May 2019: A Soggy Month for NYC

May was another month of wild temperature swings in New York City. Producing several cases of weather whiplash, highs ranged from a chilly 48°F to an unseasonably balmy 86°F. In the end, however, these extremes balanced each other out. The city’s mean temperature for the month was 62.2°F, which is only 0.2°F below average.

On the precipitation side of things, May was unusually wet. The month brought the city a relatively rare spring nor’easter and several impressive thunderstorms. One of which produced golf ball sized hail on Staten Island, one the city’s five boroughs. Overall, 19 out 31 days posted measureable rainfall that added up to 6.82 inches for the month. While that is a soggy statistic, it was not the wettest May the city has seen. That dubious honor belongs to May 1989 when 10.24 inches of rain was measured in Central Park. The city, on average, gets 4.19 inches for the month.

Credit: The Weather Gamut

Names for the 2019 Atlantic Hurricane Season

Today is the first day of the 2019 Atlantic Hurricane Season. Although one named storm, Andrea, already formed, the season officially runs from June 1 to November 30.

Since 1950, each tropical storm or hurricane to form in the Atlantic has been given a unique name. They come from a set of six rotating lists produced by the World Meteorological Organization. A name is retired only when a storm was particularly noteworthy – causing a large number of fatalities or an extraordinary amount of damage.

Some notable retired names include:  Harvey, Irma, Katrina, Maria, Michael, and Sandy. The names for this year’s storms are listed below.

Credit: NOAA

Strong Storm Pelts NYC Borough with Large Hail

A powerful thunderstorm moved through New York City on Tuesday night. Generating strong winds and heavy rain across area, it also brought hail to Staten Island, one of the city’s outer boroughs.

According to reports, hailstones measuring 1.8 inches in diameter came down in the Bull’s Head neighborhood. Roughly the size of golf balls, it was the largest hail reported in the city since 2011.

The storm was strong enough to warrant a tornado warning for the area, but luckily no twisters touched down in the five boroughs. Nonetheless, the large hail is a testament to the storm’s intensity. Simply put, the stronger the updraft of a storm, the longer hailstones remain suspended, allowing them to grow larger.

The largest hailstone ever recorded in the US was found in Vivian, South Dakota on June 23, 2010. It measured 7.9 inches in diameter and weighed 1.94 pounds.

Large hail fell from an intense thunderstorm over Staten Island, NYC on May 28, 2019. Image Credit: Staten Island Advance/ J Yates

The 2019 Atlantic Hurricane Season Outlook

The number of hurricanes that develop in the Atlantic basin varies from year to year. For 2019, NOAA’s Climate Prediction Center is forecasting a near average season.

Tropical cyclones, known as hurricanes in the United States, develop around the globe at different times of the year. In this country, we are most impacted by the Atlantic hurricane season, which affects the North Atlantic Ocean, Caribbean Sea, and the Gulf of Mexico. It runs from June 1 through November 30.

Overall, NOAA predicts a 70% likelihood of nine to fifteen named storms forming this season, of which four to eight could become hurricanes, including two to four major hurricanes. An average season produces twelve named storms, including six hurricanes and three that become major hurricanes.

A major hurricane is one that is rated category 3 or higher on the Saffir-Simpson scale.

This year’s outlook, according to NOAA, reflects several competing factors. On one side, there are above average sea surface temperatures in the tropical Atlantic to fuel any storms that develop. Additionally, there is an enhanced west African monsoon in place that can initiate disturbances that turn into storms over the Atlantic. On the other hand, there is an ongoing El Niño event. El Niño conditions in the Pacific tend to cause increased wind shear in the Atlantic, which suppresses tropical development in that basin.

Last year, 2018, saw a very destructive hurricane season in the Atlantic. It produced fifteen named storms, including, Florence and Michael.

Regardless of the number of storms that actually form this year, it is important to remember that it only takes one land-falling system to make it an impactful season.

Subtropical Storm Andrea Kicks Off the 2019 Atlantic Hurricane Season Early

Subtropical Storm Andrea, the first named storm of 2019, has kicked off the Atlantic Hurricane Season early. Its arrival marks the fifth year in a row to produce a pre-season storm.

