Archive for the ‘Weather Related’ Category

Heatwaves, Southeast Alaska style

Friday, May 19th, 2017

We’ve had some warm days lately in northern Southeast Alaska, and if perception is worth anything, it always feels warmer just coming off winter. Actually much of Alaska feels this surge of warmth in May (and sometimes in April), but it is a time of the year when southeast can keep up with the interior and southcentral areas in terms of summer-like warmth. (And compare our sunny, 70F (21C) to Colorado, Wyoming, etc., where they just got more than a little snow.) Here’s the daily high-low graph for Skagway, Anchorage, and Fairbanks since April 1.
temperature graphYou can see that Skagway (as well as other parts of the panhandle, particularly the northern parts) is an early bloomer with regard to spring temperature spikes compared to the other regions. However, this is starting to change the interior keeps getting steadily warmer, and coastal warming stalls out some as onshore flow increases.

Onshore vs offshore flow

Onshore vs offshore flow is a crucial driver of the weather/climate in coastal areas. In general, high pressure predominates over the continent in winter producing offshore flow which brings dry, cold, windy weather to the coast (yes, there are commonly interruptions that bring mild, wet weather, especially in early winter). In summer, pressure is usually lower over the continent and onshore flow results, keeping coastal areas cool, with ample clouds, fog etc. Right now we’re in the crossover season…the offshore flow has been still with us at times, but the cold interior air that hits like a ton of bricks in January is gone. The interior has thawed out, and as that moderately warm air descends to the coast, it warms further due to compression, and places like Skagway, Haines, Juneau, Valdez, and Seward might be surprised to find themselves listed as the warmest spots in the state, and sometimes get to gloat over big regions in the lower 48 that are hanging onto winter. Skagway has bagged quite a few daily Alaska hot spot medals this spring. The following meteogram shows an example day from Skagway. When the north winds picked up early in the morning the temperature jumped too. With the addition of the sun during the day it make it to 65F (18C), cooling off some as a light southerly (a weak sea breeze) developed.

Skagway, AK meteogram

Here’s the past 30 days’ winners in Fahrenheit:

19-Apr 54 at Talkeetna
20-Apr 58 at Klawock
21-Apr 58 at Annette
22-Apr 69 at Annette
23-Apr 65 at Skagway
24-Apr 60 at Annette...Northway
25-Apr 60 at Juneau...Klawock
26-Apr 61 at Haines
27-Apr 55 at Koliganek...McGrath...Whittier
28-Apr 57 at Eagle...Northway
29-Apr 62 at Skagway
30-Apr 58 at Eielson AFB
1-May 59 at McGrath
2-May 61 at Eagle...Skagway
3-May 61 at Palmer
4-May 59 at EAGLE
5-May 66 at Skagway
6-May 67 at Nenana
7-May 69 at Eagle
8-May 66 at Eagle
9-May 64 at Koliganek...Fort Yukon
10-May 68 at Skagway
11-May 71 at Skagway
12-May 70 at Kaltag
13-May 65 at Shungnak
14-May 65 at Galena Airport...Kaltag...Tanana
15-May 69 at Bethel...King Salmon...Nenana
16-May 73 at Annette...Nenana
17-May 74 at Fort Yukon
18-May 67 at Fort Yukon

As spring progresses, the crossover runs its course and the interior ends up warmer than the coast most days. Note in the list above that maritime stations such as Annette and Klawock are more represented early in the list, interior stations more so toward the end and coastal “in between” places such as Skagway, Whittier, King Salmon, and Bethel appear scattered among, but would be shown to be strong mostly in the middle if the list ran from, say, March through June. [Anyone know of a tabulated source for this state high/low data? It gets weary calling up each daily bulletin and copying/pasting.]

In spring and summer the large-scale onshore flow manifests itself as a stiff sea breeze in many places due to the local sharpening of temperature differences. More on the sea breeze phenomenon here and here.

