The Return of The Blob

I was perusing the Facebook weather-sphere the other day, and KPTV chief meteorologist Mark Nelsen pointed out that the Blob had resurfaced dramatically over the past month in the Northeast Pacific. Taking a look at weekly SSTs, I’d say he’s onto something! Below are SST anomalies in mid February and mid March – you can see a weak Blob, but nothing out of the ordinary.

But last week’s SST anomalies? Yowza! Now that’s what I call a Blob! Thankfully this Blob is pretty shallow and could disappear just as easily as it has blossomed.

Also note the symmetrical Blob in the Southern Hemisphere east of New Zealand. This feature was also visible in February and March, and, like its northern counterpart, strengthened over the last month. Maybe we can call it the bolB?

Given that we are approaching summer and the more tranquil weather associated with it, my guess is that the Blob will persist on-and-off throughout the next several months, but will NOT evolve into the mega-blob we saw in 2014 and 2015 that had disastrous effects on sea life and resulted in the 2014-2015 winter having the worst snowpack on record for many lower-elevation sites in the Pacific Northwest (such as Snoqualmie Pass) due to the extremely warm temperatures. But I wouldn’t rule out something like we saw last year, with warmer-than-average nighttime lows during periods of onshore flow. The Blob causes higher-than-average dewpoints offshore, and because water vapor is a very effective greenhouse gas, we had much milder nights than usual last summer, even though our high temperatures were less than previous summers.

The weather this week and weekend will be pretty typical for spring; fleeting periods of sun interspersed by weak/moderate systems bringing batches of showers ashore. Tuesday/Friday will be our main calm days, with showers Wednesday/Thursday and heavier showers this weekend. This weekend’s system could bring some gusty winds to the lowlands and snow to the mountains, but it won’t be anything out of the ordinary for spring.

We currently have a strong but relatively “flat” ridge in the Eastern Pacific, bringing well-above-average temperatures to California and the Desert Southwest but allowing a 150 mph jet to stream over the top of it into Western Washington.

This ridge will “amplify” tomorrow and send the storm track further north, giving the Pacific Northwest a pleasant Tuesday with cloudy skies for Western Washington and partly cloudy for the Portland metro area. Highs should be in the lower 70s for the Portland metro area; average this time of year is 64.

A weak system will primarily impact Western Washington on Wednesday, with post-frontal showers lingering Thursday. Interestingly, the UW WRF model shows precipitation dramatically increasing Wednesday and especially Thursday afternoons over NE Oregon and Central Idaho due to convection associated with this system, bringing up to 1.5 inches over both days for some of the favored, higher-elevation spots.

Friday will be dry as another weak, transient ridge moves over the Pacific Northwest, but a stronger system may make landfall on Saturday, bringing gusty winds and bursts of moderate-to-heavy rain that should persist through Sunday. Snow levels will drop to around 3,000 feet on Sunday, which would make for some great late-season skiing if the resorts were open! As is, it’ll be good for slowing our snowpack melt this spring; not only will it add to the existing snowpack, but new snow isn’t as “primed” to melt as your standard watery, coarse, dense spring snowpack and it will take additional energy to melt.

Some models hint at a transition to warmer and calmer weather next week as a strong ridge builds over the Western US. If the warmer solutions come true, we could be talking about upper 70s or potentially even 80 next week in Portland, but there’s still a lot of time for that to change.

In the meantime, enjoy our springlike weather, and be sure to download a radar app for your phone if you don’t have one! They come in handy for dodging those springtime showers. 🙂