Tag Archives: rain

NYC Monthly Summary: July 2014

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July 2014 was fairly mild in New York City with a noticeable lack of extreme heat. On average, July typically brings the Big Apple six days with readings of 90°F or higher. This year, however, there were only three. That includes the first 90° day of the season. In the end, the city’s mean temperature for the month was 76.1°F. That is only 0.1°F above normal.

In terms of precipitation, July is usually NYC’s wettest month and this year it lived up to expectations. In fact, it was the city’s wettest July in five years. We received 5.59 inches of rain in Central Park, which is 0.99 inches above average. Most of this total came down in three significant events associated with heavy thunderstorms.

Credit: The Weather Gamut

Credit: The Weather Gamut

Credit: The Weather Gamut

Credit: The Weather Gamut

North American Monsoon

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The summer phase of the North American Monsoon is in full swing. But what, you may wonder, is a monsoon?

While most people associate a monsoon with rain, that is only half the story. It is actually a wind system. More specifically, according to NOAA, a monsoon is “a thermally driven wind arising from differential heating between a land mass and the adjacent ocean that reverses its direction seasonally.” In fact, the word monsoon is derived from the Arabic “mausim”, meaning seasons or wind shift.

In general, a monsoon is like a large-scale sea breeze.  During the summer months, the sun heats both the land and sea, but the surface temperature of the land rises more quickly. As a result, an area of low pressure develops over the land and an area of relatively higher pressure sits over the ocean. This causes moisture-laden sea air to flow inland. As it rises and cools, it releases precipitation. In winter, the dry season, this situation reverses.

Monsoon wind systems exist in many different parts of the world. In the U.S., we have the North American Monsoon that impacts states across the southwest. Summer temperatures in this region – mostly desert – can be extremely hot. Readings in the triple digits are not uncommon. This intense heat generates a thermal low near the surface and draws in moist air from the nearby Gulf of California. In addition, an area of high pressure aloft, known as the subtropical ridge, typically moves north over the south-central U.S. in summer. Its clockwise circulation shifts the winds from a southwesterly to a southeasterly direction and ushers in moisture from the Gulf of Mexico. This combination of heat and moisture rich air produces thunderstorms and heavy rainfall across the region between July and September. In fact, summer monsoon rains are reported to supply nearly 50% of the area’s annual precipitation.

Replenishing reservoirs and nourishing agriculture, these seasonal rains are a vital source of water in the typically arid southwest. Conversely, they can also cause a number of hazards such as flash flooding, damaging winds and hail, as well as frequent lightning.

The summer monsoon officially begins, according to the National Weather Service, when there have been three consecutive days with a dew point above 54°F.

North American Monsoon: Summer Weather Pattern. The thermal low sets up over the desert southwest, while the subtropical high moves into the southern plains. The winds draws moisture (green arrows) from the Gulf of California and the Gulf of Mexico. Source: NOAA/NWS

North American Monsoon: Summer Weather Pattern. The thermal low sets up over the southwest, while the subtropical high moves into the southern plains. Their circulating winds draw moisture (green arrows) from the Gulf of California and the Gulf of Mexico.   Credit: NOAA/NWS

NYC Monthly Summary: June 2014

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June was warm and fairly seasonable in New York City this year. We had a few hot and humid days where the mercury made it into the upper 80s, but not a single day made it to 90°F.  That marks only the second time in ten years that the city did not see a 90°F day in June. Nonetheless, the city’s average temperature for the month was 72.5°F. That is 1.5°F above normal.

Despite getting off to a soggy start, the Big Apple came up a bit short this June in terms of precipitation. Most of the 4.26 inches of rain measured in Central Park came down in three significant events early in the month.  In the end, though, we were  0.15 inches below normal.

Credit: The Weather Gamut

Credit: The Weather Gamut

Credit: The Weather Gamut

Credit: The Weather Gamut

A Soggy Week in NYC

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One word can sum up the weather in New York City this past week – soggy.  Over the last five days, we received 2.97 inches of rain, most of which fell as heavy downpours on two separate occasions.

On Monday, 1.6 inches was measured in Central Park. Then on Friday, after a few days of scattered showers, another 1.28 inches came down in a single twenty-four hour period. It is only mid-June and the city has already had 3.96 inches of rain. The Big Apple, on average, receives 4.41 inches for the entire month.

It is interesting to note that June is now the third month in a row that NYC experienced at least one significant heavy rain event.

NYC Monthly Summary: May 2014

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May 2014 was fairly warm in New York City. High readings in the 80s on six separate days helped push the city’s average temperature for the month up to 64°F, which is 2°F above normal. Following what felt like an endless winter, May was the first time all year that NYC had an above average monthly temperature.

In terms of precipitation, the city received 4.37 inches of rain. Most of this fell during two significant rain events, 1.54 inches on May 16th and 0.91 inches on May 23rd. On average, the Big Apple normally gets 4.19 inches for the entire month.

