Bill’s Whidbey Weather Beat
Everyone loves to know about the weather, especially when it exhibits dramatic behavior, good or bad. Bill’s Whidbey Weather Beat (BWWB) is an online blog which concentrates on Whidbey-specific weather, since Whidbey Island, by its geographical location, is subject, on average, to the most extreme winds in Western Washington. I live perched high on the bluff above Admiralty Inlet and keep daily, detailed track of weather data from official weather sites on and around Whidbey. I hope you find this blog both educational and entertaining.
We’re back to regular Whidbey Winter weather.
The UW computer model predicts:
Friday: Low pressure #1 – SE winds.
Saturday: Low pressure #1 – switching to Westerly winds.
Saturday night to Sunday night: Low pressure #2 – strong SE winds.
Monday afternoon to Tuesday: Low pressure #3 – strong SE winds.
Cliff Mass recently clarified on his blog how the oft-mentioned Convergence Zone works. First, this phenomenon occurs only about 25 times per year. Second, it does not occur when we are experiencing normal storm winds from the SW, the most common situation during the storm season. Instead, it occurs when a low pressure area off the coast moves farther north and its counter-clockwise winds hit us from the West. These Westerlies divide around the Olympics, coming back together over Puget Sound. This collision of air masses causes the air to rise and pick up moisture. When the air rises high enough, it can’t hold the moisture and dumps it as rain or snow, sometimes for a long period of time over one area. Depending upon the exact position of the low pressure, this collision point and area of heavy precipitation can vary from the South Sound all the way up to Everett. I suspect the reason the more common SW winds don’t produce a similar convergence zone north of the Olympics is that the convergence in that direction is not over so much water, therefore resulting in a rain shadow effect (less precipitation) instead of a convergence zone effect. I will contact Cliff Mass to confirm this. There are times when we get neither a strong storm with SW winds nor strong Westerlies producing a Convergence Zone. During such times the winds can occur in a very complex pattern depending upon how they funnel around the mountains and waters of Western Washington. This can produce highly variable and unpredictable areas of precipitation.
UW Computer Model showing warmer temps, a low pressure off northern Vancouver Island, and winds hitting Whidbey from the SE on Firday 1-20.January 17th, 2012 at 5:53 pm by billviertel
Central Whidbey has already had ice and flurries on Sunday 1-15 and around 6″ of snow on Tuesday 1-17. The included weather satellite image shows the Tuesday storm fading into the East and the larger Wednesday snow storm closing in on us from the immediate West.January 17th, 2012 at 5:37 pm by billviertel
The latest wind storm continues after 30 hours of gale force winds (31 mph and above). Peak wind gusts in Admiralty Inlet: 59 mph. Highest sustained winds in Admiralty Inlet: 52 mph. Number of hours gusting above 50 mph in Admiralty Inlet: 8. Highest wind gusts in vicinity (within sight): 93 mph at Hurricane Ridge!
We are experiencing a moderate, short wind storm now with winds likely reaching into the low 40′s mph. Tuesday and Wednesday, however, we are very likely in for a much stronger and longer blow. Batten the hatches!
Then Thursday it will get a tad colder. First we’re breezed, then we’re freezed!
December is trying hard to make up for the first 24 days during which we had benign weather. We have now had 6 days in a row with winds gusting over 40 mph on Whidbey, 2 of them with winds over 50 mph.
It is no secret that the winds of Whidbey blow frequently and strongly, especially in the central and northern sections of the island. This has to do with the presence of the Olympic Mountains, which I will explain in a future installment. If you routinely look at the magnitude of the winds here and compare them with those in other places in Western Washington, our winds are usually the highest. That is not to say other areas of Western Washington have not had stronger storms. For example, the Columbus Day Storm of 1962 and the Hannukah Eve Storm of Dec 2007 had hurricane force winds peaking at 150 mph and 147 mph respectively, both times near the tiny town of Naselle in SW Washington (that might be a good place to avoid living).
It did not take me long to learn that living on Whidbey’s SW side was unusually exciting weather-wise, especially in a bluff side forest with 100’ tall trees. I eventually decided to record the storm results daily using the official weather stations on Smith Island and at WNAS and Point Wilson, which I am in my fifth year of doing. The resulting data is consistent and clear. There is an average of 75 storms per year with winds gusting to 30 mph or more. Here is the average number of storms of each strength:
Storms per year with winds gusting over 30 mph: 75
Storms per year with winds gusting 30-39 mph: 32
Storms per year with winds gusting 40-49 mph: 27
Storms per year with winds gusting 50-59 mph: 12
Storms per year with winds gusting 60-69 mph: 4
Storms per year with winds gusting 70-79 mph: once every 4 years
Another way of categorizing storms is by the Beaufort Scale (technically the wind speed within a category needs to last 10 minutes). Here is the number of storms on Whidbey in 2010 according to the Beaufort categories:
7 Moderate or Near Gale 31-38 mph 27
8 Fresh Gale 39-46 mph 26
9 Strong Gale 47-54 mph 13
10 Whole Gale 55-63 mph 7
11 Violent Storm 64-73 mph 1
12 Hurricane 74 mph and up 0
On average, there are 750 hours (out of a possible 8,760 hours) during which winds gust 30 mph or more. The months averaging the most storms with gusts of at least 30 mph and the most storms with gusts of at least 50 mph are November (11,4), December (10,2), January (8,4), and March (10,2).
A classic Northwest Storm Pattern (2 in succession):
# Storms with Wind Gusts of 30 mph or more by Month by Year:
# Storms with Wind Gusts of 40 mph or more by Month by Year:
# Storms with Wind Gusts of 50 mph or more by Month by Year:
# Storms with Wind Gusts of 60 mph or more by Month by Year:
So far in the Sept 2011 – Sept 2012 storm season we have had 14 storms with winds gusting 30 mph or more (189 hours), 6 of which had winds gusting 50 mph or more (19 hours). Our highest wind gusts were 66 mph on Smith Island and Point Wilson on September 26. November’s highest wind was 57 mph on Smith Island on November 21.
Hours with Wind Gusting in Each Speed Range in 2008-09 by Month:
Hours with Wind Gusting in Each Speed Range in 2009-10 by Month:
Hours with Wind Gusting in Each Speed Range in 2010-11 by Month:
Hours with Wind Gusting in Each Speed Range in 2011-12 by Month:
% of Time with Wind Gusting 30 mph or more in 2011 by Month:
# Storms with Winds Gusting in Each Wind Speed Range by Year:
# Storms with Winds Gusting in Each Duration Range by Year:
Peak Wind Speeds by Local Weather Station - Nov 2011:
Storm Duration and Intensity - Nov 2011:
Number of Hours Winds Gusting in Each Wind Speed Range by Year:
UW Weather Site Loop for Evaluating Approaching Storms:
This one map (which is only one 3 hour segment of a 34 segment loop) gives a computer model prediction of atmospheric pressure isobars, wind vectors, and temperatures.
December 2011, after a very windy November, became unusually serene due to a ridge of high pressure that built off the Washington coast, shunting all the storms to the north of us. This atmospheric High finally broke down on Christmas Day, and we have had one wind storm per day since.
I will periodically update my graphs as the 2011-12 storm year progresses.
(And don’t hesitate to ask questions.)