8/30/13, "No Atlantic Hurricane by August in First Time in 11 Years," Bloomberg, Barry K. Sullivan
"August is about to end without an Atlantic hurricane for the first time since 2002, calling into question predictions of a more active storm season than normal.
Six tropical systems have formed in the Atlantic since the season began June 1 and none of them has grown to hurricane strength with winds of at least 74 miles (120 kilometers) per hour. Accumulated cyclone energy in the Atlantic, a measure of tropical power, is about 30 percent of where it normally would be, said Phil Klotzbach, lead author of Colorado State University’s seasonal hurricane forecasts.
“At this point, I doubt that a super-active hurricane season will happen,” Klotzbach said in an e-mail yesterday.
The most active part of the Atlantic season runs from Aug. 20 to about the first week of October. The statistical peak occurs on Sept. 10, according to the National Hurricane Center in Miami. Two storms formed in August and the hurricane center is tracking two areas of thunderstorms that have low to medium chances of becoming tropical systems within five days.
Atlantic storms are watched closely because they disrupt energy operations in and around the Gulf of Mexico and cause widespread destruction when they come ashore.
In the basin now, warm sea water and a decreasing amount of wind shear that can tear at the structure of budding storms mean conditions are ripe “for a burst of activity,” said Todd Crawford, chief meteorologist at Weather Services International in Andover, Massachusetts.
A 'head scratcher'
“The very inactive season so far has been a bit of a head-scratcher,” Crawford said in an e-mail interview.
Air temperatures from the Caribbean to Africa have been warmer than normal this year, reducing the instability in the atmosphere that drives storm development, he said. In addition, dry air is being pulled off Africa into the Atlantic, which also cuts storm activity, he said.
Seasonal predictions were for an above-normal season. The 30-year average is for 12 storms with winds of at least 39 miles per hour, the threshold at which they are named. Nineteen such systems formed in each of the last three years.
Colorado State, which pioneered seasonal forecasts, retreated slightly on its outlook in an early August update, calling for 18 named storms. Eight should be hurricanes and three of them major hurricanes, a reduction of one at each level, the researchers said.
The National Oceanic & Atmospheric Administration also kept its call for an above-average season in an Aug. 8 outlook for 13 to 19 named storms, six to nine hurricanes and three to five major systems.
“If you don’t get your first hurricane by or before August, it’s extremely difficult to get those high storm counts, especially for hurricanes and major hurricanes,” said Matt Rogers, president of Commodity Weather Group LLC in Bethesda, Maryland. “Amazing we’re on the 90th day of the hurricane season and no hurricanes yet.”
While water temperatures in the Atlantic, Caribbean and Gulf of Mexico are high enough to spark hurricane formation, wind shear across the central part of the ocean has been high, Klotzbach said. Shear is when the winds at different altitudes blow at varying speeds or directions, which can tear at the structure of a budding tropical system.
According to the U.S. Climate Prediction Center, there has been a lot of wind shear in the Atlantic between the Lesser Antilles in the Caribbean and Cape Verde off the coast of Africa. This zone is often referred to as the main development region for Atlantic hurricanes, particularly in August and September.
“We haven’t had a hurricane and we don’t see anything that looks highly robust,” said Dan Kottlowski, an expert senior meteorologist at AccuWeather Inc. in State College, Pennsylvania. “It just goes to show you that having warm water isn’t everything.”
For natural gas markets, hurricanes have shifted from being major output disruptions, in part because so much production has shifted to land, to being “load killers” that cut electricity demand as temperatures drop, said Teri Viswanath, director of commodities strategy at BNP Paribas SA in New York.
The Gulf of Mexico is home to about 6 percent of U.S. natural gas output, 23 percent of oil production and more than 45 percent of petroleum refining capacity, according to the U.S. Energy Department. In 2001, Gulf waters accounted for 24 percent of U.S. marketed gas production.
A quiet first half to the Atlantic storm season doesn’t mean the second will be the same, she said. “It’s not over until it’s over,” Viswanath said.
Hurricane Sandy, which slammed into New York and New Jersey last year, developed on Oct. 22 and went ashore on Oct. 29. It killed at least 159 people and damaged or destroyed more than 650,000 homes in the U.S., according to a federal task force report Aug. 19.
Crawford also said the 2013 season could rebound now that September has begun. He expects some of the barriers that have damped activity so far to fall.
The 2002 season, the last to pass without a hurricane by the end of August, included Hurricane Lili, a Category 4t storm that caused about $860 million in damage and killed at least 13 people in the Caribbean and Louisiana from Sept. 21 to Oct. 4, according to the hurricane center. The first hurricane to form that year was Gustav, on Sept. 11.
“On Sept. 9, if there is nothing to talk about, you can call me and we can write off the season,” said Michael Schlacter, founder of Weather 2000 in New York. “I think in the next 10 days there will be a lot of things to discuss.”" via Drudge
Comment: A type of ocean wind is mentioned above as a mitigating force against hurricanes. The UN IPCC 2007 report noted importance of accurate ocean wind measurements in climate assessments, cited errors in "wind stress" measurements rendered computer model simulations of ocean heat absorption likely erroneous along with sea level rise projections: 2007 UN IPCC report, Chapter 184.108.40.206.2:
"220.127.116.11.2 Southern Ocean circulation"
"The Southern Ocean wind stress error has a particularly large detrimental impact on the Southern Ocean simulation by the models. Partly due to the wind stress error identified above, the simulated location of the Antarctic Circumpolar Current (ACC) is also too far north in most models (Russell et al., 2006). Since the AAIW is formed on the north side of the ACC, the water mass properties of the AAIW are distorted (typically too warm and salty: Russell et al., 2006). The relatively poor AAIW simulation contributes to the multi-model mean error identified above where the thermocline is too diffuse, because the waters near the base of thermocline are too warm and salty.
It is likely that the relatively poor Southern Ocean simulation will influence the transient climate response to increasing greenhouse gases by affecting the oceanic heat uptake.
When forced by increases in radiative forcing, models with too little Southern Ocean mixing will probably underestimate the ocean heat uptake; models with too much mixing will likely exaggerate it.
These errors in oceanic heat uptake will also have a large impact on the reliability of the sea level rise projections. See Chapter 10 for more discussion of this subject."
Another UN IPCC chapter again cites inability of computer models to accurately measure ocean heat:
"18.104.22.168 Summary of Oceanic Component Simulation"
"In the Southern Ocean, the equatorward bias of the westerly wind stress maximum found in most model simulations is a problem that may affect the models’ response to increasing radiative forcing."