California Weather/ Climate

[Dan the Weatherman]

.. Rain where you are more, how far into next week Dan. ?

Between Wednesday night and Friday morning with the best chance from early Thursday to Friday morning.

[richard mann]

-
With asking I'd just been trying to get a better idea of what you're seeing forecast. 
 
I've got main cold holding to its current more stepped up pace east through tomorrow, before beginning to slow gradually and progressively from one day to the next where looking more forward from there. This while at the same time more latitudinally, continuing to move and spread still daily more south through the 7th.  @
 
.. So, more basically, with where colder air is sitting to the West (NW more.) at this point, with this main combination of movements more both longitudinal and latitudinal, the forecast more general that you'd pointed to above for both cooler temps and "some" rain, would appear to fit where looked at more generally.
 
— Cold moves a bit more east, before slowing, potentially both steering warmer and wetter air Coastward where being pressed on still by derees, while also allowing its access northward.

[Guest happ]

[Alan]

Unfortunately for you guys, 40% above normal this time of year is still a low number.

Any green in CA is more than welcome, any time of year!

[Guest happ]

Pretty active day over the Southwest today; most rainfall was in Arizona [Phoenix Deer Valley:  83 / 61 / 0.54].  More rainfall chances this week and some very cool temps.  Las Vegas forecast maximum for Friday is 68°.

 

71 / 54

[Dan the Weatherman]

Pretty active day over the Southwest today; most rainfall was in Arizona [Phoenix Deer Valley:  83 / 61 / 0.54].  More rainfall chances this week and some very cool temps.  Las Vegas forecast maximum for Friday is 68°.

 

71 / 54

 

This pattern is somewhat like a summer monsoonal setup. However, it is an upper low that is causing all the convective activity in the mountains and deserts this time around. .54" for any location in the Phoenix area is quite rare for this time of year.

[richard mann]

-
Still a chance for "something", per your "between Wednesday night and Friday morning" post above Dan.=At least here where I am and as far south as "Hanford".  -  http://www.wrh.noaa.gov/FXC/wxstory.php?wfo=hnx  / http://www.wrh.noaa.gov/FXC/wxstory.php?wfo=sto  ... Could still reach a little further south.
 
Main moisture .. Eastern Pacific scope.
 
http://tropic.ssec.wisc.edu/real-time/mimic-tpw/epac/main.html

[Alan]

"Snow Likely" here for Thursday / Friday with a few or more inches possible and chance of thunder - woohoo!

 

High of 48 today with dense fog and bright sunshine peaking in occasionally.  

[Guest happ]

Loving 'May Gray' but would rather have rain with the clouds.  The next few days could deliver both.

 

66 / 56

[Dan the Weatherman]

Light rain began to fall here in Orange around 9:30 this evening and there was some off and on heavier rain from about midnight to around 1 a.m. Areas of showers are developing and moving onshore in a WSW flow, which will likely bring more showers to the region overnight. It is certainly nice to see some late season rains even though they won't break the drought, but every bit of rain helps at least to some extent.

[richard mann]

.. Good news Dan. 

 

The low moved through here earlier today (yesterday the 7th.), through the morning. Plenty of wind but no rain. 

[Alan]

4" snow and still coming down. 29F, pea size hail last night before the snow started.

[Guest happ]

Looking at overnight rain totals surprised me especially considering that I only recorded 0.02.  LA Basin/ San Gabriel Valley & Orange county recieved much more than my location.

[Dan the Weatherman]

Looking at overnight rain totals surprised me especially considering that I only recorded 0.02.  LA Basin/ San Gabriel Valley & Orange county recieved much more than my location.

What direction of flow brings the most rain for your area during storms like this? For my area in Orange, a flow directly off the ocean from the S, SW, or W or anywhere in between usually brings more rain to my area. NW or N flow is generally much drier most likely from the downsloping over the transverse ranges.

[Guest happ]

Orographic lift favors south-SW/ SE rain for foothills west of Pasadena.  A direct north storm delivers the least amount since I am down wind of 5000' San Gabriel's/ Mt Lukens.  Whatever rain we get is highly appreciated and if the trough pattern stays around we may see more storms this month.  Both 2011 & 2013 produced over 0.50.  The added benefit is keeping the atmosphere moist and cool.  People forget that 60's are not uncommon in late spring.

 

63 / 50

0.02

Rainyear [jul-jun]: 8.52   

[richard mann]

.. If this patterning goes somewhat cyclical (Things continue to look like they have more of late here in mid-April through to this point, at all similar or recurrent into the summer.) it could certainly be a good thing for the potential of severity connected to the drought, being held back some.

