March 25, 2023

A Powerful Coastal Storm Approaches

On Monday and Tuesday, a powerful Pacific cyclone will intensify off the northern California/southern Oregon coasts.   A storm that would be notable in mid-winter, but very unusual in late March.

Below is the forecast sea level pressure chart for 2 AM Tuesday morning.  Also shown are the near-surface wind barbs and low-level temperature (shading).  

Just wow.   A very deep low-pressure center (985 hPa) with a huge gradient of sea level pressure, which means strong winds.  It almost looks like it has an inner eye!


A simulated cloud field for nearly the same time is downright scary (see below).  As you might suspect, the low center is in the middle of the swirling cloud bands.  Looks like something out of a science-fiction movie.

With such strong pressure gradients (pressure differences over distance), you can expect powerful low-level winds.   Below are the predicted wind gusts for the same time as the pressure analysis above.   A ring of strong winds surrounds the low, with the most powerful gusts to the west and south of the low center (as high as 60 knots, orange color).  

This structure is classic for strong marine cyclones.  The strong wind area is something called "the poisonous tail of the bent-back occlusion.'


Needless to say, if you are in the maritime industry it would be better to avoid being offshore Monday through Wednesday.

The extraordinary thing about this low is that it will spin offshore for an extended period, slowing weakening over time (the forecast map 24 h later is shown below)


As I noted above, such a low off the coast is unusual.  The map below gives some information on how unusual (colors).  The light pink indicates pressures that are more than 4 standard deviations from average (normal) values.   That is rare.


As you are probably sick of me pointing out, this situation reflects the anomalous atmospheric circulation we have "enjoyed" for the last month or so, with the jet stream going far south of its normal location.

Finally, with this low going south of us, so will the weather action for the next few days.  As a result, there will be very heavy rain over central and northern California (see below).    Yes, they are getting our water.


A few individuals were unhappy that I noted that the drought is over in California.  Well folks, the objective evidence is absolutely clear:  the drought is finished.  Kaput.  You can speculate why some people don't want to accept this.  Take a look at the graphic below if you have any doubts.  Normal is the gray, the yellow is this year.  Just stunning.





24 comments:

  1. This note from Northwest Public Broadcasting in Pullman showed up in my email on Thursday:
    -----------------------------
    NWPB and NOVA Present: Climate Across America

    Join us for a special screening of climate change videos followed by a live panel discussion Thursday, April 6 at 7 p.m. at the Kenworthy Performing Arts Centre 508 South Main Street, Moscow, Idaho

    About the Event:

    Northwest Public Broadcasting (NWPB) has partnered with the award-winning PBS science series NOVA, a production of GBH, to produce and distribute multiplatform, climate-focused content as part of NOVA's Climate Across America initiative.

    As part of the initiative, NWPB produced two videos focused on solutions-based approaches to different aspects of climate change at the community level. This event will give our local audience the chance to preview one of those videos as well as a segment from NOVA's Weathering the Future documentary.

    The event will also feature a live panel discussion of the challenges and solutions portrayed in each video and provide inspiration that each of us can take away to continue making positive changes in our communities.

    “The mounting impacts of climate change are among the greatest challenges our society will face in the next century,” said NOVA Co-Executive Producer Julia Cort. “As crucial as it is, communicating effectively about climate has also become extremely challenging. NOVA's first climate documentary aired in 1983, and we have produced 30 more climate films since then, continually leveraging the latest research on how best to engage people in this difficult topic. We’re excited that this national-local collaboration allows us to share our expertise with the wider PBS system and the next generation of media makers.”

    The locally produced CLIMATE ACROSS AMERICA content will be timed with two new NOVA documentaries premiering this spring:

    WEATHERING THE FUTURE, premiering Wednesday, April 12 at 9pm ET/8C on PBS, will examine the dramatic ways in which our weather is changing. From longer, hotter heat waves, to more intense rainstorms, to megafires and multi-year droughts, the U.S. is experiencing the full range of impacts from a changing global climate. At the same time, many on the front lines are fighting back—innovating solutions, marshaling ancient wisdom, and developing visionary ideas. The lessons they're learning today can help all of us adapt in the years ahead, as the planet gets warmer and our weather gets more extreme.

