Tuesday, 8 December 2015

Post 65: Atmospheric Rivers and the West Coast!

At some point in the last year I learned about atmospheric rivers, or the thin bands of warm tropical air that stream from the tropics up to brush the West Coast. Due to their warmth, they hold a lot of water, and are primarily responsible for some of the major precipitation events we get on the coast.

For quite some time, I thought that one of the colloquial terms for atmospheric rivers—pineapple express—was interchangeable with the more general term, but I was totally wrong! Pineapple express is reserved for especially those atmospheric rivers that we get on the West Coast, because the warm air comes up from Hawai'i, where pineapples are grown! How neat is that? (Not to mention, pretty cute!) 

So, all of this became relevant for me earlier in November where we had some significant rain and wind events, and then over the past few days I was surprised by how warm (almost tropical) the weather began to feel, and so out of curiosity I did a bit of internet searching around, and came across the US National Oceanic and Atmospheric Administration's (NOAA) Automated Atmospheric River Detection tool (AARD). It is the coolest!

Here's a screen capture of what is currently happening, and explaining the very warm but pouring, pouring rain we're having! 

The current and 1-day forecasted atmospheric rivers from NOAA's Automated Atmospheric River Detection tool.
While I'm certain that Washington and parts of Oregon are getting even more rain (the warmer the colour (red, yellow, magenta), the more rain is coming down, and the cooler the colour (green, blue), the less intense it is, the southern tip of Vancouver Island is definitely in the 3cm band. The y-axis across measures the latitudes, and the left x-axis on the graph measures the longitude, while the right x-axis gives you the anticipated cm of precipitation (usually rain).

The righthand graphs seem to show wind circulation patterns, and I do not understand the middle Binned by Latitude graph, apologies. 

The above images are static presentations of what the model outputs are. Of course, air circulation and wind movements are constantly changing. We probably have some kind of interesting interaction of high and low pressure systems between our westerlies winds at this latitude, and the tropical trade winds, but for a quick look at these air circulation patterns in motion, check out the Atmospheric River (AR) Animation Loop on the right hand side of NOAA's main page on ARs.

As someone who likes to know what's going on, having stumbled upon NOAA's AARD was a real highlight in the past few days for me. It's helped to connect my real-time observations about the weather with my conceptual understanding of atmospheric rivers, and this is wonderful to me.

Productive and fun breaks from thesis writing are to be encouraged, and my excitement about this extra-curricular learning definitely helps keep up my energy for writing! 

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