Nor'easter hits the Northeast Saturday , then dry and cold
By
Elliot Abrams, AccuWeather chief meteorologist
Updated Dec 4, 2020 3:12 AM EDT
Scotty the dog might've felt cold, and in this picture he blended in with the surroundings. It snowed on Dec. 1 and Dec. 2 was a cold and gusty day.
Pictures of clear blue sky signaled the fact we were experiencing an early-season arctic air mass in the middle of Pennsylvania on Wednesday. The farm visible from our nearby park was surrounded by snow.
Thursday dawned cold and picturesque. Here's a picture from 20 minutes before sunrise. Photographers will notice times before sunrise to after sunrise is the golden hour; great times to take pictures...
...and sunrise.
Good morning and evening sunshine often has more red in it than at other times. This is because the sun's light travels through more of the atmosphere at those times than when the sun is more overhead. The red is scattered out (so we can see it), and you can see the effect on the terrain. Even the snow takes on a reddish tint.
The oxygen molecules in the atmosphere are the right size for sunlight to scatter out the blue light, so we see that prominently during the day.
Most of the snow melted quickly. The same scene looked different Thursday afternoon:
Moving from the past into the future, we'll start with surface pressure analysis and a satellite/radar picture, both from Thursday afternoon.
The satellite picture shows a fair amount of cloudiness from Texas to the Northeast states, but there's not a great deal of organization to the cloud pattern. We can see why by looking at the surface map below. The main low pressure area is the Upper Midwest, there is a strong westerly flow south the low pressure area that weakens south of the Ohio River. There is a high-pressure area off of the Southeast coast, and a weak low pressure in Arkansas.
By Friday evening, we should see a low pressure area in eastern Tennessee helping to organize the moisture that had come from the Gulf of Mexico. The typical snow-rain line is between the southernmost dotted blue line and the northernmost dotted red line. In accordance with us, we see the blue-shaded snow area in the lower Great Lakes but the green-shaded area coming up to the Ohio Valley. Moving ahead to Saturday, we see the low-pressure area making progress to the northeast:
At this point, there is a narrow band of snow at the northwest edge of the precipitation area associated with the low-pressure area. Notice how heavy the rain is from Maryland to Virginia. Local flooding is likely, but importantly, heavy precipitation does not reach where the air is cold enough for snow. In a borderline situation, this makes a very big deal. If the cold air extended to several Virginia at this time, some places would be getting well over a foot of snow instead of more than an inch of rain. If you were making a hydrologic forecast, you might predict an inch of precipitation and be correct. However, if you predict an inch of rain, and your audience gets about a foot of snow, try telling everyone your forecast was correct!!! I think you get my drift. Now let's see what happens next:
In between the Saturday morning map time and this map, the model shows rain briefly changing to snow pretty close into New York City, but at 7 p.m. the precipitation is coming to an end there. However, things could be getting quite slippery across central and southern New England.
This map for Sunday evening suggests that places in northern New England that have not had snow by Saturday evening will get some during the day Sunday. On both of those last two maps the isobars along the East Coast are quite close together, suggesting it feels windy and cold... a trademark of a nor'easter.
As you know, the winds are named by where the wind is coming from. You might think that a storm from the south would bring rain because the South is warm. However, the counter-clockwise flow around a low-pressure area means that a storm from the south will bring east or northeast winds at ground level. In the 18th century, Benjamin Franklin was apparently the first to point out that nor'easters came from the south. He was living in Philadelphia and his brother lived in Boston. Benjamin's brother saw an eclipse before the storm reached there. The brother asked Benjamin if he had seen the eclipse. Benjamin replied that he had not because there was a big storm at the time of the eclipse. From this information, Benjamin reached conclusion that the storm with winds from the northeast came from a storm that was actually heading toward the Northeast. I don't know this for sure, but I don't believe that this is the storm in with Benjamin Franklin flew a kite while a thunderstorm in progress. Looking back, Franklin was very lucky during the kite flying experience, because it could've had a very shocking ending. On the 300th anniversary Franklin's birth, a celebration party was held in Philadelphia to mark the event. The organizers made the guest list by guessing who Franklin would've wanted to be his party. I was one of the invitees, and I was stunned when I saw all the various scientists representing scientific disciplines that Franklin had been influential with 300 years earlier.
In a similar vein but on a lighter note, we know Thomas Edison invented the lightbulb. Just think: if Edison and not invented the lightbulb, we might have to use our cell phones and iPads by candlelight!
Looking at it Monday map, we see that the weekend storm is long gone, but there seems to be another storm developing over Florida. Will that one come up the East coast? As you can see on the next map, the GFS says no. However, if we remember back to earlier this week and computer forecasts for the storm that's approaching for Saturday, there was a point at which it seemed that storm might stay south.
Assuming this idea is correct, even though the storm would not come up to East coast, it would still have an effect by closing a renewal of cold is northerly winds.
