Hurricane season in the eastern Pacific begins today.
Tropical cyclones, known as hurricanes in the United States, develop around the globe at different times of the year. In the northeastern Pacific, they tend to form between May 15 and November 30. This early start is related to the basin’s warm sea surface temperatures and relatively low wind shear.
While powerful, these Pacific storms are generally not as familiar to Americans as those that form in the Atlantic. This is because they rarely make landfall in this country. In fact, it has only happened twice. A hurricane slammed San Diego, CA in 1858 and a tropical storm battered Long Beach, CA in 1939. This low rate of occurrence is attributed to the cold water of the California Current that flows south along the west coast. Nonetheless, Pacific hurricanes can still impact the US.
Developing in the tropics, Pacific storms deteriorate as they travel north to cooler waters and in some cases over the mountains of Mexico. However, their remnants are still laden with moisture when they reach the southwestern US, where they often unleash flooding rains.
East Pacific storms can also cross into the Central Pacific and affect Hawaii. (The dividing line between the two basins is 140°W longitude.) One such storm was Hurricane Iniki in 1992, the worst hurricane in the state’s history. With wind speeds measured up to 145mph, it was rated category-4 on the Saffir-Simpson scale.
This year, the eastern Pacific hurricane season got off to a record early start, with the development of Tropical Storm Adrian on May 9. No other storm in the basin has formed earlier during the satellite era.
After a mostly mild winter in the northeast, a late season snowstorm blasted the region on Tuesday. In New York City, the storm was less intense than originally forecast but still packed a punch.
According to the NWS, 7.6 inches of snow was measured in Central Park setting a new daily record. The previous record of 4.1 inches had been in place since 1958. Strong winds were also part of the storm with gusts reported up to 38mph. The criteria for blizzard conditions, however, were not met in the Big Apple.
Developing from two different systems that merged off the southeast coast, this nor’easter intensified as it moved northward. In weather lingo, it underwent bombogenesis. The storm’s central pressure dropped from 1007mb on Monday night to 974mb on Tuesday afternoon.
While the storm’s precipitation was plentiful, it was more of a wintry mix than a full on snow event in NYC and other cities along the I-95 corridor. This was because the storm was an “inside runner”. It tracked west of the 40/70 benchmark and pulled warmer marine air onshore. More specifically, a shallow zone of air with a temperature warmer than 32°F was wedged between zones of subfreezing air around 5000 feet above the surface. This set-up allowed the snow to melt then refreeze as sleet before hitting the ground.
For areas further inland, to the north and west, the storm lived up to its hype. Numerous communities across eight states received more than 20 inches of snow. Hartwick, NY reported an impressive 48.4 inches, the highest snow total from the storm.
NYC went from 70°F to 7.6 inches of snow in just two weeks. Credit: Melissa Fleming
The weather world has some interesting words and phrases. One of these is “bombogenesis”.
Sounding rather ominous, it is a combination of the words cyclogenesis (storm formation) and bomb. It refers to the explosive or rapid intensification of an area of low pressure. More specifically, it means the central pressure of a storm system drops at least 24 millibars in 24 hours.
Air pressure is measured in millibars (mb) and the lower it is, the stronger the storm.
Taking place along steep temperature gradients, bombogenesis is most common along the east coast where cold continental air masses meet the relatively warm waters of the Gulf Stream. Disturbances in the jet stream above this type of temperature contrast help the air to rise and the pressure to drop.
This process can develop any time of the year but is most likely between October and March. When a system “bombs out” – a variation on the original phrase – strong winds, heavy precipitation, and even lightning can be expected. Nor’easters often become “weather bombs” – another popular variation – as they move up the coast.
The biggest snowstorm of the year is expected to blast the northeastern US on Tuesday. In New York City, on top of the significant snow totals that have been forecast, a blizzard warning is in effect.
Different than a typical winter storm, a blizzard is characterized more by wind speeds and reduced visibility than the amount of snow it produces. According to the NWS, the three main factors for blizzard conditions are:
- Wind – Sustained winds or frequent gusts of 35mph or higher.
- Visibility – Falling and/or blowing snow that reduces visibility to ¼ mile or less.
- Time – High winds and reduced visibility must prevail for at least 3 hours.
These conditions heighten the risk of power outages and often produce whiteout conditions on roadways, making travel extremely dangerous. Stay Safe!
A blizzard warning is in effect for NYC. Credit: NWS
January, a winter month in the northern hemisphere, is a time when we are usually talking about snowstorms. Nevertheless, Hurricane Alex, the first named storm of the 2016 Atlantic Hurricane season has officially formed.
