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.

March 23, 2023

Cool air and snow showers on Friday for the western lowlands. More crazy stuff in California.

 No, there won't be accumulating snow near sea level, but don't be surprised if you see a few flakes west of the Cascade crest on Friday,

The visible satellite image this morning (below) shows a strong spring-time front about to make landfall on the coast, with a swirl of clouds associated with a low-pressure area evident offshore.  To the west, you can see the mottled, white and dark cloud areas associated with great instability, instability caused by cold air passing over warm water.    That air is our future.

This area of cold air is coming to us all the way from Alaska, as shown by a wider-area satellite image.  Call it the Aleutian Express.

The trouble for low-elevation snow lovers is that this maritime air (called a marine polar, MP, air mass) is generally too warm for any lowland snow.   But it is the perfect pattern for heavy snow in the Cascades.

Below is the forecast SNOWFALL total through 11 PM Friday. Some very light snow south of Tacoma, with more over southwest Washington.   Not only will the temperatures be marginal, but with the flow off the ocean being northwesterly,  Puget Sound will be rain shadowed (or snow-shadowed) by the Olympics.

The Columbia Basin will also be rain shadowed, but the mountains will enjoy as much as a foot of new powder.

On Friday and Saturday, the lowlands will not get above the upper 40s, substantially cooler than normal.

California Madness

It is hard to believe, but ANOTHER powerful, record-breaking spring storm is being predicted for California.  Below is the forecast sea level pressure and surface winds for 11 PM Monday, when a deep, intense low center will approach the coast north of San Francisco.

Will California get heavy precipitation from this system?   Do kids like ice cream?

Take a look at the forecast precipitation totals through Wednesday morning. 3-7 inches more precipitation over the Sierra Nevada and northern CA.   Perhaps the U.S. Drought Monitor will FINALLY drop severe drought over northern California.  Just silly.

March 21, 2023

Record Breaking Storm Hits California. Snow Showers for Seattle. Accumulating Snow in Portland.

Today a record-breaking intense midlatitude cyclone has hit California--the strongest on record this late in the season.   Take a look at the visible satellite image around 5 PM (below).  An intense low center is at the center of the cloud swirl near San Francisco.  While western WA and OR were high and dry!

At San Francisco, the pressure fell to 985 hPa, the lowest pressure ever observed at that location in March.  The weather observations at 4 PM showed the circulation of winds around the low, with gusts at that time reaching 46 mph at the airport.   


A plane from Seattle to Monterey even had to abort its landing this afternoon due to large low-level wind shear. Moderate to severe turbulence was observed over much of California (see below, red is severe, yellow moderate).  Not a good day to fly.

The National Weather Service radars along the CA coast revealed intense small-scale circulations embedded in the larger-scale low off the coast (see below).  Just stunning.

Lowland Snow in the Northwest

Normally, lowland snow is not an issue at lower elevations in the Northwest after early March.  But much colder air will move into the Northwest later this week and there could be some snowflakes on Friday over western Washington and accumulating snow around Portland.  The accumulated snowfall (not snowdepth) forecast through Saturday morning shows some light snowshowers over portions of the western lowlands.   Substantial snow over the mountains.

Distrurbingly, southwest Washington and Portland areas gets more--several inches, with around a half-foot in a band south of downtown Portland.  Portland is becoming the new Anchorage.😆

For some perspective, here are the record daily spring snowfall totals (March 20th and later) for Portland for the period from 1939 to today.   The record is 1.6 inches.  More is predicted by the UW WRF forecast.

In short, although there is substantial uncertainty for the lowland snowfall, there is a clear threat of lowland snow showers-- a rare treat this time of the year.

March 19, 2023

La Nina Is Dead. El Nino will replace it. What are the implications? All in my new podcast.

My new podcast (see below to access), reviews the major changes occurring in the tropics and what they imply for our future weather.

Our long-lived (3-year) La Nina is over, with the sea surface temperatures in the Nino3.4 area now nearly exactly normal (see below)

The Pacific sea surface temperatures went from about 1C cooler than normal in December to near normal today

The latest NOAA Climate Prediction Center (CPC) forecast is for the probability of El Nino conditions to be over 50% by next fall.