[richard mann]

(.. cross-reference.)
 
http://theweatherforums.com/index.php/topic/791-pacific-northwest/?p=77460

[Dan the Weatherman]

Orographic lift favors south-SW/ SE rain for foothills west of Pasadena.  A direct north storm delivers the least amount since I am down wind of 5000' San Gabriel's/ Mt Lukens.  Whatever rain we get is highly appreciated and if the trough pattern stays around we may see more storms this month.  Both 2011 & 2013 produced over 0.50.  The added benefit is keeping the atmosphere moist and cool.  People forget that 60's are not uncommon in late spring.

 

63 / 50

0.02

Rainyear [jul-jun]: 8.52   

 

.24" fell here in Orange with the latest storm.

 

I figured that a northerly flow is rather dry for the Pasadena area as well as other cities in the San Gabriel Valley due to downsloping off the high mountains. Hopefully we do get more storms this month that bring moisture in from the S or SW.

[Guest happ]

These upper-level lows that drop some rainfall and snow in California fuel the powerful storms that spill out into the Plains States.  We like the pattern in the Southwest more than they likely do in Oklahoma.

 

67 / 55

[Guest happ]

Nice day for family BBQ.  I like the chances of more rainfall later this week; too bad this pattern didn't develop during winter

 

79 / 54.

[Alan]

It's watering my spring garden (which is planted from seed) so I'll definitely take it!

 

I hope the 3rd system around the 21st-23rd happens as well!!

[Guest happ]

It's watering my spring garden (which is planted from seed) so I'll definitely take it!

 

I hope the 3rd system around the 21st-23rd happens as well!!

 

Speaking of gardens, I read an article about how the production of fruits/ nuts/ vegetables in the Central Valley/ Salinas Valley/ Imperial Valley, etc have been weeks ahead of schedule.  Some crops are doing poorly due to the lack of winter chilling.

 

80 / 57

[Guest happ]

Rain chances/ amounts look even better with the next storm this week than last week's rainfall.  Hopefully that will mean a bit more than the 0.02 that I recorded on 5/8.

 

75 56

[Alan]

Looks like up to or over 2" rain in the mountains and up to a foot of snow above snow level.

 

I'm right in the iffy zone, last week it was all snow, this time not so sure how it'll play out...

[Guest happ]

Comfortably cool temps continue as a strong trough develops over California.  Looking forward to rain within 48 hours.  These are perfect conditions for supressing/ delaying the fire season.

 

71 / 57

[Dan the Weatherman]

It has been a nice stretch of cooler weather lately with the occasional storm bringing some much needed rainfall. This sure beats the warmer than normal weather pattern that was quite prevalent between February and April.

[Guest happ]

LA Times

May 14, 2015

http://www.latimes.com/local/california/la-me-extreme-heat-20150514-htmlstory.html#navtype=outfit

 

Number of days with temperatures above 95°F to soar in L.A. County

   

 

By 2050, parts of Los Angeles County are forecast to experience triple or quadruple the number of days of extreme heat if nothing is done to control greenhouse gas emissions, placing further demand on the region’s drinking water and electricity, according to two new reports by UCLA scientists.

That could mean that by mid-century, downtown Los Angeles could see an average of 22 days of extreme heat — days in which the high temperature exceeds 95 degrees — up from an annual average of six days recorded between 1981 and 2000.

The San Gabriel Valley could see the number of extreme heat days rise from 32 a year to 74. Long Beach? From four days a year to 16.

The results point to a hotter, drier future as Los Angeles faces climate change.

Increase in extreme heat days

Below is a map of forecasted increases in extreme heat days by 2050, as analyzed by UCLA scientists by water district, if nothing is done to limit carbon dioxide emissions in the air.

                  

Proof of rising temperatures is already in the historical record: The annual average in 1878 in downtown Los Angeles was 62 degrees. By 2014, it was 68 degrees.

 

The forecasted rise in temperatures, published this week in the Journal of Climate, was done by calculating global simulations of climate change to a neighborhood scale if nothing is done to rein in greenhouse gas emissions that cause global warming.

Places in Los Angeles County farther inland, especially the valleys, will feel the pain the worst because of their distance from the Pacific Ocean, which has a moderating effect on extreme temperatures, said Alex Hall, a professor at the UCLA Department of Atmospheric and Oceanic Sciences and co-author of the study.

 

“Climate change is inevitable in this region,” Hall said. “We have to adapt to climate change.”

