PDC Updates | May 28, 2009
Central Pacific satellite image
As of 9:03 a.m. Hawaii Standard Time on May 28, 2009, the image above was the latest Central Pacific satellite image. Click on the picture to see the latest image available from the NOAA National Weather Service right now. Once on the site, many other interesting products—including an easy-to-read explanation of the satellite imagery—are just a click away.

May 20, 2009–Honolulu, Hawaii: NOAA’s Central Pacific Hurricane Center today announced that projected climate conditions point to a near- to below-normal hurricane season in the Central Pacific Basin this year.

An average season has four to five tropical cyclones, which includes tropical depressions, tropical storms, and hurricanes. The prediction was issued at a news conference called to urge Hawaii residents to be fully prepared for the onset of hurricane season, which begins June 1.

“Living on an island in the middle of the Pacific means each person and family should have an emergency plan every hurricane season. It is now time to review these plans before a storm threatens,” said Jim Weyman, director of the Central Pacific Hurricane Center. “Planning and preparation are key to surviving a hurricane.”

The forecast, a collaborative project with the Central Pacific Hurricane Center and NOAA’s Climate Prediction Center, calls for an 80% chance of a near- to below- normal season. Because of uncertainties in current predictions for El Niño, both a near-normal and below-normal season are equally likely at this time. The outlook also indicates a 20% chance of an above-normal season.

Climate patterns similar to those expected this year have historically produced a wide range of activity. Allowing for these uncertainties, the Central Pacific Hurricane Center forecasts the expected occurrence of three to five tropical cyclones in the Central Pacific during the 2009 season. People around the Hawaiian Islands with questions about the seasonal outlook or hurricanes in general, were given an opportunity to meet and talk to Weyman and NWS Warning Coordination Meteorologist Ray Tanabe. This series of events included a meeting at PDC on Maui.

This outlook is a general guide to the overall seasonal hurricane activity, and does not predict whether, where, or when any of these systems will affect Hawaii. Once a tropical cyclone forms in the central Pacific or moves into the area, however, the hurricane center swings into action.

Weyman said, “Our hurricane specialists are ready to track any tropical cyclone, from a depression to a hurricane in the Central Pacific Basin, and then provide accurate forecasts.”

The Central Pacific Hurricane Center calls in additional staff meteorologists when a system forms. They continuously monitor the weather conditions, employing a dense network of satellites, land- and ocean-based sensors and aircraft reconnaissance missions operated by NOAA and its partners. This array of data supplies the information for the complex computer modeling and human expertise that serve as the basis for the hurricane center’s track and intensity forecasts that extend out five days.

The science behind the outlook is rooted in the analysis and prediction of current and future global climate patterns as compared to previous seasons with similar conditions.

“The main factors influencing this year’s seasonal outlook are the possible development of an El Niño late in the season and the continuing multi-decadal signal. This signal is the combination of ocean and atmospheric conditions that have spawned decreased hurricane activity since 1995,” said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at the Climate Prediction Center.

Tropical Cyclones: When a “tropical disturbance” forms a center and begins to rotate, it becomes a “tropical depression.” At that point, the National Weather Service assigns the phenomenon a number and continues to monitor it. If the circling winds of the tropical cyclone reach 39 miles per hour, sustained speed, the phenomenon is given a name, such as Tropical Storm Irving or, at 74 miles per hour, Hurricane Catherine.
Tropical Storm 39–73 miles per hour 34–63 knots
Category 1 Hurricane 74–95 miles per hour 64–82 knots
Category 2 Hurricane 96–110 miles per hour 83–95 knots
Category 3 Hurricane 111–130 miles per hour 96–113 knots
Category 4 Hurricane 131–155 miles per hour 114–135 knots
Category 5 Hurricane 156 + miles per hour 135 + knots

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