Timing of Thursday snow
This is a quick Wednesday evening update to discuss timing of the snow Thursday. This NWS Sterling graphic is from their Winter Storm page:
It shows some accumulation by 1:00 pm Thursday, so road conditions could start going downhill around lunch time. This same page shows the bulk of the snow falling between 1:00 and 7:00 pm tomorrow which would pretty much trash rush hour traffic.
And for those of you who wonder how snow could accumulate given the relatively warm ground, the answer lies in the snowfall rate. The approaching surface low will quickly intensify tomorrow due to a kickstart from an upper level system. This will lead to something called “mesoscale banding” – akin to a thunderstorm squall line during the summer – which can lead to snowfall rates of several inches per hour. This in itself can put down snow faster than it can melt and wind up cooling the ground as well. In addition the intensifying low pressure will yank down colder air from the north which will also cool things off quickly tomorrow.
Buckle up! We’ll revisit things tomorrow morning to see if anything has changed.