Tag Archives: WRN

2017 Atlantic Hurricane Season Outlook: Above Average

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The number of hurricanes that develop in the Atlantic varies from year to year. For 2017, NOAA’s Climate Prediction Center is forecasting an above average season.

Tropical cyclones, known as hurricanes in the United States, develop around the globe at different times of the year. In this country, we are most impacted by the Atlantic hurricane season, which affects the North Atlantic Ocean, Caribbean Sea, and the Gulf of Mexico. It runs from June 1 through November 30.

Overall, NOAA predicts a 70% likelihood of eleven to seventeen named storms forming this season, of which five to nine could become hurricanes, including two to four major hurricanes. A major hurricane is one that is rated category 3 or higher on the Saffir-Simpson scale.

The numbers for this season’s outlook include Tropical Storm Arlene, a rare pre-season storm that developed in April.

According to NOAA, “The outlook reflects our expectation of a weak or non-existent El Niño, near or above-average sea surface temperatures across the tropical Atlantic Ocean and the Caribbean Sea, and average or weaker-than-average vertical wind shear in that same region.” El Niño conditions in the Pacific tend to cause increased wind shear in the Atlantic, which suppresses tropical development.

Regardless of the number of storms that actually form, it is important to remember that it only takes one land-falling system in your community to make it a memorable season.

Source: NOAA

Dressing for Cold Weather

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When winter rolls around, I am often reminded of the old Scandinavian saying: “There is no such thing as bad weather, only inappropriate clothing.”

Since the weather is going to do whatever it is going to do, we all need to be aware of our environment and prepare for what Mother Nature throws our way. In winter, that means cold temperatures.

Extreme cold causes the body to lose heat faster than it can be generated. Prolonged exposure, according to the CDC, can cause serious health problems such as hypothermia and frostbite.

To stay safe this winter, remember to bundle up in layers and wear hats and gloves to minimize the loss of body heat.

Credit: NOAA

Credit: NOAA

GOES-R Satellite will Improve Weather Forecasts

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Satellites have helped forecasters predict the weather for more than forty years. Now, they are getting a major upgrade.

Launched from Cape Canaveral Air Force Station on Saturday night, the GOES-R is the newest model in NOAA’s Geostationary Operational Environmental Satellite series. It has been nearly a decade since the last upgrade and this one is loaded with new technology.

Carrying 34 different weather products, the main instrument is the Advanced Baseline Imager (ABI). Essentially a camera that views the western hemisphere’s weather, oceans, and environment, it offers 3 times the spectral information, 4 times the spatial resolution, and temporal coverage that is five times faster than the previous GOES model. In other words, it will provide a clearer and faster image of what is going on in the atmosphere than ever before, allowing for better forecasts. This, in turn, means improved protection for lives and property, which is the main mission of the National Oceanic and Atmospheric Administration.

Other instruments onboard include a lightning mapper, which will continuously measure the lightning activity over both North and South America. This information is important because the rate of lightning is related to a storm’s updraft. Better lightning data can increase the lead-time for warnings on storms that could produce severe weather. Another important device is the magnetometer. It will monitor space weather such as solar storms  that produce the northern lights and can, when strong enough, disrupt power grids and telecommunications.

Once in orbit, GOES-R will become known as GOES-16 (letters are only used while it is in development on the ground). After a calibration and testing period of several months, its data will become available to forecasters. If all goes well, it should be online by next year’s hurricane season.

GOES-R satellite. Credit: NOAA

GOES-R satellite. Credit: NOAA

The Weather Gamut Becomes a Weather-Ready Nation Ambassador for NOAA

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It’s official! The Weather Gamut is now a Weather-Ready Nation (WRN) Ambassador for the National Oceanic and Atmospheric Administration (NOAA).

As a member of the WRN Initiative, The Weather Gamut is committed to working with NOAA to help increase awareness and strengthen resilience to our nation’s increasing vulnerability to extreme weather and climate events.

Be it hurricanes, tornadoes, snowstorms, heat waves, cold waves, drought, or flooding, every part of this country is subject to extreme weather. Therefore, it is vital that we, as a nation, improve our readiness, responsiveness, and resiliency to these environmental hazards that threaten lives and property.

Look for articles tagged “WRN” on our website to learn more about different types of extreme weather and climate events and how to prepare for them.

For more info on NOAA's WRN Initiative: http://www.nws.noaa.gov/com/weatherreadynation/

Weather-Ready Nation Ambassador™ and the Weather-Ready Nation Ambassador™ logo are trademarks of the U.S. Department of Commerce, National Oceanic and Atmospheric Administration, used with permission. For more information, click  here.

Why Hurricanes Hit the East Coast and Not the West Coast of the US

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It is mid-September and hurricane season is in full swing in both the Atlantic and Pacific. With these mighty oceans bordering both sides of the US, have you ever wondered why hurricanes only make landfall on the east coast?

The answer is two-fold, involving the direction of prevailing winds in the tropics and the difference in water temperature in the two basins.

Hurricanes develop at tropical and sub-tropical latitudes in both the Atlantic and Pacific, where water temperatures are at least 80°F. This part of the globe is also where the Trade Winds prevail, flowing from east to west.

