Autumn 2016 Climate Summary

Autumn Weather Conditions in Alaska 

 

G. Wendler, B. Moore and K. Galloway

Alaska Climate Research Center

 

This article presents a summary of Autumn 2016 (September, October, November) temperatures and precipitation from the first order meteorological stations (operated by the National Weather Service meteorologists) in Alaska. The deviations from the long-term mean are based on the climate normals of 1981-2010. All figures and tables are provided by the Alaska Climate Research Center, http://akclimate.org, except as noted.

 

 

 

Temperature 

 

Figure 1 shows the autumn temperature departure from the 30-year averages. It can be seen that Alaska had temperatures noticeably warmer than normal (i.e. positive deviation). All first order stations except Gulkana (-1.2°F) reported above normal temperatures. A mean deviation of 2.9°F could be calculated, identical to the 2015 autumnÕs deviation. While this would not be a large value for a single station and single month, it is notable as a mean value of 19 stations spread over such a large area as Alaska as well as for a whole season. The highest positive deviations (>5°F) were found in the northern part of Alaska at Barrow (9.3°F) and Kotzebue (5.2°F). As can be seen from the figure, the coastal eastern areas as well as the Interior recorded lower deviations. The actual values of all stations can be seen from Table A, which gives not only the seasonal mean, but also the temperature data for the three autumn months independently. All three autumn months were seasonally warmer than normal with a deviation of 2.2°F in September, 4.1°F in October and 2.3°F in November.

 

 

 

Figure A: Autumn 2016 isotherm map of the deviation in temperature (°F) from the 30-year normal (1981-2010) based on all first order meteorological stations in Alaska.

 

 

Table 1: Mean and temperature deviations (°F) from the 30-year normal (1981-2010) is presented for all first order stations for each autumn month and for the Autumn 2016 season.

Station

Temperature (°F)

September

October

November

Seasonal

Mean

Dev

Mean

Dev

Mean

Dev

Mean

Dev

Anchorage

51.7

3.1

35.9

1.1

26.1

3.9

37.9

2.7

Annette

55.5

1.7

49.5

2.8

45.1

5.1

50.0

3.2

Barrow

34.5

2.4

30.1

12.9

13.3

12.6

26.0

9.3

Bethel

47.9

2.3

37.7

7.4

13.5

-3.9

33.0

1.9

Bettles

39.9

-0.7

23.0

4.1

-0.2

0.8

20.9

1.4

Cold Bay

51.1

3.0

45.3

4.9

35.8

1.3

44.1

3.1

Delta Junction

46.2

2.3

26.3

2.2

9.4

3.2

27.3

2.6

Fairbanks

46.2

1.3

26.7

2.5

3.7

1.1

25.5

1.6

Gulkana

46.1

2.8

20.0

-6.6

5.9

0.1

24.0

-1.2

Homer

51.2

3.1

43.0

4.9

32.5

3.0

42.2

3.6

Juneau

51.2

1.2

40.2

-2.2

37.0

3.6

42.8

0.9

King Salmon

51.3

3.7

40.4

6.9

23.0

0.1

38.2

3.5

Kodiak

51.7

2.3

44.0

3.5

37.2

3.3

44.3

3.0

Kotzebue

44.1

1.8

35.3

11.0

11.8

2.7

30.4

5.2

McGrath

46.6

2.0

29.8

4.7

3.4

-2.1

26.6

1.5

Nome

43.8

1.0

37.7

9.0

15.9

-1.0

32.5

3.0

St. Paul Island

49.9

4.6

44.8

6.2

34.0

1.0

42.9

3.9

Talkeetna

48.7

1.2

35.1

1.9

23.4

3.9

35.7

2.3

Yakutat

50.1

1.7

40.8

-0.2

36.9

4.6

42.6

2.0

 

 

It was the warmest autumn on record for Barrow with 26.0°F, just topping the previous record of 25.8°F from 1998. It was also the warmest for St. Paul with 42.9°F, again just topping the old 1979 record of 42.7°F. It was the second warmest autumn for Cold Bay with 0.4°F below the 2013 record of 44.5°F. This autumn was the third warmest for Annette and Kotzebue.

                                                                                                                            

 

Figure B: Autumn 2016 time series of the mean Alaskan temperature deviations (°F) from the 30-year normal (1981-2010) based on all first order meteorological stations in Alaska.

