Tag Archives: extreme weather

Snow and Another Blast of Arctic Air

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Heavy snow is forecast to blanket the east coast from Virginia to Maine later today.  As the storm passes, temperatures are expected to plummet.

A weakened polar vortex has allowed frigid arctic air to push southward for the second time this month. Temperatures are likely to drop below freezing as far south as northern Florida. The core of the cold, however, will be centered in the mid-west and northeast.  Here in NYC, daily high temperatures are forecast to be 15°F to 20°F below average for the remainder of the week.

While conditions are not expected to be as brutal as they were during the last arctic outbreak, the frigid weather will linger this time.  Today’s snow will likely stick around for awhile.

Australian Heat Wave 2014

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Oppressive heat has been gripping southeastern Australia for days.  While it is summer there and high temperatures are expected, this heat has been extreme.

In the state of Victoria, temperatures soared above 40°C – that is 104°F – for four consecutive days.  In the neighboring state of South Australia, the mercury hit 44.2°C (112°F) in Adelaide – making it the hottest city in the world on Thursday. Officials say this intense heat has fueled wildfires, sent hundreds of people to the hospital with heat related illnesses, and caused widespread power outages.  In Melbourne, it even caused play to be suspended at the Australian Open – a Grand Slam tennis tournament.

Scorching heat waves seem to be getting more common in Australia.  Last year, the country’s hottest on record, the Bureau of Meteorology had to add two new colors to their weather map to reflect the higher temperatures.

This current heat wave is forecast to break over the weekend and a dramatic cool down is expected to follow.

Source: Australian Bureau of Meteorology

Source: Australian Bureau of Meteorology

Drought Update: January 2014

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So far this winter, snow has been plentiful across the mid-west and northeastern US. In the western states, however, long-term drought continues to leave much of the region parched.

According to the latest report from the US Drought Monitor, 61% of the West is suffering under conditions of moderate drought.  In California, where 2013 was their driest year on record, the situation has gone from bad to worse. In just this past week, the category of extreme drought jumped from 28% to 63% of the entire state.

These dry conditions are not only lowering reservoir levels and reducing crop production, they are increasing the risk of wildfires.  In fact, a large fire broke out today in the San Gabriel Mountains near Glendora, CA – a heavily populated suburb of Los Angeles.

January is usually the wettest month of the year in southern California, but a persistent ridge of high pressure over the region has pushed the storm track north. Unfortunately, this dry weather pattern is forecast to remain in place for the near future.

Image Credit: US Drought Monitor

Image Credit: US Drought Monitor

Weather Whiplash for NYC

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New York City was on a temperature roller coaster this week.  From unseasonably warm to brutally cold, we saw it all.

On Monday, it was 55°F in Central Park.  Then, in a matter of twenty-four hours, from 8 A.M. on Monday to 8 A.M. on Tuesday, the temperature in the city dropped 51°F!  With a low reading of 4°F on Tuesday morning, the Big Apple set a new record low for the date.  This dramatic change was ushered in by a weakened polar vortex and a deep dip in the jet stream.  After a few days of bitterly cold conditions, the mercury climbed above freezing on Friday and then continued to rise. On Saturday, the city’s temperature reached a relative balmy 58°F!  Our average high for this time of year is 38°F.

From the mid-50s to the single digits and back again in a matter of six days, it felt like weather whiplash!  Temperature swings of this magnitude in NYC are very unusual.

Image Credit: The Weather Gamut

Graph Credit: The Weather Gamut

The Polar Vortex

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The Polar Vortex has been making headlines across most of the United States recently.  But, what exactly is it?

According to NOAA, the northern hemisphere polar vortex is a high altitude low-pressure system anchored over the Arctic.  More specifically, it is “the pattern of winds around the North Pole.”  It is always present, but tends to be stronger in the winter.

The configuration of the polar vortex – smooth or wavy – determines how much cold air escapes the region. Driven by the temperature difference between north and south, these winds typically circle the pole from west to east in a smooth pattern that bottles up the Arctic’s cold air.   When these winds weaken, the pattern becomes wavy and cold air pushes southward.

The connection between warming conditions in the Arctic (decreasing the temperature difference between north and south) and extreme weather events in the mid-latitudes is an active area of research. Some scientists suggest that increasing Arctic temperatures may be responsible for disrupting the pattern of the polar vortex.

The polar vortex is shown in purple. Image Credit: NOAA

Polar Vortex configuration: Smooth vs Wavy.  Image Credit: NOAA

A Deep Freeze in NYC

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A massive arctic outbreak has sent most of the U.S. into a deep freeze.  From the Mid-West to the Gulf Coast and along the eastern seaboard, many cities are dealing with the coldest temperatures they have seen in nearly two decades.

