It was wet and windy on Wednesday in New York City with 0.73 inches of rain measured in Central Park. Below is a short time-lapse video that was sent to us by @dmadeo showing the Empire State Building peeking through the thick clouds as they moved through the city.
Tag Archives: rain
NYC Monthly Summary: October 2015
October was a weather roller-coaster in New York City this year. We had highs that ranged from a relatively balmy 78°F to a chilly 50°F. In the end though, the warmth won out. The city’s mean temperature for the month was 58°F, which is 1.1°F above average.
On the precipitation side of things, October was mostly dry and marked the city’s fourth consecutive month with below average rainfall. In all, we received 3.91 inches of rain in Central Park, which is 0.49 inches below normal. Of this total, 1.44 inches fell in a single heavy rain event during the last week of the month. Despite this soaker, the city remains in a moderate drought according to the latest report (released on 10/29) from the US Drought Monitor.
October was a temperature roller-coaster in NYC. Credit: The Weather Gamut
From Drought to Flood: Weather Whiplash in Texas
Bouncing between the extremes of drought and flood, the weather whiplash in Texas continued this weekend. For the second time this year, torrential rain caused widespread flooding across the Lone Star State.
The city of Corsicana, south of Dallas, saw more than 18 inches of rain between Friday and Saturday. Flash floods caused extensive damage and even derailed a Union Pacific freight train. In Houston, where they received 8 inches of rain on Saturday and Sunday, bayous swelled out of their banks and flooded roadways. Local officials say Buffalo Bayou near the downtown area rose 20 feet in just 12 hours.
The cause of this prolonged rain event involved the interaction of a few key atmospheric players. First, an area of high pressure over the east coast – with a clockwise circulation – pushed tropical moisture across the Gulf of Mexico and into Texas. Then, there was a strong upper level low – with a counter clockwise circulation – over the southwest and a cold front moving southeast. These added lift to the atmosphere. When the warm saturated air was forced to rise, it cooled. Since cool air holds less moisture than warm air, the moisture was wrung out of the atmosphere in the form of intense rain. Then, on the heels of all that, remnants of Hurricane Patricia from the Pacific Ocean traveled across Mexico and into Texas. It brought even more tropical moisture into the mix.
Ironically, much of Texas was in a drought just last week. It was considered a “flash drought” as it developed very quickly this summer after intense rains and catastrophic flooding in May brought the previous drought to an abrupt end. From drought to flood to drought and back to flood, Texas certainly has had a wild ride with weather this year.
Freight train derailed by flood waters near Corsicana, TX. Credit: NBC News
Heavy Rain Unleashes Massive Mudslide in LA County
Powerful, but slow moving, thunderstorms brought heavy rain to the mountainous region of northern Los Angeles County, California on Thursday afternoon. With the soil hardened from years of drought, the water ran off downhill and unleashed flashfloods and mudslides across the area.
Local officials say the mud – up to 5 feet deep in some spots – trapped hundreds of motorists in their vehicles on Interstate-5 and Route 58. Homes in the Elizabeth Lake area were also surrounded by mud and debris flows. Luckily, no fatalities have been reported.
According to the NWS, Antelope Valley, which sits between I-5 and Rt. 58, received 1.81 inches of rain in 30 minutes. They have described that as a “1,000 year rain event”, which means there is a 1-in-1,000 (0.1%) chance of this type of event happening in any given year. It is interesting to note that this is the second “1,000 year rain event” to happen in the US this month. The other was the historic flooding in South Carolina.
The intensity of this California deluge had two main drivers. The first was a cut-off low-pressure system over the area that provided lift. The second involved the warmer than normal sea surface temperatures in the Pacific Ocean, which allow for increased amounts of evaporation and higher levels of humidity. Combined, these two factors were able to generate enough instability in the atmosphere to produce heavy thunderstorms.
While experts say this storm was not related to El Niño, it does offer a glimpse of what may be in store for the Southwest over the next few months. The impacts of El Niño are typically strongest during the winter season.
Vehicles stuck in the mud along California’s Rt. 58. Credit: Caltrans/EPA
Historic Flooding in South Carolina
Relentless rain unleashed catastrophic flooding across South Carolina this past weekend. Officials say it was one of the worst disasters in the state’s history.
According to the NWS, an estimated 5.8 trillion gallons of water fell in the Palmetto state in just four days with some communities receiving more than 20 inches of rain. This storm total exceeds that of any tropical cyclone on record that has impacted South Carolina.
Receiving this massive amount of precipitation in such a short period of time overwhelmed rivers and streams, and even caused a number of dams to breach. The floodwaters inundated homes, businesses, and shut down major roadways, including parts of Interstate-95. Local officials say the storm also caused water mains to break, leaving more than 40,000 people without drinkable water. To date, seventeen weather-related deaths have been reported across the state.
This type of rainfall is considered a one in thousand year event in South Carolina. That does not mean it can only happen once every thousand years. It refers to the recurrence interval – a statistical calculation that means an event has a one in one thousand chance (0.1%) of happening in any given year in a given location.
The cause of this widespread and destructive flooding was the unique convergence of three different weather systems that essentially set up an atmospheric river – a fire hose of moisture – aimed directly at South Carolina. The first was Hurricane Joaquin, which sat over the Bahamas for days and pumped huge amounts of moisture into the atmosphere. The second was an upper level low-pressure area over the southeastern US and Gulf of Mexico. It helped pull some of Joaquin’s moisture westward toward the US coastline. And lastly, there was a stalled frontal boundary along the coast. When the warm saturated air encountered the cooler air along the front, it was forced to rise and cool. Since cool air holds less moisture than warm air, the moisture was wrung out of the atmosphere in the form of intense rain over the same area for days.
