Ask the Weather Team
Stephanie asks: What is your summer prediction? Lots of rain again?
Pete Bouchard says: With so many variables involved in seasonal forecasting, I'm not the committing type. But there are outward trends that sometimes reveal Mother Nature's hand. Last year we had a cold spring with a late thaw and a cold ocean. Any kind of wind off the water would give us chilly, raw weather. When the storms hit one after the other, we couldn't get a break. The incessant storms were very unusual and no one saw them coming earlier in the spring.
I don't think we're in for the same pattern this summer, but I'm not certain we're heading for drought either. After record setting rain in March, we seem to be in a dry pattern for the time being. That may change going into summer, but as far as washing out the first two months (oddly enough, June rainfall was EXACTLY normal in Boston!) I don't see that happening.
Bill asks: If the sun angle is the same as in September why isn't it warmer?
Pete Bouchard says: Makes sense doesn't it? Why on earth aren't we in the 70s and 80s now?!? Well, we could be if the sun's energy was just MAINTAINING the already warmed atmosphere that just came off a toasty summer.
It's known that there is a month lag between the highest (lowest) sun angle and the warmest (coldest) temperatures. In summer, the highest sun angle is in June, and our warmest temperatures are in July. In winter, the lowest sun angle is in December, and the lowest temperatures are in January. Coming off a cold winter, the sun is a month ahead of our temperatures. Sure, its working overtime to beat back the cold, but its energy is spread thin. It's primarily being used to melt snow and thaw the ground - AND the air. And it takes much more solar energy to thaw things and continue to heat them than it does to just merely heat them and/or maintain their temperature.
So when you get down to it, while the sun is only doing one thing in September (heat the air), it's doing triple time in March: heat the air, melt the snow, thaw the ground, warm the ocean (a task it won't complete until summer). It's a wonder we see any warmth at all.
Dan asks: How do you predict when a river will crest and/or recede?
Pete Bouchard says: There are river gauges on selected (and often problematic) rivers in the area. These gauges collect information on the water level and water flow at different points along the river and its tributaries (small streams that feed into the bigger rivers). This information is feed into a computer model that predicts when the river will reach its highest point or lowest point.
Jim Fimian asks: Can you tell me what type of pollen is active right now?
Dylan Dreyer says: Hi Jim,
Right now both pollen and mold are in the moderate category. Seems like it must be the tree pollen that's getting to you right now! Good luck!
~DylanBrandon asks: If all that weekend rain was snow, how much would it have been?
Pete Bouchard says: During the cold season, we typically use a ratio of 10 to 1 between snow and rain. In other words, for every 1" of rain, we get 10" of snow. With as much as 10" of rainfall in Massachusetts, that equates to 100" of snow! That's over 9 feet!!
It's not that simple, however. It's known that cold air cannot hold as much water vapor as warm air. So, when you lower the temperatures throughout the upper and lower atmosphere, the capacity of the air to hold water decreases. So apples to apples, you just can't get 10" of "water equivalent" out of a snowstorm. I take about 1/3 of the water equivalent in a rainstorm to convert it to a snowstorm. Given that, we could have expected almost 3 feet of snow if it was cold enough.
