California Weather/ Climate

[Guest happ]

LA Times reference: http://touch.latimes.com/#section/-1/article/p2p-83534853/

 

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-14-00197.1

 

A Hybrid Dynamical-Statistical Downscaling Technique, Part II: End-of-Century Warming Projections Predict a New Climate State in the Los Angeles Region

Fengpeng Sun¹

Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles

Daniel Walton

Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles

Alex Hall

Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles

 

 

Abstract

Using the hybrid downscaling technique developed in Part I, temperature changes relative to a baseline period (1981–2000) in the greater Los Angeles region are downscaled for two future time slices: mid-century (2041–2060) and end-of-century (2081–2100). Two representative concentration pathways are considered, corresponding to greenhouse gas emission reductions over coming decades (RCP2.6), and to continued 21^st-century emissions increases (RCP8.5). All available global climate models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) are downscaled to provide likelihood and uncertainty estimates. By end-of-century under RCP8.5, a distinctly new regional climate state emerges: Average temperatures will almost certainly be outside the interannual variability range seen in the baseline. Except for the highest elevations and a narrow swath very near the coast, land locations will likely see 60–90 additional extremely hot days per year, effectively adding a new season of extreme heat. In mountainous areas, a majority of the many baseline days with freezing nighttime temperatures will most likely not occur. According to a similarity metric that measures daily temperature variability and the climate change signal, the RCP8.5 end-of-century climate will most likely be only about 50% similar to the baseline. For mid-century under RCP2.6 and RCP8.5, and end-of-century under RCP2.6, these same measures also indicate a detectable though less significant climatic shift. Therefore, while global emissions reduction measures would not prevent climate change at this regional scale in the coming decades, their impact would be dramatic by the end of the 21^st century.

 

 

¹Corresponding author address: Fengpeng Sun, 7343 Math Sciences Building, 405 Hilgard Ave, Los Angeles, CA 90095. E-mail: sun@atmos.ucla.edu

 

 

 

 

• © 2015 American Meteorological Society Privacy Policy and Disclaimer
  Headquarters: 45 Beacon Street Boston, MA 02108-3693
  DC Office: 1120 G Street, NW, Suite 800 Washington DC, 20005-3826
  amsinfo@ametsoc.org Phone: 617-227-2425 Fax: 617-742-8718
  Allen Press, Inc. assists in the online publication of AMS journals

[Guest happ]

I followed the link to the abstract but was disappointed there wasn't more info.  I'm not that familiar with your weather patterns there, but they seem to expect onshore flow to dwindle dramatically while the jet moves much farther north.  If they're basing their findings on CMIP5, they'll be disappointed.  CMIP5 is already failing.  I posted the CMIP5 predictions vs actual in the global warming topic.

 

I think one has to subscribe to the American Meteorological Society to get the full report.  It's funny that one poster suggests this UCLA study is "an utter joke of an article" and not appropriate to the California forum. 

 

66 / 54

[Jesse]

One problem I have is how exact they are about the number of "extra" hot days each individual location will have on average. There is nothing scientific there, just pure sensationalism. They figure people don't like broad probabilities. Just hard, easily digestible numbers.

[SilverFallsAndrew]

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.

 

Ahh, thanks for pointing that out. I was at work so my post was kind of oversimplified in relation to my thoughts on the matter. Essentially though what bothered me most about the article was that 1878/2014 comparison. The way it was written, someone could easily make the mistake of concluding that the average temperature in LA has gone up 6F during that time period. 

 

Then someone reads that seemingly shocking statistic and repeats it to other non-discerning friends, family, and co-workers. 

[Dan the Weatherman]

1.54" fell here in Orange with this latest storm, a very impressive total for mid-May! This is the single largest storm for my area since the big storms back in December.

 

I just wonder why we couldn't get storms like this during January, February and March.

[Guest happ]

Ahh, thanks for pointing that out. I was at work so my post was kind of oversimplified in relation to my thoughts on the matter. Essentially though what bothered me most about the article was that 1878/2014 comparison. The way it was written, someone could easily make the mistake of concluding that the average temperature in LA has gone up 6F during that time period. 

