Dry Wednesday through Friday
We will get a break from today through Friday so lets look a little longer…. We have had a pretty soggy past few days punctuated by some very heavy periods of rain. In total if you head to the full almanac data pages you’ll see we received about 57mm of rain since last Thursday, the 12th.
That’s a fair amount! Our normal (1981-2010 Robertson Creek) rainfall for the month of September is 61mm. So we’ve received our monthly allotment in 5 straight days. The normal was a little higher in previous periods, the 1961-1990 period at Robertson Creek had a normal rainfall amount of 81mm. And the normal from the Somass station was 71mm for the same 1961-90 period.
Fall and Winter, Blob style.
If you’re wondering what the Fall and Winter is going to be like, you only need to look at what is out in the Pacific.
I tweeted a video this morning using the excellent Climate Reanalyzer website which shows how our oceans have warmed in general since the 1980s.
If you’re trying to recreate it, the settings I used in the drop downs was OISST v2, World, SST Anomaly, Monthly. And it’s the image area at the *bottom* of the page that changes. If you go there you’ll be able to see the last “Blob” event in 2015 (we talked about it back then here). In fact I noticed a similar but weaker pattern in 2004/2005.
The warm pattern seems to start in summer in the western Gulf of Alaska and down the west coast of North America reaching out to the Hawaiian Islands (the Pineapple Express route). It lasts through winter, and then continue into the following spring with warm water staying in the Gulf of Alaska and clinging to the West Coast … normal winter cooling is interrupted.
Here are August 2004 and May 2005 (click for larger).
Below are September 2014 and April 2015. You can see it is similar to 2004/2005 but much stronger.
And finally below is September 2019, as of Monday courtesy of current data from the NOAA.
The scale is a little different, but you can clearly see the area of warm water along the Alaska panhandle stretching west, and the ‘blob’ of warm water off of Western Canada and the USA. The pattern has returned.
Look at that neutral El Niño region!
What’s the most striking about that last image isn’t the blob, but the string of cool water extending from South America westward, I’ve highlighted it below.
That is the area of ocean where forecasters look for signs of El Niño and La Niña patterns. Warmer than normal (red) waters there would indicate an El Niño pattern, cooler than normal would indicate La Niña. You might look at the image above and say “well that looks like cold water!”, but most of the region is actually in the -0.5ºC to +0.5ºC temperatures, it just looks colder because the entire rest of the North Pacific is yellow.
That gives us hints for the Fall and Winter. Heavy rain and stormy at times, but likely warm and possible drought.
Without El Niño driving major precipitation and major warm weather, we can probably expect a fairly normal fall and winter. The blob will tip the scales to heavier rain events when we get them thanks to the added energy and moisture in the waters near us. But we could end up in April and May with much less rain overall than normal and the overall warmth will likely mean less snowpack in the mountains. That was certainly the pattern of the 2014/2015 Blob event. It also led us into one of the worst forest fire seasons on record.
The December, January, February forecast from the seasonal models also has generally higher than normal temperatures. But above normal precipitation. This might be an indication of that heavy rain/storm activity we could get thanks to the Blob.
So when it rains hard this fall and winter, and you can’t go skiing. Blame the Blob!