Here in New York City, the mercury fell to 4°F in Central Park this morning – a new record low for the date.  The previous record of 6°F was set in 1896. Our normal low temperature for this time of year is 27°F.

While it certainly was bitterly cold today, it was not the coldest day the Big Apple has ever experienced. That dubious honor, according to the NWS, belongs to February 9, 1934, when the low was a brutal -15°F.

Our current frigid conditions are the product of a weakened polar vortex – the pattern of winds around the North Pole.  As it slowed down, arctic air pushed southward and caused a deep dip in the jet stream. This frosty air is not likely to stick around much longer, though.  As the jet stream retreats northward, temperatures are forecast to rebound to more seasonable, and even above average, levels by the end of week.

Image Credit: Mesonet

Image Credit: Mesonet

End of the 2013 Atlantic Hurricane Season

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The 2013 Atlantic Hurricane Season officially ends today.  Contrary to early predictions, it was relatively quiet.

There were thirteen named storms this season, which is one above average, but only two developed into hurricanes – Humberto and Ingrid.  According to NOAA, that is the least number of hurricanes to form in the Atlantic basin since 1982.  Both storms were also considered very weak. Neither was rated higher than category-1 on the Saffir-Simpson Scale.  On average, the Atlantic produces three major hurricanes, category-3 or higher, every year.

Throughout the season, which runs from June 1st to November 30th, only one named storm made landfall in the U.S.  In early June, Tropical Storm Andrea brought flooding rains and tornadoes to parts of the south, causing one death.

While the exact causes behind this very mild season are being researched, experts say broad areas of high pressure, dry air, and stronger than expected wind shear hindered most tropical development.

Source: NOAA

Source: NOAA

Natural Disasters and Public Health

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Weather-related natural disasters have occurred throughout human history.  Their frequency and intensity, however, have been on the rise in recent years and health professionals have taken notice.

According to a report recently published in the New England Journal of Medicine, there were three times as many natural disasters between 2000 and 2009 as compared to 1980 through 1989. Dividing the events into two major categories, climate-related (storms, floods, heat-waves, etc.) and geophysical (volcanic eruptions, earthquakes, etc.), the report found that 80% of the increase was due to a rising number of climate-related disasters.

The report explains, “During recent decades, the scale of disasters has expanded owing to increased rates of urbanization, deforestation, and environmental degradation and to intensifying climate variables such as higher temperatures, extreme precipitation, and more violent wind and water storms.”  It also cautions that “natural disasters, particularly floods and storms, will become more frequent and severe because of climate change.”

Impacting nearly five billion people since 1990 (approximately 217 million people per year), each disaster has generated serious public health concerns including large numbers of fatalities, injuries, and the outbreak of disease.

EM-DAT International Disaster Database, Center for Research on Epidemiology of Disasters, University of Louvain.

Geophysical Disasters vs Climate-related Disasters                                                                            Graph Credit: EM-DAT International Disaster Database, Center for Research on Epidemiology of Disasters, University of Louvain.

Late Fall Tornado Outbreak in the Midwest

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Severe weather, including a massive series of tornadoes, roared across the American Midwest on Sunday.  These powerful storms caused widespread damage and knocked out power to tens of thousands of people.  Numerous injuries and at least eight fatalities have been reported so far.

NWS survey teams are currently on the ground evaluating the damage, but early reports estimate that several dozen twisters touched down across seven states. The two strongest have been preliminarily rated EF-4, the second highest ranking on the Enhanced Fujita Scale.  With winds raging between 166 and 200 mph, they devastated the towns of Washington and New Minden, both in Illinois.  Officials say these were the strongest and deadliest November tornadoes on record in the state.

This historic outbreak was the result of an explosive mix of atmospheric conditions, including instability generated by the collision of a cold front with warm, moist air moving up from the south.  In addition, the combination of a powerful jet stream aloft and a strong area of low pressure near the ground – with winds blowing in the opposite direction – helped generate spin in the atmosphere.

While autumn, the so-called second season for tornadoes, has been known to produce severe storms, they usually occur in the warmer climates of the Southeast and Gulf Coast. Twisters further north, especially powerful ones, are very rare for this time of year.

Damage from tornadoes near washington, IL

Damage from tornadoes near Washington, IL                                                                                     Image Credit: A. Koury

NOAA

Image Credit: NOAA

 

Super Typhoon Haiyan

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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.

typhoon_Haiyan_noaa

Super Typhoon Haiyan approaches the Philippines.

Image Credit: NOAA