In December, temperatures were seasonally above average for most of Alaska. However, the western and northern coastal stations were colder than average. High positive deviations were observed in declining order for Fairbanks (8.1 degrees Fahrenheit), Anchorage (4.4 degrees Fahrenheit) and Juneau (3.8 degrees Fahrenheit). Nome (minus 3 degrees Fahrenheit) and Kodiak (minus 2.8 degrees Fahrenheit) were relatively the coldest. Even Barrow, which has reported the greatest warming of all first order climatological stations in Alaska over the last decade, reported a negative deviation of minus 1.8 degrees Fahrenheit, continuing a trend that began last month.

Above normal precipitation was observed for most of Alaska. There was only one station with a below normal value – Kodiak. The amount measured was 5.92 inches, which represents 68 percent of the expected value. In Barrow, 0.6 inches of precipitation were recorded, more than four times the expected value. Anchorage (238 percent of normal) and Nome (199 percent of normal) were also wetter than expected, while the rest of the stations were above normal, yet closer to the long-term mean.

The average temperature in Fairbanks was 4 degrees Fahrenheit, a substantial positive deviation (+8.1 degrees Fahrenheit) from December’s long-term mean. As November had been much too cold, the unexpected warmth was a welcomed event. Actually, the mean monthly temperature for December was warmer than the mean temperature for November. Furthermore, the minimum temperature for December, minus 36 degrees, measured on the last two days of the month, was 5 degrees warmer than the November minimum of minus 41 degrees Fahrenheit. December 2012 tied 1963 as the tenth warmest on record. Generally speaking, the first three weeks of the month were much warmer than would be expected, while the last week was below normal. The maximum temperature of the month occurred December 4 with 47 degrees Fahrenheit. A mean temperature for the day was 37 degrees, a rare event, as mean daily temperatures above freezing are infrequent in winter. No new record absolute high or low temperatures were observed.

Precipitation in December was 0.95 inches of water-equivalent, 48 percent above the expected value of 0.64 inches and snowfall at 12.2 inches was slightly above normal. Wind speed averaged 2.8 mph, a low value typical for winter in the Interior. The highest gust was 51 mph on December 5. Cloud cover was high with a mean monthly value of 80 percent. This is not surprising as cloudy days, in winter, are usually warmer than clear ones due to weak winter solar radiation. Hence, the substantially above normal temperatures would be an indication of higher than expected cloud cover.

For December Big Delta experienced markedly warmer than normal temperatures for the first two-thirds of the month. Two new daily maximum temperature records were set. First on December 3 with 46 degrees Fahrenheit, 4 degrees above the old record set back in 1963. The next day saw the temperatures soar to 50 degrees, an amazing 10 degrees above the 1969 record of 40 degrees Fahrenheit. This was also the warmest temperature of the month. The final third of December recorded lower than normal temperatures. However, the overall monthly mean temperature was still a significant 6.1 degrees above normal. December ended up being 13.1 degrees warmer than November. The lowest temperature of the month, minus 29 degrees Fahrenheit, was experienced December 29.

Precipitation was heavier than normal in Big Delta, with a total water equivalent of 0.74 inches, nearly twice the normal of 0.38 inches. No record precipitation events were recorded.

In Juneau, the average December temperature was 33.7 degrees Fahrenheit, 3.8 degrees above the long-term mean of 29.9 degrees. The maximum temperature for the month, 44 degrees, occurred December 5. The month’s minimum temperature, 18 degrees Fahrenheit, occurred December 30. Similar to other stations in Alaska, December temperatures were warmer in Juneau than those measured in November. The monthly maximum and minimum were higher. No absolute high or low temperatures were observed.

Precipitation totaled 7.45 inches, 1.61inches above the long-term mean for the month. Snow measured in at 14.5 inches, slightly below the long-term mean of 15.6 inches. The above normal amount of precipitation, with a lower amount of snow might be surprising. However, due to the warmer temperatures, a larger amount fell as rain. An average monthly wind speed of 11 mph was observed. The top gust of 53 mph occurred December 1. There were no clear days during December.

Anchorage recorded an average temperature of 23 degrees Fahrenheit, an ample positive deviation of 4.4 degrees above the long-term mean for December. The maximum temperature of the month, 45 degrees, occurred on the 4th and 18th. The month’s minimum temperature, minus 2 degrees Fahrenheit, was observed December 31. The mean monthly temperature was colder in November than in December. Further, December’s maximum and minimum temperatures were higher than those of the previous month. No absolute high or low temperatures were observed.

