Potential atmospheric river returns rain to the Seattle forecast later this week

Well, look who is back in the forecast! Is that an atmospheric river we spy?

I did not have going an entire half month without rain in the middle of a La Niña winter on my Seattle weather bingo card this winter, which is too bad because it totally looks like it’s going to be a hit. Sunday makes 13 days in a row with no rain; that streak will make it to 15 days and maybe even 16.  The record for January is 15 set in 1963.

(The winter record is… 21 days! Set in December 1985. But at least that dry streak came off the massive Thanksgiving week snowstorm a couple weeks earlier so winter fans were probably even like: OK, we can deal with this.)

But lo and behold the current dry streak’s days are numbered! Eventually…

Not so in the short term, it’s still a sunny Sunday and dry Monday and Tuesday (though a bit more clouds running around.)

MEGARIDGE has certainly been strong, but it’s aging.

A weak weather system coming in Monday won’t have enough survival power to defeat MEGARIDGE and bring rain, just clouds.  But it’ll weaken its defense back to just “megaridge”. Or maybe even ‘mid’ridge for all the kids out there reading this.   

Then, an incoming system on Wednesday will finally strike a mortal blow, allowing the first rain to fall around much of Western Washington in more than two weeks.

With MEGARIDGE gone, the door is open and in come several more weather systems at the end of the week and into the weekend, long range forecasts suggest.

One of them may even qualify as an “atmospheric river” — the folks at UC San Diego who keep track of such things even give it a potential 3 out of 5 rating, though with river levels essentially not fed much of anything in the last two weeks, flooding is not any concern.

The 7 day river forecast maps are all green except for a yellow over the Skokomish.

The systems are trending mild which means they’re not looking like the best mountain snow producers. Meh. But winter will at least look a bit more… normal.

In the meantime, sun fans soak up the Sunday and absorb the peeks of lingering sun early in the week. Grayer weather is back on the way.