On To “Showers & Clearing Periods” Weather

Okay, now that the steady precipitation has moved on, we’ve had our rain and it’s time to cool the atmosphere a bit.  So our best chance for a little sticking snow here in the lowest elevations will be the next two mornings.

This is VERY similar to what we saw last Saturday; hail, downpours, sun, maybe thunder, and just some plain exciting weather.  I’ll give it a 50/50 chance of measurable snow at the Portland Forecast Office, maybe a 30% chance of an inch or more.

Chief Meteorologist Mark Nelsen

5pm Update: Rain Continues

Looks like that roast is totally cooked (see yesterday’s post); no snow event this afternoon/evening in the lowest elevations.  It’s been too warm not only at the surface but also above.  Better chance for snow late tonight and tomorrow morning.  6am-10am should be real interesting.  Here’s our forecast for this evening:

2pm Update: Mainly Rain So Far…

Things are working out well this afternoon with mainly rain showers falling below 1,500’ west of the Cascades.  At times some snowflakes have been mixed in, but all temps are between 36 & 43 degrees across the metro area and even the top of our transmission tower is above freezing now.  

NOW-7:00 PM:
Rain picks up, turns steady, could briefly mix with snow anywhere, but probably mainly or all rain.  Breezy too.  Temps near 40.

 7:00 PM – 11:00 PM: 
The rain backs off to light showers, mixing with snow up above 1,000’ later.  No sticking in the metro area, but turning snowy over Coast Range and Cascades.  Temps 35-40.

The Rest of the Night & Morning Commute: 
Rain and snow showers, snow could briefly stick anywhere by the time we get to the morning commute; very similar to what we saw Saturday.  Everyone will at least see snow in the air for GDO.  Higher elevations get 1-3”, mainly near and above 1,000’.

 Chief Meteorologist Mark Nelsen

Tuesday Morning Update

We still don’t expect sticking snow TODAY here in the western Valleys…it’s just a little too warm.  Take a look at our morning RPM model prediction of snowfall from 4am today to 4am Wednesday.

If anything, I think it’s a little underdone for the heavier snow showers coming in later tonight and the Wednesday morning commute.  This map would imply no snow even up on the West Hills, Mt. Scott, Bald Peak etc.  As mentioned in yesterday evening’s post, I think ANYONE could see a brief dusting early Wednesday morning, but a trace-3″ is sure possible near and above 1,000′ by tomorrow morning.

In the short term, one band of showers has raced well ahead of the main rain band (still offshore), and with it’s early arrival we could easily see snow mixed in with the rain as we continue to gradually warm up.  10am temps say it’s already too warm to stick; up around 37-40 at all the official observing sites.  Plus, I see a milder south wind arriving right now in some of the hills like Mt. Scott and the West Hills.  Good news if you DON’T want snow.

The forecast for increasing afternoon rain still looks good, but Wednesday morning should be snowy, at least in the air, for most of us.

Chief Meteorologist Mark Nelsen

Snow Arriving In Coast Range

Looks like the first band of precipitation is falling as snow in the Coast Range this morning.  So the snowy weather is beginning up there and will continue through Thursday.  It may just turn to rain, especially at these lower spots, from this afternoon through early this evening.  But then all snow after that tonight and most of tomorrow. 

Here are the two ODOT cameras from Lees Camp along Highway 6 and Murphy Hill on Highway 18:

Chief Meteorologist Mark Nelsen