Precipitation was reported at 2.66 inches, more than double the normal value of 1.12 inches. Further, 31.1 inches fell as snow during the month, 87 percent above the expected amount. The mean monthly cloudiness was relatively high with 90 percent. During December there was only one clear day observed. There were three partly cloudy days and 27 with overcast conditions. An average monthly wind speed of 7.6 mph was logged. A top gust of 59 mph occurred December 4.

In December, Nome reported a mean monthly of 6.5 degrees Fahrenheit, a negative deviation of 3 degrees from the long-term mean. The warmest monthly temperature was 33 degrees, observed December 7 and the 8th. The month’s coldest temperatures occurred on the 29th and 31st, with values of minus 32 degrees Fahrenheit. The daily temperatures were colder than normal, especially in the last ten days of the month.

Precipitation was above the expected range, totaling 2.15 inches. The mean value for December was 1.08 inches. Snowfall was 27.7 inches, closing in on twice the norm of 14.5 inches. On the 3rd, 6.5 inches of snow fell, surpassing the old record of 6.2 inches for the day, which had been established since 1979. On December 6, another snowfall record was broken when 4.1 inches of snow fell. This broke the old record of 3.9 inches set in 1993. The following day, another 5.6 inches of snow was measured, establishing a new record. The average wind speed for the month was 10.8 mph. The highest gust, 53 mph, was observed December 10.

Barrow reported an average temperature in December of minus 9.6 degrees Fahrenheit, below the normal of minus 7.8 degrees. A maximum temperature of 6 degrees occurred December 11. The month’s minimum temperature, minus 30 degrees, was observed December 31. Most of the month showed values close to those expected and no new temperature extremes were observed.

Precipitation in Barrow, which is low in northern Alaska, totaled 0.6 inches, more than four times the expected value of 0.14 inches. A strong storm occurred December 4, with average wind speeds above 30 mph and a gust that exceeded 50 mph. The storm brought 0.33 inches of precipitation, beating the previous record for the date, 0.19 inches, set in 1922. The storm was associated with a new snowfall record of 6.5 inches, surpassing the old record of 2.5 inches also set on this day in 1922. The mean monthly wind speed was 12.8 mph. The highest gust for the month, 52 mph, occurred December 4.

King Salmon reported an average temperature of 17.6 degrees Fahrenheit, below the long-term mean of 18.6 degrees. The highest temperature for the month, 51 degrees Fahrenheit, occurred December 3. This represents a new absolute high for the day. The previous record was 48 degrees set in 2002. On the following day, a maximum temperature of 46 degrees was observed, surpassing the old record set in 2008 by one degree. The low temperature of the month, minus 31 degrees, occurred on the last day of December. However, December 30 recorded a low of minus 29 degrees, which represents a new record minimum for the day. In general, the first two-thirds of the month was seasonally warm. Thereafter temperatures dropped steadily and, by the end of the month, were far below normal.

The precipitation total was measured at 1.64 inches, above the long-term mean of 1.23 inches. A record snowfall occurred December 11 with 10 inches of snow. The old record, set in 1963, was only 3 inches. The average wind speed was 8.8 mph. The month’s highest gust, 61 mph, was recorded December 10, blowing from a southeasterly direction.

Ketchikan’s average temperature of 36.6 degrees Fahrenheit in December was nearly identical with November’s average. December’s highest temperature was 49 degrees on the 19th. The month’s low temperature, 24 degrees, occurred December 7. The temperatures followed more closely with the long-term mean for the month as opposed to other stations in Alaska. No new temperature extremes were observed.

Monthly precipitation for Ketchikan was measured at 14.66 inches, slightly above the expected amount of 14.23 inches. The highest daily amount occurred December 19, with 1.66 inches.

For December, Kodiak reported an average temperature of 28.4 degrees Fahrenheit. The mean monthly temperature was 2.8 degrees below the long-term mean. The maximum temperature for the month, 47 degrees, occurred December 2. This represents a new absolute high for the specific day. The old record was 46 degrees from 1992. The daily record high temperature was matched on the 18th at 44 degrees. This ties 1985, 1969 and 1937. The lowest temperature happened on December 31 with minus 3 degrees Fahrenheit. On December 27, the low temperature went down to 4 degrees, which tied the old value set in 1970. On December 30, the temperature dropped to 3 degrees, establishing a new record for the day.

Precipitation was reported as 5.92 inches, 68 percent of the long-term value. In December, 8.8 inches of snow was measured for the month, about two-thirds of normal. The mean wind speed was 9.2 mph. A gust blowing from the south was recorded at 60 mph on December 18, which was the highest value for 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 474-7885 or visit the center web site at https://akclimate.org. Please report any errors towebmaster@akclimate.org.

Source: Geophysical Institute