July 2012 Statewide Summary

Temperature

Nearly universally below normal temperatures developed across most of Alaska for July. The exception was Barrow with a positive deviation of 3.1°F. Arctic Alaska has shown the greatest warming over the last decades and this finding is in agreement with this trend. All other nineteen first order stations exhibited below normal values. In this sense July mirrored May 2012. A mean deviation of all twenty stations from the long-term mean could be calculated as -2.1°F, and this is the third month in a row with a mean below the normal. The coldest areas were Southcentral and Southwest with: Homer (-4.3°F), Bethel (-3.8°F), Talkeetna (-3.6°F), Anchorage (-3.3°F), and McGrath (-3.3°F).

 

The cold month was noticed in Fairbanks with only one day above 80°F, compared to the average of five days above that mark, along with the mean daily maximum of only 69.7°F, which didn't even break the 70°F mark. The first half of July for Anchorage was also the coldest on record since 1920. See the table below for more details.

 

 

Station

Temperature

Observed
(°F)

Normal
(°F)

Delta
(°F)

Anchorage

55.5

58.8

-3.3

Annette

57.0

58.6

-1.6

Barrow

44.0

40.9

3.1

Bethel

52.3

56.1

-3.8

Bettles

58.1

59.7

-1.6

Big Delta

58.8

60.2

-1.4

Cold Bay

48.4

50.9

-2.5

Fairbanks

60.8

62.5

-1.7

Gulkana

54.9

57.6

-2.7

Homer

50.3

54.6

-4.3

Juneau

54.9

56.9

-2.0

King Salmon

52.3

54.5

-2.2

Kodiak

52.0

54.5

-2.5

Kotzebue

54.1

54.6

-0.5

McGrath

56.7

60.0

-3.3

Nome

51.1

52.2

-1.1

St. Paul Island

44.8

47.2

-2.4

Talkeetna

56.5

60.1

-3.6

Valdez

53.2

55.4

-2.2

Yakutat

52.1

54.3

-2.2

 

Given the persistently low temperatures across Alaska for July, it is not surprising that that there was a large number of new daily record low temperatures set or tied. The low records were set throughout the month, from across Southeast to the Southwest. Note the number of records in the Southeast on the 11th and 12th, these were preceded by a number of low daily maximum temperature records across the panhandle on the 9th and 10th (not shown). In addition, no record high temperatures were set during the month.

 

 

Temperature Records

Date

Station

Element

New
Record

Old
Record

Year of
old Record

07/06/12

Cold Bay

Low Temperature

39

39

1956

07/09/12

St. Paul

Low Temperature

31

32

1967

07/10/12

McGrath

Low Temperature

38

38

1979

07/11/12

Annette

Low Temperature

46

46

1970

07/11/12

Sitka

Low Temperature

45

45

1994

07/11/12

Sitka Observatory

Low Temperature

39

40

1929

07/12/12

Juneau

Low Temperature

38

40

1946

07/12/12

Annette

Low Temperature

45

45

1970

07/12/12

Sitka

Low Temperature

43

43

1921

07/13/12

Valdez

Low Temperature

44

44

1979

07/14/12

St. Paul

Low Temperature

33

35

1996

07/18/12

McGrath

Low Temperature

38

41

2001

07/18/12

Valdez

Low Temperature

44

44

1998

07/25/12

Kodiak

Low Temperature

43

43

2000

07/31/12

Valdez

Low Temperature

44

45

2000

 

Daily temperature ranges and precipitation for Nome for July 2012. Note the two record precipitation events near the end of the month.

