Saturday, July 14, 2007

Prevailing Winds


W TO SW WIND TO 10 KT. WIND WAVES 1 FT. W SWELL 3 FT AT 8 SECONDS.

Our summers in Oregon generally feature prevailing winds out of the Northwest which are fueled by a massive, high pressure areas hundreds of miles off the coast. The movement of air from the high pressure zone typically flows following a clockwise spiral (and counterclockwise in the Southern Hemisphere) influenced by the rotation of the earth (Coriolis effect). The consistency and strength of these summertime surface winds feeds a giant oceanic circular flow, the Japanese current, to drive surface waters continually South along the west coast.

As surface water flows southward towards the equator, the earth's rotation (and the Coriolis effect again) draws water away from the coast and deeper, colder water rises upward to replace it. Surface water temperature is largely determined by existing wind velocity, southward water movement and the resulting cold water up-welling. Thus, along the Oregon coast, our waters can often be colder during summer than in winter as the current, and upwelling, is typically stronger in the summer months.

However, things are all screwed up right now...prevailing winds are not prevailing...the water is abnormally warm...and it is sure to wreak havoc on marine ecosystems. South winds are blowing and we appear to be in as strong an El Nino pattern as I recall a decade ago. Bluefin Tuna and other sportfish being caught off the Oregon coast...5 mil wetsuits traded for boardshorts on Oregon beaches...and more south winds in the forecast...and typically tiny summertime Oregon surf too...looks like 3 foot windswell all next week...probably with some onshores mixed in!

1 comments:

Nileek said...

Nice schooling oh wise one of the sea. I was in board shorts last week and a nice fresh tuna roll would hit the spot.

~Nileek