In analyzing the forecasted rise in temperatures, researchers at the UCLA Luskin Center for Innovation published a separate analysis Thursday warning that water systems in areas such as the San Gabriel Valley will find their supplies of drinking water heavily taxed by the days of withering heat.

 

Some of the worst-hit cities will be suburbs where the thirsty lawn is cherished.

 

Pasadena might see an additional month of temperatures higher than 95 degrees, according to the UCLA Luskin report. It’s predicted to be worse farther inland: A water system serving Arcadia might see 40 additional days of extreme heat; San Marino could see 41; El Monte, 44; and Baldwin Park, 45 more days of scorching weather.

 

The situation is even worse by the year 2100. By then, downtown Los Angeles could face a total of 54 days of extreme heat a year, and the San Gabriel Valley, 117 days. By then, Palm Springs could see nearly half a year — 179 days — of soaring temperatures.

“Except for the highest elevations and a narrow swath very near the coast, land locations will likely see 60 to 90 additional extremely hot days per year, effectively adding an entirely new season of extreme heat,” the UCLA study said.

 

The pain will be especially bad in inland areas where parks, golf courses and cemeteries need lots of water to stay green.

 

“We know that most residential water use in Southern California is for irrigating landscapes and lawns. During a drought, high temperatures drive up the thirst of plants” used in that landscaping, said Henry McCann, the lead author of the UCLA Luskin report, which is part of a larger report on the vulnerabilities of the drinking water supply system in Los Angeles County.

“Water systems that seek to conserve water must incentivize residential customers to replace lawns with less thirsty plants,” McCann said.

William Patzert, climatologist with NASA’s Jet Propulsion Laboratory in La Cañada Flintridge, said the UCLA findings make sense.

“Are there going to be more extreme days? There’s no doubt about it,” he said.

 

“We’re definitely living in a warmer world. At the end of the 19th century, carbon dioxide was 280 parts per million in the atmosphere. And just recently we’ve hit 400 ppm,” Patzert said. “Carbon dioxide hasn’t been this high in 3 million years.”

 

Exacerbating the issue is the heat effect caused by urbanization — ripping out natural landscape for more shopping centers, streets and black-topped roofs, the perfect color for absorbing more heat into the city, Patzert said.

 

Even worse, Patzert said, unless efforts are made to control greenhouse gas emissions, the extreme heat will create a vicious cycle: heat causing more demand for air conditioning, drawing electricity coming from coal-fired power plants that spew more heat-trapping gases into the air. And Los Angeles can’t afford to deal with a thirstier landscape, Patzert said, as population grows.

“So you’ve got increasing population, increasing greenhouse gases, more extreme heat days, higher energy demands — so the whole thing snowballs,” he said. “That’s an appropriate term because there’s no snow,” he said, referring the disappearing snowpack in the Sierra Nevada.

 

Although climate change is inevitable, curbing the use of greenhouse gases will moderate the extreme forecasted heat, according to the study.

 

For instance, downtown Los Angeles would face only 15 days of extreme heat by 2100 under an aggressive reduction of greenhouse gases, instead of 54 if nothing is done to curb their use.

 

“The most important message we want to convey is that it really depends on each scenario we choose — whether we keep on putting carbon dioxide in the air,” said Fengpeng Sun, the lead author of the UCLA study published in the Journal of Climate. “We should probably prefer new energy, like solar or wind, and try to be not be so addicted to gasoline.”

ron.lin@latimes.com

priya.krishnakumar@latimes.com

[Dan the Weatherman]

It started raining here in Orange about 20 minutes ago or so and it looks to continue off an on this afternoon. Hopefully some of the breaks offshore fill in before reaching the coast so that the rain is more continuous.

[Dan the Weatherman]

These stories regarding the future climate always seem to mention the absolute worst case scenarios. I am not sure if I buy into the idea that the heat is going to reach the extremes they are predicting. I really believe that natural variability also needs to be taken into consideration and the past really needs to be studied much more closely such as the Dust Bowl Era in the 1930's. That heat in the plains likely wasn't caused by CO2 emissions, as they were much lower at the time compared to now. The Dust Bowl Era seems to be ignored in a lot of the media stories today.

[Dan the Weatherman]

It has been raining off and on quite heavily in Orange the last couple of hours and I would say that this is easily the heaviest storm that I have seen here since early January.

[Guest happ]

Fair amount of showers this afternoon and hopefully more to come overnight.  In-fact, today was the most daily rainfall since March 3.  If this pattern continues we could easily get more precipitation than any month since January. 

