You are good until March 23rd is when it is 9kWh per square meter. That seems to be the magic number for black bodies to insta-melt snow. When I lived in Philly I had a sun angle of 52º and falling snow, and the following day, in the extra bright sun, it was only marginally slushy. Sun angle season is only a real concern for folks south of the 40th in early-mid March.

Thirty-five years of pure unadulterated disappointment will do that.

Not about latitude, just about temperature. The March 1993 superstorm produced a foot of snow in Birmingham, AL on the 12th. They're at 33 degrees latitude. We just have a tougher time getting high end cold air advection through the gorge by March, but it can/has happened. March 2-3, 1960 produced subfreezing highs in Portland and plenty of all day snow on the roads.

With a doughnut hole over Jimmy's Pasta and Pizza.

Locked is strong word my friend.