The Ides of March will be wet! Weather pattern change arrives this weekend

Published: Mar. 10, 2022 at 9:49 PM PST
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Enjoy the sunshine tomorrow and Saturday morning, because we are headed back to “normal” March weather starting Saturday afternoon. Of course, that means lots more clouds, rain, and occasional gusty southerly wind.

Make sure you get outside in the next 36 hours. Tomorrow WILL be a fantastic early spring day and noticeably warmer than today. I think we’ll hit 60 for the last day of the workweek and it won’t be quite as cold in the morning. Then on Saturday we’ve got a nice setup where a cold front suddenly arrives in the afternoon. By that I mean we’ll have sunshine, then quickly change to clouds and rain. That’s instead of steadily increasing clouds eventually leading to rain. I’m hoping to get outside in the morning and enjoy the early sunshine.

A strong cold front arrives Saturday afternoon/evening with solid rain and breezy southerly wind. It’s time for us to see a soaking again. Rain has been about normal for 1/3 of the way through March.

(KPTV)

Looking ahead, it’s obvious that we won’t be seeing a dry March this year. Do you realize that March has been drier than normal the last four years? The last real soaker was March 2017

(KPTV)

The last month has been dominated by strong upper-level ridging near the West Coast, or at least out in the Eastern Pacific. Most of the time we’ve just seen weak systems coming at us from the northwest or north. Look at that huge positive anomaly filling the Eastern Pacific from early February to now.

Wet March Ahead
Wet March Ahead(KPTV)

But the weather pattern changes these next two weeks. The ECMWF ensemble mean forecast for this Saturday through Saturday the 19th shows an upper-level low in the Gulf of Alaska and higher than normal heights to our south = strong westerly jet stream (for March) sending numerous wet weather systems inland.

(KPTV)

That trough is still there as we head into at least the first part of Oregon’s Spring Break.

Wet March Ahead
Wet March Ahead(KPTV)

And of course, the effect is lots of rain; well above average throughout the Pacific Northwest. Although I should point out that westerly flow isn’t the best for big snow/rain east of the Cascades. We want to see upper-level lows pass overhead for significant precipitation over there.

(KPTV)

In the short term, a relatively deep surface low pressure system will move inland Saturday night. Typically that could give us strong wind, especially now that we’re in spring and wind can “mix down” more easily (no inversions). But the low is weakening as it approaches the coastline. So we’ll see gusty wind along the coast and also inland, but just a few power outages here and there.

(KPTV)

How much rain? I think the WRF-GFS model through St. Patrick’s Day is pretty reasonable. Around 2″ or a bit under in the western valleys of Oregon and SW Washington

WRF-GFS Rain Forecast (UW)
WRF-GFS Rain Forecast (UW)(KPTV)

Snow levels will be varying between 2,000′ and 5,000′ over the next week or so...it’s catch up time in the Cascades and it appears we’ll see up to 2 feet of snow by late next week

Wet March Ahead
Wet March Ahead(KPTV)

So...to summarize, get all your outdoor projects wrapped up; we’re entering a wet week...or two.