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Update #4 Irma & weird weather
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windfind



Joined: 18 Mar 1997
Posts: 1899

PostPosted: Sat Sep 02, 2017 11:28 am    Post subject: Update #4 Irma & weird weather Reply with quote

Hi Gang,

At the bottom of this tread are updates about Irma in response to some of the forum responses.

Mike

"So do not expect very accurate wind forecast for the next 2 days!"

Yea, that phrase is part of the Southern California today. We are getting used to our weather being goofy but take a look at the animation below and tell me how anyone can do a meaningful from the mess Tropical Storm Lidia will make out of Southern California winds.

Sometimes I long for the old days when both the models and my forecasts were truly crappy but at least all the Bay Area variables like the marine layer and the heat waves played the same role year after year.

Now forecasting Bay Area wind is like taking aim at a constantly changing target. Formerly rare Bay Area events like eddies now continue for weeks. The North Pacific High's surface NW winds are more often NNW. Our thinning marine layer vanishes for prolonged periods. And heat waves, once confined to Sept. and Oct. and quaintly called "Indian Summer" happen even in April.

But yesterday's temps smashed the 1874 all time temperature record for many locales. San Francisco, the town about which Mark Twain is alleged to have said “The coldest winter I ever spent was a summer in San Francisco.” reached 106 degrees. To put that in context for those who don't know The City... September is the hottest month of the year for San Francisco with an average HIGH temperature of 70 degrees. Yesterday our Anita Rock sensor, surrounded by the chilly Bay waters, recorded an amazing 86 degrees.

The Silicon Valley Mercury News published a list of some major all time heat records broken this summer:

– In July, Death Valley, California, endured the hottest month ever recorded on Earth

– In July, Shanghai registered its highest temperature in recorded history, 105.6 degrees.

– In July, Spain posted its highest temperature ever recorded when Córdoba airport hit 116.4 degrees.

– In June, Ahvaz, Iran, soared to 128.7 degrees that country’s all-time hottest temperature.

– In late May, the western Pakistani town of Turbat hit 128.3 degrees

Are record temperature evidence of Global Warming? My reading suggests the simple answer is no. Records are always being broken.

But what is clear is that the frequency of record breaking events is accelerating at an every faster pace. And that is probably related to the increasing waviness of the upper troughs and ridges that go around the globe.

The greater the north to south amplitude of those waves the slower weather travels from W. to E. and the more extreme the temperature and precipitation swings. And the more common it is for heat and cold patterns to get stuck in place like the dome of high pressure currently baking much of the west coast. And what is behind that waviness? Most likely ice or rather less ice.

But personally I like hot weather and look forward to growing mangos and papayas rather than apples and cherries.

Mike Godsey



Tropical Storm Linda .gif
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Tropical Storm Linda .gif




Last edited by windfind on Thu Sep 07, 2017 6:59 pm; edited 6 times in total
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nw30



Joined: 21 Dec 2008
Posts: 6485
Location: The eye of the universe, Cen. Cal. coast

PostPosted: Sat Sep 02, 2017 11:39 am    Post subject: Reply with quote

The graphics look like a bad hair day.
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philodog



Joined: 28 Apr 2000
Posts: 209

PostPosted: Sat Sep 02, 2017 2:23 pm    Post subject: Reply with quote

Tropical Storm Lidia
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andydavis



Joined: 11 Apr 1999
Posts: 319
Location: Point Isabel

PostPosted: Mon Sep 04, 2017 3:42 pm    Post subject: Re: Lidia and weird weather Reply with quote

windfind wrote:
Hi Gang,

... hit 128.3 degrees

Are record temperature evidence of Global Warming? My reading suggests the simple answer is no. Records are always being broken...

...And that is probably related to the increasing waviness of the upper troughs and ridges that go around the globe...