Graph: The Weather Gamut

Graph: The Weather Gamut

NYC Monthly Summary: April 2014

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April 2014 felt like a weather roller-coaster in New York City. We had highs that ranged from a chilly 47°F to a balmy 77°F.  All together, though, these extremes balanced each other out and produced an average monthly temperature of 52.3°F.  That is only 0.7°F below normal.

In terms of precipitation, April’s famous showers were intense this year. The city received a remarkable 7.85 inches of rain in Central Park. Of this impressive total, 4.97 inches fell in a single day – April 30th. According to the NWS, that is the 10th highest daily rainfall total on record for NYC. The Big Apple normally gets 4.50 inches for the entire month.

The city also received a trace amount of snow this April. While this is normally nothing to get excited about, it is worth mentioning as it came on the heels of our warmest day of the year so far. What a month of extremes!

Graph Credit: The Weather Gamut

Graph Credit: The Weather Gamut

A Day of Drenching Rain in NYC

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April is famous for its showers, but yesterday’s precipitation was extreme. Torrential downpours brought New York City more than a month’s worth of rain in a single day.

According to the NWS, 4.97 inches of rain was measured in Central Park. Not only is that a new daily record for the date, it was the 10th rainiest day ever recorded in NYC. On average, we normally get 4.50 inches of rain for the entire month of April.

Up until yesterday, the city’s rainfall total was running below average for the month. So, while the rain was beneficial for the area, the rate at which it came down and its extended duration caused a number of localized flooding problems.

Scientists say the frequency of extreme rain events like this one will increase as global temperatures rise and our climate changes.

NYC 2013: The Year in Review

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New York City experienced some noteworthy weather in 2013. We bounced between the extremes of our coldest March in seventeen years and a July with extended heat waves.  In fact, we had 17 days this summer with readings at or above 90°F, which is two above normal.  Despite these superlatives, the city’s average temperature for the year was 55.34°F. That is only 0.5°F above our long-term norm.

Precipitation in the Big Apple this year was erratic. We fluctuated between our second wettest June on record and our third driest October. In the end, though, we were mostly dry. The city received a total of 46.32 inches of rain for the entire year.  That is 3.62 inches below normal.  Snowfall, however, was abundant.  February brought the city a blizzard that dumped 11.4 inches of snow in Central Park.  March and December also delivered above average snow totals.  For the year as a whole, the city accumulated 29.6 inches, which is 4.5 inches above average.

On the storm front, the 2013 Atlantic Hurricane season left NYC unscathed. This was a welcome relief after being hit by major storms two years in a row – Irene in 2011 and Sandy in 2012.

Moving into 2014, we are off to an active start. A winter storm warning is currently in effect for the city as a nor’easter makes its way up the coast.

Graph Credit: The Weather Gamut

Graph Credit: The Weather Gamut

A Cyclone and Typhoon Batter India and Japan

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Hurricanes can develop all over the world, but they are referred to by different names – cyclones or typhoons – in different regions. This past week, two separate storms slammed India and Japan.

In India, Cyclone Phailin barreled across the Bay of Bengal and made landfall in the state of Orissa on Saturday.  Packing winds of 131-mph, it was the equivalent of a category-4 hurricane. Local officials say the storm’s flooding rains and strong winds destroyed tens of thousands of homes and claimed the lives of at least twenty-seven people.  The government’s pre-storm evacuation of nearly one million people, however, is credited with keeping the number of fatalities from being much higher. Sadly, a cyclone that hit the same area fourteen years ago left approximately ten thousand people dead.

On Wednesday, Typhoon Wipha rumbled along the coast of Japan near Tokyo. With sustained winds of 78-mph, it was the equivalent of a category-1 hurricane.  This storm’s torrential rain caused rivers to overflow and triggered deadly mudslides. One of the hardest hit areas was Izu Oshima, an island about seventy-five miles south of the capital, where a record 32.44 inches of rain fell in one twenty-four period.  Officials say this powerful storm destroyed more than three hundred homes and caused the deaths of at least seventeen people. According to the Japan Meteorological Agency, Wipha was the eighth typhoon of 2013.

Back in the United States, the Atlantic hurricane season remains fairly quiet.

Two Tropical Storms Cause Flood Disaster in Mexico

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The hurricane season in the U.S. has been fairly slow this year – at least so far.  Mexico, our neighbor to the south, however, has not been so lucky.

Hit from both sides, Mexico was slammed by two separate tropical storms this week.   Manuel moved in from the Pacific and Ingrid came ashore from the Gulf.  Both storms brought torrential rain that caused widespread flooding, landslides, and power outages.  Impacting millions of people across the country, this one-two punch of extreme weather claimed the lives of at least one hundred people and displaced thousands more. 

One of the hardest hit areas was Acapulco on the west coast, where 7.43 inches of rain is reported to have fallen in one twenty-four hour period.  The flooding was so severe in this popular resort town that it turned roads into raging muddy rivers and carried crocodiles into the city.  With the only highway out of town destroyed in a landslide and the airport submerged in waist deep water,  locals along with nearly forty-thousand tourists have been stranded there for days.  

According to the Mexican National Weather Service, the last time Mexico was hit by two tropical storms within a span of twenty-four hours was back in 1958.