In an update to my post from Monday, Colorado State University hurricane forecast experts Drs. Philip J. Klotzbach and William M. Gray released their early June Atlantic hurricane outlook this morning. Previously (on April 7), they had predicted 15 named storms, 8 hurricanes, and 4 major Atlantic hurricanes this year. Those numbers were all increased, as expected based on other recent forecasts and the conditions setting up in the Atlantic/Caribbean. Below are their forecast numbers as well as the long-term climatological averages.
| CSU Forecast | Long-term average | |
| Named Storms | 18 | 9.6 |
| Named Storm Days | 90 | 49.1 |
| Hurricanes | 10 | 5.9 |
| Hurricane Days | 40 | 24.5 |
| Major Hurricanes | 5 | 2.3 |
| Major Hurricane Days | 13 | 5.0 |
| Prob. of Cat. 3-5 Landfall on a U.S. Coastline | ||
| Entire U.S. Coast | 76% | 52% |
| East Coast + FL Peninsula | 51% | 31% |
| Gulf Coast + FL Panhandle | 50% | 30% |
Their forecast reasoning is based on the same conditions discussed in my earlier posts and noted by other forecasters. These include a move from El Nino to neutral and eventually La Nina conditions this summer and fall resulting in weakened wind shear, anomalously high/near-record sea surface temperatures across the hurricane development regions of the Atlantic and Caribbean, a weak-than-normal Azores high over the Atlantic (again weakening wind shear that limits storm formation and intensification), and the fact that we are in the midst of a multi-decadal uptick in hurricane activity.
Interestingly, in records dating back to 1851, only 5 seasons have seen 18 or more hurricanes and only 10 have had 10 or more hurricanes! 2010 could go down as one of the most active on record if these numbers hold true. Plus, with a forecast of 90 days with an active tropical storm or hurricane, the meteorologists tracking these systems will no doubt stay extremely busy!
