A very dry February, plus a cool (or cold?) spell next week

9pm Wednesday…

This has been another uneventful week weather-wise. A mix of clouds, sun, and just some sprinkles/showers here and there.

Of course, February has been very dry, just .26″ so far this month. Just 12 days to go!

(KPTV)

I’ve been curious, wondering if a dry February means anything for March. Basically, what’s the chance that we could turn wet? I found the 5 driest Februarys in Portland’s history (records go back to 1940 at PDX). Notice we are still about 1/2″ below the driest February on record (.72″ in a chilly February 1993). So it’s POSSIBLE we have a record dry February, but that would require less than 1/2″ rain in 12 days. We will see… The other driest Februarys were 1964, 1988, 2013, & 2001.

(KPTV)

Then I looked at the 10 driest Februarys and what happened the following March. I’ve assumed that most of those turn wet, but that’s not the case. 3 of them DID turn wet. 3 were just a bit drier than normal, nothing too dramatic. But 4 stayed very dry (1941, 1964, 2013, & 2020). That leaves 7 generally drier than average, and 3 wetter. That implies we have a better chance of staying dry plus there’s sure no guarantee that we’re about to get soaked.

(KPTV)

COOLER WEATHER AHEAD

Models are advertising the strong ridge just west of us in the eastern Pacific to generally remain in the same place the next 7+ days. But one relatively small change could have a big impact on our weather next week. The current view:

Jet Stream Right Now(KPTV)

Then next Tuesday. See the change? Ridge is still there…

Jet Stream Next Tuesday(KPTV)

But the ridge has amplified north a bit in the Eastern Pacific, allowing a sharp upper-level trough to drop south out of Canada. This is a very cold pattern for us. Now this is the ECMWF model, and other models are not as deep/sharp with the cold trough dropping in over us. But they do all have some sort of cooler system dropping south Sunday-Monday. How chilly might we get in this setup in late February? 850mb temps forecast from the ECMWF drops Portland down to around -9 to -11! GEM model is significantly warmer and the GFS is in-between.

It’s possible to have high temperatures in the 30s as the ECMWF shows (coldest since Christmas Break), or just a weak push of chilly easterly wind Tuesday/Wednesday might just keep us around 45 degrees (no big deal). It seemed prudent not to go “whole hog” on a big blast of cold air early next week for now. This is our forecast this evening:

7 Day Forecast Temps(KPTV)

So…after our false spring weather of last week, it appears “winter” is on life support now, but wants to make one last push to stay relevant early next week. We will see how things play out. Regardless, the much drier than normal weather continues through NEXT week too. Maybe another half-inch rainfall by next Friday at best. It does look good in the Cascades though! Check out the snow for the all-important President’s Day Weekend

(KPTV)

I will be off through Sunday, but if something really good is in the works (snow!) I’ll get a blog post out Sunday. Chief Meteorologist Mark Nelsen