 

Then someone reads that seemingly shocking statistic and repeats it to other non-discerning friends, family, and co-workers. 

 

I think the instinct of some posters is to discredit global warming; sort of a knee jerk anti-science reaction; you are Republican, right?

[Guest happ]

1.54" fell here in Orange with this latest storm, a very impressive total for mid-May! This is the single largest storm for my area since the big storms back in December.

 

I just wonder why we couldn't get storms like this during January, February and March.

 

Dan,

 

What is your total so far? 

[Guest happ]

Persistent pattern continues and may result in one of the coolest and possibly wettest months of May in many years.  San Diego has already recorded the 2nd highest amount of rainfall for May at 2.35".  Nice turn-around from prolonged warmth over the past year.

 

69 / 54  

[Dan the Weatherman]

I am not denying that there has been some warming overall for the last 100+ years, but I am getting tired of these articles that are predicting a certain region to be hotter than hell by the end of the century, as if we are heading toward a very extreme level of heat. I just don't know if the level of heat that is being predicted is realistic or not, but I am not ruling out the possibility of at least some warming in the future.

[Dan the Weatherman]

Dan,

 

What is your total so far? 

 

I will have to check my records and will post a total when I do so.

[richard mann]

Persistent pattern continues and may result in one of the coolest and possibly wettest months of May in many years.  San Diego has already recorded the 2nd highest amount of rainfall for May at 2.35".  Nice turn-around from prolonged warmth over the past year.

 

69 / 54  

 

A bit more of the same over Southern California, a bit more rain in the mountains with maybe a tad more at lower elevations more Northward, a more moderate level of main Summer heat, with not too much stronger amplification to whatever main ridging, an early beginning to both main precip. and cool next fall (with no lightning minus a good amount of rain accompanying it.), and a nice fat Nino next later fall and winter working to provide plenty of moisture for a good series of well directed "expresses" pointed at us more State-wide both North and South, ...

 

.. And we just may be able to say sow long to this "Drought". .....

[SilverFallsAndrew]

I think the instinct of some posters is to discredit global warming; sort of a knee jerk anti-science reaction; you are Republican, right?

I don't think my point really had anything to do with global warming. And I think a factually incorrect article is by definition anti science. Regardless of what it presents itself as.

[Guest happ]

I don't think my point really had anything to do with global warming. And I think a factually incorrect article is by definition anti science. Regardless of what it presents itself as.

 

Perhaps I was hasty in my response to you.  You've publicly expressed disdain for California and it's progressive politics in the past.  Keep in mind that newspapers sell stories so the science study made have been worded toward sensationalism.  But the article is referenced to the UCLA study and cites various scientists include Bill Patzert of NASA/ Jet Propulsion Laboratory; a regular speaker at AMS chapter meetings.

 

I guess the non-California poster who you associate with; the one who is predictably hostile and destructive may be the real "joke" in suggesting what is appropriate for the California forum.

[SilverFallsAndrew]

Perhaps I was hasty in my response to you.  You've publicly expressed disdain for California and it's progressive politics in the past.  Keep in mind that newspapers sell stories so the science study made have been worded toward sensationalism.  But the article is referenced to the UCLA study and cites various scientists include Bill Patzert of NASA/ Jet Propulsion Laboratory; a regular speaker at AMS chapter meetings.

 

I guess the non-California poster who you associate with; the one who is predictably hostile and destructive may be the real "joke" in suggesting what is appropriate for the California forum.

 

I can guarantee that poster is most certainly NOT a Republican.

[Jesse]

I can guarantee that poster is most certainly NOT a Republican.

You're mainly a RINO these days yourself, right?

[richard mann]

Worth re-emphasizing.

.. This more plentiful mid, even later, Spring cold is and has been better than no cold at all.

And it is, still plentiful per my gage. For the past near to 2 weeks as I've had it, main and broader cold has been in general recession more northward. And with this, is near set to move steadily more southward again beginning in a few days.  @

[Guest happ]

Worth re-emphasizing.

