Lower Snow Levels & Long Range Maps

February 13, 2012

For the first time in about 3 weeks we’re going to see snow down into the foothills tomorrow afternoon and evening as a colder weather system drops in.  It’s a brief shot of precipitation and cooler air as a disturbance and surface low moves down along the West Coast.  We only get 6-8 hours of precipitation from around midday to evening; probably less than a quarter-inch here in the lowlands.  Sticking snow level drops to around 1,500 with this system, possibly as low as 1,000′ in the evening IF the precipitation lasts longer than expected.  As a result, I wouldn’t be surprised to see Coast Range summits snowy as we head towards sunset.

Then we clear out tomorrow night with more sunshine and dry weather Wednesday.

Several more weak systems come through an upper-level ridge centered just to our west over the next week or so.  I still don’t see a stormy pattern with deep areas of low pressure, heavy rains, low elevation snow, or any other real interesting weather.  Basically a ridge of high pressure in the upper atmosphere will remain just offshore at least through the middle of next week.  After that models diverge a bit.

The GEM (Canadian) keeps the ridge nearby through the next 15 days…here is the 15 day ensemble 500mb map for the 2nd to last day of the month:

The GFS is similar until about day 12, then has colder systems punching down south much closer to us with the ridge pushing farther west: 

The ECMWF is similar, although no signs of a big deep trough like the GFS on the 28th.

It’s interesting that the ECMWF has been doing very well with the general weather pattern for about 2-3 weeks now.  Remember that almost 3 weeks ago it was showing ridging for the first half of February and then retrogression with the ridging developing farther offshore the 2nd half of the month.  Not bad…

Here are the 4 weekly ECMWF maps from last night’s run.  This is the 30 day forecast run that we get twice a week.  One minor change over the run 4 days ago is that it’s holding the ridging closer to us for most of the next two weeks.  You don’t see too much troughing until the last 3 days of February.  Then the first 10 days of March appear to be a little cooler than average and maybe turning wetter.  If the ECMWF is correct, we are probably done with lowland snow unless we somehow squeeze out a wet morning snowfall with a colder trough passing overhead. 

Chief Meteorologist Mark Nelsen