The school delay/closure forecast has been updated in a Premium forecast, which you can purchase here. Parts of it have been freely released below as well:
The forecast remains generally the same. 4-7 inches of snow at the coast, 3-6 inches inland. However, I am adding the forecast of 2-5 inches far inland, as I don’t see far inland getting more than 5 inches of snow. Only the GFS model shows that potential, with the RGEM hinting at it as well, but I would be very surprised if anywhere far north of Interstate 84 saw more than 5 inches of snow. The HRRR shows the radar looking like this at 9 AM tomorrow, and the wintry accumulations looking like this. That’s already 4 inches of snow at the coast, 3 inches inland and 2 inches far inland. That’s part of the region I differentiated far inland areas. Still, with that snow falling at 9 AM at that rate, impacts will be similar across the entire region even if a couple more inches of snow is falling at the coast.
The RAP guidance is similar as well, showing at least half an inch of liquid falling at the coast after the turn to snow, which would indicate at least 5 inches of snow falling. I am still a little worried about snow taking a little while to stick after the rain, but once the snow starts falling heavy enough that should not be much of a problem, especially as temperatures crash below freezing and any standing water turns to ice. It is this timeframe past 10 AM that I am actually most interested in the weather models, as most models do not show much easing of snowfall by 9 AM, which is why I had previously upped the snowfall totals, especially at the coast. Each run of the RAP continues to show more and more moisture for the area, and though .1-.2 inches of liquid looks to fall as rain, the rest looks to fall as snow, making me believe that we should not have much trouble falling into the forecast snowfall ranges. Surface temperatures inland drop below freezing between 1 and 2 AM, and at the coast between 2 and 4 AM. I expect the entire region to be below freezing by 4 AM with some of the heaviest snow falling between 4 and 6 AM helping to quickly ice over and cover in snow all roadways. Thus, travel goes significantly downhill past the 4 AM timeframe, and will take awhile to improve as temperatures stay below freezing for awhile tomorrow.