 

 

Precipitation

Unlike temperature, precipitation was solidly mixed with half of the first order stations reporting above normal totals, and half reporting below normal totals. The greatest positive deviations of normal were found along the western and southeastern parts of Alaska: Nome (197%), Kotzebue (140%), King Salmon (107%). On the other side of the spectrum were the dry stations of: Barrow with only 55% of the expected value, or 0.54" of the normal of 0.98", Talkeetna (65%), Yakutat (67%). While the number of stations with above and below normals precipitation values were equal, the above normal stations had more extreme values, hence the mean precipitation deviation for all stations was 23% above normal. Barrow was the only first order station to register snowfall in July with a total of 0.2", matching the normal value of 0.2". As with the temperature, the precipitation deviations for the twenty first order stations are given in the table below:

 

 

Station

Precipitation

Observed
(in)

Normal
(in)

Delta
(in)

(%)

Delta
(%)

Anchorage

2.14

1.83

0.31

117%

17%

Annette

8.25

4.65

3.60

177%

77%

Barrow

0.54

0.98

-0.44

55%

-45%

Bethel

3.91

2.36

1.55

166%

66%

Bettles

1.91

2.36

-0.45

81%

-19%

Big Delta

1.91

2.68

-0.77

71%

-29%

Cold Bay

2.19

2.48

-0.29

88%

-12%

Fairbanks

1.72

2.16

-0.44

80%

-20%

Gulkana

1.41

1.81

-0.40

78%

-22%

Homer

1.22

1.55

-0.33

79%

-21%

Juneau

5.37

4.60

0.77

117%

17%

King Salmon

4.77

2.30

2.47

207%

107%

Kodiak

4.05

4.93

-0.88

82%

-18%

Kotzebue

3.48

1.45

2.03

240%

140%

McGrath

3.96

2.38

1.58

166%

66%

Nome

6.27

2.11

4.16

297%

197%

St. Paul Island

2.32

1.85

0.47

125%

25%

Talkeetna

2.20

3.39

-1.19

65%

-35%

Valdez

4.34

4.04

0.30

107%

7%

Yakutat

5.28

7.88

-2.60

67%

-33%

 

There were a fair number of precipitation records set in July, stretching along the coast from Annette in the Southeast to Kotzebue in the Northwest. The only Interior station with a new record was Bettles. Nome broke both a 90-year-old record on the 18th, followed by smashing a 101-year-old record on the 25th. The five days of precipitation in Nome starting on the 25th dumped a total of 4.73", more than twice the normal for the whole month of July. Note the records set in the Southeast on the 9th, as a cyclonic system moved across the region.

 

 

Precipitation Records

Date

Station

Element

New
Record

Old
Record

Year of
old Record

07/06/12

King Salmon

Precipitation

0.59

0.31

1956

07/08/12

Bettles

Precipitation

0.49

0.46

1976

07/09/12

King Salmon

Precipitation

0.71

0.63

1994

07/09/12

Annette

Precipitation

1.70

1.59

1969

07/09/12

Juneau

Precipitation

1.64

0.96

1984

07/09/12

Sitka

Precipitation

1.25

0.81

2007

07/09/12

Pelican

Precipitation

1.10

0.73

1968

07/09/12

Haines Airport

Precipitation

0.82

0.30

1973

07/18/12

Nome

Precipitation

1.13

0.87

1911

07/21/12

McGrath

Precipitation

0.67

0.59

1975

07/21/12

Valdez

Precipitation

1.00

0.79

1976

07/25/12

Nome

Precipitation

1.38

1.35

1922

07/29/12

Kotzebue

Precipitation

1.04

0.43

1981

 

The month started off with flood watches set for the eastern Interior on the 3rd. The 5th saw the Mendenhall glacier dam break near Juneau prompting a flood watch. Then a similar event occurred on the 30th at Tulsequah glacier. The cool temperatures resulted in only one day of recorded thunder at the Fairbanks Airport, and fewer lighting strikes were record this July then any July since 2003. The fire season has thankfully fizzled and only 207,000 acres that have burned this year statewide.

 

 

This information consists of preliminary climatological data compiled by the Alaska Climate Research Center, Geophysical Institute, University of Alaska Fairbanks. This summary is based on the 20 first order stations in Alaska operated by the National Weather Service. Extreme events of other stations are also mentioned. It should be noted that the new climate normals for the time period of 1981-2010 are applied for the calculations of the deviations, and they can be slightly different from the old normals (1971-2000), which were in use up until end of July 2011.