Unseasonable Nor’easter Soaks NYC

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

Weather Gamut Founder Talks about NYC’s Record Rainfall on WUTV

It was a thrill to be asked back to The Weather Channel’s WUTV show on Friday. As a New York City-based contributor to their PWS network, we discussed the record rainfall that swept through the city and the numerous flooding situations it caused.

The show, which dives into the science behind different weather events, airs weeknights from 6 to 8 PM EST on The Weather Channel.

Weather Gamut writer, Melissa Fleming, talks about record rainfall in NYC on WUTV. May 5, 2017. Credit: TWC and Melissa Fleming.

NYC Breaks Rainfall Record that Stood for 146 Years

An intense rainstorm swept through New York City on Friday afternoon. With bands of heavy downpours, it unleashed more than half a month’s worth of rain in just a few hours.

According to the NWS, 3.02 inches of rain was measured in Central Park, setting a new record for the date. The previous record of 1.55 inches had been in place since 1871. On average, the Big Apple gets 4.19 inches of rain for the entire month of May.

The heavy rain disrupted travel across the city, with flash flood warnings issued in all five boroughs. Significant delays and cancellations were also reported at the area’s airports.

This type of heavy rain event, according to NOAA, is expected to become more common in the northeast as global temperatures rise and precipitation patterns change.

Flooding on NYC’s West Side Highway. Credit: New York Patch

A Look at Why Death Valley is the Hottest, Driest, and Lowest Place in US

Death Valley National Park is famous for being the hottest, driest, and lowest place in the United States. The interesting thing about all these extremes, as I learned during a recent visit, is how they interconnect.

Situated in eastern California near the Nevada border, the park’s topography is known as basin and range. This is where the earth’s crust is rifting apart, creating mountains in some areas and deep basins in others. Death Valley is a long, narrow basin that reaches a depth of 282 feet below sea level. It is also in the rain shadow of four different mountain ranges to the west – the Coastal Range, the Sierra Nevada, the Argus Range, and the Panamint Range.

As storms move inland from the Pacific, they must rise up and over each range. In doing so, they cool and their water vapor condenses into rain or snow that falls on the western side of these mountains. By the time a storm system reaches Death Valley, it has lost most of its moisture. The average annual rainfall in the park, according to NOAA, is just 2.36 inches.

These dry conditions, along with the valley’s below-sea-level elevation, help to produce the park’s famous heat. With cloud free skies and sparse vegetation, a maximum amount of sunlight can reach the ground. The rocks and parched soil absorb the heat and radiate it into the air. The warm air rises but becomes trapped by the steep valley walls. After cooling slightly, it is recycled back toward the valley floor where it is heated even further by atmospheric compression. During the summer months, this process generates hot winds and sizzling temperatures. The average high temperature in the park ranges from 67°F in January to 116°F in July. The hottest temperature ever recorded was 134°F on July 10, 1913 – a world record.

Looking ahead, as the climate changes, the southwestern region of the US is expected to become even hotter and drier. It seems like only a matter of time before Death Valley breaks its own heat record.

At 282 feet below sea level, Basin in Death Valley National Park is the lowest point in the US. Credit: Melissa Fleming

Intense Rain Puts a Big Dent in California’s Drought

Over the past week, a cavalcade of intense rain and snowstorms battered the west coast of the US and put a major dent in California’s five-year drought.

According to the latest report from the US Drought Monitor, the northern third of the Golden State is now drought free. This is a major change from just three months ago, when the entire state was in some form of drought.

Across the region, copious amounts of precipitation were reported. More than a foot of rain fell in the Sierra Nevada, with 20.7 inches measured locally at Strawberry Valley, CA. Higher elevations saw tremendous snowfall totals. Heavenly Ski resort in South Lake Tahoe, according to the NWS, received an incredible 12 feet of snow in just one week.

These staggering totals came courtesy of a weather phenomenon known as an “atmospheric river”. These are narrow, but intense bands of water vapor sourced from the tropics. Often originating near Hawaii, this fire hose of moisture is sometimes called a “pineapple express.”

While this excessive rainfall did cause flooding events across the region, reservoir levels have benefited. Lake Shasta, the largest largest reservoir in California, is currently at 81% of total capacity and 126% of its historical average for the date.

Southern California also picked up some much-needed rainfall, but still remains in drought. That said, only 2% of the state is currently in exceptional drought, the worst possible category.

Northern California is drought free for the first time in five years. Credit: US Drought Monitor

Weather Lingo: Rain Shadow

The world of weather has some interesting words and phrases. One of these is “Rain Shadow”.

While it sounds rather poetic, a rain shadow refers to the land area on the leeside of a mountain that is exceptionally dry. Mountains act as barriers for weather systems traveling in a region’s prevailing winds, forcing them to drop most of their moisture on the windward side before they can pass.

As an air mass rises up and over a mountain, it enters an area of lower atmospheric pressure where it expands and cools. As a result, the moisture it contains condenses, clouds form, and precipitation falls. After the air mass moves over the mountain, it starts to descend the other side. The air is warmed by compression and the clouds dissipate. This means little to no rain falls on the leeward side.

