Upper Midwest midweek; severe thunderstorms are also possible in this region. Read More >

There was quite a contrast in the temperatures for December 2017 across central and northeast South Dakota along with west central Minnesota.   Across the region, temperatures were much above normal through the 20th of December before the bottom fell out through the 31st of the month as Arctic air settled in.  For the first 20 days, high temperatures were regularly in the 30s and 40s along with some 50s.  Record highs were set at Pierre and Mobridge on the 10th and the 12th.  Record cold along with extreme wind chills occurred across the region around Christmas time and from December 30th into the first of the New Year.  Record lows and record low daily highs were set at several locations.  In fact, the last week of December was the coldest on record for all locations across the region ranging from 10 to 25 degrees below normal.  Despite the cold at the end of the month, December finished out about 2 to 4 degrees above normal.

Monthly precipitation and snowfall was near to below normal across most of the region except for areas in north central South Dakota where the precipitation and snowfall was near to above normal.

DECEMBER 2017

       

Temperature Data

Aberdeen

Sisseton

Wheaton

Watertown

Warmest Temperature / Date

51 / 2nd

53 / 2nd

51 / 3rd

50 / 2nd

Coldest Temperature / Date

-32 / 31st

-25 / 31st

-25 / 31st

-27 / 31st

Average High / Departure from Normal

28.6 / +3.1

28.2 / +2.1

26.1 / +3.2

26.6 / +1.8

Average Low / Departure from Normal

6.5 / +0.6

9.3 / +1.4

8.6 / +2.6

9.1 / +1.9

Monthly Average / Departure from Normal

17.6 / +1.9

18.7 / +1.7

17.3 / +2.9

17.9 / +1.9

Precipitation Data

       

Monthly Precipitation / Departure from Normal

0.35 / -0.17

0.30 / -0.09

0.12 / -0.60

0.25 / -0.28

Monthly Snowfall / Departure from Normal

3.6 / -3.3

3.8 / -3.8

1.1 / -7.1

4.5 / -2.6

Most Precipitation in 24 hours / Date

0.14 / 29th

0.07 / 29th

0.09 / 28th

0.11 / 29th

Most Snow in 24 hours / Date

1.8 / 29th

2.0 / 29th

0.8 / 28th

2.0 / 29th

         

Temperature Data

Pierre

Kennebec

Mobridge

Timber Lake

Warmest Temperature / Date

58 / 10th

58 / 2nd

54 / 12th, 18th

52 / 2nd, 12th

Coldest Temperature / Date

-25 / 31st

-29 / 31st

-30 / 31st

-31 / 31st

Average High / Departure from Normal

33.5 / +2.2

34.2 / +1.5

31.7 / +3.0

29.5 / 0.0

Average Low / Departure from Normal

13.5 / +1.4

13.8 / +2.5

11.9 / +4.2

10.6 / +0.7

Monthly Average / Departure from Normal

23.5 / +1.8

24.0 / +2.0

21.8 / +3.6

20.0 / +0.3

Precipitation Data

       

Monthly Precipitation / Departure from Normal

0.47 / -0.08

0.39 / +0.01

0.54 / +0.10

0.86 / +0.38

Monthly Snowfall / Departure from Normal

4.4 / -0.5

7.9 / +1.3

8.2 / +2.5

10.8 / +3.3

Most Precipitation in 24 hours / Date

0.14 / 29th

0.13 / 21st

0.20 / 4th

0.36 / 4th

Most Snow in 24 hours / Date

1.5 / 30th

2.3 / 21st

3.2 / 29th

4.2 / 4th

 

2017 Climate Summary

2017 was a drier and warmer than normal year across most of central and northeast South Dakota as well as west central Minnesota.  Average temperatures were from near to almost 2 degrees above normal for the year due mostly to the hot summer with many days above 90 degrees along with several 100 degree plus readings. The heat was mainly a result of the dry spring and summer across the region where drought conditions became severe to exceptional across central and north central stretching over to the James River Valley.  This drought brought large devastation to the crops across the region. Yearly precipitation amounts ranged from just above normal to over 6 inches below normal.  Watertown was the only location to finish the year above normal with just over an inch above normal from a few periods of heavy rain from thunderstorms. The warmest temperature for the year was 110 degrees 4 miles northwest of Onida in July. The coldest reading was 40 degrees below zero at Lantry near Eagle Butte at the end of December. 

January 2017

Temperatures for January 2017 were above average on a whole across eastern South Dakota and west central Minnesota, and below average across central South Dakota. The temperatures varied quite a bit from west to east across the region ranging from nearly 5 degrees above normal at Wheaton, MN to almost 7 degrees below normal at Timber Lake. The overnight lows, ranging from 3 to 8 degrees above normal, were the main reason for the above average monthly temperatures across the east. Cloud cover along with extensive fog were likely the main reasons for the warmer overnight lows. Out west, the daytime highs were from 4 to nearly 10 degrees below normal mainly as a result of the deeper snowpack.