Warm vs Hot

Now for those of you in Hawaii or the lower 48 chuckling over the upper 60s to low 70s (18-23C) we call warm, lets consider what might happen if a strong offshore flow sets up, not in the winter when those on the coast endure -20F (-30C) wind chills, or the spring boosting us to 70F or so, but in the middle of summer when the interior has heated to 80 or 85 F (~28C). That’s a rare combination, but that’s when coastal towns push into the upper 80s and even upper 90s (30-37C). Let’s look at the few stations in any part of Alaska that have been 95F (35) or above:

map of Alaska record highs 95F+Click on the map for a larger version, or see the list below for details. (Note: on the map I’ve left off a couple locations that were virtually on top of each other, and several labels where several adjacent stations had the same temperature.)

deg F station    date (YYYYMMDD)
100 FORT YUKON 19150627
99 TENAKEE SPRINGS 19760801
98 HAINES 19760731
98 RICHARDSON 19690616
98 MATANUSKA VALLEY 16 19660806
97 EAGLE 19500618
96 CLEAR 4 N 19690616
96 FAIRBANKS WSO AIRPORT 19690615
96 GLENNALLEN KCAM 20090709
96 MC KINLEY VIEW 19690614
96 SUSITNA MEADOWS 19710625
96 TOK 19690615
96 WEST FORK 19690615
96 WILLOW WEST 20090707
95 LADD AFB 19550725
95 NORTH POLE 19690615
95 SEWARD 19660812
95 SNOWSHOE LAKE 19910621
95 COLLEGE UNIV EXP STN 19690615

I’ve highlighted non-interior stations in green. My data only run through 2010, so if any readers know of any updated records to this list, please share them. The records at Tenakee Springs and Snowshoe Lake seemed a bit implausible to me, so I looked at the scans of the original paper forms…nothing obviously fishy…they are official records. Would you have guessed that coastal or near coastal towns are 3 of the hottest 5 in Alaska? Grab an ice-cold lemonade and let me know your thoughts on the topic via the comments link below.

Why does the snow sparkle so?

Saturday, January 7th, 2017

Lately around here we’ve been blessed with decent snow cover. A nice change from the last two winters. Nice fresh show that stays fresh thanks to lack of warm surges. To add to the beautiful scene, the snow has had lots of sparkles of light reflecting off the surface from the bright moon or nearby lights (there’s plenty of time to see this with days still solstice short). Here’s a couple photos (click on them for larger versions).

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Precipitation patterns & perceptions

Saturday, October 22nd, 2016
20160930_172321-rduced

Pick-up soccer on the Haines school sports field on 30 Sep 2106. Most years the field or the weather are not in too good of shape at this time of year.

Of all the weather elements, precipitation seems the most chaotic when it comes to spatial and temporal patterns. In reality, I think wind is probably more variable over both time and distance, but I guess we must understand that, since we don’t talk about it nearly as much as peculiar precipitation patterns such as long wet or dry periods, heavy precipitation events, adjacent areas getting very different amounts or types of precipitation, etc. When do these peculiarities rise above perception and prove to be truly unusual? (more…)

Are you SAD yet?

Monday, November 9th, 2015

Everybody is different, but the reduced light in the North and the gloomy weather in many parts of Alaska at this time of year affect almost everyone to some degree or another. Seasonal Affective Disorder (SAD) is the fancy name for the winter blues, bad weather blahs, cabin fever, hibernation instinct…fill in the blank with your term. If you are not familiar with the phenomenon, here’s the Mayo Clinic’s briefing.

hours of sunup on Nov 15th

November 15th potential sunlight

Daylight

Northern areas have much shorter days than more southerly parts of Alaska or elsewhere at this point in the winter, but there are mitigating factors helping them: longer twilight morning and evening, fewer clouds and more reliable snow cover to reflect available light and provide contrast. (more…)

