An unseasonable nor’easter soaked the northeastern US this Mother’s Day weekend. Heavy rain and gusty winds were reported across the region.
Here in New York City, 1.61 inches of rain fell in Central Park. This impressive total was only a few one-hundredths on an inch shy of the daily record of 1.66 inches that was set in 1971.
This storm also marked the second consecutive wet weekend for the Big Apple. Last Friday, a record-shattering 3.02 inches of rain came down in just a few hours. Between these two storms, the city has already received more precipitation than it typically sees for the entire month of May.
With an area of low pressure intensifying as it traveled north along the Atlantic coast, this storm was a textbook nor’easter. While this type of storm is more common during the fall and winter months, they can develop any time of the year.
Satellite view of the unseasonable May nor’easter. Credit: NOAA
In the northeastern United States, nor’easters are well known for producing heavy precipitation, strong winds, and coastal flooding. Despite approaching the region from the south, they take their name from the steady northeasterly winds that blow in off the ocean.
Nor’easters can occur any time of the year but are most common between November and March. This is because the cold air that dips south in a jet stream trough during fall and winter often meets warmer air moving north over the Gulf Stream, which is just off the east coast. This contrast in temperature strengthens the storms. That said, there are a few different ways in which they can develop.
The first is called a “Miller Type-A” storm and is considered the “classic” nor’easter. These occur when an area of low pressure develops along the Gulf Coast or Atlantic Coast and intensifies as it tracks northward along the eastern seaboard.
The second type originates in the mid-west and is known as a “Miller Type-B” storm. Traveling east, these low-pressure systems weaken when they run into the Appalachian Mountains and transfer their energy to the coast. Often called a “center jump”, this transfer strengthens or creates a secondary low on the lee side of the mountains, which then moves northward. These types of storms are notoriously difficult to forecast as everything depends on the timing and location of the energy transfer between the two lows.
Both Miller “types” are named after James E. Miller, an atmospheric scientist who studied storm formation in the Atlantic coastal region during the mid 20th century.
Typical Miller Type A and B storm tracks. Credit: NOAA
November was unusually chilly in New York City this year. In fact, we had 24 out of 30 days with below normal temperatures. This extended stretch of cool weather helped lower the city’s average monthly temperature to 43.9°F, which is 4.2°F below normal.
In terms of rainfall this November, NYC collected a meager 1.81 inches. That is 2.21 inches below average. More significant precipitation, however, came in the form of snow. A nor’easter blustered its way through the city on November 7th and brought the Big Apple its first snowfall of the season – 4.7 inches in Central Park. This accumulation not only set a new daily snowfall record, but also made November 2012 the 6th snowiest November on record.
A nor’easter blasted the eastern seaboard yesterday from the mid-Atlantic states to New England. This type of storm is not unusual in the area, but its timing left a lot to be desired.
Arriving only nine days after Super-Storm Sandy devastated the region, this winter storm slammed the area with high winds and heavy, wet snow. In New York City, 4.7 inches of snow was reported in Central Park – a new daily snowfall record.
The weight of the snow on the region’s already storm damaged trees caused many branches to break and fall. This, in turn, resulted in even more power outages in communities still struggling to recover from Sandy, adding insult to injury for tens of thousands of people.
The local forecast is calling for a significant warm-up over the next few days, so the snow will not be sticking around for long.