As described in the podcast, the typical atmospheric configuration with El Nino is a low-pressure area over the Gulf of Mexico, warmer than normal conditions over the Northwest, and wetter than normal conditions over southern and central California (see below).  But as demonstrated this year, long-term prediction has substantial uncertainties, with the guidance based on El Nino/La Nina more like weighting the atmospheric dice.

To listen to my podcast, use the link below or access it through your favorite podcast service.

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March 17, 2023

Massive Migration Occurring Aloft and Even Warmer on Saturday

 This is the season for northward bird migration and the weather is now perfect for northward flight.

As a result, there is a massive northward movement of birds occurring and the weather radars are lighting up with birds each night.

As I noted in previous blogs, many birds prefer to fly at night, so let me show you the regional radar imagery over the past 24 h.

5 PM yesterday (Thursday) there was nothing

At 2 AM, bird returns were everywhere with radar coverage.  Notice our birdy friends don't like to fly offshore.   You can also see where we lack low-level radar coverage, like the central and southern Oregon coast and eastern Oregon.  Oregon bird watchers need to complain!

This morning at 8 AM, the birds are gone.

I rarely show Dopper radar imagery (which shows winds towards or away from the radar), but here is last night's image from the Langley Hill radar in Hoquiam (the radar is in the center of the circles).  Green indicates the targets (birds) are approaching the radar, red shows targets moving away.

The radar targets are going northward!

There is a nice website Birdcast, which collects all the radar information and shows migration patterns over the US.  Here is theeir graphic from last night, with arrows showing the direction of migration.  A large northward movement of birds along the West Coast.

I have noted that birds are a bit picky about nighttime flying weather.

They don't like heavy rain and stormy periods.  They also appear to appreciate a tailwind.  

And last night they had one.    Below are the winds overnight at 700 hPa (about 10,000 ft).  The little barbs show the direction and speed.  Southerly and southwesterly flow (from the south to the southwest) was apparent.  Not too strong.  Just like our feathered friends prefer.


    Today will get near 60F in western Washington and some places will get into the lower 60s on Saturday.  Take a look at the forecast surface air temperatures on Saturday at 5 PM (below).  Red is warmer than green and blue.  Wow.  Lower 60s all over the place in the western interior.

Warm southerly (from the south) winds aloft plus low-level downslope (easterly) winds over the Cascades are the reasons for the warmth.  This will be the warmest period since last October (see plot below, with 60F highlighted).  And it will feel good.

Have a good St. Patrick's Day.

March 16, 2023

Serious Climate Misinformation In Seattle Time Headline Article

Whether you are a climate activist, a governmental official, or a citizen hoping to be well-informed on climate issues, getting accurate and reliable climate information is important.

Unfortunately, the Seattle Times continues to provide unfactual information, with screaming headlines and stories that can easily be shown to be incorrect.

This disappointing behavior by Seattle's only newspaper was obvious on Tuesday (see below).

A blaring, big-type headline heralded that "DATA CONFIRMS THAT WARMING IS WORSENING FLOODS, DROUGHT".

And in the subtitle, they double down:  "WHAT HAD BEEN AN EXPECTED CONNECTION IS BACKED UP BY A NEW STUDY"

As I will demonstrate below, these claims are unfounded.  The study does not confirm anything.   And the "expected connection" subheadline is very revealing of the editorial approach of the Seattle Times.

The article

The article, like so many stories in our local newspaper, was a reprint of a Washington Post article (by Kasha Patel):  A WARMER WORLD CAUSES EXTREME DROUGHT AND RAIN.  INDISPUTABLE NEW RESEARCH PROVES IT.

When a reporter describes research as "indisputable" you know they have little understanding of the scientific process.  Science is ALL about disputing and questioning each other's facts and interpretations.   

The  "indisputable" information in question comes from a single new research paper "Changing intensity of hydroclimate events revealed by Grace and Grace-FO" by Mathew Rodell and Bailing Li of NASA Goddard and published in the journal Nature Water.

This article describes the measurement of the Grace satellites, which can measure the water content of soils from space.  Importantly, they only analyzed the period 2002-2021.  

Their whole claim of a global warming signal is based on two observations:  the last few years had several droughts/heavy rain periods, and the earth has been warming over the past decades. 

 Therefore, global warming/climate change is probably the cause.  Correlation proves causation.  Poor science logic (see below).

Why these claims are wrong

Let me begin with something that should be obvious: you can't determine a global warming/climate change signal with a 20-year record--it is not long enough.