 

In Figure B the daily mean Alaskan temperatures from the normal are presented. It can be seen that days in the second half of October and first half of November were especially warm with some temperature deviations exceeding 10°F. In opposition to this, the latter part of November was seasonally too cold. In the following section, we are discussing the temperature deviations on a monthly basis in greater detail.

 

September 2016 marks the 12th month in a row with statewide mean temperatures above normal. The monthly mean temperature of all stations was 47.8°F, 2.2°F above the normal of 45.6°F. This is 3.5°F above the September 2015 mean of 44.3°F. Calculating the mean daily temperatures of the First Order Stations, 28 days of the month were above the 30-year normal, and two days (25th and 26th) were below normal. The peak positive deviation for the month occurred on the 21st at 5.0°F. Monthly mean temperatures were above normal for 18 of the 19 First Order Stations. The only station with a below normal mean monthly temperature was Bettles with -0.7°F below its normal of 40.6°F. St. Paul Island had the greatest positive deviation of 4.6°F above its normal of 45.3°F.

 

The highest daily maximum temperature of the First Order Stations for September was 75°F reported at King Salmon on the 1st. Annette held the spot for the highest mean temperature for the month at 55.5°F. The lowest temperature of 16°F was observed at Gulkana on the 30th. Barrow reported the lowest September mean monthly temperature with a value of 34.5°F.

 

October's monthly mean temperature was 36.1°F, 4.1°F above the normal of 32.0°F. Twenty-eight days of the month were above the 30-year normal, with three days (16th, 17th and 23rd) being below normal. The peak positive deviation for the month occurred on the 31st at a very significant value of 21.1°F. Monthly mean temperatures were above normal for 16 of the 19 First Order Stations. The only stations with a below normal mean monthly temperature were Gulkana with -6.6°F below its normal, Juneau (-2.2°F) and Yakutat (-0.2°F). Barrow had the greatest positive deviation with an impressive of 12.9°F above its normal of 45.3°F. Kotzebue had the next greatest positive deviation with 11.0°F.

 

The highest daily maximum temperature of for October was 63°F reported at King Salmon on the 13th and Annette on the 24th. Annette also held the spot for the highest mean temperature for the month at 49.5°F. The lowest temperature of -17°F was observed at Gulkana on the 24th and Gulkana reported the lowest October mean monthly temperature with a value of 20.0°F.

 

There were a quite a few daily temperature record events in October, and most were high events, and occurred during the first half of the month, and during the last week of the month. Many of the events were focused in the southwestern area of the State. St. Paul Island had 19 events both set and tied high records. King Salmon had nine such events. Kodiak had two new low records, while Juneau had one new low record temperature. The high of 44°F at Barrow on the 10th not only set a daily record, but was the warmest temperature in October on record. The average temperature at Fairbanks dropped to 32°F on the 13th, giving a total of 194 days (start on April 3rd) where the temperature was greater than or equal to 32°F, breaking the old record of 188 days from 1943. The time period with temperatures above the freezing point is also called the length of the growing season, and is, of course, highly important for the local agriculture.

 

November's monthly mean temperature was 21.5°F, 2.3°F above the normal of 19.2°F. The first 17 days of the month were above normal, while below normal temperatures dominated the end of the month. The peak positive deviation for the month occurred on the 13th at 11.6°F. The greatest negative deviation occurred on the 29th with -11.3°F. Monthly mean temperatures were above normal for 16 of the 19 stations. The only stations with a below normal mean monthly temperature were temperature was observed in Bethel with -3.9°F below its normal of 17.4°F, McGrath (-2.1°F) and Nome (-1.0°F). Note that these stations are located in the western portion of the State. Like October, Barrow held the spot with the greatest positive deviation with an impressive of 12.6°F above its normal of 0.7°F. Annette had the next greatest positive deviation with 5.1°F.

 

The highest daily maximum temperature of the First Order Stations for November was 62°F reported at Annette on the 10th. Annette also held the spot for the highest mean temperature for the month at 45.1°F. The lowest temperature of -44°F was observed at Bettles on the 30th and Bettles also reported the lowest November mean monthly temperature with a value of -0.2°F.

