BOSTON (CBS) – Up until now, this winter has been all about the snow. No rain-snow line or ice concerns for our two blizzards.
That all changes Tuesday, when we have our first “winter mess” (second, if you count what happened at Foxboro Sunday night) on the way – snow, sleet, freezing rain and rain all a concern for different reasons on Tuesday.
Watch Melissa Mack’s Forecast
Begins as snow nearly everywhere Tuesday morning between 6-and-8 a.m. The ice-rain begins to move from south to north during the morning and should reach Boston by mid-day.
During the afternoon, this mix line moves farther north and west so that by the evening commute on Tuesday it should be raining in all of eastern Massachusetts, an icy mix in Worcester County and snow up in New Hampshire. The precipitation tapers from west to east Tuesday night.
Clearly with this storm it is all about where you live – the farther north and west you are, the more snow you will get.
Right now it looks like a dusting to an inch in Boston and nearby suburbs before the change.
1-to-3 inches looks likely around 495 and 3-to-6 inches northwest of the Mass Pike and 495, such as Northern Worcester County and southern New Hampshire.
We could see some spots over 6 inches in elevated areas of central and western Mass. and southern N.H.
Even more of a concern than the snow is the ice potential with this storm.
Areas most likely to be affected by sleet and even worse, freezing rain would be western Middlesex County, Worcester County and Southern New Hampshire.
There will be spots where ice accumulates on roads, power lines and trees. A 1/4″ to 1/2″ ice accretion is possible. Scattered power outages and some tree damage would occur in those locations.
I should note that there is a big difference between freezing rain and sleet.
Sleet is occurs when the precipitation falls through a large layer in the atmosphere which is below freezing and these are the ice pellets almost like small hail. Sleet can accumulate like snow and is generally less dangerous than freezing rain.
Freezing rain occurs when just the very bottom layer of the atmosphere is below freezing (right at ground level). This creates a glaze over everything and is what can cause ice to stick to power lines, roads and outdoor objects.
All of the big ice storms of recent memory, when widespread damage happens, have been caused by large amounts of freezing rain. I should say that at this point we are not forecasting a major ice storm, but it will be one facet of this storm that we will monitor very closely.
Rain will be the primary form of precipitation in southeastern Mass. and eventually in and around the Boston area.
While this may seem like no big deal, considering the large snowpack we have and the forecast of an inch or more of rain falling on Tuesday, this could be a classic case for roof failures and localized flooding where storm drains are not cleared.
If you get the chance today, get out and clear your roof of snow and ice dams and try to clear away any snow from your storm drains as well.