Friday, April 18, 2014
Maine is still under the gun for a very problematic storm this weekend. There are a lot of warnings and advisories up for the state today so let's review them.
First, we have a freezing rain advisory for the coastal plain. This advisory is used when freezing rain will be an issue, but amounts will stay around a quarter of an inch. This can still cause power outages, tree damage and hazardous travel.
Then we have an ice storm warning. This is basically a more severe version of the previous advisory. Areas under an ice storm warning can see half an inch or more of ice accretion and damage, power outages and hazardous travel conditions are much worse.
There is also a winter storm warning for northern sections of the state. There, it will be cold enough so much of the precipitation will fall in the form of snow. These warnings are issued when snow and sleet can accumulate over 6 inches. You can follow my twitter updates to the forecast @growingwisdom.
Currently, there are areas of light rain, freezing rain, sleet and snow across the region.
Overnight, steadier and heavier precipitation will move through the region. At first, over southern coastal areas, the rain will not freeze. However as colder air pushes southward, freezing rain will ensue. Freezing rain is very difficult to predict where the line will set up. There have been storms when one side of Portland is getting icing and another, closer to the water seeing just plain rain.
Sunday morning could present a real issue with icy roads, some tree damage and power outages. The further away from the coast you go, the worse the conditions will be in the morning. It remains to be seen how bad coastal towns become from the freezing rain.
The models give us a break in the precipitation later Sunday, although there will still be some freezing rain still in the morning Sunday and throughout the day, but the steadiest will be over. Other periods of freezing rain or rain will continue into early Monday.
The reason for the icing situation is a front sitting across New England. As warm and moist air rides up and over the cold air at the surface, it will create copious amounts of rain. If the air at the ground is cold enough, the rain will freeze upon contact. The map below shows temperatures Sunday morning. Notice how cold it is statewide at the ground.
If the air cools enough, above the ground, then we can see the precipitation fall in the form of sleet or snow. This will be the case over northern areas and why there is a winter storm warning there.
When is it over?
While there is a risk for precipitation Sunday afternoon through Monday, 80 percent of the storm will be over by Sunday midmorning. Any additional accumulation of snow, sleet or ice, will be much less beyond that timeframe.
Drier weather returns for Tuesday and Wednesday, Christmas Day, with highs in the 20s Tuesday and upper teens for Christmas. There will be dry roads and bright sunshine both days so getting around should be easy, provided the ice and snow is cleaned up from the weekend storm.Tweet
David Epstein has been a meteorologist for more than 25 years. He spent 16 years in Boston and currently freelances at WGME13 in Portland.
In 2006, David founded GrowingWisdom.com, a business producing educational and marketing videos for the green industry. He currently is a professor at Framingham State College, teaches Jan Plan at Colby College and owns Bloomscapes Inc., a landscape design business.
David authored "Gardens Of New England" and his work has been published in Grolier's Science Annual for 10 years. He lives in South Natick, Mass., and has a summer home in Harpswell.