Mike Godsey


and, therefore, what are you suggesting is the base mechanism?
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windfind



Joined: 18 Mar 1997
Posts: 1899

PostPosted: Mon Sep 04, 2017 4:04 pm    Post subject: Re: Lidia and weird weather Reply with quote

andydavis wrote:
windfind wrote:
Hi Gang,

... hit 128.3 degrees

Are record temperature evidence of Global Warming? My reading suggests the simple answer is no. Records are always being broken...

...And that is probably related to the increasing waviness of the upper troughs and ridges that go around the globe...


Mike Godsey


and, therefore, what are you suggesting is the base mechanism?



Briefly: http://iopscience.iop.org/article/10.1088/1748-9326/10/1/014005/pdf
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Jorionw96



Joined: 18 Mar 2001
Posts: 33

PostPosted: Tue Sep 05, 2017 8:26 pm    Post subject: Reply with quote

But mankind isn't causing any of this right? Der Der
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windfind



Joined: 18 Mar 1997
Posts: 1899

PostPosted: Tue Sep 05, 2017 10:31 pm    Post subject: Reply with quote

Jorionw96 wrote:
But mankind isn't causing any of this right? Der Der


It sounds like you did not read the cited article.

Mike
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loopless



Joined: 30 Jun 1997
Posts: 426

PostPosted: Thu Sep 07, 2017 2:28 pm    Post subject: Reply with quote

Part of the abstract of that interesting paper...

"These results suggest that as the Arctic continues to warm faster than elsewhere in response to rising greenhouse-gas concentrations, the frequency of extreme weather events caused by persistent jet-stream patterns will increase."

Clearly the authors are fully in agreement about human-induced climate change, caused by CO2 emissions, affecting the Artic, and thus our weather down here. They must be part of the 99% of climate scientists.
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windfind



Joined: 18 Mar 1997
Posts: 1899

PostPosted: Thu Sep 07, 2017 3:16 pm    Post subject: Reply with quote

Hi Loopless,

Looking at today's upper level winds below you can see that today is a perfect example of extremes in the range of upper level troughs and ridges getting locked place.

Think of the upper level winds at 18,000 ft. as being like a snake of wind winding around the earth. If the "snake" is making slight N. and S. loops it, and the weather, progresses pretty fast from west to east. This is what we grew up expecting.

In recent decades the "snake" of upper level winds and its upper troughs and ridges are making much larger loops to the N. and S. like you see in the image. When this happens it means that the "snake" and our weather moves much more slowly or even gets locked in place more often.

And when you get huge loops like this your are more likely to get Cut-Off Lows that really linger or Rex Blocks that create really lingering weather.

If it is an upper ridge that is stuck over your locale you have a longer than normal heat wave. If it is an upper trough stuck over you then you have a longer than normal cool or rainy or snow period depending upon the season and your latitude.

Looking at the image below you can see the upper ridge that has been locked in place for days over the west coast bringing heat to the Gorge, Bay Area, Southern California and much of the west. This has enhanced the wildfire potential.

Now check out the 3 hurricanes at the bottom right of the image. Irma is the fat scary one in the middle. But to partially defuse Irma all we need is the upper level winds you see north of Irma to drop over Florida. The resulting wind shear would disrupt the hurricane and lessen any damage.

So looking at today's upper trough and ridges and remembering that these winds move from West to East... Do you think Irma is likely to be weakened in the next few days?

The second animation shows what one model thinks about this question.

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



UpperTroughUpperRidge.gif
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UpperTroughUpperRidge.gif



IRMAnam12Carib.gif
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IRMAnam12Carib.gif




Last edited by windfind on Thu Sep 07, 2017 4:21 pm; edited 1 time in total
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windfind



Joined: 18 Mar 1997
Posts: 1899

PostPosted: Thu Sep 07, 2017 3:48 pm    Post subject: Reply with quote

More Irma imagery:

Here is what the NAM12Carib is forecasting for Irma. A lot could still change but clearly this is an exception hurricane.



IrmaNAMcarib.gif
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IrmaNAMcarib.gif


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