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The Free Press WV

►  Science Says: Sorting the ‘spaghetti’ of hurricane scenario

Hurricane Irma, with its record strong winds, is lashing the Caribbean but where will it go from there?

Forecasters turn to computer simulations to try to predict a storm’s path and how strong it will be.

Different computer models — often run by different governments and various agencies — use different recipes or formulas to mimic the atmosphere.  They all also approximate current conditions differently.

So the resulting models look like a plate of spaghetti thrown on a map. But in that messy mass, meteorologists can get an increasingly strong idea of where a storm like Irma is heading.

A look at how those predictions are made:


WHO TO TRUST

The place to start is the National Hurricane Center’s official forecast, say several meteorologists who are not part of the federal government. “You can’t beat the hurricane center forecast,” said Miami television meteorologist Max Mayfield, who was the director of the hurricane center from 2000 to 2007.

The hurricane center sees computer models other people don’t, judges individual models and uses a consensus of the better performing models, he said. The center also shows how well they do over time — and they are doing better.  The trouble, say those experts, is that those same images of models are spreading over social media and they are getting misread. There are even bogus hurricane tracks spreading on social media.


HOW GOOD ARE THE PREDICTIONS

Forecasters track the beginnings of storms, whether they come out of unstable weather that pops up in the Gulf of Mexico, or chug off Africa in classic Atlantic storm mode like Irma. The models usually agree about where the storm will go for the next 12 to 24 hours and the spread out with time.

Today, the five-day forecast is as good as the three-day forecast was 15 years ago. And the margin of error for the five-day track forecast is nearly half of what it was when it was first introduced in 2001. What’s key is that meteorologists don’t stick to a single line or track because a slight change can mean a big difference, Mayfield said. For example, a tiny turn over Cuba, where mountains can eat up storms, can weaken Irma considerably.


WHAT GOES INTO A MODEL

Computer models are like massive apps that try to solve complex equations that simulate the behavior of the atmosphere and oceans, said MIT meteorology professor Kerry Emanuel. Usually they don’t go much farther out in time than five days, and if they do, it’s with decreasing accuracy. They use real-time readings of wind, temperature, air pressure, humidity and more. But those real-time readings are sparse and spread out over the open Atlantic.

Sometimes the models point to the same general conclusion, like Superstorm Sandy hitting the New York-New Jersey area. The models did well about five days out in 2012, said Emanuel. Sometimes they are all over the place. This time they are in between, not widespread but not clustered, he said.


THE BETTER MODELS

The top performing model is usually the European model, which is slightly ahead in long-term accuracy over the American one, Emanuel said. But that doesn’t mean the European will be better every time, he said.

“Good forecasters look at the whole suite” of models, Emanuel said.

And sometimes one model is just nailing a certain storm so you stay with the hot model.

Forecasters also run so-called ensembles with as many as 51 tweaks to the data and formulas. They are lower resolution and quality but provide more information and possibilities for forecasters.


WHAT SHOULD YOU LOOK FOR

“The best guide for risk is to look at the cone” of projected landfall, often called the “cone of uncertainty,” said Jeff Masters, meteorology director at the private forecasting service Weather Underground. If you are in the cone, you should be concerned and prepared, he said. Even if you aren’t in the cone but nearby, you need to pay attention.

The trouble is with the spaghetti of models, people focus too intently on one line, Masters said. The hurricane center cone only goes out five days — and people want to know if they are in danger earlier, Masters said. So that’s when they turn to the longer range models even if it is beyond that cone.

Hurricane Irma Strengthens to Category 4 on Its Track Toward the U.S.

The Free Press WV

It’s looking more likely that Hurricane Irma will affect the U.S. coast - potentially making a direct landfall - starting Friday. The powerful storm strengthened to a Category 4 on Monday with maximum sustained winds of 130 mph.

As it tracks west toward the Caribbean, hurricane warnings have been issued for portions of the Leeward Islands and the Greater Antilles. A hurricane warning is in effect for Puerto Rico.

“Preparations within the warning area should be rushed to completion,“ the National Hurricane Center said in an update Monday afternoon.

Over the weekend, the forecast track for this potentially devastating hurricane shifted south and west. It seems likely now that the storm will impact or strike the U.S. coast early next week, although meteorologists don’t know exactly where. Florida and the Gulf Coast continue to be at risk. The East Coast, including the Carolinas and the Delmarva Peninsula, are also potential candidates for landfall - or, at the very least, heavy rain, strong winds and coastal flooding.

Predictions will improve over the coming days, narrowing down exactly which region will endure the effects of the season’s next major hurricane.

Irma has entered into a favorable environment for strengthening, with warm sea surface temperatures and favorable upper-level winds allowing the storm to intensify even more over the next 24 hours. As of 11 a.m. Monday, the National Hurricane Center predicted the storm will pass just north of the island of St. John on Wednesday morning as a Category 4 with winds over 130 mph.