 

.. This more plentiful mid, even later, Spring cold is and has been better than no cold at all.

 

And it is, still plentiful per my gage. For the past near to 2 weeks as I've had it, main and broader cold has been in general recession more northward. And with this, is near set to move steadily more southward again beginning in a few days.  @

 

The "Spring cold" has been remarkably resilient.  Today was the 14th day this month of below normal maximums.  Average May max is 78°.  And another chance of rainfall later this week.

 

71 / 59

[Dan the Weatherman]

The "Spring cold" has been remarkably resilient.  Today was the 14th day this month of below normal maximums.  Average May max is 78°.  And another chance of rainfall later this week.

 

71 / 59

 

If it does rain later this week, than that will be the 3rd storm with measurable rainfall for Socal for the month of May. There hasn't been a series of 3 storms since at least December and series of storms have been almost nonexistent during the heart of winter for the past 3 seasons. This has certainly been an interesting change in the pattern for mid spring and even though it hasn't eradicated the drought, it has helped to delay fire season for at least a few weeks and has helped in other ways as well.

[Front Ranger]

The San Diego airport has smashed the record for wettest May with 2.35". Old record was 1.79" from 1977.

 

Many other May precip records being set or on their way across the Southwest.

[SilverFallsAndrew]

The San Diego airport has smashed the record for wettest May with 2.35". Old record was 1.79" from 1977.

 

Many other May precip records being set or on their way across the Southwest.

 

That is good news. Obviously it would have been better if it had come during the winter months when much of the precip could have been stored as snow pack, but any rain is good rain at this point. 

[Guest happ]

The San Diego airport has smashed the record for wettest May with 2.35". Old record was 1.79" from 1977.

 

Many other May precip records being set or on their way across the Southwest.

 

"San Diego is also experiencing its second wettest May as of Friday evening, with a monthly total of 2.35 inches. The current record for wettest May is 2.54 inches set in 1921".

http://www.weather.com/forecast/regional/news/california-rare-may-rain-sierra-snow-2015

[Front Ranger]

"San Diego is also experiencing its second wettest May as of Friday evening, with a monthly total of 2.35 inches. The current record for wettest May is 2.54 inches set in 1921".

http://www.weather.com/forecast/regional/news/california-rare-may-rain-sierra-snow-2015

 

Yup...that was before the airport.

[Guest happ]

http://www.wrh.noaa.gov/lox/scripts/animate.php?root=sat_4km&list=VIS4.GIF.3.jpg,VIS4.GIF.4.jpg,VIS4.GIF.5.jpg,VIS4.GIF.6.jpg,VIS4.GIF.7.jpg,VIS4.GIF.8.jpg

 

deep circulation over California

 

Lo: 58

[Guest happ]

http://www.wrh.noaa.gov/lox/scripts/animate.php?root=sat_4km&list=IR4.GIF.3.jpg,IR4.GIF.4.jpg,IR4.GIF.5.jpg,IR4.GIF.6.jpg,IR4.GIF.7.jpg,IR4.GIF.8.jpg

 

Not much reaching the ground but later in the day, showers may focus on San Diego county.   

[richard mann]

Still cool with some, cover here.

[Guest happ]

It is cool down here, too.  But it seems to be usually cool around Memorial Day except well inland.

 

70 / 58

[Dan the Weatherman]

It has been quite cool for much of May so far here in Socal, which has been a nice change from the heat earlier this late winter and early spring and the extreme heat from the first half of last May.

[richard mann]

(.. cross-reference.)

http://theweatherforums.com/index.php/topic/862-may-2015-in-the-pacific-northwest/?p=78148

[richard mann]

(.. cross-reference.)

http://theweatherforums.com/index.php/topic/862-may-2015-in-the-pacific-northwest/?p=78153
 

[Guest happ]

Some of the best weather lately has been at the beach due to reverse clearing.  Enjoyed Laguna w/ family and even went swimming [water temp: 65].  It was cloudy all day inland.

 

70 / 58

[Dan the Weatherman]

No rain fell here in Orange with this last storm as most activity was in the mountains and San Diego County.

