This year's storm activity began early, in late May, when Tropical Storm Arthur formed and drenched the Yucatan Peninsula.
Last month proved to be the third-most-active July since 1886 - after 2005 and 1916. Bertha was born on July 3. It became a Category 3 hurricane far out in the Atlantic and was the longest-lived July storm on record - 17 days. Tropical Storm Cristobal crept past the North Carolina coast in midmonth. Dolly made landfall in Texas on July 23 as a Category 2 hurricane, followed on Aug. 5 by Tropical Storm Edouard.
Tropical Storm Fay meandered back and forth across Florida last week, inundating many communities with more than 20 inches of rain. It was Fay's remnants that brought yesterday's rain to Maryland.
With so much activity early in the season, government prognosticators now expect a total of 14 to 18 named storms. (The average is 11.) Eight have already formed. Seven to 10 storms are forecast to become hurricanes. Three already have.
The stage for busy storm seasons was set in 1995, scientists say, when atmospheric and water temperatures in the Atlantic shifted into a pattern conducive to storm formation that typically lasts 10 to 40 years.
"It's a whole set of conditions," Bell said. One is low wind shear, meaning that wind speed and direction don't change much as warm air rises inside a hurricane, allowing the storm to grow stronger. High shear aloft will cut off storm formation.
Another factor fueling the active season is warmer-than-normal ocean temperatures. High sea-surface temperature - typically above 80 degrees - is the fuel that powers hurricanes.
A similar hurricane-friendly setup prevailed in the Atlantic from 1930 to 1970, and those decades saw a series of powerful storms make landfall in the U.S.
After that, the Atlantic calmed and remained relatively quiet, on average, until 1995. Devastating storms can still boil up during "quiet years," however. An example was Andrew, which flattened parts of South Florida in 1992.
There have been several punishing seasons in recent years. In 2004, four hurricanes made landfall in Florida in just six weeks. They killed 152 people, demolished 27,000 homes and caused $45 billion in property damage.
Before the 2005 season ended, forecasters had run through 27 storm names, a record. The most infamous storms - Katrina and Rita - devastated New Orleans and the Texas, Louisiana, Mississippi and Alabama coasts. Storm deaths in 2005 totaled 2,280.
Then we caught a break. Only 10 tropical storms formed in 2006, and only five reached hurricane strength. The comparative lull, Bell said, was related to increased wind shear in the Atlantic basin.
Last year was busier; there were 15 named storms, more than the average of 11. But they had little impact on the mainland U.S.
The key to this year's resurgent activity, Bell said, may be the lingering, long-range effects of last year's La Nina event - which has suppressed convection and thunderstorm activity in central Pacific and wind shear in the Atlantic.
