US forecasters lower Atlantic hurricane outlook
By Jennifer Kay, Associated Press Writer, Posted to Yahoo News Aug 6, 2009
MIAMI – The Atlantic hurricane season will be less active than
originally predicted, government forecasters said Thursday after the
first two months of the half-year stretch passed without any named
storms developing.
Updating its May outlook, the National Oceanic and Atmospheric
Administration said a warmer weather pattern called an El Nino over the
Pacific Ocean was acting as a damper to tropical storms in the
Caribbean and neighboring Atlantic.
But forecasters at NOAA's Climate Prediction Center in Washington
warned people to remain vigilant because the peak period for hurricanes
runs from this month through October. The overall season lasts from
June through November.
The updated forecast calls for a below-normal to near-normal season
with seven to 11 named tropical storms, down from a range of nine to 14
in the May forecast.
Three to six storms could become hurricanes, down from four to seven in
the earlier forecast. The new projection says one or two hurricanes
could become major storms, instead of one to three major hurricanes.
Tropical storms get names when sustained wind speeds reach 39 mph. They
become hurricanes when sustained winds reach 74 mph. Major hurricanes
blow at 111 mph or more. The strongest hurricanes are labeled Category
5, with winds greater than 155 mph.
So far this year, one tropical depression formed off Cape Hatteras,
N.C., on May 28, four days before the official start of the season; it
quickly fizzled and never threatened land.
Researchers at Colorado State University also have lowered their
forecast for the Atlantic season to 10 named storms, including four
hurricanes, two of them major.
The El Nino warming of the Pacific sea surface suppresses storm formation, said lead seasonal hurricane forecaster Gerry Bell.
"El Nino produces stronger upper-level westerly winds over the
Caribbean Sea and tropical Atlantic Ocean, which help to reduce
hurricane activity by blowing away the tops of growing thunderstorm
clouds that would normally lead to tropical storms," Bell said.
Competing with El Nino, however, are conditions that mark an ongoing
high-activity era that began in 1995, forecasters said. Those factors
include enhanced rainfall over West Africa and warmer Atlantic water
temperatures, which favor storm development.
"By no means do we expect the season to be dead," Bell said.
Hurricanes have struck the U.S. during previous El Ninos, including
Camille in 1969, a Category 5 storm, Betsy in 1965, Bob in 1991 and
Lili in 2002.
A calm start doesn't mean the rest of the season will stay quiet,
forecasters warned. The first storm of the 1992 season — a below-normal
year — did not form until late August. But Hurricane Andrew leveled
parts of South Florida when it roared ashore as a Category 5 storm.
The 2004 season also had a slow start. By the time it was over, Florida
alone had suffered strikes from four separate hurricanes, one of which
also caused 3,000 deaths in Haiti.
"It only takes one storm to put a community at risk," said Federal
Emergency Management Agency Administrator Craig Fugate. "That is why we
need to take action and prepare ourselves and our families before the
next storm hits, including developing a family disaster plan."
The first storm of this year in the Atlantic, Caribbean or Gulf of
Mexico will be named Ana, followed by Bill, Claudette and Danny.
By this time last year, there had been five named storms, including two
hurricanes. In all of 2008, there were 16 named storms, including eight
hurricanes. About 1,000 people lost their lives, mostly in flash
flooding in the Caribbean.
Gas prices spiked last summer when hurricanes Gustav and Ike slammed into the nation's energy complex in the Gulf of Mexico.
In the Pacific, six named storms, including three hurricanes, have
developed so far this year. Hurricane Felicia, a Category 4 storm, was
expected to weaken Thursday as it moves over colder water far out in
the Pacific. Meanwhile, Tropical Storm Enrique maintained its strength
with sustained winds near 50 mph about 1,035 miles west of the southern
tip of Baja California.
Dr. Jeff Masters' WunderBlog
Late-starting hurricane seasons
Posted by: JeffMasters, 10:01 AM EDT on July 29, 2009
There are no threat areas in the Atlantic worthy of mention today, but
the GFS model is pointing to the possibility that a tropical wave off
the coast of Africa could develop this weekend. However, none of the
other models are predicting this, and the previous run of the GFS model
did not develop anything. So, any development in the tropics this week
looks unlikely. The hurricane season of 2009 is off to a slow start,
and it will be August before our first named storm appears. How does
this late-starting hurricane season compare to other years?
Well, the first named storm of the year didn't occur until August in
ten of the past fifty years (20%). Only two of these ten seasons ended
up with more hurricanes than average (seven or greater). The record for
the latest starting hurricane season since 1851 was set in 1914, when
the only storm of the season formed on September 15. The year 1941 was
also late starting, with the season's first storm arriving on September
11. Of course, we didn't have satellites back then, so it's a good bet
there were storms earlier in these seasons that got missed. However,
there's a good possibility that 1914 really did have only one storm. A
re-analysis of the hurricane activity in the decade1911-1920 (Landsea
et al., 2008) found 1.3 missing tropical cyclones per year, thanks to
the inclusion of a new database of ship weather reports called COADS.
However, 1914 was not one of those years. Various authors have
estimated that we missed an average of between one and three tropical
cyclones per year during that time period, so it is quite possible 1914
had only one storm.
The latest dates for the first named storm of the season in the recent
past, followed by the number of named storms, hurricanes, and intense
hurricanes that year are:
2004 (August 1) 15,9,6
2000 (August 4) 15,8,3
1988 (August 7) 12,6,3
1987 (August 9) 7,3,1
1984 (August 18) 13,5,1
1983 (August 15) 4,2,11
1977 (August 30) 6,5,1
1967 (August 30) 8,6,2
1963 (August 2) 9,6,2
1962 (August 22) 5,3,1
For comparison, an average Atlantic hurricane season has 10 named
storms, 6 hurricanes, and 2 intense hurricanes. So, it is a good bet
that 2009 will be a below-average season. We have two experimental
seasonal forecast models that agree with this idea--the UKMET Glosea
models, which is forecasting only six named storms this year, and the
newly-released Florida State University Center for Ocean-Atmospheric
Prediction Studies (COAPS) model, which is forecasting eight named
storms and four hurricanes. The Phil Klotzbach/Bill Gray Colorado State
University seasonal forecast updates on Tuesday August 4, and it will
be interesting to see what forecast numbers they come up with.
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