 

There were only a limited number of new daily temperature record events in November. Kotzebue set a new daily high of 38°F on the 1st, breaking the 2002 record of 36°F. At the other end of the state, at Annette on the 9th the high of 60°F broke the previous high of 58°F from 1997. Also on the 9th, Juneau set a new high with 53°F, 1°F warmer than the 1997 record. Then the next day Annette set another record with 62°F topping the old record of 59°F also from 1997.

 

The colder temperatures across the State at the end of the month broke an unusual record. The high of -21°F at Fairbanks on the 28th ended a record 658 consecutive days where the daily high was above -10°F. The previous record was 346 days that ended on November 17th, 2001. Similarly, the low of -31°F at Fairbanks also on the 28th ended a 624 day streak where the temperatures had been above -30°F. This is the second longest such streak, with the record being 642 days that ended on November 26th, 1977.

 

 

Precipitation

 

The mean autumn precipitation was slightly below normal (-9%). This value was obtained by calculating the mean of the deviations in percentage of the First Order Stations. As there is a wide range of "normal" precipitation amounts in different climate zones of Alaska, this method was considered preferable over the use of actual amounts. Values are presented in Figure D:

 

 

Figure C: Autumn 2016 map of the precipitation departures (%) from the 30-year normal (1981-2010) based on all first order meteorological stations in Alaska.

 

 

It can be seen from Figure C that Bettles (+52%) and St Paul Island (+48%) recorded the highest positive deviations, while Delta Junction (_63%), Anchorage (-48%), Gulkana (-44%) and Yakutat (-42%) were much drier than normal. The St. Paul Island value tied 1949 for the highest precipitation with 11.44". On the other side of the coin, it was the third driest autumn for Delta Junction. The actual values for all stations by month and for the season are presented in Table 3:

 

 

Table 3: The total precipitation (inch) and deviation in % from the 30-year normal (1981-2010) is presented for the first order stations for each autumn month and for the autumn 2016 season.

Station

Precipitation (in)

September

October

November

Seasonal

Total

Dev

Total

Dev

Total

Dev

Total

Dev

Anchorage

2.35

-21%

0.59

-71%

0.25

-78%

3.19

-48%

Annette

10.23

4%

4.59

-67%

11.61

-6%

26.43

-27%

Barrow

0.77

7%

0.28

-32%

0.43

105%

1.48

10%

Bethel

3.17

15%

0.74

-55%

0.47

-71%

4.38

-27%

Bettles

5.34

180%

0.26

-75%

0.25

-73%

5.85

52%

Cold Bay

5.87

24%

7.11

49%

3.78

-24%

16.76

16%

Delta Junction

0.73

-29%

0.10

-88%

0.07

-89%

0.90

-63%

Fairbanks

2.08

89%

0.02

-98%

0.29

-57%

2.39

-8%

Gulkana

0.89

-44%

0.37

-63%

0.61

-15%

1.87

-44%

Homer

4.86

47%

1.57

-39%

3.49

25%

9.92

14%

Juneau

11.64

35%

2.59

-70%

6.55

9%

20.78

-11%

King Salmon

4.84

52%

1.12

-46%

0.94

-32%

6.90

4%

Kodiak

4.99

-32%

11.58

40%

9.31

36%

25.88

15%

Kotzebue

2.02

28%

0.30

-70%

0.10

-87%

2.42

-28%

McGrath

5.08

104%

0.38

-74%

0.24

-83%

5.70

7%

Nome

2.29

-7%

1.70

6%

0.71

-42%

4.70

-11%

St. Paul Island

4.45

49%

5.29

70%

3.59

24%

13.33

48%

Talkeetna

5.22

21%

0.48

-83%

0.28

-83%

5.98

-32%

Yakutat

16.10

-24%

3.00

-86%

14.34

-1%

33.44

-42%

 

 

Looking at the three autumn months separately for all of Alaska, September reported a surplus of 26% in precipitation, while October (_45%) and November (-28%) were too dry, resulting in a mean seasonal value of -9%. More details can be obtained from Figure E, which represent the statewide mean daily precipitation deviation for autumn.

 

 

 

Figure D: Autumn 2016 time series of the mean Alaskan precipitation deviations (%) from the 30-year normal (1981-2010) based on all first order meteorological stations in Alaska.