Late Sunday afternoon, Hurricane Hunters began regular flights into Irma, providing extremely valuable data that has improved forecasts. The immediate track of Irma through the middle of the week is not much of a question at this point; an area of high pressure is firmly in place over the central Atlantic, preventing Irma from recurving and escaping out to sea. That high won’t move much over the next several days, steering Irma due west into the Leeward Islands by midweek.

Overnight, both the American and European models started to show more consistency in a forecasted track for Irma that increases the chances of impacts on the U.S. coast. Irma will probably continue to be suppressed by the strong Atlantic high pressure beyond Wednesday, keeping the storm at major hurricane status and on a trajectory that places the storm in close proximity to Florida by next weekend.

- - -

Forecasts beyond the five-day mark are still full of uncertainties, but the trend in both the American and European ensemble members is concerning. It’s becoming less likely that Irma will escape out to sea, and the chances of a U.S. landfall have increased.

At this point, trying to predict the exact location for Irma’s landfall is no better than a guessing game. There is strong agreement in Irma’s path through Friday, at which point Irma will probably be a major hurricane located just to the south of the Bahamas. Beyond that, the large-scale features that will ultimately control Irma’s final destination are not predictable at this point.

Given what we know at this juncture, it’s best to plan for potential impacts rather than exact forecasts. The National Hurricane center is forecasting tropical storm conditions to begin affecting Florida by late Friday afternoon. All of the usual hazards are at play here; strong winds, heavy rain and dangerous storm surge. Storm surge may become the largest concern over the next few days, given the amount of time that Irma is spending over open water combined with the low lying topography of southern Florida.

Again, it should be noted that the forecasted track for Irma will continue to change as we start to receive more aircraft data on the storm and as the large scale environment features become more clear. At this point, residents from the gulf all the way to Maine should take special interest in forecast updates for Irma throughout the week.

How to Make 500-Year Storms Happen Every Year

The Free Press WV

Here’s a bit of Houston history for you, courtesy of the Harris County Flood Control District:

When the Allen brothers founded Houston in 1836, they established the town at the confluence of the Buffalo and White Oak bayous. Shortly thereafter, every structure in the new settlement flooded.

And so things continued for the next century:

Harris County suffered through 16 major floods from 1836 to 1936, some of which crested at more than 40 feet, turning downtown Houston streets into raging rivers.

In 1937, the flood control district was founded. Together with the U.S. Army Corps of Engineers, it set to work building dams and deepening channels to keep floodwaters away from downtown Houston and residential neighborhoods throughout the county. For more than half a century, these efforts succeeded in preventing region-wide floods, although there were certainly some terrible local ones, like the 1994 rainfall that devastated areas north of Houston.

Then, in 2001, came Tropical Storm Allison, a “500-year storm” that dumped more than 2 feet of rain on the area and flooded 73,000 homes. More recently there were the paralyzing Memorial Day floods of 2015 and Tax Day floods of 2016, also “500-year” events by some standards.

And now the soggy remnants of Hurricane Harvey, which have already generated at least a 500-year-flood, and maybe a 1,000-year event.

So either Houston has been desperately unlucky lately, or something has changed to sharply increase the likelihood of epic floods.

One much-discussed potential culprit is global warming, which while it hasn’t clearly increased the frequency of tropical storms does appear to be bringing periods of much more intense rainfall. By causing sea levels to rise it’s also raising the risk from hurricane storm surges, although that hasn’t been the issue with Harvey and Houston.

A far more dramatic change, though, is that in 1940, when organized flood control efforts were just getting going, there were 528,961 people in the Houston metropolitan area. Now there are 6.8 million. That not only means millions more houses to flood, but also fewer places for water to soak harmlessly into the ground. Just between 1996 and 2011, marine science professor Sam Brody, of Texas A&M University at Galveston, estimates the Houston area saw a 25 percent increase in the area covered by impervious surfaces such as buildings and pavement.

This argument – that the Houston area has built its way into recurring disaster – is still pretty controversial in a place where development is gospel. As the outgoing head of the flood control district, Mike Talbott, told the Texas Tribune and ProPublica last summer, the idea that “these magic sponges out in the prairie would have absorbed all that water is absurd.“

But something is different. As the 2016 Texas Tribune/ProPublica series in which his quote appeared documented – and Harvey has made even clearer – neighborhoods in and around Houston that never flooded before are flooding now. Successfully reducing the risk of floods after 1937 enabled the Houston area to boom so spectacularly that the flood-risk-management measures that worked from 1937 to 2000 just aren’t doing the trick anymore.

