Is April a dire weather month in Alaska?

I try to keep the number of errors in my Alaska Weather Calendar to a minimum. I have a team of freelance editors and proofreaders to help me, otherwise it would be hopeless. My hat is off to them. Nonetheless, errors slip by, mostly because I introduce them via last minute changes that few if any of my checkers get to to check. Nobody’s perfect, so I don’t fret over the occasional slip-up. In fact, the typo just brought to my attention gave some levity to local author Heather Lende who spotted it and used it in her blog, so I decided to play it a little more here.

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On various calendar date blocks I give a short review of a historical weather event or weather or climate lesson appropriate for the day or season. For April 13th on the current calendar, I wanted to relate that this is the driest time of year for most parts of Alaska. Instead I called it the direst time of the year. Let’s look at both questions.

Dire?

I’d say at this time of year we have a strange interplay between the dire and the hopeful. Dire when there is more sideways snow and you know it will not be the kind you can ski on. Hopeful when the wind dies, the sun comes out and it gets warmer than it has been in many months. Hopeful, too, when the snow melts back day by day, but dire when the melting seems to reveal only mud and things that should have been put away last fall. I think a real biggie is that April starts the teasing season: days are longer, some nice weather comes along, but when it backslides it is still early enough to be real wintery. And remember, “nice” and “wintery” are relative considering the vastly differing  range of weather from Ketchikan to Barrow. But the contrast is still there…maybe more so in May for the Arctic. On a more serious note, many people struggle at this time of year because they have been looking forward to Spring to improve their personal outlook and when it doesn’t, things can look dire.

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Dry?

Easy question here. April is the driest time or about as dry as any time of year for about three quarters of Alaska’s area. The Arctic Coast is very dry from December through May…very little difference, month to  month at Barrow, for one, so “about as dry as” works here. April is more clearly the driest month in the interior and southcentral Alaska. Along the south and southeast coasts and the in the Bering Sea and Aleutians, April is relatively dry, but the months keep getting drier as spring turns to summer and June or July is typically driest in those areas.

The other weather answer: Warming

How about April warming? Here is a table showing how much warming happens at various locations from April 1 to May 1 of an average year. The data is from the daily normals (1981-2010) published by the NCDC. These are smoothed averages from 30 years of data. Both highs and lows are important and it is instructive to see how they differ. You can also see the differences in diurnal range from place to place, though that is not what we are after here.

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Notice that the places which warm the most in April are the coldest places (they have a lot of catching up to do), then interior stations (the land warms quickly, especially when the snow is gone–the days are very long and the skies fairly clear). After that are the south and southeast coasts (they have much moderating water nearby, but also the continental land mass to aid warming) and the least amount of warming happens in the Bering Sea and Aleutian islands (due to the overpowering influence of the cold, cold ocean surrounding the small land masses). This is one of the reasons Unalaska/Dutch Harbor is featured in the “world’s Worst Weather” special section of my 2015 Alaska Weather Calendar. Only about 4 or 5 degrees F (2-3  C) of warming in the month compared to 20-25 F (11-14  C) in the northern interior!

I’ve included two stations that lie a ways above their towns. The Keystone Ridge station is about 1,150 ft (140m)  higher than the Fairbanks Airport. The high temperature there warms about as much as at the airport during April, staying a little cooler. However the low temperatures are much milder (hard to say warmer) at the start or April, as they are all winter. By May 1 the difference is mostly gone…the large winter inversions that give the higher elevation locations the break from the worst of the cold become weak, shallow or nonexistent in spring through fall. Glen Alps is over 2,000 ft (600 m) above the Anchorage “bowl.” There are plenty of days in mid winter where Glen Alps is getting warm wind off Prince William Sound and the flat parts of Anchorage are stuck in a stagnant cold pool, but by April these situations are fewer and the averages show it: less warming in April and the highs are quite cooler by May 1.

How do you look at April? Dire? Hopeful? A little of each? Let me know your outlook as well as any thoughts, additions, corrections (typos?) questions etc via the comments link below. And hang in there…Spring always comes eventually.

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