The snow forecast has been pretty good this morning in western Washington, with parts of central Puget Sound up 1-2 inches as predicted (see observed snowfall recorded this morning by the CoCoRahs collaborative network. ).
This is a very difficult forecast, with marginal temperature. The kind of forecast that we couldn’t do 15-20 years ago.
But there is a downside to this increased forecasting skill, a negative impact that hit me directly this morning (see below). I’m REALLY looking forward to a cake and a cup of coffee before coming to work at UW. Bad luck.
Another snowfall is imminent in western Washington…..and another difficult forecast.
Why is it difficult? Because major weather models don’t agree on a key weather feature, and we’re near the temperature boundary west of Washington and Oregon.
There have been slight differences in the location of the low pressure trough along the Washington/Oregon Coast affecting rainfall and therefore snow in western Washington.
Central Europe expected more snow in the heart of Puget Sound, but now the latest US GFS model simulation (initialization 6 hours later) has joined the snowy fun.
Below are the cumulative total snowfall forecast for both models through 4 p.m. Tuesday.
Central Europe shows more than 5 inches for Seattle and Portland, except right near the water.
The updated US GFS model has a little less (note the different proportions) but is still a few inches taller than Seattle and Portland. The mountains are hammered in both.
When will the snow come? Tuesday morning.
Central Europe is quite confident that snow will appear in our future. Below is the cumulative total of snowfall in Seattle from the large and excellent EC aggregator of multiple forecasts. Each line represents a different forecast run. Almost every run turns blue (snow). Purple is more than that.
The average of the Seattle snow aggregation forecasts is shown below (light blue bars)–approximately 5 inches of snow is expected. Solid line is a higher resolution prediction…. even more so.
Tomorrow I will provide more details based on higher resolution local simulations.
One final note: I ask that no one tell Grand Central Bakery about the forecast. The reasons are obvious.
