Tag Archives: national

Subtropical Storm Ana: First Named Storm of 2015 Atlantic Season

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Subtropical storm Ana, the first named storm of the 2015 Atlantic Hurricane Season has officially formed. With winds measured at 45mph earlier today, the center of this pre-season storm is located about 180 miles southeast of Myrtle Beach, SC.

According to the National Hurricane Center (NHC), Ana is expected to bring heavy rain and gusty winds to parts of both North and South Carolina over the next few days. It will also produce rough surf and dangerous rip currents along the coast.

A subtropical storm is a hybrid of a regular storm, fueled by the clash of warm and cold air, and a tropical storm, powered by the heat and moisture of warm ocean waters. Ana’s hybrid nature means that it has the potential to transition into a fully tropical system, especially as it sits over the warm waters of the Gulf Stream. This is why the NHC assigned it a name.  In May 2012, this type of transition happened with Tropical Storm Beryl, which was the strongest pre-season tropical cyclone to make landfall in the US.

While pre-season storms tend to occur every five years of so, Ana is the earliest named storm to form in the Atlantic since April 2003 when a tropical storm also named Ana developed. The Atlantic hurricane season officially begins on June 1.

Satellite view of Subtropical Storm Ana off the Carolina coast. Image Credit: NASA

Satellite view of Subtropical Storm Ana off the Carolina coast. Image Credit: NASA

Deadly Tornado Devastates Towns in Northern Illinois

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A tornado outbreak barreled across the mid-west on Thursday night. The strongest of these twisters caused widespread destruction, two deaths, and at least twenty injuries in the neighboring towns of Fairdale and Rochelle in northern Illinois.

The National Weather Service has given the deadly tornado a preliminary rating of EF-4, the second highest ranking on the Enhanced Fujita Scale. Measuring a half-mile wide with winds near 200mph, the wedge shaped twister is reported to have traveled nearly thirty miles on the ground.

Local officials in Fairdale say the storm affected every home in the community with eighteen swept completely off their foundations. The tornado also destroyed many trees and power lines across the area and even toppled a tractor-trailer on Interstate-39.

Tornadoes of this intensity are not that common in northern Illinois. The NWS says Thursday’s storm was the strongest tornado on record (since 1950) for the two counties where Fairdale and Rochelle are located – DeKalb County and Ogle County, respectively.

Year to date, tornado season – which typically begins to ramp up in March – has been fairly quiet. But, as this latest storm shows, it only takes one tornado to devastate a community.

Tornado Damage. Image Credit: Rockford Fire Dept.

Tornado Damage. Image Credit: Rockford Fire Dept.

Mandatory Water Restrictions Issued for Drought-Stricken California

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In response to the multi-year drought that has been plaguing California, Governor Jerry Brown issued an executive order on Wednesday that requires water usage across the state to be reduced by 25%. This is the first time statewide mandatory water restrictions have been enacted in California.

Standing on a dry patch of land in the Sierra Nevada Mountains that is normally covered with five feet of snow at this time of year, the governor said, “We are in a historic drought and that demands unprecedented action.” Last year, the state declared a drought emergency and asked residents to voluntarily reduce their water usage by 20%. This year, the reductions are compulsory and will be enforced with hefty fines for those who do not comply.

Statewide, according to the California Cooperative Snow Survey Program, the Sierra Snowpack is about 5% of normal for the date. Acting like a savings account, the snowpack is a critical part of the state’s water supply. They store water from the wet winter  season and slowly release it to rivers and reservoirs as they melt in the spring and summer.

The current California drought – now in its fourth year – is considered the worst drought on record in the state since 1895. Scientists who study historical climate proxies, such as tree-rings, say this drought is possibly the worst the region has seen in 1000 years.

California is no stranger to drought, but experts say warming conditions related to climate change are making this event worse than it would be otherwise. Once drought takes hold of a region, it tends to feed on itself in a vicious cycle. To start, high temperatures increase evaporation rates causing the soil to dry out.  Without plentiful rain to replace the moisture, the sun’s energy heats the ground and the air even further making the affected area even drier.   California, according to NOAA, just had its warmest winter on record. The previous record was set only last year.

