How to read a hurricane cone graphic

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The National Hurricane Center’s forecast cones aren’t what some people think.

The cone is the best estimate of where the center of the storm will land. That’s why it’s unwise to focus on the center of the cone. The cone is not the prognosis. It is in fact the average of the errors.

The average error on the fifth day of the cone is about 200 miles. For this reason, meteorologists advise us to pay attention to the entire cone. A third of the time, on the fifth day, the center of the hurricane is not even in the initial cone.

The National Hurricane Center says it “builds the cone by enclosing the area swept by a series of circles along the forecast track (at 12, 24, 36 hours, etc.)”. These circles are the labels you see on the trace line. The National Hurricane Center states:

One can also examine historical traces to determine how often a cyclone’s entire 5-day path stays entirely within the cone area. This is a different perspective that ignores most time errors. For example, a storm moving very slowly but in the expected direction would still be within the range of the cone, even though the course prediction error could be very large. Based on forecasts over the past 5 years, the entire tropical cyclone track can be expected to stay within the cone about 60-70% of the time.

The size of the cone is not an indication of how severe a storm will be.

The National Hurricane Center updates its forecast at 5:00 a.m., 11:00 a.m., 5:00 p.m. and 11:00 p.m

While the cone is sometimes referred to as the “cone of uncertainty,” hurricane tracking has become extremely accurate. But as with any weather forecast, the further you forecast, the less accurate it becomes, as there are so many factors to consider.

It may be human nature to worry about the upcoming emergency and forget about the one a week ago. Puerto Rico is still suffering from Hurricane Fiona. Almost half of the island’s population has no electricity and every fifth inhabitant has no water connection.

I want to be sure that the damage done to Canadian Maritimes doesn’t blow us up. It was the strongest tropical storm in Canadian history. The CBC reports:

Communities in southwest Newfoundland are grappling with significant damage, including lost homes, flooding and road washing from post-tropical storm Fiona.

Everything east of City Hall in Port aux Basques is under an emergency evacuation order as high winds and storm surges hit the town.

“What is actually happening here is total devastation,” Mayor Brian Button said.

NASA reminds us, “21 percent more storms form for every 1.8 degrees Fahrenheit (1 degree Celsius) that sea surface temperature rises. … ‘It is reasonably common sense that severe storms will increase in a warmer environment.’”

NASA research shows, “Extreme storms — those that produce at least 0.12 inches (3 millimeters) of rain per hour over an area 16 miles (25 kilometers) — formed when sea surface temperatures were higher than about 82 degrees Fahrenheit ( 28 degrees) was Celsius).”

And sea temperatures have risen around the world:

Here are “real-time” Gulf of Mexico water temperatures that will affect the current system entering the Gulf.

Water temperature alone does not determine how strong a storm will be, it is a factor. The WeatherOps blog explains, “Generally, for intensification to occur, water temperatures must be at least 80°F (27°C). Hurricanes can be thought of as large heat engines; As the warm seawater in a system evaporates, latent heat is released. The warmer the water, the more latent heat is released. This latent heat causes the system to intensify. Winds can also play a role to some extent; Stronger winds carry that heat through the storm more efficiently.”

Storm surges are the other factor, along with wind, that people fear in the path of a hurricane. Storm surge is not the same as the flooding that occurs when sewer systems are flooded by heavy rain.

The National Oceanic and Atmospheric Administration reminds us, “Storm surges are often the greatest threat to life and property from a hurricane. In the past, the rise in the ocean associated with many of the major hurricanes that made landfall has caused large casualties. Hurricane Katrina (2005) is a prime example of the damage and devastation that storm surges can cause. At least 1,500 people lost their lives during Katrina, and many of those deaths occurred directly or indirectly as a result of the storm surge.”

NOAA says, “Storm surge is an abnormal rise in water generated by a storm above predicted astronomical tides. Storm surge should not be confused with storm surge, which is defined as the rise in water level due to the combination of storm surge and astronomical tide. This rise in water levels can cause extreme flooding in coastal areas, particularly when storm surges coincide with normal tides, resulting in storm surges of up to 20 feet or more in some cases.”

So how does a storm surge occur? NOAA says, “Storm surge is created by water being pushed toward shore by the force of winds moving cyclonically around the storm. The impact of the low pressure associated with intense storms on swell is minimal compared to the water being carried inshore by the wind.”

