There’s a term some meteorologists use called “model hugging.” Basically, this means buying those models you hear so much about hook, line and sinker. The thing about the models, they are guides to what will happen in the future, not gospel.
Any model is not 100 percent correct, just ask an economist. When I forecast a storm I certainly review all the models, but ultimately I have to make the call myself. When it’s three or four days before a storm, the models often are still all over the place predicting how the atmosphere will come together.
The models are amazing and it’s a wonder to me we can forecast the formation of anything 10 days in advance. Yet, they often don’t have the accuracy needed for a confident forecast more than 72 hours ahead of time. This is why you hear so many "ifs" in the long range.
On a planetary scale, knowing a storm will form is important, but to get the forecast right for an area that includes Bangor to Bridgton and south to Portland, the model has to predict the track of a storm within 50 to 100 miles – otherwise the forecast won’t be accurate. The model could show a storm’s track correctly 10 days in advance, but the odds are much higher it will do so two days before an event.
The basic way the models work is that weather balloons are sent up from weather offices across the globe twice each day. The map below shows where these balloons, known as radiosondes, are launched. This gives us a good picture of what the atmosphere looks like right now. That information is given to computers where physical and mathematical equations move the picture of the current state of the weather ahead in small time steps. Some models keep doing these steps to eventually predict 16 days into the future. The further ahead in time you go, the better chance the model will have errors. While climate models are somewhat different, they too predict far into the future and the further out you go, the less accurate those forecasts – but that’s for another discussion.
The models show agreement for the next couple of days. Today is certainly milder with highs in the 30s. There will still be a busy wind from the northwest so it feels colder than the actual temperature indicates.
Overnight, as even milder air streams north, some precipitation will break out. At the onset there will be light sleet or freezing rain, but by 7 a.m. just a few rain showers remain. During the afternoon the sun will break out and highs will jump into the 40s over southern Maine and mid 30s in the mountains. Driving could be slippery from any light overnight precipitation.
As another cold front crosses Saturday night it’s back to the deep freeze for a few days and a renewed chance at another snowstorm.
Another Snowstorm
Storms love to form on the boundary between arctic air and milder air with more moisture. All the models agree there will be a storm forming on this boundary Sunday and Monday. Similar to a storm 10 days ago, if the cold air pushes far enough south, the storm will ride the boundary of the cold air and stay south of New England. However, if the cold air doesn’t move as far south, it paves the way for the boundary of air masses to be much closer and therefore the snow to fall over our region.
Back in 1956, multiple snowstorms belted southern Maine leaving feet of snow in their wake. That year remains one of the snowiest March’s on record and came on the heels of a cold and snowy winter. Portland saw 46.6 inches of snow during just that one month.
Over the weekend forecasters will be watching the models closely and those wishing for spring will also be hoping for a bit of Irish luck.
I’ll be updating the forecast on Twitter @growingwisdom. Follow @growingwisdom
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