Alaska Weather Summary for May 2012

June 8, 2012

 

Temperatures were below normal this May for all but one of the nine stations discussed here. Only Barrow was slightly (0.5 degrees Fahrenheit) above the long-term mean, most likely an affect of the substantial warming observed for Northern Alaska over the past decades. The observed below normal temperatures are in contrast to April, which was warmer than normal. Negative deviation in excess of -3 degrees, in declining order occurred in Juneau (minus 3.9 degrees), Nome (minus 3.7 degrees) and King Salmon (minus 3.1 degrees). The mean of the 10 stations gave a deviation of minus 2.3 degrees Fahrenheit.

 

Precipitation was above normal, with a mean deviation of 50 percent. Only Anchorage reported below normal values (deviation minus 40 percent). On the other side of the spectrum was Barrow (deviation plus 178 percent) and Ketchikan (deviation plus 135 percent), both with more than twice the expected amount.

 

In Fairbanks the average May temperature was 47.9 degrees Fahrenheit, 1.3 degrees below the long-term mean. The high temperature for the month was 71 degrees on May 22, while the low temperature for the month was 18 degrees observed on the 3rd. The temperature followed fairly close the expected trend for the month and no new extremes were reported.

 

Precipitation in May was fairly close to normal (0.60 inches) with an observed value of 0.73 inches. Remarkable was the precipitation on the 25th with 0.52 inches, setting a new record for this day. The old record had been 0.50 inches set in 1973. The mean wind speed was 5.1 mph, with the highest gust of 33 mph occurring on the May 11, blowing from a southerly direction.

 

In Big Delta, the mean May temperature was 45 degrees Fahrenheit, 2.6 degrees below the long-term mean. The highest monthly temperatures of 67 degrees was observed on May 22, while the minimum temperature (18 degrees) occurred on the 3rd. As for Fairbanks, the temperature, while being below normal, followed fairly close to the expected trend for May. And no new daily records were observed. 

 

Precipitation in March was reported as 1.3 inches water-equivalent, 44 percent above the expected amount of 0.90 inches.

 

In Juneau, the average temperature was 44.7 degrees Fahrenheit, a substantial minus 3.9 degrees below the long-term mean. The maximum temperatures for the month (59 degrees) occurred May 24; this value is lower than the maximum temperature observed in April and it was the eighth coldest May in terms of the daily maximum temperature ever observed in Juneau. One has to go back to 1955 to find a May with a lower average maximum temperature. The minimum temperature (35 degrees) was recorded May 15. However, no new daily extremes were observed.

 

Precipitation totaled 5.73 inches, 77 percent above the normal of 3.24 inches. It rained on 29 days of the month and May 2012 was the fourth wettest May on record. Trace snowfall occurred on three days. The trace snowfall on May 15 was a “record” in that snowfall had not been recorded on this day before. The mean monthly wind speed was 9.9 mph, with a maximum gust of 44 mph occurring on May 20, blowing from the southeast. Furthermore, mean cloudiness was high with 90 percent. 

 

Anchorage recorded an average temperature in May of 45.5 degrees Fahrenheit, 2.3 degrees below the normal of 47.8 degrees. It is also the first month of this year, when the temperature was lower than that in Fairbanks. The more maritime climate of Anchorage has warmer temperatures in winter, but lower temperatures in summer when compared to the more continental climate of Interior Alaska. The maximum temperature of the month occurred on May 23 with 65 degrees Fahrenehit, while a minimum temperature of 27 degrees was observed on the 3rd. The temperature followed the expected trend fairly close the whole month. 

 

Precipitation was reported at 0.43 inches, which is 40 percent below the normal of 0.72 inches. The average cloudiness was high with 80 percent and the mean monthly wind speed was calculated as 8.4 mph. The peak wind speed was 43 mph on May 11, blowing from a southerly direction. 

