The Large Effects of El Nino On Our Current Weather

Our current weather is being profoundly influenced by El Nino.   

And that influence is not about to end.

Let me demonstrate this to you.

The following is a map of the anomaly (difference from normal) of upper-level heights at 500 hPa pressure for the past week.  You can think of this as the difference from normal of pressure around 18000 ft.

A huge trough of low pressure is off our coast (purple color).  Higher pressure/heights over the western U.S. (yellow color)

Here is the forecast of the same upper-level heights/pressures for the next 5 days.  Very similar pattern.  Deep low off our coast aloft.

Now, let me show the pattern for very strong El Nino winters. 

Mamma Mia!  A strong offshore trough/low just like the last week!

This upper-level El Nino pattern is associated with a persistent low-pressure area off our coast (see below).

Which is VERY like the pressure pattern we have seen the last few days.

To illustrate, here is the sea level pressure forecast for tomorrow morning at 8 AM. Looks just like the strong El Niñoino pattern!  Impressive low off our coast.

Moisture tends to wrap around such "El Nino" lows, resulting in the heaviest precipitation on the coast and south of us (see plot of moisture transport below)

During El Nino years, southern Oregon and northern California tend to get a lot of precipitation, and the current forecasts show exactly that (see total precipitation forecast through Wednesday morning below).

Vancouver Island gets a lot of precipitation as well because of the strong southerly flow circulating around the low-pressure system, which is forced to rise by the island's terrain.

There is a lot of gloom and doom in some of the media about this pattern, but it is actually quite favorable. 

The northern CA reservoirs are currently below normal, as are the reservoirs of southwest BC.  They will get a welcome refill.

El Niño brings substantial precipitation to the Colorado River drainage, which is badly needed to fill the reservoirs such as Mead and Powell. 

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Announcement

I will hold a special online Zoom session at 10 AM on Saturday for Patreon supporters. I plan to talk about the seasonal forecast in much more depth and answer your questions.

The Atmosphere is Providing Water Where It is Needed

There is a deep connection between meteorology and religion, and there are times when one wonders about divine intervention in our weather.

This is such a time.

Last year brought low snowpack for most of the West.  

Some were worried about water shortages and poor crops.   

But well-timed rain and substantial reservoir storage saved the day, with agriculture doing well and sufficient water available for human consumption.

Divine intervention?

This fall started out relatively dry, and some folks were worried, including a certain local newspaper.

But again, higher powers intervened.   During the past 72 hours, there have been substantial amounts of precipitation over the region (see below)

 A potent atmospheric river was the cause of our wet bounty (see below).  

Local reservoirs are refilling, including some low ones on the Olympic Peninsula (such as Wynoochee Lake below)

Other regions have been in need, and divine intervention has been and will be evident.

For example, California, the source of many of our fruits and vegetables.

Well-timed rainfall last year filled the reservoirs, but snowpack was low.   As a result, some of the big reservoirs are now below normal, such as Shasta and Oroville (see below).

Fortunately,  the current forecasts promise significant intervention, with massive amounts of precipitation over the Golden State during the next ten days (see below).   Remarkable.

This wet bounty includes LOTS of snow in the Rockies and over the drainage of the Colorado River (see below). A miracle.

Not getting religion yet?   What about British Columbia, which has suffered from a lack of precipitation this fall?    

Vancouver's reservoirs are quite low.

Fortunately, impressive amounts of precipitation are forecast for southwestern BC through next Monday morning

The water situation is rapidly improving on the West Coast.  The forecasts are highly promising.

There is only one thing to say about it: