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El Nino

Busy hurricane season predicted

Welcome to summer, y’all.

The nation’s climate agency on Thursday predicted an above-normal 2017 hurricane season with 11 to 17 named storms, five to nine of them hurricanes.

The National Oceanic and Atmospheric Administration predicted a 45 percent chance of the hurricane season that begins June 1 being above normal, a 35 percent chance of a normal season and a 20 percent chance of a below-normal season. An average season is 12 named storms, six hurricanes and three major hurricanes.

The agency said it expected two to four of the hurricanes to be Category 3 or higher.

“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 Caribbean Sea and average or weaker-than-average vertical wind shear in that same region,” said Gerry Bell, lead seasonal hurricane forecaster with NOAA’s Climate Prediction Center.

Bell said a strong El Niño causes more intense wind shear, which tends to break up tropical disturbances before they can grow into a hurricane. He cautioned that chances were 50-50 that a stronger El Niño could develop later in the hurricane season, which ends Nov. 30.

[…]

The United States has had a long run of good luck, said Ben Friedman, acting NOAA administrator. “It’s been a record 12 years since a Category 3 or higher storm has hit the United States, Friedman said.

And it’s been nine years since Hurricane Ike, which caused a lot of problems even if it wasn’t nearly as bad a storm as it could have been. It’s not unreasonable to think that people have relaxed a bit recently, given how mild the storm seasons have been since then. Be prepared, don’t panic, and if you live in Katy go ahead and start evacuating now. Texas Monthly has more.

We’re going to get more big rain storms

Better get used to it.

The weather is getting worse, says one expert.

Torrential rains fall in the Houston area more often than they used to, according to an unpublished analysis from state climatologist John Nielsen-Gammon.

Heavy precipitation of any particular magnitude are twice as likely to fall in the Bayou City today as they were in the early 20th Century. Downpours that struck every two years back then come every year on average now. Deluges that used to drop each 100, 500 or 1000 years should fall more frequently as well.

Nielsen-Gammon, a climate scientist at Texas A&M University who was appointed state climatologist by Gov. George W. Bush in 2000, reviewed data from rainfall gauges across the state, some with records dating to the late 19th Century. For Harris County, he drew from 17 gauges.

“We’ve confirmed that there’s an overall increase in extreme rainfall in Texas over the past century,” he said. “Specifically for Houston the increase has been particularly large.”

[…]

An independent analysis of local rainfall data from the National Weather Service also confirmed the state climatologist’s findings. Of the 100 rainiest days in Houston since 1890, as measured at multiple gauge sites, the wettest of the wet are skewed dramatically towards the last four decades.

You can see the charts and graphs and stuff at the story link. If you’re saying to yourself “weren’t we worried just a few years ago that we’d dry out and turns to dust from lack of rain?”, the answer is yes, and the reason is because we’re getting fewer rain events with more rain in them. Fewer rainstorms, in other words, but more of the storms we do get are big, and they’re more likely to come in groups rather than be spread out more or less evenly over time. Isn’t that awesome? But don’t worry, climate change is still a myth propagated by liberals, so we don’t have anything to worry about and we surely don’t have to change any of our habits in any way.

Droughts will always be with us

Remember how wet and rainy it was earlier this year? It ain’t like that now, though we do have some rain coming later this week.

After an uncharacteristically wet early-summer across Texas, the Lone Star state’s weather has turned dry since early August.

An estimated 14 million Texans are now living in drought-affected areas, with Houston being the only major metro area with reasonably moist soils.

But even Houston is starting to feel the pinch. Most parts of the region have received just about a quarter of an inch of rain during the last four weeks.

Three months ago less than 1 percent of Texas was in a drought, today nearly 50 percent of the state is. Along with the upper Texas coast, only the Panhandle, far west Texas and South Texas are free of drought.

“Many in the agricultural industries are already dealing with another drought,” said John Nielsen-Gammon, a professor of atmospheric science at Texas A&M University, and the state’s climatologist. “The dry conditions have not lasted long enough to make too much of a dent in water supplies, though.”

[…]

This overall dry pattern could change during the final 10 days of the month, as forecast models indicate a more southwesterly flow that would be more conducive to showers.