According to the National Hurricane Center, Alex is the first Atlantic hurricane to form in January since 1938. With sustained winds of 85 mph, it is the second strongest January hurricane on record. Hurricane Alice, which formed at the end December 1954 and lasted through early January 1955, had winds that peaked at 90 mph.
Alex transitioned from a sub-tropical storm – a storm that has both tropical and non-tropical characteristics – into a fully tropical system on Wednesday and then strengthened into a category-one hurricane on Thursday morning. This type of rapid intensification is usually associated with the storm moving over very warm ocean waters. In this case, however, the sea surface temperatures in the area were above average, but just barely warm enough to support tropical development. So, according to NOAA, Alex likely got an extra boost from an unstable atmosphere. The wide temperature spread between the warm surface air and a pocket of unusually cold air aloft encouraged convection and helped strengthen the warm core of this off-season storm.
Alex is currently located 490 miles south of the Azores and moving north-northeast at about 20 mph. It is expected to bring strong winds, heavy rain, and storm surge flooding to that archipelago over the next 24 hours.
The Atlantic hurricane season traditionally runs from June 1 to November 30th.
The forecast track for Hurricane Alex. Credit: NOAA/NHC
Gonzalo, the 7th named storm of the 2014 Atlantic hurricane season, made landfall in Bermuda on Friday night. Despite being downgraded from a category-3 to a category-2 hurricane just prior to coming ashore, the storm still caused extensive damage.
Producing a top wind gust of 140-mph and generating waves over 40 feet high, the storm toppled trees and downed power lines. Approximately 90% of the island chain lost power. Crediting advanced preparations, local officials say no fatalities or serious injuries have been reported.
Gonzalo was the second tropical system to hit Bermuda is less than a week. Tropical Storm Fay slammed the popular vacation spot just last Sunday with strong winds and heavy rain. The last time Bermuda was hit twice in one week was when Tropical Storm Emily and Hurricane Floyd both moved over the archipelago in early September 1981.
Hurricane Gonzalo makes landfall in Bermuda. Credit: PTZ_TV
A rare winter storm paralyzed large sections of the southeastern United States yesterday. Serious impacts from snow, sleet, and freezing rain were felt from the Gulf Coast to Virginia.
According to the NWS, 2.6 inches of snow fell in Atlanta, GA – a new daily record for the region’s largest city. As a whole, the Deep South is not accustomed to wintry precipitation and most cities and towns are not equipped to deal it. Salt spreaders and snowplows are in short supply across the region. As a result, major roads turned into sheets of ice creating very hazardous travel conditions.
The timing of the storm made the situation even worse. Arriving in the afternoon, many people were caught on the roads trying to make their way home. Officials have reported hundreds of traffic accidents and stranded vehicles. Many people were even forced to shelter in place overnight in cars, schools, and stores.
Snow and ice bring travel to a stand still near Atlanta, GA. Image Credit: GuardianLV.com
A major winter storm dumped heavy snow from the Mid-Atlantic states to New England yesterday. With some areas getting more than a foot of accumulation, records fell across the region.
Here in New York City, we received 11 inches of powdery snow in Central Park. That is a new snowfall record for the date, according to the NWS. The previous record of 6 inches was set in 2001. The city’s snow total for the month is now 17.4 inches. On average, we normally get 7 inches for the entire month of January.
Moving in from the mid-west, this storm started out as an Alberta Clipper. This type of system does not typically produce much snow, as it originates over land. This one, however, intensified when it reached the eastern seaboard and morphed into a nor’easter with heavy precipitation.
NYC taxi making its way through heavy snowfall. Image Credit: The Weather Gamut.
Super Typhoon Haiyan hammered the central Philippines late last week. Locally known as Yolanda, it was the strongest tropical cyclone to ever make landfall.
According to the Joint Typhoon Warning Center, Haiyan came ashore with sustained winds of 195-mph, the equivalent of a category-5 hurricane in the U.S. Destructive on their own, these powerful winds also helped produce a devastating 20-foot storm surge that washed out numerous coastal towns and villages. Local officials say the storm impacted approximately ten million people across forty-one provinces, with Tacloban City being the hardest hit area. While the full extent of this natural disaster is still unknown, the Philippine Military reports that 942 people are confirmed dead – primarily from drowning and collapsed buildings. Sadly, government officials expect this number to increase as more areas become accessible and communications are restored. Some fear the death toll could climb as high as 10,000.
The Philippines, a nation of nearly seven thousand islands, is no stranger to serious storms. Situated in the warm waters of the tropical western Pacific, they are often hit by typhoons, including four this year alone. None, however, have been as powerful as this recent event. If the government’s staggering death toll projections are realized, Haiyan will become the Philippines’ deadliest storm on record.
Super Typhoon Haiyan approaches the Philippines.
Image Credit: NOAA