March wraps up, late season frost, gardening outlook, plus a winter wrap

Plenty to talk about this evening! It’s been a bit busy at work recently, plus the weather itself really slows down in spring around here. The result is fewer posts now through October.

WINTER RECAP

First, we had a great Oregon AMS meeting about two weeks ago. I presented a recap of winter 2021-22. You can find the whole presentation here: https://oregonams.files.wordpress.com/2022/03/winterwxmeet2022.pdf

I think Karl Bonner (an AMS member) stated this best...this past winter was “abnormally normal”. He meant that in the end temperatures and precipitation departures were quite close to normal. It won’t be remembered as warm/cold/dry/wet...just a normal winter. But remember how mild it was through the first week of December, then 3-4 weeks of stormy/snowy/cold weather, then just about nothing for the following 7 weeks. That pretty much wrapped up winter. Here are two of the graphics

I think what is most surprising is that once again a La Nina winter did not give us a cold/wet winter. We (meteorologists and media) need to be more careful with our wording leading up to these winters. We need to emphasize that not all La Ninas give us a stormy/wet/cold winter and that’s never a guarantee. That said, we have done just fine with snowfall in Portland lately. 7 winters with at least a LITTLE snow each year. Everything you want to know about this past winter is in that presentation link above.

MARCH SO FAR

March sure didn’t turn out cool & wet, but near normal or drier than average for many of us in Washington and Oregon. I’m feeling confident these numbers won’t change much in the next 27 hours.

Temperatures have been a bit warmer than average across most of the West this month.

This has been terrible for our mountain snowpack. Take a look at the numbers! Bad news everywhere except extreme NW Oregon and into western Washington.

I’ve had lots of questions about the “last frost” or last 32 degree temperature in spring. Here in Portland, typically it’s about this time of year. But in outlying suburbs it tends to be in April. That’s a 30 year average. This graphic shows the last frost each of the past few years in Portland (blue) and Hillsboro (pink). It sure shows the cooler nights in outlying areas doesn’t it?

I wouldn’t be surprised if some of the colder spots see frost either tonight or the middle of next week, but there’s a good chance the urban area is done with frost for this season.

GARDENING OUTLOOK

It has been pretty good weather for gardening so far this spring. Not crazy warm, but a bit warmer than average. And we’re not seeing week after week of soaking rain. I sure DO see a soaking coming up Sunday PM through Tuesday...maybe an inch of rain in the western valleys. I live in a cool spot (compared to much of the metro area), but I think I’ll get the cool weather stuff going: spinach, carrots, beets, etc...

EARLY APRIL WEATHER

I still don’t see any long rainy period as we head into the first week of April either. We get a wet westerly jet early next week, then some ridging mid/late week, then occasional rain after that. ECMWF ensembles give the Willamette Valley less than 2″ rain in the next two weeks, and this is often overdone. One item that sticks out is brief and sharp upper-level ridging around next Wednesday-Thursday. The 6 hour maximum temperature product from the ECMWF ensembles really shows the good agreement with that idea. It might be our first episode of 75+ degree weather.