Wednesday, August 20, 2014

Coho Ho Ho Rally 2014: Weather Brief, August 20 Wednesday


Coho Weather August 20 compiled at 0900

 

There are a few changes to the forecast this morning, however the large scale pattern remains the same with thermal low inland of N. CA combined with an entrenched pacific high, which will continue to produce moderate to strong northerly winds in the Southern Oregon, N. CA region.  The National Weather Service has issued a gale warning valid until Thursday evening for Cape Blanco to as far South as Crescent City for more than 10 miles out.  Small craft warning are issued all the way to Point Arena.   Not a lot new here as the wind continues to blow in this area.  This is not nearly as bad as it can get in these waters though.  The NWS forecasters actually call this moderate N. to NW winds.  It should be manageable for a well prepared boat with crew that have experience.  It will be bouncy with some breaking waves.

 

The changes to the forecast I spoke of, have to do with the Strait of Juan de Fuca (SJDF) and the waters off the Washington coast down to the central Oregon.  With an upper trough settling over the PNW and a forecasted weak cold front to pass through on Thursday, the WA interior will heat up a lot less than it has been.  The result should be less intense peak winds in the SJDF over the next four days.  Gradients should remain mostly onshore resulting in westerly winds when it blows, but there will be periods of light winds from random directions.  Though there will be some diurnal effect the peak winds will be more susceptible to other forces as the onshore pressure increases or decreases.  What I'm basically saying is if you are leaving the strait there is a good chance you will motor, but be prepared for some headwinds at times.  I believe the winds will stay under 20 kts during the next 4 days, and definitely much less much of the time.

 

For The WA and Oregon Coast the forecast now includes Southerly winds for Thursday into Friday till mid-day.   The culprit is a weak front passing through.  Wind speed and direction will vary depending on your location, but there is a good chance you will be bucking the wind for about a day and a half if you are travelling along WA or OR coast from about Newport North.  The wind speed will generally be light, under 10 kts, but I wouldn't be surprised if there are moments of stronger winds for some of you, perhaps to 15 with higher gusts at times.   I alluded to this in the past forecast and now the models show it more clearly and the National Weather service guys have also taken the bait as well and have included it in their forecast.  Oh yeah it will probably be cloudy at best, light rain and fog at worst.

 

Without further rambling here is the 4 day forecast

 

Today

 

SJDF  -  It's funny they changed the forecast while I was compiling this and now I'm re-typing.  West wind to 15 kts today, perhaps building tonight with potential to 25 kts tonight for central and eastern strait.  For western 3rd winds under 15 kts initially from SE then potentially to the W.  It will very likely be quite light right at Flattery.

 

WA down to Central Oregon – note I moved this forecast area South a bit to about Newport – Wind N to NW from 5 – 20 knots with the potential of winds to as high as 25 knots from about Westport N.  Don't let this fool you though as it will be probably 15 or less or much of the area.  Seas NW swell 5-7' with wind waves 3' or less except to 5' north of Westport.

 

S. OR to N. CA – wind N to NW 15 – 30 with gusts to 35 kts.  Wind less within 10 miles of shore except at the capes.  Seas, swell and wind waves from the N 8' at 8 seconds mixed with a SW swell 2' at 14 seconds.  

 

Thursday August 21

 

SJDF – Wind 0-15 mostly from the W to SW during the day, possibly building to 20 for the evening for central and eastern strait.  For the western 3rd expect light winds in general perhaps building from the west a bit in the late afternoon and evening, and oh yeah, drizzle.

 

WA to Central OR – Wind somewhere between W to SW to as high as 15 knots and as low as 0 kits.  High potential for drizzle, low clouds and or fog.  Seas, W. Swell 5 to 6'.  Wind waves generally 0 to 1'

 

S. OR to N. CA -  Windy at times to 25 kts from the N to NW. Higher gusts are likely.   I've mentioned this before, in this part of the world sometimes the conditions exceed what is expected from what the models show and the weather service forecasts.  So, be prepared.  Seas, mixed swell to 3' from NW and SW with longer period.  Wind waves to 8' and they will be coming from the direction of the wind. 

 

Friday August 22

 

SJDF – On the whole I'm forecasting a pretty mellow day for Friday with winds likely to not exceed 15 kts and likely blowing at 0 kts at times.

 

WA to Central OR – Probably some lingering W to SW winds first half of the day 0-15 kits.  Switching to the NW to N by evening also 0 to 15 kts.   It is possible for some gusts to 20 in the evening hours, especially in the northern portion of the forecast area.   My forecast does contradict the NWS a bit, which is calling for only N to NW winds all day Friday.  Take your pick.  The good news is I think the drizzle will go away though.  Seas, W swell 5 – 7' at 10 seconds.  Wind waves 2' or less.

 

S. OR to N. CA – not much change here, wind 10 – 25 with gusts likely into the 30's.  Probably lighter closer to shore except at the capes.  Seas Mixed N Swell to 8' at 8 seconds and S. swell to 3' at 13 seconds.  Wind waves to 7'.  Sounds like fun!

 

Saturday August 23

 

SJDF – How about SW to W winds 0-15 for the entire strait.

 

WA to Central OR – N to NW winds 5-15 kts.  W swell to 5' wind waves 0 – 2'.  I wouldn't be surprised if there is also a S or SW swell mixed in to this area as well, though the NWS isn't calling for it.

 

S. OR to N. CA – N to NW 10 to 25 with higher gusts.  Yucky waves

 

Sunday August 24

 

SJDF – Mostly west wind 0-20.  Diurnal effect may be stronger as the weather should be improving inland with heating of the interior.

 

WA to Central OR – the Northerly looks like it will be building and could reach speeds as high as 20 kts.   For seas the NWS says NW swell to 5' and wind waves to 3'.

 

S. OR to N. CA – Read from the previous day.  That's the official forecast anyway.  The most recent GFS weather model shows the inland low migrating a bit offshore.  It's possible that the wind will be easing quite a bit especially closer to shore.  Too far out now to trust this, but I'll keep an eye.

 

 


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