This is the point where, as a card-carrying East Coast opinion merchant, I’m supposed to shake my head disapprovingly about people choosing to live in a sprawling, freeway-laced city built on boggy flatlands abutting a hurricane-prone sea. But all big cities are nature-defying creations, and Houston’s build-first-ask-questions-later approach to development has in some ways been its greatest economic strength. It has produced a gloriously vibrant, diverse, inventive, adaptable metropolis.

Now comes another opportunity for adaptation. In 1937, Houston and Harris County figured out a way to keep floods from thwarting their growth. They and surrounding counties are going to have to do it again.

This time political advances – revamping flood insurance, reclaiming green space and so on – seem at least as important as technical ones, and political advances are usually much harder. Still, figuring out new ways to grow is what Houston does. Don’t count it out.

NWS: Harvey Rains Could Near 2 Inches in Parts of West Virginia

The Free Press WV

The storm named Harvey is “in the process of dying,” according to the National Weather Service.

“As it kind of dies, it doesn’t have a whole lot of energy left to work with,” explained Jonathan Wolfe, a meteorologist with the National Weather Service in Charleston, on Thursday.

By the time it gets to West Virginia, “It will still be a fairly wet system,” he said.

“You’ll have a couple of soggy days, mainly Friday afternoon through Saturday morning should be pretty soggy, but, besides that, you probably won’t even realize that it’s part of this massive storm that crippled the Gulf states.”

As of Thursday morning, the National Weather Service had issued no Flash Flood Watches for West Virginia.

Watches and Flood Warnings were in effect in southern Ohio, much of Kentucky, western Tennessee, western Mississippi, eastern Arkansas and eastern Louisiana.

Five to seven inches of rain from Harvey was possible in western Kentucky, with three to four projected in an area stretching up into southern Ohio.

Harvey’s rainfall in West Virginia was not expected to top two inches, with the heaviest rain projected for the Huntington Tri-State, Mid-Ohio Valley and north central Mountain State counties.

“There’s always ambiguity in there,” Wolfe said when asked about potential changes to the forecast.

“If the remnants of Harvey drift a little more to the south, we could see the higher amounts that are showing more to the west there but, right now, most models do have the track going over the Ohio River and that would put the heavier precipitation to the northwest of West Virginia.”

Largely dry conditions in the Mountain State could help, Wolfe said.

“The one area that we are a little concerned about is over near Huntington just because they did have an inch or more of rainfall this week so they can’t hold quite as much water,” he said.

“If those higher amounts kind of do inch into that area, that could be an issue but, right now, we’re thinking the higher amounts will still be a little farther west.”

On Thursday, Flood Warnings were still posted for southeastern Texas into southwestern Louisiana which were the areas that recorded feet of rain out of Harvey.

A Category 4 hurricane at its first landfall last Friday, Harvey stalled over Houston and surrounding areas as a tropical storm.

Harvey Headed To WV, But Impact Expected To Be Mild

The Free Press WV

The massive storm known as Harvey has already delivered the largest storm total for rain in the history of the Continental United States when it left 52 inches of rain in Cedar Bayou, Texas this week.  Now its headed our way. However, Harvey’s impact on West Virginia isn’t expected to be nearly as drastic as when it came ashore for a third time on the Texas/Louisiana border.

“The remnants of Harvey is coming up and will cross over us Friday and Saturday,” said Meteorologist John Victory at the National Weather Service in Charleston. “However, it’s losing a lot of its moisture as it goes north. We’re looking at no widespread or significant flooding problems at this point.”

In fact, Victory said Harvey’s impact on West Virginia may be nothing more than a typical rain and thunderstorm system.

“It will probably transition into a non-tropical system. It’s losing a lot of its moisture and its going to be interacting with a frontal system coming down,” explained Victory.

Some high school football teams adjusted their game times ahead of the storm. The forecast for Friday into Saturday is for all of West Virginia to get one to two inches of rain from Harvey’s remnants. The heavier amounts will fall in northern West Virginia, but flooding danger appears unlikely at this point.

“Right now, we’re trending optimistic,” Victory said. “It doesn’t look like any significant problems at this point.”

Harvey Spins Deeper Inland; Full Scope of Damage Is Unknown

The Free Press WV

Harvey spun deeper into Texas and unloaded extraordinary amounts of rain Saturday after the once-fearsome hurricane crashed into vulnerable homes and businesses along the coastline in a blow that killed at least one person and injured up to 14.

Throughout the region between Corpus Christi and Houston, many people feared that toll was only the beginning. Authorities did not know the full scope of damage because weather conditions prevented emergency crews from getting into the hardest-hit places. And they dreaded the destruction that was yet to come from a storm that could linger for days and unload more than 40 inches of rain on cities, including dangerously flood-prone Houston, the nation’s fourth-largest.

In the island community of Port Aransas, population 3,800, officials were unable to fully survey the town because of “massive” damage. Police and heavy equipment had only made it into the northernmost street.

