The short term forecast is simple this evening. Cold front plunges through tomorrow morning, then cold showers drop in behind. This airmass is quite a bit more stable than previous post-frontal airmasses; it’ll be tough to get heavy showers or thunderstorms.
Not much to talk about Saturday either, just cold with some brief sunshine, lots of higher clouds later.
Sunday through Tuesday is the real challenge. Models (especially the GFS) have become more splitty and slower with the upper-trough to our west over the last 2 days. Sunday we are on the southern edge of sloppy warm-frontal rain. Light stuff and maybe some drizzle too. Boring! Monday the bulk of the rainfall may lift to the north. Then Tuesday afternoon a secondary system develops well to the southwest and actually gives California a good dose of rain by Wednesday AM. I see the 00z GFS now has NO rainfall over PDX from midday Sunday until Tuesday night! That’s quite a change from 48 hours ago when it looked like a very wet period with even a possible windstorm setup Tuesday.
The split should “heal” a bit later next week.
Okay, I’m off for one day Friday. So does that mean a surprise snowfall to relatively low elevations? Could be. Seems like each time Drew Jackson fills in for me we get some sort of weather event.
Chief Meteorologist Mark Nelsen