 

 

Looking at the monthly precipitation separately, September's amount was significantly above normal, with the overall precipitation calculated as 26% above the average; 13 of the First Order Stations and 17 days of the month reported above normal values. There were no days during the month without any measureable precipitation at all of the 19 First Order Stations. This is slightly drier than September 2015, which reported a positive deviation of 28%. The highest amount in precipitation when expressed in percent was Bettles with 280% of normal. This represents the wettest September on record for Bettles (5.34"), breaking the old record of 4.80" from 2002. This September was the 4th wettest on record for Juneau and 5th wettest for McGrath. Gulkana was the relatively driest station at just 56% of normal precipitation observed. September's highest monthly precipitation total was observed at Yakutat (16.10"), and Yakutat also reported the highest daily total of 3.74" on the 12th, a new daily record.

 

October's precipitation was significantly below normal, with the overall precipitation calculated as 45% below the average. Fifteen of the First Order Stations and 25 days of the month reported below normal values. There were no days during the month without any measureable precipitation at all of the 19 First Order Stations. This is quite a bit drier than October 2015, which reported a negative deviation of -4% below normal. The greatest daily deviation of 105% occurred on the 28th. The leading station with a greater than normal monthly precipitation amount was St. Paul Island with 5.29", or 170% of normal.

 

Like October, November's precipitation was below normal, with the overall precipitation calculated as 28% below the average. Fourteen of the First Order Stations and 22 days of the month reported below normal values. This is quite a bit drier than November 2015, which reported a positive precipitation deviation of 75% above normal. The greatest daily deviation of 33% occurred on the 11th. The leading station with a greater than normal monthly precipitation amount was Barrow with 0.43", or 205% of normal. The relatively driest station was Delta Junction with just 11% of normal.

 

The total snowfall for the stations for the autumn season as a whole is presented in Table 4. Compared with the precipitation data, these values are even more reduced. However, this does not come to any surprise, as temperatures were mostly above normal. This resulted in a higher percentage than normal of the precipitation falling as rain, and not as snow.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 3: The total snowfall (inch) and deviation in % from the 30-year normal (1981-2010) is presented for the first order stations that measure snowfall for the Autumn 2016 season.

Station

Snowfall (in)

Seasonal

Total

Normal

Deviation

Anchorage

3.9

21.4

-82%

Annette

0.0

3.6

-100%

Barrow

11.2

19.2

-42%

Bethel

3.6

17.9

-80%

Bettles

14.2

31.0

-54%

Cold Bay

1.8

12.6

-86%

Fairbanks

5.2

25.8

-80%

Juneau

8.4

13.9

-40%

King Salmon

4.6

9.8

-53%

Kodiak

2.0

7.5

-73%

Kotzebue

5.6

17.4

-68%

McGrath

8.3

31.0

-73%

Nome

8.6

17.3

-50%

St. Paul Island

6.6

10.3

-36%

Yakutat

4.3

20.7

-79%

 

 

 

While there are, of course, climate related newsworthy stories, we did not discuss these in this seasonal summaries. However, if you go on the ACRC website to the Monthly Statewide Summaries, you will find them there for each of the three autumn months.

 

 

 


Figure A: Autumn 2016 isotherm map of the deviation in temperature (°F) from the 30-year normal (1981-2010) based on all first order meteorological stations in Alaska.

 

Figure B: Autumn 2016 time series of the mean Alaskan temperature deviations (°F) from the 30-year normal (1981-2010) based on all first order meteorological stations in Alaska.

 

Figure C: Autumn 2016 map of the precipitation departures (%) from the 30-year normal (1981-2010) based on all first order meteorological stations in Alaska.

 

Figure D: Autumn 2016 time series of the mean Alaskan precipitation deviations (%) from the 30-year normal (1981-2010) based on all first order meteorological stations in Alaska.

 

Table 1: Mean and temperature deviations (°F) from the 30-year normal (1981-2010) is presented for all first order stations for each autumn month and for the Autumn 2016 season.

 

Table 2: The total precipitation (inch) and deviation in % from the 30-year normal (1981-2010) is presented for the first order stations for each autumn month and for the Autumn 2016 season.

 

Table 3: The total snowfall (inch) and deviation in % from the 30-year normal (1981-2010) is presented for the first order stations that measure snowfall for the Autumn 2016 season.

year_list: 
2016
Season: 
Autumn
Seasonal Image: