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Alaska weather makes no sense

Craig Medred

 

alaska-weather-radar-09-13-10
NOAA.gov screen shot
Average Southcentral Alaskans confused by a gorgeously warm week of June-like weather to begin the month of September aren't alone. The professionals can't figure out the region's weather either.

 

National Weather Service meteorologist John Papineau, a man with a doctorate in weather, last month went to considerable length trying to find a pattern to define the main months of the snow-free season in the Anchorage area and came away with the conclusion that there is no pattern.

"...There is considerable variability from one year to the next," he wrote in a six-page report (PDF) posted on the weather service's website.

Some summers are cold and wet -- to summarize Papineau's findings -- and some summer are warm and dry. And it doesn't take much of a shift in temperature to define them.

"Note that a warm summer is only two to three degrees above the long-term average of 56.6 degrees Fahrenheit," he reports, while a "cold" summer drops two to three degrees below the average.

The summer of 2008 -- wet, rainy, hardly ever warmer than 70 degrees -- might have seemed like the summer from hell for many in Anchorage, while the sun-kissed summer of 2009 felt almost too good to be true, but in reality the average temperatures for the two were only about 2.5 degrees apart.

Of course, as Papineau also notes, a lot of detail can get lost in the average. A sunny, 75 degree day that drops into a 45 degree night beneath clear skies might average out no warmer than a dreary, drizzly days that fluctuates around a steady 60 degrees.

"In general, the presence of clouds during the daytime (summer only) generates cooler temperatures because of the shading affect," he writes. "(But) cloud cover at night tends to produce warmer temperatures because they trap infrared energy emitted by the earth's surface."

In other words, clouds can make the whole average temperature thing pretty misleading. This is one thing worth noting in a lengthy report that is pretty interesting reading even if a little ominous.

Papineau warns that it appears summer weather is getting both more variable and cooler.

He sketches a temperature trend line that shows that 56.6 degree summer average dropping below 56 degrees like it was back in the bad old, cold old mid-1950s. Four of the five years in the last half of that decade were below or just at 56 degrees.

In present times, say from 2000 on, Anchorage has been a warmer, friendlier place, although 2008's average summer temp of 54 degrees is hellacious enough that it almost jumps off Papineau's graph of temps since 1954. The same can be said for the glorious summer of 2004, which ended with a magical 60 degree average. That is a mark that has been hit only one other time since record keeping started in 1954, and that year was 1977, which had an Anchorage summer hard to believe.

Maximum, daytime temperatures in July 1977 averaged -- AVERAGED! -- 70.4 degrees. The year 2008 saw only two days when the maximum temperature reached 70. Two days! 2008 set a record for the summer with the fewest days to hit 70. The summer ended tied with 1973 for the all-time number two worst summer on average. Only 1971 was worse, but only on average.

Consider this: The average maximum for June of 1971 was 58.3 and for July 61.8. The highs for 2008 in those same months? 57.6 and 61.3.

Anyone who thought this summer was bad (official rank: 13th coolest) should have been here then. It was so unseasonsal the bees didn't make honey and the swallows didn't breed. And there was no run of glorious September weather to make up for it.

Contact Craig Medred at craig(at)alaskadispatch.com.