 

Nome reported a mean monthly temperature in May of 33.1 degrees Fahrenheit, considerably below the normal of 36.8 degrees. This might have been caused by the substantial amount of sea ice in the Bering Sea, which went out later than normal. The warmest monthly temperature was 63 degrees, observed on the 18th. This represents a new daily record, surpassing the old record of 62 degrees set in 1980. The coldest temperature, 5 degrees Fahrenheit, occurred on the 4th.

 

Precipitation totaled 0.88 inches, very close to the normal value for May of 0.86 inches. However, nearly all the precipitation (0.84 inches) occurred on one day -- May 16. This set a new record high for this specific day, surpassing the old record of 0.40 inches set in 1990 by more than a factor of two. Furthermore, it represents the highest amount of rain ever observed on any one day in May in Nome, where the record stretches back to 1907. The previous daily May record had been set on May 28, 1996 at 0.76 inches. The average wind speed for the month was light with 5.8 mph. The highest gust observed was 28 mph on the 16th, blowing from a southeasterly direction.

 

Barrow reported an average temperature in May of 21.6 degrees Fahrenehit, 0.5 degrees above normal. The month was fairly close to the expected values, with the exception of a cold spell around the 7th. The trend shows a strong seasonal warming during the month. On May 17, the maximum temperature of 36 degrees was reported. The month’s lowest temperature, minus 11 degrees, was observed on the May 6. No new temperature records were observed during the month. 

 

Precipitation in Barrow totaled 0.50 inches water equivalent, far above the long-term mean of 0.18 inches. Some snowfall was observed on 22 days, for a total amount of 5.5 inches. The mean monthly wind speed was 10.2 mph. A gust of 31 mph occurred May 11, blowing from an easterly direction.

 

King Salmon reported an average temperature of 41.1 degrees Fahrenheit, 3.1 degrees below normal. The high temperature was 62 degrees on May 23. The low temperature, 22 degrees, occurred May 13. The minimum of the 13th tied the old record low set in 1965. 

 

The precipitation total was measured as 1.62 inches, 30 percent above the normal of 1.25 inches. The snowfall on May 4 with 1.8 inches surpassed the old record for this day of one inch set in 1971. The rainfall if 0.33 inches on the 10th set a new record by topping the 1991 record of 0.32 inches. Average wind speed was 9.3 mph. The highest gust was recorded at 38 mph on both May 18 and 28, blowing from an easterly direction. 

 

Ketchikan’s average temperature of 46.1 degrees Fahrenheit in May was 2.5 degrees below the long-term mean. While being below normal, the temperature trend was close to the expected values for most of the month. The highest temperature of the month was 64 degrees, which occurred May 24. The month’s low temperature of 36 degrees occurred on the 8th, 9th and 13th of May.

 

Monthly precipitation was high with 19.25 inches, more than doubling the long-term mean of 8.2 inches. Remarkably, 4.73 inches of rain fell May 6, surpassing the old record for the day of 2.4 inches set in 1959. This total received within a single day surpasses the long-term annual total for Barrow. On the following day, 4.26 inches of rain were reported, again smashing the previous record for this day of 2.6 inches, which was set in 1973.

 

Kodiak's average temperature, 42.5 degrees Fahrenheit, in May was 1.8 degrees below the long-term mean. The highest temperature measured was 61 degrees on the 23rd. The low temperature of 29 degrees occurred May 13. The minimum temperature on the 13th matched the old minimum of 1965 for this day. 

 

Monthly precipitation was measured at 5.93 inches, close to the normal of 5.62 inches. On May 12, 0.8 inches of snow was reported, setting a new daily high. The old high was 0.7 inches set in 1971. Even later in the season, 2.4 inches of snowfall was reported for the 13th, which also was the coldest temperature for May 2012. This surpasses the old record of 0.2 inches set in 1971. The monthly average wind speed was calculated as 9.2 mph. On May 1, a gust of 40 mph was recorded, blowing from a westerly direction. 

 

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 474-7885 or visit the center web site at http://akclimate.org. Please report any errors to webmaster@akclimate.org.

 

 

IMAGE COURTESY OF ACRC.