January featured a number of accumulating snowfalls with one primary snowstorm, which occurred from the 24th into the 25th. While the bulk of this system impacted the South Dakota/Nebraska border (with some locations picking up nearly 2 feet of snow), central South Dakota accumulated over 6” in several locations. On a whole, the result was an above average month for precipitation and snowfall.

An outbreak of Arctic air arrived from the 3rd into the 4th, when wind chill values reached 35 to 45 degrees below zero across mainly north central South Dakota. A strong Alberta Clipper system impacted roughly the northern half of South Dakota during the day of the 30th. Several locations gusted to the high wind warning/severe thunderstorm criteria of 58 mph, including near Peever, Aberdeen, Eureka, and McLaughlin.

February 2017

February 2017 on a whole featured slightly below average amounts of precipitation across central and northeastern South Dakota. Most locations were only down up to half an inch of moisture. However snowfall was lacking, by over half a foot across eastern South Dakota and west central Minnesota. Essentially, next to no snow fell in some locations throughout the entire month which put them into the record books: 0.3” in Watertown is the 4th lowest monthly snowfall on record. 0.8” in Pierre ties for 5th place in record lowest monthly snowfalls. 0.9” in Mobridge ranks in 6th place in record lowest monthly snowfalls. 1.0” in Wheaton ties for 3rd place and finally, 1.1” in Aberdeen is the 9th record lowest monthly snowfall. February snowstorms generally followed the same track, south of the area around the SD/NE border. The only real stand-out precipitation event across the area wasn’t even winter-related – a severe thunderstorm on the evening of the 21st produced 1” hail just north of Hettinger, North Dakota. This was the earliest 1” hailstone on record in the state of North Dakota. Thunderstorms then tracked southeast into South Dakota and produced a 55 mph recorded wind gust near McLaughlin. This evening featured other thunderstorms across the area as well… quite rare for February.

While temperatures were generally seasonable or below average for the first ~10 days of the month, February on a whole ended up much warmer than normal. Generally the farther east you were, the warmer it was. For example, far west central Minnesota ended around 10 degrees above average, which is an amazing amount for a monthly average. Areas west of the James Valley were very mild as well, with temps around 5 degrees above average. A number of record high temperatures were set between the 10th and 22nd. Additionally, Aberdeen reached 50+ degrees 7 times this month (record of 10), Watertown 6 times (record of 7), Sisseton 7 times (record of 8), and Pierre reached 60+ degrees 5 times (record of 7). Sisseton recorded their 7th warmest February on record while Watertown had their 8th warmest.

March 2017

Average temperatures for March 2017 across central and northeast South Dakota as well as west central Minnesota were near to above normal. There was quite a range in high and low temperatures for the month with highs in the mid 60s to the mid 70s with lows from around zero to nearly 10 degrees below zero.  Overall, the month of March was drier than normal across the region with precipitation amounts ranging from a quarter of an inch to nearly an inch and a third below normal.

There were two significant weather systems to note during March with one on March 7th and another one on March 12th.  The March 7th system was a high wind event that affected the entire region with 35 to 45 mph winds with gusts to over 60 mph. The March 12th system brought 6 to 10 inches of snow mainly to north central and northeast South Dakota. 

April 2017

April on a whole was near normal in terms of temperature across the area, with a few locations slightly above normal. However, it was a tale of two halves: the first 15 days were 5-8 degrees above average while the last 15 were generally 4-7 degrees below normal. The late month cold snap featured a few record cold temps as values reached the low 20s.

Despite a couple widespread rain systems, much of central and northeast South Dakota finished the month below average for total precipitation… by as much as 1.5” for some. A couple days featured thunderstorms which produced small hail across the area. This is not overly uncommon for April. Snowfall was also very lacking across the board, especially from Pierre to Redfield where 4-5” less snow than typical accumulated… or in other words where essentially no snow fell.

May 2017

Much of northeastern and central South Dakota observed much below average precipitation during the month of May, the only exception being far eastern South Dakota where more than an inch of rain above average fell. Aberdeen recorded their 10th driest May on record with 0.65” of moisture (2.46” below normal). Additionally, Mobridge recorded their 9th driest with 0.67” (2.15” below normal) and Timber Lake had their 8th driest with 0.69” (2.15” below normal). Interestingly, Mobridge recorded their wettest May on record two years ago in 2015 with 9.32”. Regarding 2017, no drought existed across the area on May 1st, but moderate drought had developed across much of northern South Dakota. On the 28th, a series of showers and storms with 50-60 mph wind gusts made this obvious after lofting large amounts of dust.