In the Atlantic, storms traveling west-northwest often run into the east coast or Gulf Coast of the US. There, the warm waters of the Gulf Stream that flow along the eastern seaboard sustain them as they move northward.

In the Pacific, storms tend to be pushed out to sea by the Trade Winds.  Any hurricanes that manage to move north quickly dissipate when they encounter the cooler waters of the California current that flows southward along the west coast from Canada.

Only two tropical systems have ever made landfall on the west coast of the US. A hurricane slammed San Diego, CA in 1858 and a tropical storm battered Long Beach, CA in 1939. That said, hurricanes and tropical storms generally have indirect impacts on the western states. When a named storm makes it as far north as Baja California, remnants of it can travel across the border and cause heavy rain and flooding in parts of the American southwest.

1851_2013_hurr

All North Atlantic and Eastern North Pacific hurricanes, through 2013. Credit: NOAA/NWS

What is a Heat Dome?

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Summer is the season for warm weather. So, when temperatures reach 5°F to 10°F above average, it can be excessively hot. When this type of weather lasts for multiple days, it is usually the result of a phenomenon known as a “heat dome”.

Although not an official meteorological term, it does help paint a picture of what is happening. To start, an area of high pressure develops under a ridge in the jet stream. Acting like a lid in the upper atmosphere, it forces warm air that would normally rise to sink back toward the surface. As it sinks, it compresses and warms even further. Unable to escape, the hot air is remains in place until the ridge breaks down or moves.

Heat domes are not rare events, but when they produce extended heat waves and poor air quality, they can pose serious dangers to human health.

A Heat Dome forms in the upper atmosphere. Credit: NOAA

A Heat Dome forms in the upper atmosphere. Credit: NOAA

How Dangerous is Lightning?

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Big summer thunderstorms are impressive to watch. However, they are also extremely dangerous.

According to NOAA, lightning is the second deadliest type of weather in the US after floods. On average, it claims the lives of 49 people every year in this county and seriously injures even more. This year, to date, lightning has killed 16 people across nine states. Two were struck just this week.  Sadly, this number will likely go up before the summer is over.

Lightning comes in variety of forms, but the cloud to ground variety is the most threatening to us at the surface. A typical bolt carries a current of about 300 million volts and can heat the air around it to 50,000°F. That is five times hotter than the surface of the sun.

Around the globe, lightning hits the Earth about 100 times per second. In the US, the odds of a person being struck by lightning in any given year are 1 in 960,000 or 1 in 12,000 during an average lifetime of 80 years.

So, to avoid becoming a statistic, follow the advice of the NWS – “When thunder roars, go indoors.”

Credit: NOAA

Credit: NOAA

thunderroars_goindoors

Credit: NOAA/NWS

2016 Atlantic Hurricane Season Outlook

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The number of hurricanes that develop in any given year varies, and this year, NOAA’s Climate Prediction Center is forecasting a “near normal” season in the Atlantic.

Tropical cyclones, known as hurricanes in the United States, develop around the globe at different times of the year. In this country, we are most affected by the Atlantic hurricane season, which impacts the North Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. It runs from June 1 through November 30.

Overall, NOAA predicts a 70% likelihood of ten to sixteen named storms forming this season, of which four to eight could become hurricanes, including one to four major hurricanes. A major hurricane is one that is rated category 3 or higher.

The numbers for this season’s outlook include Hurricane Alex, the unusual storm that developed in the eastern Atlantic in mid-January.

One of the main drivers behind this season’s average to slightly above average forecast is the diminishing presence of El Niño and the likely development of La Niña in the autumn. El Niño conditions tend to suppress tropical activity in the Atlantic while La Niña conditions do the opposite.

After three consecutive below average hurricane seasons in the Atlantic, a normal season will likely feel very active. But regardless of the number of storms that actually form, it is important to remember that it only takes one landfalling system in your community to make it a memorable season.

Source: NOAA

Source: NOAA

How Does Hail Get to be the Size of a Grapefruit?

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Spring is considered severe weather season in the Central US and on Tuesday the power of Mother Nature was on full display across the region. More than 300 severe storm reports were counted and the vast majority included very large hail.

In Kansas and Nebraska, hailstones the size of a grapefruit were reported. Those are balls of ice measuring about four inches in diameter. According to the NWS, once a thunderstorm produces hail with a one inch diameter or more it is considered severe. So, how does hail get that big?

The answer to that question lies with the speed of a storm’s updraft. Basically, the stronger the updraft, the longer the ice remains suspended in the cloud where it can grow larger. Below is a chart that shows approximately how strong an updraft has to be to support different sizes of hail.

The largest hailstone ever recorded fell in Vivian, South Dakota on July 23, 2010 and measured eight inches in diameter – about the size of a volleyball. To support a hailstone that size, the updraft likely exceeded 150mph.

Credit: NWS

Credit: NWS

What is a Blizzard?

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A blizzard is expected to blast a large part of the northeastern United States, including NYC, this weekend. Different than a typical winter storm, a blizzard is characterized more by its winds than the amount of snow it produces.

According to the NWS,  the three key factors in a blizzard are wind, visibility, and time. More specifically, they 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 – Wind and reduced visibility conditions must prevail for at least 3 hours.

These conditions heighten the risk for power outages and often produce whiteout conditions on roadways, making travel extremely dangerous.  Stay Safe!