Hilary Rapidly Intensifies to Category 4

As of 8:00 p.m. PDT on Thursday, September 22, 2011 (NHC Advisory #8): After being upgraded to a hurricane earlier this morning, Hilary has rapidly intensified over the past 12 hours and is now a Category 4 hurricane, with maximum sustained winds of 135 mph.

Hurricane Hilary is moving west-northwest (295°) at 9 mph, and is expected to continue in that direction over the next 24 to 48 hours. Despite the small size of the hurricane, the National Hurricane Center warns that additional strengthening is still possible, with a slight chance of Hilary reaching Category 5 status.

The latest long range forecast expects Hilary to now enter the Southern California swell window Monday afternoon, with maximum sustained winds of 110 mph, just below Category 3 strength. The official forecast also shows Hilary turning a bit more northerly once she enters the swell window.

With the increased intensity and a more northerly long term forecast track, conditions are becoming more favorable for Southern California surfers. At this point it looks like Hilary will definitely produce some moderate-period south swell late next week, but it’s unclear right now exactly how big.

We’ll continue to monitor Hilary and provide updates as the official forecasts are released by the National Hurricane Center.