May 2017 Statewide Summary

Alaska Statewide Climate Summary

May 2017

 

Temperature

 

The mean monthly temperature for May 2017 was above normal with the mean temperature of all First Order Stations at 44.4°F, 1.6°F above the normal of 42.8°F. This is 3.2°F below the May 2016 mean of 47.6°F. Calculating the mean daily temperatures of the First Order Stations, the first 23 days of the month were above the 30-year normal, followed by a week of below normal temperatures. The last day of the month was again above normal. The greatest positive deviation occurred on the 11^th with 5.4°F above normal, and the greatest negative deviation occurred on the 26^th with -4.0°F. (see Figure). Monthly mean temperatures were above normal for 17 of the 19 of the First Order Stations (see table). Gulkana was the only station reporting a below normal mean temperature with 44.4°F, 0.8°F below its May normal of 45.2°F. Barrow held the spot with the greatest positive deviation in May with 3.5°F above its normal of 21.1°F. The only other station with deviations greater than or equal to 3°F was Bettles with 3.0°F above its normal of 44.4°F.

 

 

 

The highest daily maximum temperature of the First Order Stations for May was 73°F reported at Annette on the 16^th and 27^th, and Talkeetna on the 31^st. Annette held the spot for the highest mean temperature for the month at 52.2°F. The lowest temperature of 5°F was observed at Barrow on the 1^st, and Barrow also reported the lowest May mean monthly temperature with a value of 24.6°F. 

 

Daily mean temperature deviation from the normal temperature for the mean of the First Order Stations for May 2017.

 

There were a very limited number of new temperature record events this May. On the 12^th, Kotzebue's high of 64°F broke the old 1954 record by 1°F. St. Paul hit a high of 48°F on the 19^th, breaking the 2014 record of 46°F. Kodiak set a new daily low of 32°F on the 26^th, 2°F below the old record from 1939.

 

 

Precipitation

 

Reversing the trend from the last two months, May's precipitation was decidedly above normal, with the overall precipitation calculated as 48% above the average; this calculation was based on the mean of the deviations in percentage of the First Order Stations. Fourteen of the First Order Stations and 15 days of the month reported above normal values. This is considerably wetter than May 2016, which reported a precipitation deficit of 33%. The greatest daily precipitation amount occurred on the 24^th. The station reporting the greatest precipitation deviation was Barrow at 422% above normal with 0.94", 0.76" above its normal of 0.18". The relatively driest station was King Salmon at just 86% of normal. Kotzebue matched its normal for May with 0.41".

 

 

 

Daily mean precipitation deviation from the normal for the First Order Stations for May 2017.

 

 

May's highest monthly precipitation total reported for a First Order Station was 9.58" at Annette. Yakutat reported the highest daily total of 3.25" on the 21^st, a new daily record, breaking the old record of 1.50" from 1975. It was the wettest May on record for Barrow with 0.94", just topping the 2014 record of 0.90". Also for Barrow, it was the second snowiest May on record with 10.3", 2.6" less than the 1933 record. It was the third wettest May for Haines, and fifth wettest for Bethel.

 

There were a fair number of daily precipitation records set this May, and most were set in the Southeastern area during the storm on the 21^st. Barrow set a snowfall record of 4.2" on the 25^th, breaking the old record of 1.0" from 1973.

 

 

 

Newsworthy Events

 

The Nenana Ice Classic ended on at 12 pm ADT on May 1^st as the ice moved on the Tanana River at Nenana and stopped the clock. The same day the snow depth officially dropped to zero at the Fairbanks International Airport. The next day the temperature at the Fairbanks Airport hit 60°F for the first time for 2017. Also on May 2^nd, avalanche reduction efforts were initiated on the Dalton Highway in Atigun Pass. A strong storm in the Gulf of Alaska generated high winds along the Panhandle on the 2^nd with gusts up to 74 mph reported at Cape Sensor and Cape Decision, 59 mph at Hydaburg, 46 mph at Ketchikan and Sitka, 43 mph at Juneau and Skagway and 41 mph at Annette. The storm had a reported low pressure of just 968 hPa. Pea-sized hail fell at Juneau on the 3^rd.

 

On the 3^rd the Kuskokwim River broke up at Aniak, and the same day the Yukon broke up at Dawson in the Yukon Territory. The next day Kuskokwim River broke up at Kalskag, while hazardous driving conditions were reported along the Dalton Highway near milepost 29 due to water flowing over the road. The problem persisted into the 5^th. Also on the 4^th, the Yukon River was reported broken up at Eagle, while the Kuskokwim Ice Classic tripod tipped at Bethel. Minor flooding was reported at Circle on the 6^th, and then the Yukon River broke up at Circle two days later. The Koyukuk River was also reported to have broken up at Bettles on the 8^th. Finally, the Yukon broke up at Rampart on the 13^th. All considered, it was a quiet breakup along the Interior Rivers with just minor flooding reported at Circle and Manley Hot Springs.

 

May 8^th was Green Up Day at Fairbanks. Also on the 8^th, Manly Hot Springs reported the first 70°F temperature for 2017. The sun rose at Barrow at 2:54 am on the 10^th and will stay above the horizon until August 21^st. The same day Anchorage reported 60°F for the first time in 2017 and the next day the same happened at Skagway. Anchorage did not report 70°F mark until the 31^st.

 

This VIIRS satellite image shows the low-pressure system in the Gulf of Alaska on 3 May 2017. Image provided courtesy of the National Weather Service.

 

Snow was reported falling and sticking at Eureka on the 14^th. Avalanche reduction efforts were held in Atigun Pass on the Dalton Highway on the 14^th. Almost 3.5" of rain fell at Fawn Lake near Ketchikan on the 15^th. Both Fairbanks and Juneau reported the first high of 70°F on the 16^th. For Juneau, this is about two weeks earlier than usual. The Denali highway opened to summer traffic on the 16^th, and final avalanche reduction efforts were happening in Atigun Pass on the Dalton Highway.

 

A strong storm impacted the Panhandle on the 21^st with high winds and heavy rain. Little Port Walter recorded 8.52", 3.25" fell at Yakutat, 2.52" at Pt. Baker and 2.03" at Sitka. Wind gusts up to 57 mph were reported at Cape Decision, 52 mph at Lincoln Island, 46 mph at Hydaburg, 40 mph at Juneau, 35 mph at Annette, and 33 mph at Sitka.

 

With the plunging temperatures on the 25^th, hail was reported along Turnagain Arm, while both hail (up to pea-sized) and snow were reported around Fairbanks on the 26^th, with up to an inch of snow reported in the hills out of town. Snow was reported falling and sticking along the Richardson Highway at Thompson Pass. Snow was also reported at higher elevations in the Denali Park area. Up to two feet fell at the 7,200 ft. basecamp on Denali. More snow, up to 3", was reported in Denali Park on the 30^th.

 

Burn prohibitions were issued for Eastern Interior areas of Delta Junction to Tok on the 25^th. The suspension remained in effect till the end of the month.

 

This information consists of preliminary climatological data compiled by the Alaska Climate Research Center, Geophysical Institute, University of Alaska Fairbanks. For more information on weather and climatology, contact the center at 907-474-7885 or visit the center web site at http://akclimate.org. Please report any errors to webmaster@akclimate.org. This summary is based on the 19 First Order Stations in Alaska operated by the National Weather Service. Extreme events of other stations are also mentioned.