The below abbreviated Note contains part of our Premium forecast that goes through our expectations for the storm tonight. Generally, 1-2 inches of slushy snow is expected to accumulate across inland portions of the region with a coating-1 inch expected at the coast. Far inland areas around/primarily north of I-84 could see isolated amounts as high as 3 inches, but generally 1-2 inches inland looks likely. Precipitation is a rain or rain/snow mix through much of the evening and early overnight hours, not accumulating. Around 1 AM enough snow begins mixing in far inland to start to see the first accumulations, and a burst of moderate snow between 2-6 AM is what drops that general 1-2 inches of snow on top of any rain that falls. Surface temperatures far inland fall below freezing around 2 AM, getting below freezing across all inland areas by 4 AM and then the coast by 5 AM. As they drop below freezing we turn to snow and that snow begins to stick, with all snow moving out between 5:30 and 7 AM from west to east.
As temperatures fall below freezing we will see standing water and slush turn to ice, which is what has us so concerned about slippery conditions tomorrow. At this time the forecast is decent confidence as models agree on exactly what occurs quite a lot, it is more the resulting impacts that are harder to determine. We see a strong consensus for about half an inch of liquid falling across the region, at least half of which will either be rain or snow that is unable to stick. The real question is how much ice can form once temperatures drop below freezing and how much snow can stick, with the slightly colder scenarios allowing for sizable travel impacts down to the coast tomorrow that linger through 7-8 AM, and the slightly warmer scenarios keeping the coast from seeing many impacts while it is the inland areas that are most slippery.
