March 30, 2024

Northwest Wind Generation Collapses Again: Can We Blame El Nino?

 The latest Northwest energy generation statistics are available from the Bonneville Power Administration and they are sobering:   wind energy generation (green line) has collapsed over the past several days (see below).   Spring is normally a time when wind generation increases robustly, but not this year.


What is going on?

Something happened between March 25th and March 27th.  But what?

Winds are driven by pressure differences, so let's examine the changes in the regional pressure fields.

At 5 PM on March 25th, there was high pressure offshore and low pressure over eastern Washington, resulting in westerly (from he west) flow descending into eastern Washington (see pressure map below).  Good for wind energy generation.


A look at the winds at 5 PM on March 25th (below, with gusts in red), shows substantial winds (greater than 20 knots) over many of the prime wind-generation areas of eastern Washington and Oregon.


But the pressure situation on the 27th at 5 PM is radically different, with a strong low offshore (see below).


This greatly weakens the pressure difference across the Cascades and thus the winds.  To see this explicitly, here are the regional winds at 5 PM on the 27th.  Can you see the difference?


A plot of the sustained windspeed and gusts at Ellensburg Airport further illustrates the situation (below)


We have repeatedly been in a situation with a low-pressure area offshore this winter.   As noted in my previous blogs, this is a classic situation during El Nino years, something shown by a composite analysis of pressure differences from normal during El Nino years (see below, from a NOAA website).   The blue colors indicate enhanced low pressure offshore.

For those hoping for wind energy to lead the way to independence from other energy sources, this situation is a warning.  Wind energy alone can not fill the gap: it is too variable, both by season and by weather regime.  

This situation is particularly concerning considering the rapid rise in electricity usage, driven by increasing numbers of electric cars, massive new computational centers, and the push by many governmental groups and others to reduce the use of natural gas for heating and cooking.

The problems with wind generation make the consideration of nuclear energy critical for any serious reduction in fossil fuel use.

March 28, 2024

First Look at the Weather for the April 8 Solar Eclipse

 I have gotten a lot of inquiries about the weather on April 8, the day of the total solar eclipse of the sun over the eastern half of the U.S.

Our operational forecast models reach that far in time and have for a few days.  But considering the uncertainty at such a long projection, I have refrained from commenting until now.

The model solutions are starting to settle down and I have increasing confidence that I can provide useful information.  So let me do the first of several updates on the weather associated with the event.

The area of totality will extend from Texas to Ohio to northern Maine (see below).


Totality will occur at roughly 1800 UTC (11 AM PDT) for most of the path (earlier to the southwest, later to the northeast).   Here in Seattle, only about 20% of the sun will be covered (see below).  You would hardly notice this, even if the skies were clear.


The Forecast Situation

Below is the forecast 700-300 hPa (10,000-30,000 ft) relative humidity, a good measure of cloud cover, at 1800 UTC 8 April based on the U.S. GFS model.

Portions of southwest Texas might have a good view, but I worry about viewing conditions over much of the Midwest.  Some openings in Ohio and northern Maine.


But at this projection (270 hours), there is still substantial uncertainty.   Only when we get within roughly 5 days (120 hr) will confidence be relatively high in the forecast.

To illustrate the uncertainty, let me show you are series of forecasts for the above humidity field for four different forecast projections, but verifying at the same time (1800 UTC 8 April).  Specifically, you are viewing an animation of 288, 282, 276, and 270-hour forecasts of sea level pressure (solid lines) and the moisture field.  

All have some kind of low-pressure system and a plume of clouds in the middle part of the country and it appears the solutions are converging.  But there are significant changes between the forecasts.  

For Seattle, the variations are quite large.


An animation of the precipitation forecasts valid for the same eclipse time is shown below.   Enough precipitation to get a Midwest eclipse watcher nervous. And not promising for western Washington.


Another approach for such a long-term forecast is to look at the forecasts of ensembles of many forecasts.  

Below is the North American Ensemble Forecast System (NAEFS) prediction of clouds over Dallas/Fort Worth Texas over time.  I put a red arrow at the time of the eclipse.  Remember:  an ensemble forecast shows the results of many different forecasts all valid at a certain time.

10 indicates total cloud cover.  The horizontal line shows the median cloud cover for that location and the yellow box around the medium shows the range of 50% of the ensemble forecast members. (remember that the median is in the middle of a distribution of many forecasts, as many above as below).

 Lots of clouds and lots of uncertainty at that location.


Anyway, if you are planning to go to the eclipse, don't expect perfect conditions and be prepared to move, depending on the closer-in forecasts. 



Northwest Wind Generation Collapses Again: Can We Blame El Nino?

 The latest Northwest energy generation statistics are available from the Bonneville Power Administration and they are sobering:    wind ene...