[Guest happ]

http://www.wrh.noaa.gov/lox/scripts/animate.php?root=sat_1km&list=VIS1LAX.GIF.3.jpg,VIS1LAX.GIF.4.jpg,VIS1LAX.GIF.5.jpg,VIS1LAX.GIF.6.jpg,VIS1LAX.GIF.7.jpg,VIS1LAX.GIF.8.jpg

 

Satellite shows how far inland stratus can move.  Due to the west to east transverse mountains/ valleys from Santa Monica to Yucaipa/ San Bernardino, coastal clouds can move almost 100 miles inland.  There is no other place in California where marine clouds penetrate further inland.  

 

L: 57

[Guest happ]

Preliminary data suggests that May 2015 will be one of the coolest across the Southwest and nobody is complaining except maybe the tourists.  In-fact this could be the coolest month since January for maximum temps and the wettest month for many locations this year.  California finally got a break from the interminable winter ridge before summer hits. 

 

74 / 56

[Guest happ]

http://www.wrh.noaa.gov/lox/scripts/animate.php?root=sat_1km&list=VIS1LAX.GIF.3.jpg,VIS1LAX.GIF.4.jpg,VIS1LAX.GIF.5.jpg,VIS1LAX.GIF.6.jpg,VIS1LAX.GIF.7.jpg,VIS1LAX.GIF.8.jpg

 

Satellite shows how far inland stratus can move.  Due to the west to east transverse mountains/ valleys from Santa Monica to Yucaipa/ San Bernardino, coastal clouds can move almost 100 miles inland.  There is no other place in California where marine clouds penetrate further inland.  

 

L: 57

 

Maybe the Salinas Valley allows the marine layer to reach 100 miles inland.  But sometimes the stratus ['high fog'] in the southern valley [Paso Robles] comes over the coastal range from San Luis Obispo.

[Guest happ]

Some valley locations [western San Fernando] hit 80's yesterday; today should be more widespread.

[Guest happ]

http://www.latimes.com/local/california/la-me-el-nino-returns-20150528-story.html

 

"In Texas, Oklahoma and Mexico, destructive storms flooded communities and unleashed a tornado, leaving more than two dozen dead.

 

Across Southern California, this month has been decidedly cooler and wetter. San Diego had its wettest May in 94 years, and Los Angeles saw nearly four times its average rainfall. This month, the San Diego Padres were forced to call a rain delay — only the fifth time that has happened in Petco Park's 11-year history. Even the Mojave Desert is running as much as 5 degrees cooler than normal.

 

To some scientists, these are signs that the elusive, unpredictable El Niño weather phenomenon is gaining strength — and offering a glimmer of hope after more than three years of extreme drought.

 

El Niños have been responsible for two of California's wettest and most destructive rainy seasons: the winters of 1982-83 and 1997-98.

 

Now, experts say, a potentially powerful El Niño this winter could be the beginning of the end of the drought.

 

This month's weather suggests how El Niño's building strength is already affecting the United States. It's giving weather scientists reason to be cautiously optimistic that it has the stamina to see it through California's rainy season, which typically begins in October and ends in April.

 

"Can one big year ease the drought conditions? Yes, it can," said Michael Anderson, state climatologist with the California

Department of Water Resources. "It can definitely replenish the surface storage and can have some benefit to starting to replenish some of the groundwater."

 

 

In December, California water officials said that it would take 75 inches of precipitation in the northern Sierra Nevada — a major source of water for the state — to end the drought and bring reservoir storage and runoff back to normal levels.

 

So far, the traditional rain season has been a bust — only 34.9 inches have fallen, below the average of 50 inches.

 

But the infamous winter of 1982-83 dropped 88.5 inches of precipitation into the northern Sierra Nevada, the wettest season on record, according to the Department of Water Resources.

 

That year, El Niño's influence was also seen in the Rocky Mountains, another source of California water. So much runoff flowed down the Colorado River that Glen Canyon Dam almost burst in 1983. The situation was so precarious that chunks of rock and pieces of concrete poured out of the dam's spillways.

