Late March Bluster

The frontal system of a deep and mature cyclone reaches the Pacific coast of North America. Image time is 0100 PDT 29 Mar 2012. Infrared satellite photo courtesy of the US National Weather Service.

At 0130 PDT, the sound of the wind awoke me, and I listened to the trees roar under periodic heavy gusts. As with yesterday's bluster, the noise did not quite reach the crescendo of the 12 Mar 2012 windstorm, but did have some force. This latest front brought stronger winds to Vancouver, BC, than yesterday's shortwave trough (more on this below).

Peak Wind and Gust: km/h (knots) Minor Windstorm 28-29 Mar 2012 (PDT)
Location	Wind	Dir	Time	Gust	Dir	Time
Vancouver	50 (27)	SE	0300	67 (36)	SE	0200
Abbotsford	44 (24)	SSE	0400	59 (32)	SSE	0400
Bellingham	48 (26)	SSE	0353	85 (46)	S	0358
Victoria	50 (27)	SE	0151	65 (35)	SE	0151
Comox	59 (32)	SE	0200	70 (38)	SE	0000
Port Hardy	28 (15)	ESE	0100	37 (20)	ESE	0100
Navy Whid	56 (30)	SSE	0422	81 (44)	SSE	0412
Everett	30 (16)	S	0653	54 (29)	S	0641
Sea-Tac	33 (18)	S	0153	52 (28)	S	0215
Portland	24 (13)	SSW	1053	43 (23)	SSW	1053
Solander I	100(54)	ESE	0000	137(74)	ESE	2300
Estevan Pt	56 (30)	ESE	2200	89 (48)	ESE	2200
Quillayute	30 (16)	SE	0053	70 (38)	SE	2233
Hoquiam	46 (25)	SSE	0053	72 (39)	SE	0054
Astoria	46 (25)	S	0055	72 (39)	SSW	0133
Newport	57 (31)	S	0235	80 (43)	S	0335
North Bend	44 (24)	S	0535	65 (35)	S	0555

Interestingly, save for the usual spot—Solander Island—the coast did not receive a particularly strong wind relative to much of the north part of the interior. The storm has not completely departed the region at the time of this writing, and I may have to update this table as winds could climb higher in places where the front has yet to pass through, such as the southern section. Plus, the broad, mature 96.9 kPa (at 12:00 UTC) low center is only slowly departing toward the north, moving to the west of Haida Gwaii. The region will be under the influence of this system for much of the day, though it is likely maximum winds have been achieved here in Southwest British Columbia.

Yesterday, a shortwave trough moved through the region in the late morning and early afternoon, triggering strong SE to S winds in places. Here in Vancouver, a very dark sky preceded the feature, with periodic waves of rain that climbed to moderate intensity at times. The precipitation did not persist long enough to produce major accumulations, with 6.8 mm (0.26") in total for the entire day at Vancouver International. Wind speeds and direction were more interesting.

Peak Wind and Gust (mph) Minor Windstorm 28 Mar 2012 (PDT)
Loc	Wind	Dir	Time	Gust	Dir	Time
Vancouver	44 (24)	S	1400	59 (32)	S	1400
Abbotsford	50 (27)	S	1404	65 (35)	S	1404
Bellingham	46 (25)	SSE	1353	76 (41)	SSE	1408
Victoria	24 (13)	SW	1339	37 (20)	S	1512
Comox	33 (18)	SSE	1500	56 (30)	SSE	1500
Port Hardy	28 (15)	ESE	1600	41 (22)	ESE	1600
Navy Whid	61 (33)	SSE	1356	87 (47)	SSE	1405
Everett	50 (27)	S	1453	74 (40)	S	1347
Sea-Tac	39 (21)	S	1853	56 (30)	S	1142
Portland	48 (26)	SSW	1353	65 (35)	SSW	1505
Solander I	67 (36)	SSE	1700	80 (43)	SSE	1700
Estevan Pt	48 (26)	ESE	1200	69 (37)	ESE	1200
Quillayute	31 (17)	S	1453	54 (29)	SSW	1531
Hoquiam	43 (23)	SSE	1253	72 (39)	S	1728
Astoria	MM	MM	MM	MM	MM	MM
Newport	50 (27)	SSW	1255	74 (40)	SSW	1355
North Bend	44 (24)	SSW	1615	65 (35)	SSW	1555

Astoria had a reporting outage between 0655 and 1355 (not inclusive) on 28 Mar 2012, missing the shortwave trough response entirely.

Vancouver International reported peak winds out of the south. This is unusual. More typically, when strong winds arrive, Vancouver is visited by one of two classes of windstorm: the westerly surge with winds from a W-NW direction, or the southeaster with winds from a ESE to SSE direction. This is a product of the terrain surrounding Vancouver Metro, with favours winds from the ~NW down the Georgia Strait, or the opposite direction of ~SE up the Georgia Strait. East is also a favoured direction at Vancouver, BC, due to a strong tendency for offshore flow from the Fraser Valley in the cold season, but winds speeds rarely reach gale force from this direction. Yesterday's shortwave trough brought unusual strong southerly winds to Vancouver, a direction more typically seen at places like Seattle and Portland due to North-South terrain channeling by the Cascades and coast ranges. Strong south winds at Abbotsford are not unusual.

These two weather systems also exemplify that strong wind events can sweep through the region back-to-back in 12 hours or less. In a rare 24 hour period, three separate systems can affect the area, keeping winds going strongly for a long period of time--in other words, the lulls between systems may not get all that low. This can confound statistical techniques for calculating high-wind return intervals, such as the "method of independent storms".