As expected, most of the precipitation will hold off until after the evening commute. We do have some echoes in the Valley this afternoon but there haven't been any ground confirmation of these isolated echoes. We are moistening up the atmosphere at this point. Temperatures reached the mid 30's today and have already fallen back below freezing in some areas (I'm at 31.5 degrees now).
We're still looking to get minimal precipitation - that hasn't changed much. The National Weather Service in Sterling has issued a Winter Weather Advisory from 8PM Mon to 9AM Tues - in line with the times we were talking about in the last blog. The best chance of icing is going to occur from 10PM to 5AM. By 8 or 9am, temperatures will be approaching the freezing mark and eventually crossing over to above freezing from south to north. Also, most of the precip will bypass us to the east so we're not looking at extended periods of any one form of precipitation.
I'm sticking with the original forecast of around or less than a tenth of an inch of ice in the central and southern Valley. The northern Valley may reach .10"-.20" of ice (that's freezing rain and/or sleet) with a little bit of snow mixed in since the atmosphere's temperature profile will stay as snow for a little longer.
(A snow profile means that it's below freezing throughout the entire atmosphere. When you start adding warm pockets over the cold surface layer, that's when we get ice profiles. The depth of the surface cold layer will determine whether it's sleet or freezing rain.)
Total precipitation amounts will likely be between .10"-.25" with the majority of that being frozen. Most of the precip should be out of here by the time temperatures rise above freezing - the mid morning - we're not looking at much rain actually falling in the morning.
So we're onto event #2 - the second area of energy that comes through Tuesday evening through Wednesday morning. The majority of this will be rain, however the tail end of the precipitation may mix with snow showers as temperatures fall back toward freezing (and this will be overnight). However, with temperatures being marginal after a day of temperatures in the 40's, I don't think accumulation will be an issue.
Let me know if you have any questions - otherwise I'll see you bright and early at 5am!