Monday, August 17, 2015

Coho Ho Ho Rally 2015 - Brads Weather and boat reports August 16th

Brads Weather August 16th

Brad Baker Coho ho ho Weather August 16 2015


Looking at the boat position map this morning I see that we have North Star in Crescent City and two other boats currently off the Washington Coast.   Safe travels everyone!


The National weather service has either small craft or gale warning pretty much up and down the entire coasts from Cape Flattery to San Francisco.    The reason is an above normal Pacific high (1038 mb!) currently centered at about 44N, 146W.  This is a bit further to the East than the models were predicting a couple of days ago and the result should be moderate to heavy N to NW winds all the way.  The pressure gradients do become closer together (more gradient = more wind) from about Newport Oregon to just South of Cape Mendocino and the highest winds can be expected in these areas.   The model does have the high weakening a bit starting Tuesday and retrograding further to the West which should serve to moderate the conditions a bit, though the NW winds should continue to blow at some level through my forecast period.  The models hint late in the week and into next weekend an upper level trough will slide down out of the Gulf of Alaska and the pacific high will weaken further and retrograde even more west.  If this occurs the conditions should lighten more.  This is too far in the future for any confidence, but if it verifies should be a good window for safe travel in the Southern Oregon Northern California waters.   In the short term the winds should be strongest from now through Wednesday.  Because of the strength of the high and its position, strong winds will extend 300 miles or more out from the coast.  So sailing further offshore may not be the solution.  The pattern is such that more often than not there will be less wind closer shore, this will be especially true between Capes Blanco and Mendocino and South of Cape Mendocino to San Francisco, as the inland thermal low extend out over the water at times.  Also in this pattern the winds tend to be diurnal with stronger winds in the afternoon,  evening and very early morning hours.  Lighter winds typically occur just before sunrise until noon.  This is due to the thermal low deepening as the dessert is hottest and weakening as things cool down. 


That all said, my experience when sailing the offshore waters around Cape Mendocino, conditions can change quickly for no apparent reason.  One moment you can be motor sailing with relatively light winds and the next thing you know it will be nuking!   Best to stay prepared and have a plan for reefing.


For the Strait of Juan de Fuca we should have a reasonably strong onshore push today, then things are forecast to mellow a bit for Monday and Tuesday, before another stronger push on Wednesday and late into the week.


Now for the 4 day forecast:




SJDF – West winds 10-25 knots, with the strongest winds in the later afternoon and evening hours.  The strongest winds should be central and eastern strait with things mellowing out as you reach Cape Flattery.  Wind waves 1-4 feet.


Cape Flattery to Newport Oregon – The NWS has issued small craft warnings for this entire part of the coast.  Small craft warnings mean that winds from 21 to 33 knots are expected.   So with that in mind I predict NW winds 10-25 knots, with stronger winds in the afternoons and evening.  Also you can expect the winds at the higher end of the range the further south you go in the forecast area.  Don't be surprised if you have gusty periods exceeding 25 knots.  Seas, NW wind waves 5-6' with a short period over a longer period 2-3 foot swell.


Newport to SF – Windy with Gale force winds likely more than 10 miles off the coast, especially from Cape Blanco to well south of Cape Mendocino.  Gale force winds mean 34 to 47 knots.  Sustained winds in the windiest areas are likely to be around 30 to 35 knots with gusts to 40 knots.   Seas 12 to 13' at 9 seconds.  Remember the height forcast is for the average of the tallest 1/3 of the waves.  Individual sets can and will be bigger, up to twice as big.  Closer to shore (10 miles or closer) the NWS says small craft warning meaning 21-33 knots.


Time for a short story.  My wife sailed down the coast back in 2005 helping some friends on a Hallberg Rassy 46.  The forecast was almost identical to this one.  Just south of Cape Mendocino they experienced sustained winds of over 50 knots for about 12 hours.  They did fine, flying only the staysail.    They were about 100 miles off the coast.  While they experienced 50 knots a buddy boat was about 15 miles off the coast and had about 20 knots sustained.  The point is forecasters don't always get it right and sometimes mother nature decides to do the unexpected.  There also can be a pretty good variance form in shore to offshore.   The best thing you can do is be prepared or wait for a lighter forecast.


Monday August 17


SJDF – West winds 0 – 20.  It will likely be light in the morning then potentially build later in the day and evening.  Wind waves 0-3'


Flattery to Newport - NW winds 15 -  25 knots with gusts to 30.  Strongest of the winds are likely to be late afternoon and early evening.  Seas, combined seas to 7'


Newport to SF – NW wind 20-30 with gusts to 40.  Seas to 12' at 9 seconds.  Less wind closer to shore and South of Pt. Arena.


Tuesday August 18 ……. Is it just me or is the forecast taking forever to read and or type?!


SJDF – Look like gradients will have gone offshore overnight and you could have light easterlies in the strait for the morning.  The easterlies should shut off by midday than switch to light to moderate Westerlies by late afternoon perhaps to 15 knots.  Wind waves 1' or less.  This offshore breeze means we will likely have a pretty warm day in Seattle on Tuesday, maybe 90 degrees.


Flattery to Newport – NW winds 10 – 20 with higher gusts possible to 25.  More wind closer to Newport OR.   Seas N to NW wind waves to 7' at 8 seconds over a 2' NW swell at a longer 13 second period.


Newport to SF – NW winds 15 – 25 with gusts  to 30.  Seas 10' at 9 seconds


Wednesday August 19


SJDF – West winds 5-15 in the morning rising 20-30 in the afternoon and evening wind waves 1-4'


Flattery to Newport – NW winds 15 – 30.  Seas to 8' from the NW


Newport to SF – NW wind 15 – 25 with gusts to 30, NW seas to 10' at 10 seconds


Thursday August 20


SJDF –  West wind 10-30 with strongest winds afternoon and evening.  Stronger winds Central and eastern strait.  Seas 2-5' wind waves


Flattery to Newport – NW wind 15 – 25 knots, NW waves to 8' at 9 seconds


Newport to SF – NW wind 15 – 30 knots, seas to 12' at 10 seconds.


Finally I'm done!





Brad Baker   l   Swiftsure Yachts

2500 Westlake Ave N. Suite F   l   Seattle, WA 98109

Office: 206.378.1110    Cell: 206.920.7147   l   Fax: 206.378.1124

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