William Gray and Colorado State Team Issue October Hurricane Forecast

Note to Editors: October and updated seasonal forecast totals and the complete update, including the new October monthly forecast, is available on the Web at http://typhoon.atmos.colostate.edu.

Following an August-only forecast that was right on the mark and a September-only forecast close to the mark, William Gray and the Colorado State University hurricane forecast team today issued a monthly prediction for October. The team also issued a seasonal update. The team’s new October-only forecast calls for three named storms, two hurricanes and no major hurricanes.

For September, Gray and his colleague Phil Klotzbach had forecast four named storms, two hurricanes and one intense hurricane for the Atlantic basin. September witnessed four named storms, three hurricanes and one intense hurricane. For August, Gray and his colleagues had forecast three named storms, one hurricane and one intense hurricane for the Atlantic basin, which is exactly what occurred. Hurricane activity through September is on target for the team’s early forecast of an active season.

"We feel very positive about the progress of our monthly forecasts," said Gray. "These monthly forecasts are adding greater insight into our understanding of hurricane variability."

Gray and his colleagues keep their overall seasonal Atlantic basin forecast close to their earlier April, June, August and September updates. For the entire 2003 hurricane season, Gray and his team are calling for 14 named storms (11 have occurred through September), eight hurricanes (6 have occurred through September) and two major hurricanes (2 have occurred through September). The long-term average is 9.6 named storms, 5.9 hurricanes and 2.3 intense hurricanes per year. The entire detailed report is available online at http://typhoon.atmos.colostate.edu.

This is the first year that Gray and Klotzbach are issuing monthly forecasts for October, and this was only the second year for issuing September-only forecasts. The monthly forecasts use different predictors than the seasonal forecasts, but also serve to aid with the seasonal predictions.

"The same factors that can make individual months active or inactive are often not the same factors that can make the entire season active or inactive," said Philip Klotzbach, an atmospheric science researcher and member of Gray’s forecast team. "We are continually improving our forecasts to provide people with specific monthly hurricane forecasts and specific landfall probability forecasts."

Gray and Klotzbach recently developed a methodology for calculating the probability of landfall along the entire U.S. coastline on a one-month basis and are providing monthly U.S. hurricane landfall probabilities for September and October. For October, they estimate the probability of at least one named storm making landfall along the U.S. coastline is 35 percent (29 percent is the long-term average). The probability of at least one hurricane making landfall along the U.S. coastline is 17 percent (15 percent is the average). The probability of at least one major hurricane (Saffir/Simpson category 3-4-5) crossing the U.S. coastline in October is 9 percent (6 percent is the average).

Gray warns that people living along the East Coast still need to be aware of the possibilities of landfalling hurricanes.  

"The United States has been very lucky over the past four decades in witnessing few major hurricanes making landfall compared with earlier decades, while at the same time, we have seen large coastal population growth," said Gray. "Regardless of whether a major hurricane makes landfall this year, it is inevitable that we will see hurricane-spawned destruction in coming years on a scale many times greater than what we have seen in the past."

William Gray and his Colorado State colleagues have issued seasonal hurricane forecasts for the past 20 years. The forecasts, issued in early December of the prior year as well as early April, June and August, have steadily improved through continuing research. The Colorado State forecasts now include individual monthly predictions and seasonal updates of Atlantic basin storm activity and hurricane landfall probabilities issued in early August, September and October.

The research team will issue a seasonal summary for the 2003 Atlantic basin hurricane activity in late November. The summary will be available on the team’s Web site at http://typhoon.atmos.colostate.edu.

In addition to Gray, team members include Philip Klotzbach, William Thorson, Jason Connor and others.