Celebrating the end of the snow drought

Tuesday, February 3rd, 2015

happy skierWhile some folks back east may have been mightily inconvenienced by recent snows, here in Alaska most people like to see a little snow in the winter. This winter many of us have seen very little. Here in Haines, one of the snowiest sea level towns anywhere, things were looking pretty brown until last week, when we got almost a foot of nice light snow. You could almost hear the relief around town, as folks got back into the swing of snow removal, or dusted off their skis. My family did both, plus made a batch of snow ice cream. (Never made snow ice cream? Strangely, as a meteorologist, Alaskan, skier, etc, I’d not even heard of it for my first 20-some years in Alaska! I was going do a whole post on snow ice cream but discovered it’s not the novelty I thought it was…just Google it.) (more…)

Sea breezes: an Alaskan spring-summer staple

Friday, May 30th, 2014

You’ve heard it said…Alaska has sooo much coastline… We do, about 34,000 miles (54,700 km) worth, and we have the perfect weather phenomenon to go with it: the sea breeze. The sea breeze is a local wind blowing from water to land arising from the relative warmth of the land vs. the water. Warmer land leads to rising and/or expanding air and lowers the surface pressure, drawing in the cool  air off the water. It is not unique to Alaska–It is found (more…)

Alaska weather on a roller coaster

Tuesday, February 11th, 2014

Wind-blown dust in Haines and other places.

forecast-map

Red flag wildfire danger for the Mat Valley.

Strong pressure gradient along coast.

Back into the freezer

The strong “January thaw” that pushed well into the interior and tied the all time January record for Alaska is being pushed toward the back of our memories by seasonal and colder weather. Boy, it feels colder after a long warm spell! Wind chills here in northern Southeast Alaska are bouncing down to 5 to 15F below zero (-20C to -26C) at times. (more…)

Signs of Spring in Alaska

Monday, March 25th, 2013

We’re a few days into Spring, at least according to astronomers. Last Wednesday (3/20) was the Vernal (Spring) equinox–equal night, equal day. While the flowers may be blooming many places in the Lower 48, such traditional signs of spring are a long way off here in the frozen north. But here are a few signs of the season for this equinox time of year in Alaska: (more…)

The power of the sun

Saturday, January 12th, 2013

Although the world apparently did not end on Dec 21, 2012 the date triggers strong feelings for most Alaskans every year. Of course it is because it marks the winter solstice…the shortest day of the year…and the promise of longer days ahead. It’s a few weeks past the solstice before most Alaskans notice any change, and even longer for the increasing solar radiation to have any noticeable effect on the weather. So, congratulations, we’re about at that point, and in my psychological bag of tricks for keeping upbeat through the Alaskan winter, it is the point beyond which things have got to just keep getting better. My advice is to get outside as much as possible and ingest some of the increasing daylight. At this point in the cycle (January 12th) here are the daylight stats:

city day length (hr:min) daily change (hr:min)
Barrow 0:00 n/a
Kotzebue 3:45 +0:08
Fairbanks 4:54 +0:06
Nome 5:02 +0:05
Anchorage 6:16 +0:04
Bethel 6:22 +0:04
Juneau 7:00 +0:03
Kodiak 7:08 +0:03
Ketchikan 7:37 +0:03
Adak 8:13 +0:02

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Why is it so cold in Glennallen?

Wednesday, December 19th, 2012

The question in the title came to me in an email, but for every email I get there are probably hundreds asking the same question in Glennallen. Sure, there are thousands more asking it about where they live, be it Fairbanks or Juneau or Orlando for that matter. But I want to look at what appears to be a unusually cold spot this winter, the capital of the Copper River Valley, population, after throwing in close neighbors Gulkana, Gakona, Copper Center, etc, of a 1,100 or so very tough Alaskans.

Let’s look at the weather depiction map from yesterday Morning, courtesy of the Alaska Aviation Weather Unit. A great example, as Gulkana (that’s where the weather station is located), labeled with its 4 letter code PAGK, was the colder than any station except Northway (PAOR)! It was 40 below (Fahrenheit or Celsius, take your pick), colder than Fairbanks at the time and most of the rest of those off the map to the north. Those around it are way warmer, with only Eureka (PAZK) being in the same ballpark. Talkeetna (PATK) and Anchorage (PANC) are not even below zero! Are not all these places in the Southcentral zone?

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