    CHASING CARBON ZERO, premiering Wednesday, April 26 at 9pm ET/8C on PBS will look at the ambitious climate goal recently set by the U.S. to achieve net-zero carbon emissions by 2050 and slash emissions in half by 2030. But is that even feasible? What exactly would it take? The film examines the problem and identifies the most likely real-world technologies that could be up to the task. From expanding the availability of renewable energy options, to designing more energy-efficient buildings, to revolutionizing the transportation sector, and more, the film casts a hopeful but skeptical eye. Can these solutions be scaled and made available and affordable across the country? Find out why there is still hope that we can achieve carbon zero and avoid the worsening impacts of climate change.
    -------------------------------
    The Kenworthy Performing Arts Centre in Moscow isn't very large, IIRC about 300 seats. Attendance at this event is by reservation only. Maybe they will capture the panel discussion portion of the event on video.

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    1. I live in Seattle, drive truck through south central Oregon. This is highly unusual.
      Yes they have a lot more snow than the past ten years. Klamath lake might actually fill. Thing, this is high desert. They never really got this much moisture.
      This cyclone is sitting over the area. Not good for anybody. This moisture is sitting here, instead of traveling north to Snoqualmie/ Baker.

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    2. Washington is not critically dry the snowpack is decent and it still rained quite a bit this winter. I'd be alot more worried if the snowpack was way below normal. California had years where it hardly rained at all and they will likely have more of those years in the not too decent future so the more rain they get this year the better.

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  2. With all the Mt snow and valley rain in California and the SW could that help keep down the extreme heat this summer compared to the last several?.

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    1. The trouble is most of the southwest is desert that doesn't get alot of rain/snow even in good years. This desert will get hot no matter what I think its more a question of does the upper level airflow support a strong 4 corners high pressure or not. If the 4 corners high is stronger than normal than there is a greater chance of desert heat reaching the northwest. The good thing is I don't see any sign of the 4 corners high building in the near future so long as the West is getting hit by trough after trough the 4 corners high will have a hard time getting established. A really strong 4 corners high doesn't form instantly it starts as a small high pressure and slowly builds and if it doesn't start building in April then it probably won't have time to get really strong.

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  3. Will California count their blessings and still choose to conserve or blow it all? It's the USA. Guessing those reservoirs will be tapped out in a few years since we are...well.. idiots. We do not learn. Tomorrow never comes, right?!! So blow that windfall on something stupid like a true American! Green up some lawns in a desert. Wash some cars.

    Washington has a water deficit now. Probably would behoove is to go easy on the snow pack and let our lawns turn brown this summer. Buuuut....we won"t.

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    1. Actually California is using some of the "surplus" water to add ground water back to aquifers. Not that "they" don't waste a lot of water.

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  4. Well...It would be good to hear about how this large storm is going to affect Puget Sound areas?....apparently, not much.

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  5. I noticed in the last chart of Calif reservoir status that 'Normal' is the years 2000-2015. Why would we use such a limited, and recent, data set for establishing the normal range? It seems like a shortcut path to drawing faulty conclusions. I have seen this mistake with temperature analysis as well. I wonder if it is sloppy, for convenience, or intentional on the part of various authors? Comments on this trend appreciated Cliff.

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  6. Aquifers Cliff - c'mon! They are a long way from fully replenished especially out east of the Sierra. A ten year drought is not wiped out or kaput in one winter. Ground water sampling in the central valley is starting to show a recovery but various salt levels and overall ground water table levels are a long way from "back to normal".

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    1. The aquifers and ground water have been overdrawn terribly and irresponsibly. This has little to do with climate or weather. Has nothing to do with drought. This is about mining a resource at a rate far greater than replenishment.

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    2. This sounds a lot like the selective semantics used by just about everybody in the climate debate. Mr. Cook rightly points out that when people who are looking at California's water budget point out that it is too early to say the "drought" is over, they are talking about the groundwater. It is indeed obvious that for those who do their work above ground like Prof. Mass, the "drought" is over. Atmospherically, and all short term water storage (snow, reservoir) clearly show, as Prof. Mass says, the "drought" is over.

      Unfortunately for the water managers who actually have to supply water to farmers in the central valley as well as the cities and everybody else, the "drought" is definitely not over, not finished, not kaput. I only spent a few decades as a hydrogeologist looking at the subsurface before switching careers and no longer have access to a lot of sources, but in looking at the publicly available data sources, it looks like there is no indication the long term water supply "drought" is over.