 

64 / 55

0.25

Year [jul-jun]: 8.77

[Dan the Weatherman]

Excerpt from tonight's AFD from San Diego showing how impressive rainfall down there was earlier today:

 

SAN DIEGO LINDBERGH FIELD HAD 1.51 INCHES IN ABOUT 90 MINUTES...INCLUDING 0.71 INCHES IN 9 MINUTES...MORE TYPICAL OF A CONVECTIVE STORM IN THE MIDWEST OR SOUTHEAST THAN SAN DIEGO.

 

This would be quite extraordinary for a midwinter storm, let alone in May!

[SilverFallsAndrew]

LA Times

May 14, 2015

http://www.latimes.com/local/california/la-me-extreme-heat-20150514-htmlstory.html#navtype=outfit

 

Number of days with temperatures above 95°F to soar in L.A. County

   

 

By 2050, parts of Los Angeles County are forecast to experience triple or quadruple the number of days of extreme heat if nothing is done to control greenhouse gas emissions, placing further demand on the region’s drinking water and electricity, according to two new reports by UCLA scientists.

That could mean that by mid-century, downtown Los Angeles could see an average of 22 days of extreme heat — days in which the high temperature exceeds 95 degrees — up from an annual average of six days recorded between 1981 and 2000.

The San Gabriel Valley could see the number of extreme heat days rise from 32 a year to 74. Long Beach? From four days a year to 16.

The results point to a hotter, drier future as Los Angeles faces climate change.

Increase in extreme heat days

Below is a map of forecasted increases in extreme heat days by 2050, as analyzed by UCLA scientists by water district, if nothing is done to limit carbon dioxide emissions in the air.

                  

Proof of rising temperatures is already in the historical record: The annual average in 1878 in downtown Los Angeles was 62 degrees. By 2014, it was 68 degrees.

 

The forecasted rise in temperatures, published this week in the Journal of Climate, was done by calculating global simulations of climate change to a neighborhood scale if nothing is done to rein in greenhouse gas emissions that cause global warming.

Places in Los Angeles County farther inland, especially the valleys, will feel the pain the worst because of their distance from the Pacific Ocean, which has a moderating effect on extreme temperatures, said Alex Hall, a professor at the UCLA Department of Atmospheric and Oceanic Sciences and co-author of the study.

 

“Climate change is inevitable in this region,” Hall said. “We have to adapt to climate change.”

In analyzing the forecasted rise in temperatures, researchers at the UCLA Luskin Center for Innovation published a separate analysis Thursday warning that water systems in areas such as the San Gabriel Valley will find their supplies of drinking water heavily taxed by the days of withering heat.

 

Some of the worst-hit cities will be suburbs where the thirsty lawn is cherished.

 

Pasadena might see an additional month of temperatures higher than 95 degrees, according to the UCLA Luskin report. It’s predicted to be worse farther inland: A water system serving Arcadia might see 40 additional days of extreme heat; San Marino could see 41; El Monte, 44; and Baldwin Park, 45 more days of scorching weather.

 

The situation is even worse by the year 2100. By then, downtown Los Angeles could face a total of 54 days of extreme heat a year, and the San Gabriel Valley, 117 days. By then, Palm Springs could see nearly half a year — 179 days — of soaring temperatures.

“Except for the highest elevations and a narrow swath very near the coast, land locations will likely see 60 to 90 additional extremely hot days per year, effectively adding an entirely new season of extreme heat,” the UCLA study said.

 

The pain will be especially bad in inland areas where parks, golf courses and cemeteries need lots of water to stay green.

 

“We know that most residential water use in Southern California is for irrigating landscapes and lawns. During a drought, high temperatures drive up the thirst of plants” used in that landscaping, said Henry McCann, the lead author of the UCLA Luskin report, which is part of a larger report on the vulnerabilities of the drinking water supply system in Los Angeles County.

“Water systems that seek to conserve water must incentivize residential customers to replace lawns with less thirsty plants,” McCann said.

William Patzert, climatologist with NASA’s Jet Propulsion Laboratory in La Cañada Flintridge, said the UCLA findings make sense.

“Are there going to be more extreme days? There’s no doubt about it,” he said.

 

“We’re definitely living in a warmer world. At the end of the 19th century, carbon dioxide was 280 parts per million in the atmosphere. And just recently we’ve hit 400 ppm,” Patzert said. “Carbon dioxide hasn’t been this high in 3 million years.”

 

Exacerbating the issue is the heat effect caused by urbanization — ripping out natural landscape for more shopping centers, streets and black-topped roofs, the perfect color for absorbing more heat into the city, Patzert said.