Texas typically has wetter and cooler winters when El Niño develops in the Pacific Ocean.

However, when particularly strong El Niños develop,which are currently happening, that does not mean an extra wet upcoming winter for Texas, Nielsen-Gammon said.

“The two strongest El Niños, as strong as the one presently in place, were among the near-normal El Niños rather than the wet ones,” he said. “So just because this El Niño is super-strong doesn’t mean that rainfall will be super-heavy.”

However, even normal rains during the winter should be enough to quench the state’s developing drought.

Let’s hope so, because anything resembling what we went through in 2011 would be devastating. Not much more we can do about it right now, but a little basic water conservation would be helpful and is never a bad idea. And let’s hope the system that’s coming our way brings plenty of the wet stuff.

Your annual “don’t get complacent about hurricanes” warning

You should know the drill by now.

It’s been seven years since a large hurricane – Hurricane Ike – threatened the Gulf states, and increasingly there’s talk among scientists that the Atlantic Ocean may be moving toward a more “quiet” period.

Hurricanes tend to come in bunches, and since about 1995 the Atlantic Ocean has burned hot with storms, spawning monster years in the 2000s when hurricanes like Katrina, Rita and Wilma pounded Florida, Louisiana and Texas.

Before then, in the 1970s, 1980s and early 1990s, the Atlantic was comparatively quiet, with fewer named storms each season.

Now, after a 20-year, frenetic period, the cycle may be swinging back down. For the first time in a long time, sea surface temperatures in the Atlantic where hurricanes commonly form are cooler than normal. Seasonal forecasters predict fewer than 10 named storms this year, far below the 15 or more storms that have formed in most years since 1995.

[…]

[Chris Landsea, a senior scientist at the National Hurricane Center] says we need a few more hurricane seasons to know whether we really have entered a quiet period. Phil Klotzbach, a Colorado State University scientist known for publishing seasonal forecasts for hurricanes, is a little more confident.

The hurricane cycle is known as the Atlantic Multidecadal Oscillation, or AMO, and it reflects changes in sea surface temperatures from the equator to the Arctic Circle in the North Atlantic Ocean. Periods of increased hurricane activity correlate to warmer sea temperatures, and slower periods correspond to cooler temperatures.

Klotzbach tracks the AMO closely, and it has essentially been negative – cooler than normal – since 2012.

“I would say at this point that my confidence that the AMO has flipped to negative has grown somewhat,” he said. “If this hurricane season ends up being as quiet as we are predicting, that would make three below-average seasons in a row. The odds of three below-average seasons in a row in a positive AMO would be quite unlikely.”

You can see the NHC’s 2015 forecast here. As the story and the NHC scientists take pains to remind us, it only takes one storm to make a given season a catastrophe. Hurricane Alicia in 1983 hit during a similarly “quiet” period. So remember the lessons that have been drilled into us all over the years – have bottled water at hand, know your evacuation route or be prepared to shelter in place, and stay on top of the news. And if you live in Katy, run for your lives.

It’s hurricane season prediction time

And this year’s forecast is for a fairly quiet summer.

On Thursday, forecasters with the National Oceanic and Atmospheric Administration released their seasonal outlook for 2014, predicting eight to 13 named storms would form. This means, most likely, the Atlantic season total will fall below the normal 12 tropical storms and hurricanes during a given year.

Like NOAA’s, other seasonal forecasts issued this spring have predicted 75 to 90 percent of normal activity levels this year. The season runs from June 1 to Nov. 30.

[…]

Principally, they expect El Niño to develop this summer in the Pacific Ocean. El Niño, a rise in tropical Pacific sea temperatures, has global weather effects including stronger wind shear in the Atlantic tropics, which reduces the number and intensity of tropical systems.

“Atmospheric and oceanic conditions across the tropical Pacific are already taking on some El Niño characteristics,” said Gerry Bell, NOAA’s lead seasonal forecaster.

Other factors are suggested as well. A number of signs suggest water temperatures in the area of the Atlantic Ocean where storms most commonly form, between Africa and the Caribbean Islands, will be a bit cooler than normal later this summer.

“Cooler water means less heat content available for hurricanes to intensify, resulting in fewer strong hurricanes than normal,” said Chris Hebert, a hurricane forecaster with ImpactWeather, a Houston-based company.

See here for the official NOAA forecast page. Last year’s prediction of a busy season didn’t work out so well, but even the best are going to strike out now and again, and if the process is sound then the results will be there more often than not. Of course as noted even in an otherwise very light season, all it takes is one hurricane to hit where you are and the rest doesn’t matter. So be prepared and remember that if you live in Katy it’s never too early to start evacuating.

It’s like the drought never really went away

If it ever did go away it didn’t go far, because here it is again.

Even as light rain moved through the region Thursday, Houston officially slipped back into a moderate drought.

Although most areas only recorded a few hundredths of an inch of rain, it nevertheless was the first measurable precipitation much of the city has received in more than three weeks.

The rain-free second half of April capped a very dry spring, pushing nearly all of the region back into a moderate drought, according to the U.S. Drought Monitor. The drought is more severe to the west of the metro area.

[…]

Houston has only received a little more than 7 inches of rain this year, which is less than half the city’s normal total of 15 inches through early May.

However forecasters believe the city is unlikely to suffer a repeat of the catastrophically dry summer of 2011, which killed millions of trees in the area and forced widespread water rationing.

“If it was not for the current strong El Niño signal coming along over the Tropical Pacific, I indeed would be very concerned that another 2011 type drought could occur over the metro area due to the very dry soil west of the area,” [ImpactWeather forecaster Fred] Schmude said. “Fortunately, the upcoming El Niño is starting to shuffle the flow pattern around a bit more which should allow for more rain producing systems as we move into the late spring and summer months.”

Any time 2011 is being invoked as a comparison, even in a “not as bad as” way, it’s not a good thing. The fact remains that much of the state has been in a multi-year drought, while our state leaders remain in denial about the underlying factors. It’s a scary place to be.

The drought is back

Bad news, y’all.

The latest report from the U.S. Drought Monitor, released this morning, shows that more than three-quarters of Texas is now in at least a “moderate” drought, and nearly half the state is in a “severe” or worse drought.

Now to be clear, conditions are still far better than 13 months ago, when the great 2011 drought peaked. At the time 100 percent of Texas was in a moderate drought, 99 percent in a severe drought, and 88 percent in an exceptional drought.

But conditions have gotten quite a bit worse since May, when the drought was at bay for about half of Texas, including the Houston metro area. Now the majority of greater Houston has returned to drought conditions.

Although November isn’t over, it’s possible Texas could end with its driest October and November period since 1950, says Victor Murphy, a climate specialist with the Southern Region Headquarters of the National Weather Service.

Statewide average rainfall for Texas in November 2012 should be about 0.5 inches versus a normal of nearly 2 inches, he said. That would make the October/November time period total about 1.3 to 1.4 inches, or about 30 percent of the state’s normal of 4.60 inches.

More from the print edition.

The current October-November period may end up being drier than the same period in 2010, when 1.85 inches of rain fell. That launched the state in the great drought of 2011.

“This is not a good way to be moving into winter,” Murphy said.

Also of concern is the latest winter outlook from the National Oceanic and Atmospheric Administration, which finds that without an El Niño pattern developing in the Pacific Ocean as expected, Texas can no longer look for a wetter-than-normal winter.

The greater Houston region, NOAA says, has an equal chance of above- or below-normal rainfall, and a 40 percent chance of having significantly above-normal temperatures this winter.

Last year’s drought primarily affected Texas and Oklahoma, but this year it has spread to much of the midwestern United States.

More than 60 percent of the contiguous 48 states are gripped by some level of drought, erasing two weeks of improvement, the Drought Monitor reported, with widespread agricultural effects.

We got lucky at the beginning of the year, when winter and spring were far rainier than we had any right to expect. We better hope we get at least some of that luck this winter and spring. Now would be a good time for us all to start conserving water again.

Here comes El Niño

Our hurricane season could be short.

The formation of Tropical Storm Debby last weekend in the Gulf of Mexico brought the tally of Atlantic storms to four this season, the earliest that’s ever happened.

But despite the quick beginning, scientists say this season may have a much quicker end, with an El Niño system likely to ride to the rescue later this summer.

“I’m becoming fairly confident that we will have a weak to moderate El Niño by the peak of this year’s hurricane season in September,” said Phil Klotzbach, a seasonal hurricane forecaster at Colorado State University.

Scientists have long understood that El Niño, a natural warming of the tropical Pacific Ocean, tends to suppress hurricane activity in the Atlantic.

But now, through a combination of research techniques, they’re beginning to gain a much deeper understanding of not only why but how El Niño changes the tracks of Atlantic storms and, crucially for Houston, how it may affect activity in the Gulf of Mexico.

[…]

Studies have found that, during the last 60 years, when an El Niño pattern prevailed during the Atlantic hurricane season, only one-quarter of those seasons had more activity than normal. During La Niña years, when Pacific tropical temperatures are cooler, two-thirds of years had more activity than normal.

El Niño years also produced fewer than average major hurricanes as well as fewer landfalling hurricanes.

Read the story for the technical details. Bottom line is that the early signs are for a less active hurricane season than usual. All it takes is one big one, of course, but I’d rather have the odds in our favor. As long as this doesn’t also presage another abnormally dry summer, it’s all good.

Bye bye, hurricane season

More like this next year would be nice.

The Atlantic hurricane season ended Monday with barely a whimper: Not a single hurricane came ashore in the United States.

Since June, when the season began, just nine named storms developed. Only three of them became hurricanes, and those stayed out at sea or weakened before passing over land.

[…]

The 2009 season was on target with the lower end of forecasters’ predictions. Before the season began June 1, the National Hurricane Center had anticipated nine to 14 storms, with four to seven hurricanes — a prediction that the Miami-based center scaled back slightly in August before the arrival of the season’s first storm, Tropical Storm Ana.

James Franklin, the center’s chief hurricane specialist, credited much of the quiet season to El Nino, the periodic warming of the central Pacific Ocean. El Nino, he said, produced strong winds in the Atlantic that cut down storms before they could develop into hurricanes.

Franklin said forecasters also noticed drier conditions in the atmosphere, which limited the potential for storms.

“Lately we’ve had busy seasons,” Franklin said. “To get a year this quiet, it’s a little bit unusual.”

As Eric Berger, who has a nice map here noted, the recent higher level of activity we’ve seen around here is more in line with historic norms than the long quiet spell we had in the 90s and first few years of this decade. If we’re really lucky, we’ll go back to that quietude for a few more years.

Hurricane season quiet so far

That’s nice, but it doesn’t mean we’re in good shape.

Although the first Atlantic named storm typically forms by July 10, the real activity doesn’t usually begin until August, and a lull in early season activity doesn’t necessarily presage a weak overall season.

The 2004 season, for example, didn’t see its first storm until Hurricane Alex began developing on July 31.

Yet after Alex the season rapidly ramped up, finishing with 15 storms and 6 major hurricanes, including Hurricane Ivan. A storm the size of Texas, Ivan was one of the 10 most intense hurricanes ever in the Atlantic basin before striking Gulf Shores, Ala., and causing $19 billion in damage.

And while El Niños may suppress overall activity, such years can still produce savage storms. One of the three most-intense storms at a U.S. landfall, Hurricane Andrew, developed during an El Niño in 1992.

So have some of the most famed storms ever to strike Texas and Louisiana: Alicia (1983), Betsy (1965) and the great storm of 1900, which came during a severe El Niño, said Jill Hasling, president of Houston’s Weather Research Center.

“There might be fewer storms during an El Niño,” she said. “But it only takes one.”

Yeah, that’s been my mantra of late – it’s not how many hurricanes there are, it’s how many big ones there are, and one of them is plenty. Conditions this year are such that there’s also the possibility of a storm forming in the Gulf of Mexico and striking land quickly, as was the case with Hurricane Humberto in 2007, or more scarily the Hurricane of 1932. So, you know, keep those emergency supplies in stock, and don’t rest easy.