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Why west coast heat and coming changes to CA and Gorge

 
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windfind



Joined: 18 Mar 1997
Posts: 1453

PostPosted: Wed Aug 08, 2018 3:52 pm    Post subject: Why west coast heat and coming changes to CA and Gorge Reply with quote

Hi Gang,

The Gorge has had blazing heat much of the last several weeks. Northern California has seen very hot temps and Southern California has had 108 degrees just a few miles from the coast. And now the biggest wildfire in California's history is burning.

The proximal cause of the heat is a nagging upper ridge at about 18,000 ft. over the entire western USA. Upper ridges bring warmer air from the south and also descending air which compresses near the surface creating more heat. But still....why is the heat lasting so long?

Looking at the animation below notice the heat producing upper trough over the western USA. Then note the upper Cut-Off Low over the Pacific. Notice how the Cut-Off Low is almost pinched off. Once this happens the Cut-Off Low is disconnected from the 500 mb. and jet stream winds so it just wobbles around rather than moving from west to east. This has allowed:

1. The heat making upper ridge to loiter over the USA.
2. It has held the surface storm below Cut-Off Low almost stationary for days.
3. Which has reduced the North Pacific High to a sliver along the west coast so milder N and NW coast winds.

So when does the heat wave end?

That Cut-Off Low becomes an upper trough in the next 2 days and moves towards the coast.

For the Gorge, Friday brings cooler air and a deeper air and higher pressure brings a blast of air all the way to the desert.

For the Bay Area, it also means a deeper marine layer Friday but also a ramp-up of NW ocean wind.

Looking at the long term it looks like, in theory, upper troughs and upper ridges on the average become more elongated N. and S. This means they move slower around the globe. Which in turn means longer periods when you have an upper ridge or upper trough over you. Hence, on the average, longer summer heat waves and longer spells of cold winter weather.

Mike Godsey
iwindsurf.com/ikitesurf.com
Weatheflow.com



Cut-Off LowLongHeatWestCoast.gif
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Cut-Off LowLongHeatWestCoast.gif


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Arrgh



Joined: 05 May 1998
Posts: 856
Location: Rio

PostPosted: Thu Aug 09, 2018 8:38 am    Post subject: Reply with quote

Well, crap!
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nw30



Joined: 21 Dec 2008
Posts: 5195
Location: The eye of the universe, Cen. Cal. coast

PostPosted: Thu Aug 09, 2018 12:29 pm    Post subject: Reply with quote

I really appreciate your non-political analysis of our weather, "just sticking to the facts ma'am".
Keep up the great work.
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mac



Joined: 07 Mar 1999
Posts: 11301
Location: Berkeley, California

PostPosted: Thu Aug 09, 2018 6:57 pm    Post subject: Reply with quote

It's easy. It's weather, not climate.
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windfind



Joined: 18 Mar 1997
Posts: 1453

PostPosted: Fri Aug 10, 2018 10:15 am    Post subject: Reply with quote

Hi Gang,

Here is a great post by Weather West about the California heat waves.:

http://weatherwest.com/archives/6411

If you reside in the Bay Area natural AC you may not be aware that July 2018 was the warmest month in the recorded history California. Also good stuff about the 143 mph fire vortex that went up to 39,000 feet!

Unfortunately, the European model has another huge heat producing upper ridge at about 18,000 ft. over the entire west USA and Canada by mid-August. Check out the image below!

Mike Godsey
iwindsurf.com/ikitesurf.com
Weatheflow.com



heatTEMP.jpg
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heatTEMP.jpg


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fxop



Joined: 13 Jun 1998
Posts: 154

PostPosted: Fri Aug 10, 2018 10:34 am    Post subject: Reply with quote

This triggers my pitch to west coast residents to buy a whole house fan!

We have a 6,000 cfm fan that we run in the morning to suck in the 58 deg outside air. House gets down to 68. Then shut the house up for the day, then at sundown start sucking again. Rarely use A/C.

Only trick is you need a lot of attic ventilation for the output.

fxop
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windfind



Joined: 18 Mar 1997
Posts: 1453

PostPosted: Fri Aug 10, 2018 10:51 am    Post subject: Reply with quote

Hi fxop,

We also have a whole house fan. For those who have never heard of them. It is basically a quiet but powerful fan installed in your ceiling behind shutters. When you flip the switch in the late evening when the air is cool outside the shutters open and the fan blasts the hot air in the house into the attic where it exits via your ridge vents. So the house and the attic become filled with cooler air which gives you a cool head start to the next day. Easy to retrofit to an existing house since there are no ducts. It will definitely decrease the need for AC.

That said....being a meteorologist with an eye on the future I designed and owner built our Gorge house with 15 inch thick insulated concrete walls containing 146 cubic yards of concrete thermal mass. With that insulated thermal mass and our whole house fan my calcs said we would never need air conditioning. And I was right for our first 9 years in the Gorge.

Now I have been proved wrong. As the heatwaves become more frequent and longer the thermal mass and whole house fan still help but AC has become necessary.

Mike Godsey

PS: You should never use these fans to get rid of food odors etc. during the winter since it would promote attic condensation, mold and even rot if done on a frequent basis.
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carl



Joined: 25 Feb 1997
Posts: 2646
Location: SF bay area

PostPosted: Fri Aug 10, 2018 11:17 am    Post subject: Reply with quote

It seems we are getting many more medium heatwaves in San Jose, like many weeks in the low 90s upper 80s. It's hot enough that the evening seabreeze stops early or is non-existent and a whole house fan wouldn't keep the wife happy. A/C has become necessary so we got a mini-split central A/C so we don't have to cool the whole house when we only need a few rooms. Then you can select which rooms get a/c and which rooms you just leave the window open. Wife happy.
Plus we got 18 solar panels to cut the energy use.
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