Monday, April 21, 2014
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.
The word nor’easter typically conjures up thoughts of a snowstorm. However, the reality is the term is used for any storm moving up the east coast and bringing a wind from the northeast with precipitation.Meteorologists, when speaking about the wind, name the wind by the direction it comes from, not the direction it’s going. The convention is completely opposite of the way we name highway direction. If you are on the Mass Pike heading from Boston to Worcester, you are going west, but if you were the wind, we would name you an east wind because you’re coming <em>from</em> the east. During a nor’easter, the wind comes from the northeast and mariners in particular, realized that wind direction often brought high seas and dangerous conditions.
We do have a nor’easter on the way for the weekend and it’s a slow moving one too. This means a prolonged period of rain once it begins accompanied by chilly air coming off the cold Atlantic.
Before we get to our weekend storm, we do have a mild but breezy/blustery sort of day today. A southwest wind (coming from the warm part of the country) will help boost temperatures above normal for a change. Highs this afternoon will reach the 50s.
Later this evening, a cold front will move through and this brings with it a chance of a few showers. I am not expecting much in the way of rainfall and any shower activity should hold off until late this afternoon and evening.
A very windy afternoon has translated into a windy night. Portland and surrounding areas have seen wind gusts over 50 miles per hour and this from a storm which stayed hundreds of miles off our coastline.
This year marks 23 years since Hurricane Bob hit New England. That’s the last time a hurricane made landfall anywhere in the area. I bring this up because the storm that is now moving into the Canadian Maritimes has winds as powerful as a hurricane. Had this storm been 150 to 200 miles closer to the coast, it would be created major or even catastrophic damage and brought the region to a standstill for days.
It’s only a matter of time before a monster storm like this does hit the New England Coastline and it’s likely to be a hurricane. If you go by averages, we should have had at least one hurricane hit the area during the past decade. We’ve now gone longer than at any recorded period without an official hurricane making landfall along the New England coastline.
While today’s monstrous nor’easter isn’t a hurricane, it’s big. The reason it’s not a hurricane is because hurricanes are born over warm tropical water and respond negatively to the kind of upper level winds and energy that created today’s storm.
We all know Maine is a big state and as such the weather can be wildly different from west to east and north to south. Tomorrow a big ocean storm is going to continue to gain strength as it passes by the area on its way to Canada.We will be on the western fringe of the storm so the impact to most areas will be minimal, but eastern sections of Maine are going to get a very big storm.
In southern Maine there may be a few hours of snow tomorrow and the ground could become coated or even leave up to an inch or two, but I am not expecting more than that. You will have to go east of Penobscot Bay to really see significant snow amounts.
Winds will be the main player in this storm and a windy advisory is now in place in Portland and along the coast. Winds will be much stronger Down East and a blizzard warning is in place for that part of the state.
Tonight meteorologists and weather enthusiasts are quite excited to watch the upcoming development of the big ocean storm which will form tomorrow. You may be wondering what the big deal is about a storm that is more of a miss than a hit and you are certainly justified in that thinking. However, let me put the size of the storm in perspective.
When we evaluate storms, one of the ways we note the strength of a low pressure center is by its pressure. Storms exist to balance the atmosphere. Their purpose is to mix cold and warm air and try to achieve equilibrium. When a large difference in temperature exists and energy from the jet stream rides over this contrast storms often develop.
Air rises in storms, and as the air leaves the planet the pressure lowers. Wind is the air rushing into the storm trying to fill the void being created by its formation. If the storm is really large the air can’t fill the void fast enough and the pressure continues to fall. The faster the pressure drops the more wind we experience as those winds are attempting to balance the rising air.
Normally, on an average day, the pressure of the air above you exerts about 1013 millibars of pressure. In a typical strong storm this pressure can fall to 980 millibars. At that level of pressure a storm would generate a considerable amount of wind and precipitation. The faster the pressure falls each hour during a storms development the greater the intensity.
Astronomical spring arrives today just before 1PM at 12:57, if you are being precise. The reason I write astronomical spring is because meteorological spring began 3 weeks ago. Meteorologists and astronomers see the seasons differently. For those of us in the weather business, spring is the 90 days between the coldest and warmest 90 days of the year. Autumn therefore becomes the 90 days of transition between the hottest and coldest 90 day periods heading in the other direction.
This might seems like semantics, but when you purely focus on temperature the seasons are all shifted back about three weeks. It’s actually quite logical because the first three weeks of March are likely warmer than the first three weeks of December.
At any rate, spring has arrived on both fronts and while we haven’t seen much prolonged spring weather this will change.