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.