Think of it this way: imagine you put your hand in the middle of a bathtub full of water and twirl it around. The faster you twirl, the more undulations or waves you’ll see at the edge of the tub. The damage from a hurricane doesn’t just come from the wind over the surface; It can be caused by the pressure of the water on the land.

Some NOAA Surge Susceptibility Facts:

• From 1990 to 2008, population density increased by 32% in the Gulf Coast counties, 17% in the Atlantic Coast counties, and 16% in Hawaii (US Census Bureau 2010).
• Much of the densely populated United States coastline on the Atlantic and Gulf Coasts is less than 10 feet above mean sea level
• Over half of the nation’s economic productivity is in coastal areas
• 72% of the ports, 27% of the main roads and 9% of the railroad lines within the Gulf Coast region are at or below 4 feet elevation
• A 23-foot storm surge can inundate 67% of the highways, 57% of the arterial roads, nearly half of the rail miles, 29 airports and virtually all ports in the Gulf Coast region

Here are some NOAA historical storm surge events:

• Ike 2008 (SLOSH Historical Run): Hurricane Ike made landfall near the north end of Galveston Island as a Category 2 hurricane. Storm surges of 15 to 20 feet above normal tide levels occurred along the Bolivar Peninsula in Texas and much of the Galveston Bay area. Ike’s property damage is estimated at $24.9 billion. More…
• Katrina 2005 (SLOSH Historical Run): Katrina was one of the deadliest hurricanes in United States history. It caused catastrophic damage – estimated at $75 billion in the New Orleans area and along the Mississippi coast – and is the costliest US hurricane on record. Storm surge flooding of 25 to 28 feet above normal tide levels has been associated with Katrina. More…
• Dennis 2005 (SLOSH Historical Run): Dennis affected much of Florida, and its impacts extended well inland across parts of the southeastern United States, with the maximum rainfall of 12.80 inches occurring near Camden, Alabama. Storm surge flooding of 7-9 feet caused significant storm surge damage near St. Marks, Florida, far east of the landfall. The damage associated with Dennis in the US is estimated at $2.23 billion. More…
• Isabel 2003 (SLOSH Historical Run): Isabel was the worst hurricane to hit the Chesapeake Bay region since 1933. Storm surge levels in excess of 8 feet inundated rivers that entered the Bay across Virginia, Maryland, Delaware and Washington, DC, making the most violent hurricane of the 2003 season, directly resulting in 17 deaths and more than $3 billion in damage. More…
• Opal 1995 (SLOSH Historical Run): Hurricane Opal made landfall near Pensacola Beach, Florida as a Category 3 hurricane. The storm caused extensive storm surge damage from Pensacola Beach to Mexico Beach (a 120-mile span) with a maximum storm surge of 24 foot recorded near Fort Walton Beach. Damage estimates for Opal were close to $3 billion. More…
• Hugo 1989 (SLOSH Historical Run): Hugo influenced the Southeastern United States, including the cities of Charleston and Myrtle Beach, South Carolina. Hugo was responsible for 60 deaths and $7 billion in damage, with the highest storm surge estimated at 19.8 feet at Romain Retreat, South Carolina. More…
• Camille 1969 (SLOSH Historical Run): Camille was a Category 5 hurricane, the strongest on the Saffir-Simpson hurricane wind scale, with maximum winds exceeding 155 miles per hour and 24-foot storm surge flooding that devastated the Mississippi coast. The final US death toll is 256, including 143 on the Gulf Coast and another 113 from the Virginia floods. More…
• Audrey 1957 (SLOSH Historical Run): There were 390 Audrey-related deaths as a result of a storm surge over 12 feet that inundated the flat coast of southwest Louisiana in some places as much as 25 miles inland. More…
• New England 1938 (SLOSH Historical Run): The Long Island Express was a fast-moving Category 3 hurricane that struck Long Island and New England without warning on September 21. A 10- to 12-foot storm surge inundated the shores of Rhode Island. Connecticut in southeastern Massachusetts and Long Island, NY, particularly in Narragansett Bay and Buzzards Bay. The storm killed 600 people. More…
• Galveston 1900 (SLOSH Historical Run): At least 8,000 people died when hurricane storm surges (the surf plus the astronomical tide) from 8 to 15 feet high inundated most of the island city of Galveston, TX, and adjacent mainland areas. More…

Chris Wallace’s new show debuted Sunday night on CNN. Is this the clip that will last? Oh, and he did interview former Supreme Court Justice Stephen Breyer, but there was no singing in that segment.

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