      I'm hoping that Prof. Mass is simply referring to the atmospheric and surface storage when he summarily declares the "drought" to be over, perhaps he glances over the bigger picture because he doesn't like people confusing the specific way he thinks of a "drought" with the way that others legitimately refer to a "drought." Though I have been concerned when he cites soil moisture data to also show a "drought" is over, when soil moisture is a very short term and very shallow look at the sub-surface hydrology.

      These are all analogous to saying you're hunger problem is over because you just had three big meals in a row, but you're not sure when the next meal is coming. Or the famine is over because the 10,000 people all got full meals for a week, or a month. The famine might be on a short hiatus, or it might be trending towards ending, but a full belly today, doesn't help you much next week.

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    3. I concur. Surface water conditions and status shouldn't be extrapolated to apply to subsurface conditions and status. Another analogy is national spending. Deficits and debt are related, but not the same. They measure different aspects of budgeting. Even if government manages to realize positive revenue position instead of deficits it can't be reasoned from that specific that debt is no longer a problem. "Drought" is a general term whose components are surface water and subsurface water. Scientists in the field of water management in California and the SW have stated publicly that they estimate that it would require multiple water seasons such as the one California is having to replenish subsurface water supply to the extent that it can be claimed that CA's "drought" is over. https://www.npr.org/2023/03/23/1165378214/3-reasons-why-californias-drought-isnt-really-over-despite-all-the-rain https://www.vox.com/science-and-health/2023/1/6/23542194/california-atmospheric-river-flood-drought

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  7. "You can speculate why some people don't want to accept this." No need to speculate, we know the reason. Cult members will never accept the reality of cognitive dissonance, and will never take responsibility for their actions.

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    1. It depends upon your starting point. The media have a built in pessimism coupled with addiction to sensationalism. They are using the toughest metric for the end of the drought, which is aquifer recharge. It's not a cult.

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    2. Perhaps for some it's not an exact definition of a cult. But for many others, no weather news (no matter how beneficial it may appear) will get them to accept any other narrative but AGW/Armageddon time.

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  8. Given that State of California water resource managers exhibit reservations about their drought status, despite recognizing very good data, I feel justified in harboring less unrestrained enthusiasm than you do about their status.
    https://water.ca.gov/News/News-Releases/2023/March-23/Harnessing-Series-of-Winter-Storms-California-Increases-State-Water-Project-Allocation

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  9. There is a public benefit to encouraging conservation. Even with plentiful water resources, continued growth dictates caution. In some professions we use propaganda to move the populace to make certain choices. Cliff is not one of us :) He believes everyone has a degree from Cornell, MIT or Cal Tech.

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  10. Although Cliff and some of the commenters here are all too happy to cast aspersions at people slow to accept improved drought conditions in CA, I don't think there is any reason to do so. This winter has been desperate needed and much welcomed after several very dry years.

    It's not hard to understand why, psychologically, people might be slow to adjust to such a radical change in conditions, especially for those who have grown accustomed to conserving water over the last few years.

    Perhaps hesitance to accept the end of the drought is in fact healthy. It seems preferable to everyone rejoicing and turning the sprinklers back.

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  11. Totally fair to call the drought over. California still has big water problems... drawing down aquifers at a reckless pace etc (as mentioned above by Michael Cook).

    It's important for all to note that California's water problem is made much more visible and real by drought, but the drought isn't actually the water problem. The water problem is lack of will to properly regulate and manage natural resources, and the end of the drought doesn't end the need to change the way water is being used in the central valley, nor does it change the long term problems with putting mega cities in places with very limited natural water resources (Vegas, LA, etc).

    But the end of the drought will make everyone sigh with relief..

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    1. California has big problems, but not nearly as bad as Utah, Arizona, and Colorado.
      There is a huge difference between an entire lake drained that size, as opposed to irrigation water reservoirs.
      Holding the water if the snow melts is going to be the challenge. Understanding that your grass water in September comes from a finite source, when your house flooded in March is hard to argue to people that have had to rotate showering during the summer for years.

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  12. I haven't seen a spring break this cold in a long time. Even death valley will be low 60s next week

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Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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