Temperature-wise, northeastern South Dakota was slightly below normal overall while parts of north central South Dakota was slightly above normal. Several nights towards the end of the month were cold enough for the potential for patchy frost to develop (mid 30’s). Finally, and impressively, two systems across eastern South Dakota were cold enough to produce snow. The first occurred on May 1st where 1.6” fell in Watertown (daily record) and a few more yet across Deuel County and surrounding areas. Isolated areas also received snowfall during the early morning hours of May 21st – about 2.5” accumulated at Willow Lake, SD.

June 2017

Climatologically, June is the wettest month of year across our area, and some locations lived up to expectations thanks in large part to widespread storms on June 13th. Pierre and Aberdeen both set daily precipitation records with 1.53” and 2.98” respectively. Unfortunately, a large outbreak of severe weather accompanied the beneficial rain that day (link to http://www.weather.gov/abr/2017_June13_WidespreadSevere). 10 confirmed tornadoes and damaging straight-line winds to over 90 mph led to widespread damage across northeastern South Dakota and west central Minnesota. In addition to June 13th, portions of east central South Dakota were impacted by two more significant straight-line wind events (June 11th and 22nd). Despite these events, drought conditions expanded and intensified over the course of the month such that over 50% of South Dakota ended in at least D1/Moderate Drought (as defined by the US Drought Monitor), and portions of Dewey, Campbell, Potter and Walworth counties ended in D3/Extreme Drought. These areas are down generally 4-6” of precipitation from normal since the beginning of the year.

It was a tale of two Junes regarding temperatures. June 1-15th ranked in the top 10 warmest on record for most locations, and several record high temperatures were broken (Mobridge: 100° on the 2nd, 95° on the 4th and 103° on the 9th, Pierre: 103° on the 9th, 98° on the second 2nd, Aberdeen 100° on the 2nd). However, record cold followed during the second half of the month (Mobridge: 42° on the 26th, Aberdeen: 39° on the 24th, 41° on the 25th, 39° on the 26th, 42° on the 27th,). Frost developed across parts of north central South Dakota on the mornings of June 25th and 26th, particularly in low-lying areas. Already severely stressed crops were damaged as a result. This is a rare occurrence for this time of year, but not unprecedented meteorologically. In fact, the drought contributed to such extreme temperature swings this month as it takes less energy to heat dry air compared to moist air, and dry air cools down faster at night compared to moist air. For instance, Aberdeen hit 39° at 5:21 am on the 1st. Then, about 34 hours later at 3:47 pm on the 2nd, the temperature soared to 100°, a 61 degree change!

July 2017

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 t-storms 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.

August 2017

August 2017 was cooler than normal across central and northeast South Dakota along with west central Minnesota.  Average temperatures were anywhere from 3 to 5 degrees below normal.  After many 100 degree plus readings in July, temperatures in August had a hard time reaching 90 degrees for most locations.  In fact, several locations had one of their top ten coolest August on record. Pierre had its second coolest August on record, Kennebec had their seventh coolest, and Timber Lake had their eighth coolest August on record.

August was wetter than normal across the region with rainfall amounts from 3 to nearly 6 inches. These amounts ranged from a quarter inch above to nearly 4 inches above normal.  With the much needed rainfall, the drought conditions improved across parts of the region.  In fact, parts of central and north central South Dakota went from extreme drought at the beginning of August to moderate drought at the end of August.

September 2017

September 2017 temps were generally near or 1-2 degrees above average. A lack of major cold air outbreaks meant a lack of widespread frost, which typically happens by this time of year, climatologically speaking.

Precipitation-wise, it was an above average month for most of the area. For some locations that’s quite an understatement. Watertown tied for their 6th wettest September with 5.35” of rain (4.92” of this came during a 7 day period, which turned out to be the wettest 7 day period on record for the month). 1.57” of rain fell in just one hour in Watertown from 10 to 11 pm on the 19th, which resulted in some flooding. Sisseton also had a wet month, ranking 11th in their history. The 1.61” that fell there on the 23rd set a daily record. Unfortunately, those still burdened by severe drought across central South Dakota missed out on the bulk of these heavy rains.

Finally, a late-season severe weather outbreak which involved 3 tornadoes occurred on the 19th. More information can be found here: https://www.weather.gov/abr/September19StormSummary

October 2017

October finished slightly above average temperature-wise for most across the area. That said, the first two-thirds of the month were much warmer than the last third. A late large scale pattern change ushered in several clipper systems and cold air funneled in behind each one. This pattern led to increased winds as well, making it feel colder than it actually was. Wind gusts near or over 50 mph were not uncommon during this time.