 

"To get the wettest winters possible, you almost need an El Niño," said Kelly Redmond, regional climatologist at the Western Regional Climate Center. "The biggest winters, almost without exception, are El Niño winters."

The problem is there's no reason to believe such a year wouldn't be followed by another arid one.

 

"This drought is not a one shot deal [in which] when it goes away, everything goes back to normal," said Bill Patzert, a climatologist for the Jet Propulsion Laboratory in La Cañada Flintridge. "You're living in an even warmer world" and a world of declining snowpack, all of which will test water supplies for years. "The warmer it is during the day, the more evaporation you get. So to maintain your landscaping, it takes more water."

 

"It's the continuation of the long dry years that are the real problem, as we're seeing now," said Jeanine Jones, deputy drought manager for the Department of Water Resources.

 

El Niño is the warming of Pacific Ocean waters along the equator, from Peru to the International Date Line, that causes changes to the atmosphere and can influence weather globally.

 

Last year, scientists thought El Niño was forming in the Pacific, only to watch it fade out.

 

There's reason to believe this coming winter could be different, as El Niño appears to enforce its will elsewhere in the country — offering a possible preview of what California could see.

 

Record storms in Texas and Oklahoma over the last few weeks have dramatically ended a 41/2-year drought, said Oklahoma state climatologist Gary McManus, erasing "all short-term and long-term impacts, from agriculture all the way down to deeper soil moisture levels and those reservoirs that were going dry."

 

Whether California gets another epic El Niño by winter is "the $64,000 question," said Dan Cayan, climate researcher for the Scripps Institution of Oceanography and the U.S. Geological Survey. "There are a number of models, some of which point strongly in that direction."

 

Though El Niños are often seen as synonymous with rain, in fact it is only the strong ones that are reliable forecasters for above-average precipitation. Some El Niño years gave Southern California extremely dry weather. The driest year in L.A.'s recorded history, from July 2006 to June 2007, happened during a weak El Niño.

 

Conversely, some very wet years have happened during non-El Niño years.

 

But even if big rains come, experts warn that it would be foolish to ease up on the water conservation measures California has taken.

 

Dry years, after all, have been the rule, not the exception for California and the rest of the Southwest for the better part of 15 years. Because of warmer temperatures, the intensity of future droughts is expected to worsen.

 

"We most likely will be having an increasing population," said Jones of the Department of Water Resources. "We expect a future with climate change. We expect greater risk of drought, so we should be preparing for that."

ron.lin@latimes.com

[Guest happ]

Happy with trend toward return of ULL influence next week.   Today was warmest max since 5/2.

 

85 / 58

[Alan]

Warmest day of the year here at 71F - it felt downright hot!  Also the highest minimum at 50F this am.  Currently 60F, yikes!

 

Termites are doing their once a year swarming which always signals the first arrival of warmer weather, every termite on the mountain takes flight in a 24hr period and within 2 days, gone.

[Guest happ]

Fairly typical late Spring conditions: morning overcast/ hazy afternoon.

 

85/ 60

[Guest happ]

http://www.wrh.noaa.gov/total_forecast/getprod.php?prod=XXXAFDLOX&wfo=LOX

QUICK UPDATE ON THE END OF THE WEEK. 12Z GFS IS NOW DRY THROUGH 
  FRIDAY BUT DOES STILL SHOW DECENT MOISTURE COMING IN SATURDAY FROM 
  ANDRES FOR POSSIBLE SHOWERS/TSTORMS, ESPECIALLY THE ERN PORTION OF 
  OUR AREA. LAST NIGHT`S ECMWF DEFINITELY NOT ON BOARD WITH THIS IDEA 
  BUT WILL SEE WHAT TODAY`S RUN SAYS. STILL A VERY LOW CONFIDENCE 
  FORECAST AT THIS POINT.

 

Tropical storm watchers have been speculating on the path of Andres for several days.

 

'June Gloom' big time this week.  Haven't tabulated May data yet; nearby stations were 3-4 degrees below monthly normal.  This week could be 10+ degrees below normal.

 

L: 58