Windsday 2019

Happy Windsday!

It's been years since we've experienced a proper jet stream-induced Windsday.

Consider the jet stream, a fast-moving horizontal river of air at approximately the 300 millibar level (about 30,000 feet above sea level). Bernoulli's principle explains that, where the air is flowing fastest, the air pressure is lowest. It's a positive feedback loop because the jet stream sits over the regions of the lowest pressure and the pressure is lowest where the air is moving fastest. It's like a mountain pass that allows the air to blow through--only this pass can move and change course.

High pressure systems are associated with warm and sunny weather. Low pressure systems are associated with 'disturbed', cloudy and stormy weather.

Last night, I read several tweets from journalists remarking about the ripping Santa Anas. It didn't feel like a Santa Ana--too cold and not dry enough. I quickly took a look at the California Regional Weather Server Jet Stream Analysis webpage.

Universal time/UTC/Z is 7 hours ahead of PDT so this was 23PDT 9 APR 2019.  Note the peak of 136 knots right over LA in the jet stream analysis.

We've lived with the Ridiculously Resilient Ridge for so long, we forgot what it feels like when the jet stream dips south over us.

It seems like the satellite image overlay is no longer active at either CRWS or the Naval Research Lab links I provided earlier.  Research funding scarcity and the privatization of data from public satellites was just too much to overcome.