Local water agencies across the state will be responsible for implementing the cutbacks required by the governor’s executive order and for monitoring compliance.

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Lack of Snow Pushes Iditarod Race North

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Record cold and snowy conditions have dominated the weather in the eastern US this winter. The western part of the country, however, has been exceptionally warm and dry. That includes Alaska, where the famous Iditarod Dog Sled Race got underway today.

Due to a lack of snow, this year’s Iditarod had to be moved north 225 miles from its traditional starting point in Anchorage, AK to Fairbanks, AK. In a typical winter season, the city of Anchorage collects 60 inches of snow. So far this year, they have only received 20 inches.

Meteorologists at the NWS office in Anchorage attribute Alaska’s unseasonably warm winter and its dearth of snow to a highly amplified jet stream, which allowed warmer Pacific air to dominate the region. Above average sea surface temperatures along the coastline of this country’s northern most state also contributed to its unusually mild conditions.

Ending in Nome, AK, the annual race spans 1000 miles of arctic tundra and commemorates the journey made by dogsledders in 1925 to deliver medical supplies for a diphtheria outbreak in that city. This year was the second time in the event’s 43-year competitive history that the starting point had to be moved because of poor snow conditions. The last time was in 2003.

Iditarod

Musher and dog sled team on the Iditarod Trail, AK.   Credit: ADN

Weather History: National Weatherperson’s Day

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Today is National Weatherperson’s Day in the United States. While not an official federal holiday, it is a day to recognize the work of all individuals involved in the field of meteorology – not just prognosticating groundhogs.

According to the NWS, February 5, 1744 was the birthday of Dr. John Jeffries – one of America’s first weather observers.  As a Boston based physician with a deep interest in weather, he kept detailed records of daily weather conditions from 1774 to 1816.  He also took the first known weather observation from a hot air balloon in 1784. Recognizing the significant contributions Dr. Jeffries made to the science of weather, this date was chosen in his honor.

Technology has grown by leaps and bounds since the 18th century, but the core work of meteorologists has not changed. They continue to gather and analyze weather data to provide forecasts and warnings to the public in an effort to protect lives and property across the country.

Dr. John Jeffries taking weather measurements from hot air balloon. Source: Wonderful Balloon Acesnts

Dr. John Jeffries taking weather measurements from a hot air balloon in 1784.  Source: Wonderful Balloon Ascents.

Groundhog Day 2015

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Today is Groundhog Day, the midpoint of the winter season.

On this day, according to legend, the weather conditions for the second half of winter can be predicted by the behavior of a prognosticating groundhog.  If the groundhog sees its shadow after emerging from its burrow, there will be six more weeks of winter.  If it does not see its shadow, then spring will arrive early.

The practice of using animal behavior to predict future weather conditions goes back to ancient times.  The particular custom that we are familiar with in the United States grew out of the old world tradition of Candlemas brought by German settlers to Pennsylvania in the 1880s. Today, many communities across the U.S. and Canada continue this age-old ritual with their own special groundhogs.

The most famous of these furry forecasters is Punxsutawney Phil from Pennsylvania – he was portrayed in the 1993 film, “Groundhog Day”. This year, despite an overcast sky, Phil saw his shadow and is calling for six more weeks of wintry conditions.

In New York City, our local weather-groundhog is Charles G. Hogg – more popularly known as “Staten Island Chuck”.  Coming out of his burrow this morning, he did not see his shadow and is predicting an early spring for the Big Apple.

Long-range forecasts are a tricky business, so a difference of opinion is not that uncommon. Either way, the spring equinox is 46 days away.

The Chances for a White Christmas 2014

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The Holiday Season is here and many people are dreaming of a white Christmas. The likelihood of seeing those dreams come true, however, are largely dependent on where you live.

According to NOAA, a white Christmas is defined as having at least one inch of snow on the ground on December 25th.  In the US, the climatological probability of having snow for Christmas is greatest across the northern tier of the country. Moving south, average temperatures increase and the chance of snow steadily decreases.

Here in New York City, the historical chance of having a white Christmas is about 12%. This low probability is largely due to the city’s proximity to the Atlantic Ocean and its moderating influence on temperature. This year, with rain and unseasonably warm temperatures in the forecast, the city’s already minimal chance for snow has largely melted away.