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Weather Blogs / Northeast US weather
Nor'easter hits the Northeast Saturday , then dry and cold
By Elliot Abrams, AccuWeather chief meteorologist
Updated Dec 4, 2020 3:12 AM EDT
Scotty the dog might've felt cold, and in this picture he blended in with the surroundings. It snowed on Dec. 1 and Dec. 2 was a cold and gusty day.
Pictures of clear blue sky signaled the fact we were experiencing an early-season arctic air mass in the middle of Pennsylvania on Wednesday. The farm visible from our nearby park was surrounded by snow.
Thursday dawned cold and picturesque. Here's a picture from 20 minutes before sunrise. Photographers will notice times before sunrise to after sunrise is the golden hour; great times to take pictures...
...and sunrise.
Good morning and evening sunshine often has more red in it than at other times. This is because the sun's light travels through more of the atmosphere at those times than when the sun is more overhead. The red is scattered out (so we can see it), and you can see the effect on the terrain. Even the snow takes on a reddish tint.
The oxygen molecules in the atmosphere are the right size for sunlight to scatter out the blue light, so we see that prominently during the day.
Most of the snow melted quickly. The same scene looked different Thursday afternoon:
Moving from the past into the future, we'll start with surface pressure analysis and a satellite/radar picture, both from Thursday afternoon.
The satellite picture shows a fair amount of cloudiness from Texas to the Northeast states, but there's not a great deal of organization to the cloud pattern. We can see why by looking at the surface map below. The main low pressure area is the Upper Midwest, there is a strong westerly flow south the low pressure area that weakens south of the Ohio River. There is a high-pressure area off of the Southeast coast, and a weak low pressure in Arkansas.
By Friday evening, we should see a low pressure area in eastern Tennessee helping to organize the moisture that had come from the Gulf of Mexico. The typical snow-rain line is between the southernmost dotted blue line and the northernmost dotted red line. In accordance with us, we see the blue-shaded snow area in the lower Great Lakes but the green-shaded area coming up to the Ohio Valley. Moving ahead to Saturday, we see the low-pressure area making progress to the northeast:
At this point, there is a narrow band of snow at the northwest edge of the precipitation area associated with the low-pressure area. Notice how heavy the rain is from Maryland to Virginia. Local flooding is likely, but importantly, heavy precipitation does not reach where the air is cold enough for snow. In a borderline situation, this makes a very big deal. If the cold air extended to several Virginia at this time, some places would be getting well over a foot of snow instead of more than an inch of rain. If you were making a hydrologic forecast, you might predict an inch of precipitation and be correct. However, if you predict an inch of rain, and your audience gets about a foot of snow, try telling everyone your forecast was correct!!! I think you get my drift. Now let's see what happens next:
In between the Saturday morning map time and this map, the model shows rain briefly changing to snow pretty close into New York City, but at 7 p.m. the precipitation is coming to an end there. However, things could be getting quite slippery across central and southern New England.
This map for Sunday evening suggests that places in northern New England that have not had snow by Saturday evening will get some during the day Sunday. On both of those last two maps the isobars along the East Coast are quite close together, suggesting it feels windy and cold... a trademark of a nor'easter.
As you know, the winds are named by where the wind is coming from. You might think that a storm from the south would bring rain because the South is warm. However, the counter-clockwise flow around a low-pressure area means that a storm from the south will bring east or northeast winds at ground level. In the 18th century, Benjamin Franklin was apparently the first to point out that nor'easters came from the south. He was living in Philadelphia and his brother lived in Boston. Benjamin's brother saw an eclipse before the storm reached there. The brother asked Benjamin if he had seen the eclipse. Benjamin replied that he had not because there was a big storm at the time of the eclipse. From this information, Benjamin reached conclusion that the storm with winds from the northeast came from a storm that was actually heading toward the Northeast. I don't know this for sure, but I don't believe that this is the storm in with Benjamin Franklin flew a kite while a thunderstorm in progress. Looking back, Franklin was very lucky during the kite flying experience, because it could've had a very shocking ending. On the 300th anniversary Franklin's birth, a celebration party was held in Philadelphia to mark the event. The organizers made the guest list by guessing who Franklin would've wanted to be his party. I was one of the invitees, and I was stunned when I saw all the various scientists representing scientific disciplines that Franklin had been influential with 300 years earlier.
In a similar vein but on a lighter note, we know Thomas Edison invented the lightbulb. Just think: if Edison and not invented the lightbulb, we might have to use our cell phones and iPads by candlelight!
Looking at it Monday map, we see that the weekend storm is long gone, but there seems to be another storm developing over Florida. Will that one come up the East coast? As you can see on the next map, the GFS says no. However, if we remember back to earlier this week and computer forecasts for the storm that's approaching for Saturday, there was a point at which it seemed that storm might stay south.
Assuming this idea is correct, even though the storm would not come up to East coast, it would still have an effect by closing a renewal of cold is northerly winds.
Report a Typo