Forming south of Bermuda on Monday, it generated winds measured up to 40mph. However, did not last long. It dissipated quickly as it moved north into cooler conditions.

Classified as subtropical, Andrea was a hybrid between a tropical storm and a regular low-pressure system usually found at higher latitudes. A tropical system is fueled by the latent heat released by the evaporation of ocean water while a regular storm is powered by the temperature contrast between air masses. Hybrids are able to access both energy sources.

Hurricane season in the Atlantic is officially designated as June 1 to November 30, but there is nothing inherently magical about those dates. While conditions for storm development are traditionally more likely during that time, storms can form anytime when given the right environment.

Other recent out-of-season storms include: Alberto and Beryl in 2012, Ana in 2015, Alex and Bonnie is 2016, Arlene in 2017, and Alberto in 2018. It is worth nothing that Alex formed in January 2016, but was really more of a late remnant of the 2015 hurricane season.

Subtropical Storm Andrea becomes first named storm of the 2019 Atlantic hurricane season. Credit: NOAA

Spring Nor’easter Brings Unseasonably Cold, Wet Weather to NYC

A late season nor’easter soaked the northeastern United States on Monday. Heavy rain triggered flood alerts and advisories from Virginia to Connecticut, and areas further north reported snow.

Here in New York City, 0.70 inches of rain fell in Central Park. This came on the heels of the 1.32 inches that fell the day before when a separate storm system moved through the area. To date this May, the city has received 3.70 inches of rain and it is only the middle of the month. May, on average, brings the city a total of 4.19 inches of rain.

The storm also ushered in unseasonably cool temperatures, making it feel more like March than May. The high in NYC only made it to 48°F on Monday, setting a new record for the coldest high temperature for the date. The old record of 49°F was set in 1914. The normal high for this time of year is 70°F.

This storm was the result of a deep dip in the jet stream that moved over the region, which, in turn, helped generate an area of low pressure off the coast. Producing gusty northeasterly winds, it was categorized as a nor’easter. While this type of storm is more common during the fall and winter months, they can develop any time of the year.

A late spring nor’easter soaked the northeastern US. Credit: weather.com

Hurricane Names Florence and Michael Retired by WMO

There will never be another hurricane by the name of Florence or Michael. The World Meteorological Organization (WMO) has announced that it is officially retiring these names from its list of Atlantic cyclones.

The WMO is responsible for naming tropical storms and hurricanes around the world.  It maintains a set of six rotating lists for each hurricane-prone region. After a six-year cycle, names are re-used.  Names are only retired when a storm was particularly noteworthy – causing a large number of fatalities or an extraordinary amount of damage.

Hurricane Florence. Credit: NOAA

The 2018 Atlantic Hurricane Season was active, but two storms were particularly destructive. Hurricane Florence made landfall in North Carolina in September as a cat-1 storm and dumped a massive amount of rain on the area. Traveling inland, it caused catastrophic flooding in parts of both North and South Carolina. In Elizabethtown, NC, 35.93 inches of rain was reported, making it the wettest tropical cyclone on record for the state. For the contiguous US, it ranked as the eighth wettest.

Hurricane Michael. Credit: NOAA

In October, Hurricane Michael hit the Florida panhandle as a cat-4 storm. With winds measured up to 155mph, it was the strongest storm on record to strike the region and the third strongest storm to make landfall in the continental US. Its powerful winds and storm surge flooding decimated the Panama City area.

To date, according to the National Hurricane Center, 89 storm names have been retired since the current naming system began in 1953. The 2005 hurricane season holds the record for the most retired names – five – in one season.

Starting in 2024, when last year’s list is recycled, the names Florence and Michael will be replaced by Francine and Milton.

The 2019 Atlantic hurricane season officially begins on June 1.

Weather Lingo: Lake Effect Snow

Winter snowstorms have a variety of names, such as Nor’easters and Alberta Clippers. It all depends on where and how they develop. In the Great Lakes region of the US, the vast bodies of fresh water influence the weather and create something known as lake effect snow.

