Doyle Rice, USA TODAY
A tornado onslaught that pummeled Oklahoma twice in 12 days and killed 37 people there is likely to ebb this week, setting the stage for a new focus for the nation's storm outlook: hurricanes.
Meteorologists are watching the Gulf of Mexico for development of a tropical storm that could drench Florida later in the week.
"It's possible that we'll see something forming in the Gulf this week," said AccuWeather meteorologist Alan Reppert. But whether it becomes a storm or not, more rainfall is likely in Florida throughout the week, which could lead to localized flooding, he said.
The six-month Atlantic hurricane season officially began Saturday and lasts until Nov. 30. The first tropical storm to develop will be named Andrea.
The federal government predicts an above-average hurricane season in the Atlantic this year, with seven to 11 hurricanes expected. A typical season, based on the years 1981-2010, has six hurricanes. Two of the biggest private weather forecasting companies, AccuWeather and The Weather Channel, also predicted an active hurricane season.
After a calm start to the tornado season, the last two weeks of May unleashed a series of deadly tornado outbreaks across the nation's midsection. This includes the terrifying outbreak Friday night near Oklahoma City that killed 13 people, including three storm chasers, and injured dozens. Twenty-four died in nearby Moore, Okla., in a twister May 20.
The 37 people killed by tornadoes in Oklahoma last month made it the deadliest month for twisters in the state since May 1999, when 40 people died, according to data from the Storm Prediction Center.
The volatile weather moved east Sunday. Heavy rain, thunderstorms, high winds and hail moved through sections of the Northeast, knocking out power to more than 40,000 in Vermont, New Hampshire and Maine. In South Carolina, a tornado knocked a home off its foundation, but there was no widespread damage or injuries, said Taylor Jones, director of emergency management for Anderson County.
Some strong thunderstorms could hit the Plains tonight and Tuesday, but mostly in lightly populated areas. "It doesn't look anything like last week," Reppert said.
May is usually the busiest month for tornadoes in the USA, according to the National Climatic Data Center. There were more than 200 reports of tornadoes in the nation in May, the vast majority in the final two weeks of the month, the Storm Prediction Center reports. That's actually below the recent average for May of 250 tornadoes.
In addition to the tornadoes, much of the central USA also has been dealing with extremely heavy rain and flooding: The 5.64 inches of rain that fell in Oklahoma City on Friday was the sixth wettest day in the city's history. It also brought the total rainfall for May to 14.52 inches, the wettest May in Oklahoma City's history, according to Weather Underground meteorologist Jeff Masters.
Heavy rain brought flooding across much of the Midwest over the past few days. Three people in Missouri died as a result of the flooding. As of Sunday afternoon, 170 river gauges were at flood stage, the National Weather Service said.
Many parts of Missouri, Iowa, and Illinois are at continued risk from flooding this week. Areas near the Mississippi River are at highest risk.
Contributing: The Associated Press