Snow or no snow, The Weather Gamut wishes you and your family a very Happy Holiday!

Source: NOAA

Data based on the latest (1981-2010) U.S. Climate Normals from NOAA’s National Climatic Data Center. Source: NOAA

Drought Update: Late Autumn 2014

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Over the past few weeks, rounds of intense rainstorms fueled by a phenomenon known as a Pineapple Express have soaked the west coast of the United States and helped put a modest dent in California’s nearly 3-year drought.

According to the latest report from the US Drought Monitor, 32% of California is currently facing conditions of “exceptional drought”, the worst possible category. That is an improvement from last week’s 55%.   Nonetheless, 100% of California – a state generally considered to be one the most productive agricultural regions in the world – is still in some form of drought.

Water levels in reservoirs throughout this country’s most populated state also remain low. Lake Shasta and Lake Oroville, the two largest reservoirs in California, are both currently at 33% of total capacity and only 55% of the historical average for the date.

With winter considered the “rainy season” in California, it is possible for additional storms to continue slowly reducing the region’s long-term drought conditions. Scientists working with NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites say that California needs 11 trillion gallons of water, enough to fill more than 16 million olympic-size swimming pools, to completely end the drought.

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Credit: US Drought Monitor

Lake-Effect Snow

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A relentless snowstorm buried the Buffalo area of western New York State with more than 5 feet of snow this week. Situated on the shore of Lake Erie, the impressive accumulation was the product of a meteorological phenomenon known as “Lake-Effect Snow.”

Lake-effect snowstorms, according to NOAA, develop when cold air blows across the warmer waters of a large unfrozen lake. The bottom layer of the air mass is warmed by the water and allows it to evaporate moisture, which forms clouds. When the air mass reaches the leeward side of the lake its temperature drops again, because the land is cooler than the water. This releases the water vapor as precipitation and enormous amounts of snow can accumulate. The effect is enhanced if the air is lifted upward by local topography.

With the clouds typically forming in bands, the snowfall is highly localized. Some places can see the snow come down at a rate of more than 5 inches per hour, while others will only get a dusting. The shape of the lake and the prevailing wind direction determines the size and orientation of these bands.

Fetch, the distance wind travels over a body of water, also plays a key role. A fetch of more than 60 miles is needed to produce lake effect snow. In general, the larger the fetch, the greater the amount of precipitation, as more moisture can be picked up by the moving air.

The massive surface area of the Great Lakes in the northern United States make them excellent producers of lake-effect snow. With northwesterly winds prevailing in the region, communities along the southeastern shores of the lakes are often referred to as being in the “Snowbelt.”

Credit: NOAA

Credit: NOAA

The Polar Vortex: A Widely Misused Weather Term

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An early season arctic blast has sent temperatures across most of this country plummeting well below average this week and brought last winter’s buzzword, the polar vortex, back into the spotlight. From advertisements for winter coats to social media hashtags for almost anything cold, this technical meteorological term is being widely misused.

A polar vortex, according to NOAA, is a massive and persistent high altitude low-pressure system present over both poles of this planet. Basically a whirlpool-like wind pattern, the northern hemisphere’s polar vortex is anchored above the Arctic. It, as a whole, does not move south over the US.  That said, pieces of it can ocassionally meander southward and influence our weather via the position of the polar jet stream.

When the polar vortex is strong, the jet stream generally flows in a smooth circular pattern from west to east and bottles up the Arctic’s coldest air.  When weak or displaced by an area of high pressure, the shape of the jet stream distorts into a wavy, more north to south pattern.  This allows cold air influenced by the polar vortex to push southward.  When this happens, it is called a polar outbreak.

This week’s unseasonably cold temperatures are the result of a large ridge in the jet stream to our west that was enhanced by former typhoon Nuri in the Pacific.  It, in turn, has caused a sizable trough to develop east of the Rocky Mountains and allowed cold arctic air to flow deep into the US.

In the video below, Dr. Mark Serezze, Director of the National Snow and Ice Data Center, explains exactly what the polar vortex is, how it works, and how climate change may play a role in its future.

Video credit: EarthVisionTrust and YouTube