Now that we are within 18-24 hours of our snow (or no snow for some) event, the general plan is coming together nicely. This evening it was time to put some numbers on the table and put a forecast plan together. Let’s hope the actual weather decides to stick to that plan this time! I’m sure there’s going to be some wrinkle at the last moment…there always is.
TRENDS I’M SEEING THIS EVENING
- The stationary front is situated slightly farther north and the surface low pressure system that moves across the Northwest is progged by all models farther north than morning runs, and this has been the trend for at least 24 hours now.
- This means the snow/rain line is farther north = light snow totals from the metro area south into the Willamette Valley.
- If this is correct, Super Bowl travel plans within the metro area may be just fine with a wet snow/rain mix falling all the way through the evening.
- The possibility exists that there will be little to no snow on the ground in the metro area by Monday AM. I give that about a 30% chance, thus the TRACE-3″ forecast
- Areas farther north really get dumped on…Longview to Olympia could be big winners with that elusive one foot of snow in that area.
FORECASTS I USED ON-AIR TONIGHT
Note there is a good chance Astoria/Tillamook get far more snow than Salem? That’s because the heavy snow falls just north of the front and specifically just north/northwest of a low pressure center as it moves onshore. If you are south of the low pressure area, than at least part of the next 36 hours you’ll see rain. In fact the evening run of the trusty ECMWF did exactly that, changing snow to rain in the metro area tomorrow evening even in the hills. If that model is correct we’ll see almost nothing (snow) out of this in the lowest elevations around the metro area.
WHAT COULD GO WRONG WITH THE FORECAST?
Here’s the most obvious wrinkle. If the front decides to sit about 70 miles farther south than expected and the low tracks inland well to our south, Portland gets a huge snowstorm from tomorrow midday through Monday AM. But as I mentioned, the trend is the opposite direction.
Be aware that between 8am and 1pm there’s a decent chance we switch to lots of snow mixed in or even all snow in the metro area. But with temps above freezing I think a large area of sticking snow on roads is unlikely. Of course it’ll be close and roads WILL turn snowy high up in the hills. Factor that into your Super Bowl travel plans.
I’ll be here at work from Noon-11pm; likely doing some live Facebook videos during the afternoon while we are not on the air. You can find those on my feed MARK NELSEN page over on the right.
Chief Meteorologist Mark Nelsen