 

Even worse, Patzert said, unless efforts are made to control greenhouse gas emissions, the extreme heat will create a vicious cycle: heat causing more demand for air conditioning, drawing electricity coming from coal-fired power plants that spew more heat-trapping gases into the air. And Los Angeles can’t afford to deal with a thirstier landscape, Patzert said, as population grows.

“So you’ve got increasing population, increasing greenhouse gases, more extreme heat days, higher energy demands — so the whole thing snowballs,” he said. “That’s an appropriate term because there’s no snow,” he said, referring the disappearing snowpack in the Sierra Nevada.

 

Although climate change is inevitable, curbing the use of greenhouse gases will moderate the extreme forecasted heat, according to the study.

 

For instance, downtown Los Angeles would face only 15 days of extreme heat by 2100 under an aggressive reduction of greenhouse gases, instead of 54 if nothing is done to curb their use.

 

“The most important message we want to convey is that it really depends on each scenario we choose — whether we keep on putting carbon dioxide in the air,” said Fengpeng Sun, the lead author of the UCLA study published in the Journal of Climate. “We should probably prefer new energy, like solar or wind, and try to be not be so addicted to gasoline.”

ron.lin@latimes.com

priya.krishnakumar@latimes.com

 

 

I really get annoyed by articles like this that portray information in misleading ways. So the average annual temp was 62 in 1878 and the average annual temp was 68 in 2014...Yes, that is true, and 2014 was a record warm year, there also was not an UHI present in 1878. But cherry picking data like that helps no one. 

[Jesse]

I really get annoyed by articles like this that portray information in misleading ways. So the average annual temp was 62 in 1878 and the average annual temp was 68 in 2014...Yes, that is true, and 2014 was a record warm year, there also was not an UHI present in 1878. But cherry picking data like that helps no one. 

 

It's an utter joke of an article. Not sure why it was posted here.

 

Alarmist stuff like this gives reasonable people who are concerned about AGW a bad name.

[Guest happ]

I really get annoyed by articles like this that portray information in misleading ways. So the average annual temp was 62 in 1878 and the average annual temp was 68 in 2014...Yes, that is true, and 2014 was a record warm year, there also was not an UHI present in 1878. But cherry picking data like that helps no one. 

 

To be fair, the article includes several graphs that couldn't be reproduced on The Weather Forums that shows the steady increase in temperatures over the past century.  But to suggest significant warming based on the specific data in 1878 [when records begin] to today is misleading.

[Guest happ]

I didn't have time to check the rain gauge this morning but last night's thunderstorm produced some briefly heavy showers.  I was too preoccupied watching the Clippers play but observed the lightning display that lasted nearly as long as the game.   

 

Having a dreary day of light rain is a real treat in SoCal. 

[richard mann]

(.. cross-reference.)

 

http://theweatherforums.com/index.php/topic/609-approaching-pattern-discussion/?p=77842

 

Basically, my effort to explain the odd patterning.

[BLI snowman]

I really get annoyed by articles like this that portray information in misleading ways. So the average annual temp was 62 in 1878 and the average annual temp was 68 in 2014...Yes, that is true, and 2014 was a record warm year, there also was not an UHI present in 1878. But cherry picking data like that helps no one. 

 

I agree with your point, but LA's warmest year on record was actually 1981 (which means their climate is now cooling!!1)

 

And sadly that type of article is just the norm now for climate science journalism. It certainly has an impact on the issue since most everyday folks aren't science savvy enough to deconstruct its gaping holes.

[Guest happ]

(.. cross-reference.)

 

http://theweatherforums.com/index.php/topic/609-approaching-pattern-discussion/?p=77842

 

Basically, my effort to explain the odd patterning.

 

Climatology argues against this pattern.  Baja California/ desert SW getting rain during statistically arid conditions [pre monsoon].  Perfect conditions!

 

I measured 0.65 from convective showers.  There's a chance of recording 10' for the first rainyear since 2012 [start of the drought] 

 

May: 0.92

RainYear: 9.42

[richard mann]

-
.. A bit more specifically than I'd gone into the idea where routed to above, .. I'm looking at the retrograde of "other cold" having moved SSW out of the more upper reaches of Canada, West .. having effectively "blocked" main colder air's from more upstream West's, main progress more Eastward, South .. being the main component having lead to this patterning. This, with that retrograde (In fact similar to that that we'd seen last winter.) having been a product of a greater / stronger, more over-all force of movement where looking at main cold air's more general movement potential at this point. .. And with this, significant cold having been dammed up fairly significantly, just east of the Northern Rockies 5 or so days ago, this stronger force of movement more over-all, having worked to bring about the retrograde.