Lake-effect snowstorms, according to NOAA, develop when cold air blows across the warmer waters of a large unfrozen lake. The bottom layer of the air mass is warmed by the water and allows it to evaporate moisture, which forms clouds. When the air mass reaches the leeward side of the lake its temperature drops again, because the land is cooler than the water. This releases the water vapor as precipitation and enormous amounts of snow can accumulate. The effect is enhanced if the air is lifted upward by local topography.

With the clouds typically forming in bands, the snowfall is highly localized. Some places can see the snow come down at a rate of more than 5 inches per hour, while nearby, others will only get a dusting. The shape of the lake and the prevailing wind direction help to determine the size and orientation of these bands.

Fetch, the distance wind travels over a body of water, also plays a key role. A fetch of more than 60 miles is needed to produce lake effect snow. In general, the larger the fetch, the greater the amount of precipitation, as more moisture can be picked up by the moving air.

The impressive depths of the Great Lakes allow them to remain unfrozen longer into the winter season than more shallow bodies of water. This combined with their massive surface area, make them excellent producers of  lake effect snow. With northwesterly winds prevailing in the region, communities along the southeastern shores of the lakes are often referred to as being in the “Snowbelt.”

Credit: NOAA

Destructive 2018 Atlantic Hurricane Season Comes to a Close

The 2018 Atlantic Hurricane Season officially ends today.  It marked the third year in a row with above average activity.

According to NOAA, there were fifteen named storms this season. Of these, eight developed into hurricanes and two were major hurricanes with ratings of category 3 or higher on the Saffir-Simpson Scale. An average season produces twelve named storms, six hurricanes, and three major hurricanes.  It is also interesting to note that this season was the first since 2008 to have four named storms active at the same time – Florence, Helene, Isaac, and Joyce.

Officially running from June 1 to November 30, the season got off to an early start with Tropical Storm Alberto forming in May. This was the fourth consecutive year to see a pre-season storm develop. The biggest names of the season, however, were Florence and Michael.

In September, Hurricane Florence made landfall in North Carolina and dumped a massive amount of rain on the area. Traveling inland, it caused catastrophic flooding in parts of both North and South Carolina. In Elizabethtown, NC, 35.93 inches of rain was reported, making the wettest tropical cyclone on record for the state. For the contiguous US, it ranked as the eighth wettest.

A few weeks later, Hurricane Michael hit the Florida panhandle as a cat-4 storm. With winds measured up to 155mph, it was the strongest storm on record to strike the region and the third strongest storm to make landfall in the continental US. Its powerful winds and storm surge flooding decimated the Panama City area.

Causing so much destruction, both Florence and Michel will likely be retired from the World Meteorological Organization’s list of storm names.

This active hurricane season was largely the result of above-average sea surface temperatures in the Atlantic and ENSO neutral conditions in the Pacific. With warm water to fuel storms coupled with reduced wind shear across the Gulf of Mexico, tropical development in the Atlantic basin was essentially unhindered.

Overall, the season is reported to have claimed the lives of 154 people and caused an estimated $33 billion in damages. The official tally from NOAA will not be available until early 2019.

Source: NOAA

First Nor’easter of the Season Slams NYC

The first nor’easter of the season slammed the northeastern United States on Saturday. Heavy precipitation, strong winds, and coastal flooding were reported across the region.

Here in New York City, the storm dumped 1.34 inches of rain in Central Park. Its powerful winds knocked down trees and caused power outages around the city’s five boroughs. The storm also caused significant travel delays, including shutting down part of the FDR Drive because of flooding.

While nor’easters are not uncommon at this time of year, this one was interesting because it started off as a hurricane in the eastern Pacific. Hurricane Willa made landfall near Mazatlan, Mexico on Tuesday night and then moved inland toward Texas. From there, the storm’s remnants merged with a cold front and became re-energized. Traveling in the jet stream, it worked its way up the eastern seaboard and became a nor’easter.

First nor’easter of the season downed trees and branches in Queens. Credit: D. Herrick