There are many natural sources of climate variability:  El Nino/La Nina with a period of 3-7 years, the Pacific Decadal Oscillation with a period of 20-30 years (see below), and others.

So with all these natural sources of variability of precipitation, temperature, and other variables, it is very difficult to pull out a global warming signal over shorter time periods (several decades or less), particularly since the global warming signal is relatively small and slowly growing.  Note:  it is generally accepted that the Earth has warmed by approximately 1.2°C over the past 150 years.

The Pacific Decadal Oscillation goes between warm and cool phases.

A closer look at the paper itself reveals several serious additional issues.  Let me show you a few.  

Below is the key figure of the publication.   The extreme hydrological events sensed by satellite are shown by colored dots.    The black dashed line shows the monthly "intensity" of the extreme hydrological events, essentially multiplying the number of events by their intensity.

The paper (and the Seattle Times/WA Post article) highlight that the number and intensity of extreme events have risen.

However, the increase in the intensity of extreme hydrological events has been limited to THE LAST THREE YEARS ONLY.  That is true for the number of "events" as well.  

What was global warming doing during the previous 15 years?   On vacation?

In short, there is no longer-term trend in extreme hydrological events that would make you think that global warming/climate change was the cause. Virtually no change from 2002 through 2018.  

This is a substantial problem for their hypothesis

They also plot the change in global mean temperature on the lower panel.  You can see a small warming (about 0.2C) over the 20-year period, with 2016 being the warmest year.

The change in extreme hydrological events (abruptly increasing only in the last few years ) is very different from the trend of the global temperature (distributed over the entire period), undermining the authors' claim that global warming might be the cause.   

You will note that the warmest year 2016, did not have more extreme events.  Furthermore,  their plot shows little evidence that the intensity of the extreme events has increased.

Considering the above, does it seem likely that the Washington Post is correct in claiming that the research proves that the forcing of hydrological extremes by global warming is "indisputable"?  Of course not.

In fact, the evidence provided in this paper is so thin that a weather researcher (Daniel Swain) is quoted saying:

    " I think if this were just coming out of the blue and this is the only evidence we had that hydroclimate extreme was becoming greater in warming climate, it wouldn't be super strong evident unto itself"

Finally, the Seattle Times does not allow comments on stories from outside sources (such as the Washington Post).    Obviously, this allows them to publish questionable information without anyone being able to question or comment on it.  They do the same thing for their cartoonist, David Horsey, who continuously provides exaggerated and unfounded claims regarding climate.

Newspapers should not be in the advocacy business.

They should be in the business of communicating facts and where there is controversy, both sides of the debate.

March 14, 2023

The Upcoming Northwest "Heatwave"


On Friday afternoon at 4 PM, where would be the better place to put on your sunglasses and go outside for a warm St. Patrick's Day stroll?

Seattle or Los Angeles?

The surprising answer:  SEATTLE!

To illustrate the stunning situation, here is the latest European Center surface air temperature forecast at that time.    59F in Seattle and even higher over Chehalis and Portland.

In contrast, about 55-56F in LA on Friday afternoon.

A stroll is enhanced by dry weather.  The total precipitation forecast through Saturday at 5 PM, shown below, indicates that Seattle will be dry, with light precipitation in the mountains.

In contrast, during the same period, Los Angeles will be inundated by heavy precipitation, with 1-2 inches through Saturday afternoon from San Diego through Santa Barbara.

Let's take a closer look at the upcoming warmth, with Friday being the warmest day.  Here is the predicted surface air temperature at 4 PM Friday,  the warmest hour of that day.

Western Washington will be quite warm, with temperatures ranging from the upper 50s to lower 60s.  Temperatures will be cooler in eastern Washington.

And this blessedly warm day should also have a lot of sun.  Here is the forecast cloud pattern at 2 pm Friday.  Relatively clear over Washington, but with a veil of high clouds moving into Oregon.  You don't want to know about LA.

Why are we enjoying this warm/dry bounty?   On Friday afternoon there will be high-pressure inland and lower pressure offshore, resulting in easterly (from the east) flow over the Cascades (see below for 2 PM Friday).  Thus, air will be compressed (and warmed) as the air descends the western slopes of the barrier.

I asked the machine learning app, Dalle-E, to show me how the nice weather will change Seattle.  Its answer is below.

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...