Precipitation-wise, the general theme that has persisted for several months, of wet conditions along/near the South Dakota/Minnesota border while dry across central South Dakota, continued in October. Thus, there was little to no observed change in the drought across central South Dakota. These areas finished between one and 2 inches below average on precipitation for the month. While few low pressure systems brought an abundance of moisture across far east-central and southeastern South Dakota and west central Minnesota during the first week of the month, dry conditions became the norm for the second half of the month generally speaking.

The final week of October brought a few rounds of light snow as well, the first of the season. Around an inch of snow over the course of the month is typical, but no measurable snow was recorded this year.

November 2017

November 2017, while averaging out to be generally near or slightly above average, featured two very distinct halves temperature-wise. The first 10 days of the month were well below average, by between 5-10 degrees. However, incredibly mild air overtook the area during the 2nd half with averages above normal by 5-12 degrees. Thanksgiving Day as well as the 27th featured record daily high temperatures in the 60’s and 70’s.

Regarding precipitation, it was dry. The most significant system brought around a tenth of an inch of liquid and up to around an inch of snow on the 3rd, but otherwise much of the month was almost completely void of precipitation. This meant little to no snow, either. Much of the area had snowfall deficits between 4 and 7 inches, as November is one of our snowiest months on average. Historically, this lack of moisture is by no means unprecedented however. Many Novembers have yielded little to no precipitation in the past. That said, Pierre’s total of 0.05” ranked as tied 14th driest November on record, Watertown’s 0.08” total ranked as tied 15th driest, and Wheaton’s 0.10” tied for 13th driest. Furthermore, drought conditions remained entrenched across central South Dakota. Rounds of warm temps, low relative humidity and strong winds led to a number of days of fire concerns.

December 2017

There was quite a contrast in the temperatures for December 2017 across central and northeast South Dakota along with west central Minnesota.   Across the region, temperatures were much above normal through the 20th of December before the bottom fell out through the 31st of the month as Arctic air settled in.  For the first 20 days, high temperatures were regularly in the 30s and 40s along with some 50s.  Record highs were set at Pierre and Mobridge on the 10th and the 12th.  Record cold along with extreme wind chills occurred across the region around Christmas time and from December 30th into the first of the New Year.  Record lows and record low daily highs were set at several locations.  In fact, the last week of December was the coldest on record for all locations across the region ranging from 10 to 25 degrees below normal.  Despite the cold at the end of the month, December finished out about 2 to 4 degrees above normal.

Monthly precipitation and snowfall was near to below normal across most of the region except for areas in north central South Dakota where the precipitation and snowfall was near to above normal.

2017 CLIMATE REVIEW

       

Temperature Data

Aberdeen

Sisseton

Wheaton

Watertown

Warmest Temperature/Date

104 / Jul 17th

101 / Jul 17th

98 / Jul 18th

94 / Jul 17th

Coldest Temperature/Date

-32 / Dec 31st

-25 / Dec 31st

-25 / Dec 31st

-27 / Dec 31st

Average Yearly High/Departure from Normal

57.3 / +2.7

56.8 / +2.3

54.6 / +0.8

54.6 / +1.0

Average Yearly Low/Departure from Normal

32.1 /  +0.6

34.5 / +1.5

34.8 / +1.0

33.8 / +1.3

Yearly Average/Departure from Normal

44.7 / +1.7

45.7 / +2.0

44.7 / +0.1

44.2 / +1.2

Precipitation/Wind Data

       

Yearly Precipitation / Departure from Normal

15.22 / -6.50

18.98 / -3.35

20.75 / -3.90

23.12 / +1.04

Highest Wind Gust MPH / Date

58 / Mar 7th

64 / Mar 7th

N/A

56 / Mar 7th

         

Temperature Data

Pierre

Kennebec

Mobridge

Timber Lake

Warmest Temperature/Date

106 / Jul 9th

107 / Jul 9th

106 / Jul 9th

101 / Jul 4th

Coldest Temperature/Date

-25 / Dec 31st

-29 / Dec 31st

-30 / Dec 31st

-31 / Dec 31st

Average Yearly High/Departure from Normal

60.5 / +1.3

63.3 / +1.7

59.0 / +2.2

58.1 / +1.5

Average Yearly Low/Departure from Normal

35.9 / +0.3

36.1 / +0.8

34.9 / +1.8

33.9 / +0.3

Yearly Average/Departure from Normal

48.2 / +0.8

49.7 / +1.2

47.0 / +2.1

46.0 / +0.9

Precipitation/Wind Data

       

Yearly Precipitation / Departure from Normal

13.93 / -6.08

16.22 / -3.37

15.60 / -2.27

12.24 / -6.18

Highest Wind Gust MPH / Date

72 / Jun 13th

N/A

65 / Jul 18th

N/A