SnowForecast

Good news!  With less than 24 hours to go, models have come into very good agreement this morning.  They agree a 2nd winter storm will track through Oregon late tonight and Monday.  They also agree the storm center (lowest pressure) comes onshore around Cape Blanco Monday morning and moves northeast to around Baker City by evening.  Heavy snow will develop on the north side (within 100-150 miles) of this low center as it tracks through the state.  All models agree on this now so the only questions are: how far north do we get heavy snow (4″+), and how far north will ANY snow make it?

Here are my forecasts; reasoning follows after

PORTLAND/VANCOUVER METRO AREA FORECAST

(This includes all areas from St. Helens/Woodland down to a Newberg/Wilsonville/Mollala line)

  • Rain showers late tonight turn to steady snow between 4-7am Monday and it sticks
  • Expect a Trace to 2″ on the ground for the morning commute.
  • Temps barely drop to freezing, so freeways/highways may not turn completely icy
  • Light snow continues through the day, a total of 1-3″ heavy/wet/slushy snow by the time it ends late in day.
  • Late February sun angle means roads warm well above freezing by 10am; I DO NOT EXPECT THE METRO AREA TO BE LOCKED IN FROZEN ROADS ALL DAY
  • MAIN ROADS/FREEWAYS WILL LIKELY BE WET MIDDAY & AFTERNOON

I wouldn’t cancel ANYTHING until we see exactly what happens in the morning.  If we only get 1″ of sloppy/wet snow (low-end forecast), driving will be okay all day long.

COASTAL TOWNS & LONGVIEW/KELSO

  • Either dry or just showers/flurries from Pacific City north and Longview/Kelso
  • Little or no impact on your life there
  • Trace-2″ Lincoln City to Florence.  Very wet/slushy, not too much impact on roads

WOODBURN/SALEM/SILVERTON (CENTRAL VALLEY)

  • Heavy, wet snow 4am-Midday
  • Snowy roads, especially morning
  • 3-5″ total by afternoon, a snowstorm!

ALBANY/CORVALLIS/EUGENE (SOUTH VALLEY)

  • A snowstorm!
  • 4-8″ by afternoon, same starting time
  • Snowy roads much of the day

COLUMBIA RIVER GORGE

  • A snowy day
  • 3-8″, heaviest middle/east end, lightest west end
  • Gusty east wind blowing/drifting snow at west end

TECHNICAL WEATHER GEEK DISCUSSION

It was great to see models fall into line the past two runs with that low pressure center.  It’s also nice that the WRF-GFS and ECMWF are much closer together with the snow totals.   Just looking at the precipitation forecast from the ECMWF you get the picture and see why there’s a much better chance for a big snow event central valley southward.  2″ of precipitation at Eugene but pretty much dry Astoria to Chehalis.  What could go wrong???  Praying that this precip shield isn’t 100 miles farther north = biggest February snowstorm on record, a foot of heavy/wet snow in the metro area!  Or that it’s 50 miles farther south in the end and we have a regular Monday with flurries/showers at times with NO snow.

12zECMWFPrecip

This converts to a snowfall map like this, Eugene to Roseburg gets BURIED by a major snowstorm tomorrow, over a foot!  This would shut down I-5 and bring lots of power lines down in the south valley.  Remember I said SOMEONE between Olympia and Roseburg was going to get a big snowstorm?  At this point Eugene/Roseburg are ground zero.

Euro_Snow_SunAMForecast

Meanwhile the GFS/WRF-GFS had us dry (no snow) on last night’s run, but now has decided to turn things a bit wetter (more white).    That’s ZERO to 2″ metro area, and 8-14″ Eugene to Roseburg!

or_snow24.48.0000

Here are a few more models…the GEM, GFS, HRRR, & RPM.  All produce very little snow in metro area.  Which actually means the ECMWF is the only model giving us significant snow in Portland.  So once again I’m trusting the “King Euro”.  Here are snow totals through 9am tomorrow, when all models except Euro say we’re pretty much done with snowfall

Notice I’m hitting the “roads won’t be that bad with 1-3″ of snow” in the metro area tomorrow pretty hard?

That’s because the last few days of February we get a lot of energy from the sun even through thick cloud cover.  A good example is this morning.  Snow fell in many hilly parts of the metro area.  The pavement surface temperature at Division/I-205 and Sylvan/US26 both dropped to right around 32 degrees at sunrise with snow showers.  Yet at 11am they are both already up to 40-42 degrees.  The result is that less than 2″ snow, or snow that doesn’t fall very heavily during the day won’t be able to accumulate on pavement after about 9am all the way through about 7pm.  Now if it just DUMPS snow, (central/southern valley) it can still stick.  But at this point I don’t see that in the Portland metro area.

BEYOND TOMORROW AFTERNOON

Cold east wind continues to blow tomorrow night through Wednesday, so with any clearing, those wet roads freeze for the Tuesday morning commute.  Some models bring a little more precipitation over us Tuesday night or Wednesday AM.  We’ll see if that’s the frozen variety or not.  Clearly the northern part of the jet stream wants to hang on into early March.  We still have another week of cold weather ahead…

Chief Meteorologist Mark Nelsen

Chief meteorologist

Recommended for you

Load comments