Although the rain has now cleared, South Carolina is not out of the woods just yet. As swollen rivers make their way to the Atlantic, more flooding is expected in the state’s coastal low country.
Credit: NOAA/NWS Columbia
NYC Monthly Summary: September 2015
Summer-like weather extended well into September in New York City this year. With an average temperature of 74.6°F, it was the city’s warmest September on record! It surpassed the previous record set in 1961 by 1.1°F.
Overall, we had twenty-seven out of thirty days with high temperatures above average. Six of those days posted readings in the 90s, including September 8th when the mercury soared to 97°F in Central Park, marking a new record high for the date. Typically, we only see one 90-degree day during September in NYC. Historically, our average temperature for the month is 68°F.
This extended period of warmth was produced by a persistent ridge in the jet stream over the eastern US. It allowed warm air from the south to flow further north than it normally would at this time of year.
In terms of precipitation, September was unusually dry and marked the third consecutive month that NYC received below average rainfall. In all, we received 3.28 inches of rain, which is one inch below normal. The vast majority of this modest total fell on two separate days in the form of intense downpours. In fact, September 10th set a new daily rainfall record with 1.58 inches measured in Central Park. Nonetheless, despite these soakers, NYC remains in a moderate drought according the latest report (9/29) from the US Drought Monitor.
NYC Monthly Summary: July 2015
July is normally the warmest month on the calendar for New York City, and this year was no exception. Despite getting off to a relatively cool start, the month brought us five days with temperatures in the 90s. These hot days helped bring the city’s mean temperature for the month up to 78.8°F, which is 2.3°F above average.
While we had a few stretches of very warm and humid days, including some where the heat index reached the triple digits, it is interesting to note that we did not technically have a single heat wave all month. In this part of the US, a heat wave is defined as three consecutive days with temperatures reaching 90°F or higher.
On the precipitation side of things, NYC was mostly dry. In all, we received 3.98 inches of rain in Central Park, which is 0.62 inches below average. Of this total, 1.95 inches fell in a single day as a cold front moved through the area triggering thunderstorms and intense downpours. July is typically the wettest month of the year in the Big Apple.
NYC Monthly Summary: June 2015
June 2015 felt a bit like a weather rollercoaster in New York City. We had highs that ranged from an unseasonably cool 55°F to our first 90-degree day of the year. In the end, however, the cold and warmth averaged each other out. The city’s mean temperature for the month was 71.2°F, which is only 0.2°F below normal.
On the precipitation side of things, the city had 14 days with measurable rainfall. In all, we received 4.79 inches of rain, which is 0.38 inches above normal. Of this total, 1.41 inches fell in a heavy rain event during the last weekend of the month. June marked the first time since March that the city had above average monthly rainfall.
Tropical Storm Bill Slams Texas
Tropical Storm Bill, the second named storm of the 2015 Atlantic Hurricane Season, made landfall on Tuesday at Matagorda Island, which is between Houston and Corpus Christi in Texas. It slammed the southeast section of the Lone Star state with winds measured up to 60 mph and relentless heavy rain.
Rainfall totals, according to the NWS, averaged around 3 inches for most places, but some areas southwest of Houston saw much heavier precipitation. The cities of Ganado and El Campo received 11.77 inches and 9.91 inches, respectively. With the soil already saturated from a record wet May, there was widespread flash flooding. Luckily, no serious injures have been reported.
Moving inland toward Oklahoma, another state that experienced a record wet May, the storm was downgraded to a tropical depression on Wednesday. The rain, nonetheless, is ongoing. Looking ahead, the storm is forecast to travel northeast, riding a large ridge of high pressure situated over the southeastern states. The rainy remnants of Bill will likely arrive here in the NYC area by Sunday.
Given that this is an El Niño year – a time when the number of Atlantic hurricanes is usually below average – it is interesting to note that two named storms have already made landfall in the US this season. First Ana in May and now Bill. This shows that land-falling storms can occur even in “quiet” years and that it is important to be prepared throughout the hurricane season.
Tropical Storm Bill making landfall on Texas coast. Credit: NOAA
Traveling from the Gulf of Mexico across the mid-west, remnants of Tropical Storm Bill are forecast to impact the east coast by the weekend. Credit: NOAA
May 2015: Wettest Month Ever Recorded in US
When it rains, it pours – this old adage was literally proven to be true last month. With national weather data dating back to 1895, May 2015 was the wettest month ever recorded in the contiguous United States.
According to NOAA, an average of 4.36 inches of rain fell across the lower 48 states, which is 1.45 inches above average. The vast majority of this impressive total came down in the southern plains. Colorado experienced its wettest May on record. Texas and Oklahoma each had their single wettest month ever, with rain totals that were more than twice their respective long-term averages.
For people living on the either the west or east coasts of the country, this news may come as a bit of a surprise. California continues to be plagued by a devastating drought and many states along the eastern seaboard saw drier than average conditions for the month with six states recording a top-ten driest May.
While the torrential rain in the south central US caused deadly and destructive flooding this spring, it also abruptly ended the region’s multi-year drought. Nationally, the latest report from the US drought monitor shows that only 24.6% of the country is in some form of drought. That is down from 37.4% at the end of April. It is also the smallest national drought footprint since February 2011.
There were many factors that contributed to May’s excessive rainfall, including El Nino – a natural oceanic-atmospheric phenomenon that tends to bring wet weather to the southern part of the country. However, the National Climate Assessment, a US government report that came out last year, says that climate change has caused heavy rain events to become heavier and more frequent across most of the US. Experts expect this trend to continue, but as we saw last month the distribution of rainfall is not likely to be equal.
Credit: NOAA