Rain shadows are found all over the world, from the Tibetan Plateau in Asia to the Atacama Desert in South America. Here in the US, Death Valley is a famous example as it lies in the rain shadow of four different mountain ranges.

The Rain Shadow Effect. Credit: Kagee Commons

NYC Monthly Summary: November 2016

November felt like a weather roller coaster in New York City this year. We had highs that ranged from a relatively balmy 72°F to a chilly 41°F. However, with 19 out of 30 days posting above average readings, the warmth won out in the end. The city’s mean temperature for the month was 49.8°F, which is 2.1°F above our long-term norm. This was the Big Apple’s 17th consecutive month with an above average temperature – its longest streak on record.

In terms of precipitation, November was unusually wet and marked the first month since July that NYC received above average rainfall.  In all, we received 5.41 inches of rain which is 1.39 inches above normal. The majority of this plentiful total fell during two separate heavy rain events. In fact, November 29th was the city’s wettest day of the year and set a new daily rainfall record with 2.20 inches measured in Central Park. Nonetheless, despite these soakers, NYC remains in a moderate to severe drought according the latest report (12/1) from the US Drought Monitor.

November 2016 was NYC's 17th consecutive month with above average temperatures. Credit: The Weather Gamut

November 2016 was NYC’s 17th consecutive month with an above average temperature. Credit: The Weather Gamut

Nov 2016 was first month since July that NYC received able average rainfall. Credit: The Weather Gamut

November was the first month since July that NYC received above average rainfall. Credit: The Weather Gamut

Rainstorm Brings NYC its Wettest Day of the Year

A rainy day in New York City is typically nothing to write home about, but Tuesday’s precipitation was extreme. Heavy downpours brought the city more than half a month’s worth of rain in a single day.

According to the NWS, 2.2 inches of rain was measured in Central Park. Not only is that a new daily record for the date, it was the wettest day the city has seen so far this year. On average, we normally get 4.02 inches of rain for the entire month of November.

Suffering through moderate to severe drought conditions for several months, this rainstorm was largely beneficial for the area even if did put a damper on the Rockefeller Center Christmas Tree Lighting Ceremony. That said, even more rain is needed to bust this drought completely. Year to date, the city’s rainfall deficit is 7.24”.

This type of heavy rain event, according to NOAA, is expected to become more common in the northeast as global temperatures rise and precipitation patterns change.

NYC Monthly Summary: October 2016

October felt like a weather roller coaster in New York City this year. We had highs that ranged from a balmy 85°F to a chilly 51°F.   But, in the end, the warmth won out. The city’s mean temperature for the month was 58.8°F, which is 1.9°F above our long-term norm.

On the precipitation side of things, the city received near average rainfall for the first time in months. In all, we received 4.15 inches of rain in Central Park, which is only 0.25 inches below normal. Of this total, 1.41 inches fell during a single heavy rain event on October 27th – the city’s wettest day since last May. Despite this soaker, the Big Apple remains in a moderate to severe drought according to the latest report (released on 10/27) from the US Drought Monitor.

October was a temperature roller closer in NYC. Credit: The Weather Gamut

October was a temperature roller coaster in NYC. Credit: The Weather Gamut.

Rainfall was near average in NYC for the first time in months. Credit: The Weather Gamut

Rainfall was near average in NYC for the first time in months. Credit: The Weather Gamut

Hurricane Matthew Slams the Southeastern US

Hurricane Matthew, the 13th named storm of the Atlantic Hurricane Season, hammered the southeastern United States this weekend from Florida to Virginia.

Tearing up the coast as it trekked northward, Matthew made landfall near McClellanville, SC on Saturday as a category-1 hurricane with 75mph winds. It had reached category-5 status in the Caribbean – the first storm to do so since Hurricane Felix in 2007- but weakened as it moved toward the US.

Despite this downgrade, Matthew still packed a powerful punch. Its strong winds, flooding rains, and storm surge caused significant property damage and widespread power outages throughout the region. The death toll from this storm currently stands at 26 people from across five states and is expected to increase in the coming days.

With successive bands of heavy rain, Matthew also caused catastrophic inland flooding. In Fayetteville, NC – 100 miles from the coast – 14.82 inches of rain was reported. As a result, several rivers in the region rose to record or near-record levels and overflowed their banks, inundating communities.

All told, Matthew dumped 13.6 trillion gallons of water on Florida, Georgia, South Carolina, North Carolina, and Virginia before heading out to sea as a post-tropical storm. That is enough water to fill over 20 million Olympic-size swimming pools. The highest rainfall total, 17.49 inches, was reported near Savannah, GA.

The damage caused by Matthew is currently estimated at $6 billion.

Hurricane Matthew batters the south eastern US. Credit: NOAA/NASA

Hurricane Matthew batters the southeastern US. Credit: NOAA/NASA