“I can tell you I have a very bad feeling and that’s about it,“ said Mayor Charles Bujan, who had called for a mandatory evacuation but did not know how many heeded the order.

Some of the worst damage appeared to be in Rockport, a coastal city of about 10,000 that was directly in the storm’s path. The mayor said his community took a blow “right on the nose” that left “widespread devastation,“ including homes, businesses and schools that were heavily damaged. Some structures were destroyed.

Rockport’s roads were a mess of toppled power poles. A trailer blocked much of one major intersection. Wood framing from ripped-apart houses was strewn along Route 35 on the town’s southern end.

Harvey’s relentless wind tore the metal sides off the high school gym and twisted the steel door frame of its auditorium.

“We’re still in the very infancy stage of getting this recovery started,“ said Aransas County spokesman Larry Sinclair.

Rockport Mayor Charles “C.J.“ Wax told The Weather Channel that the city’s emergency response system had been hampered by the loss of cellphone service and other forms of communication.

A day earlier, Rockport Mayor Pro Tem Patrick Rios offered ominous advice, telling people who chose not to evacuate to mark their arms with Sharpie pens, implying that the marks would make it easier for rescuers to identify them.

As many as 14 people suffered minor injuries, including slips and falls, scrapes and a broken leg, Aransas County Judge C.H. “Burt” Mills Jr. said. The lone fatality confirmed so far was a person caught in a fire at home during the storm, Mills said. He did not identify the victim.

About 300,000 customers were without power statewide. Governor Greg Abbott said it would probably be several days before electricity is restored.

Meanwhile, the storm slowed to a crawl of only 2 mph. Rainfall totals varied across the region, with Corpus Christi and Galveston receiving around 3 inches, Houston 7 and Aransas 10. Tiny Austwell got 15 inches.

Elsewhere in the storm’s immediate aftermath, Coast Guard helicopters rescued 18 people from boats and barges in distress, said Capt. Tony Hahn, commander of the Corpus Christi sector.

The Corpus Christi port was closed with extensive damage. Because the city is the third-largest petrochemical port in the nation, the agency will be on the lookout for spills, Hahn said.

The fiercest hurricane to hit the U.S. in more than a decade came ashore late Friday about 30 miles northeast of Corpus Christi as a mammoth Category 4 storm with 130 mph winds.

Harvey weakened to a tropical storm by midday Saturday. At 6 p.m., its maximum sustained winds had fallen to about 60 mph. The storm was centered about 70 miles southeast of San Antonio, the National Hurricane Center said.

The hurricane posed the first major emergency management test of Donald Trump’s administration.

Trump met with his Cabinet and other senior administration officials to discuss the federal response to the damage and flooding, the White House said Saturday in a statement.

The president held a video conference from Camp David in which he instructed departments and agencies to “stay fully engaged and positioned to support his number one priority of saving lives,“ the statement said.

Trump, who on Friday signed a federal disaster declaration for coastal counties, also reminded department heads that the full impact of the storm will not be apparent for days. On Twitter, he commended the head of the Federal Emergency Management Agency for his handling of the disaster.

In Corpus Christi, the major city closest to the storm’s center, wind whipped palm trees and stinging sheets of horizontal rain slapped against hotels and office buildings along the seawall as the storm made landfall.

Daybreak revealed downed lamp posts and tree limbs and roof tiles torn off buildings. Along Interstate 45 leaving Galveston, the rain was so intense that drivers stopped under bridges because they could not see in front of them.

Rain fell on Houston at nearly 3 inches an hour, leaving some streets and underpasses underwater. The many drainage channels known as bayous that carry excess water to the Gulf were flowing freely and rising.

“Flooding is a minor issue so far,“ Harris County Judge Ed Emmett, the chief administrator of the county that includes Houston, said. “Most of the watersheds are well within banks, but we’re not out of this.“

Francisco Sanchez, with the Harris County Emergency Management Office, said the storm would be around for a while.

“Someone is going to get those very high rainfall totals,“ he said. “Hopefully it’s not us, but we’re in that possibility area.“

South of the city, about 4,500 inmates were evacuated from three state prisons in Brazoria County because the nearby Brazos River was rising.

The turbulent weather extended into southern Louisiana, where motorists were cautioned about the potential for high water, road hazards, high winds and tornadoes.

Harvey came ashore as the fiercest hurricane to hit the U.S. in 13 years and the strongest to strike Texas since 1961’s Hurricane Carla, the most powerful Texas hurricane on record.

The storm’s approach sent tens of thousands of people fleeing inland.

Just hours before landfall, the governor and Houston leaders issued conflicting statements on evacuation.

The governor urged more people to flee, but Houston officials recommended no widespread evacuations, citing greater danger in having people on roads that could flood and the fact that the hurricane was not taking direct aim at the city.

The last Category 4 storm to hit the U.S. was Hurricane Charley in August 2004 in Florida.

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