Hurricane Sandy is expected to rank as the second-costliest tropical cyclone on record, after Hurricane Katrina of 2005, and will probably be the sixth-costliest cyclone when adjusting for inflation, population and wealth normalization factors, the National Hurricane Center said in a report released on Tuesday afternoon.
The number of deaths caused by Sandy is estimated to be 147. In the United States, 72 deaths occurred, making Sandy the deadliest U.S. cyclone outside of the southern states since Hurricane Agnes of 1972, the report said.
Meteorologists classify hurricanes, tropical storms and tropical depressions as tropical cyclones.
Editor's Note: Sandy unleashed powerful winds and torrential rains Monday in the mid-Atlantic and Northeast as it sped toward shore. Subways and bridges were shut down and streets were quiet as gusts howled over a huge region encompassing hundreds of miles. At 7 p.m., the National Hurricane Center stopped classifying Sandy as a hurricane, though it still continued to pack a wallop. Here is the full story.
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Here are the latest developments:
[Updated at 11:55 p.m.] Lisa Greiner, spokeswoman with New York York University's Langone Medical Center, offers some more details about why the facility is evacuating about 200 patients:
"Due to the severity of Hurricane Sandy and the higher than expected storm surge, we are in the process of transferring approximately 200 patients within the medical center to nearby facilities. We are having]
Tent camps dot the streets in Port-au-Prince, Haiti. The shelters, sometimes just draped tarps, are all that stand between residents and Mother Nature.
More than 400,000 of those residents live in the tents, all they've called home since a 7.0-magnitude earthquake rocked the Haitian capital in 2010, reducing many of of the structures in the capital and its suburbs to rubble.
Two years removed from the earthquake, Haitians are praying again. This time, they hope they will be spared Tropical Storm Isaac, which appears to be headed straight for them.
The country is still trying to battle back from a deadly cholera outbreak after the 2010 earthquake. So as the storm threatens to bring winds of about 74 mph and 12 inches of rain, the challenges are mounting. The U.S. National Hurricane Center warned that the rain could cause life-threatening flash floods and mudslides.
Aid organizations are preparing for the worst.
Tropical Storm Isaac formed in the Atlantic Ocean and churned toward the Caribbean Sea on Tuesday afternoon, and it could become a Category 1 hurricane by Thursday, forecasters at the National Hurricane Center said.
Late Tuesday afternoon, Isaac was 500 miles east of Guadeloupe in the Leeward Islands and moving west at 17 mph. Maximum sustained winds were 40 mph, just beyond the threshold for a tropical storm. It would become a hurricane if winds reach 74 mph.
Tropical storm watches and warnings cover much of the Leeward Islands as well as Puerto Rico and the Virgin Islands.
Conditions are favorable for strengthening as the storm enters the northern Caribbean Sea, forecasters said.
It could become a Category 2 hurricane, with maximum sustained winds above 95 mph, as it approaches Cuba on Saturday.
Forecasters caution that the forecast track is uncertain and the storm could be anywhere from the Bahamas to the north and the Cayman Islands to the south on Saturday.
It is still too early to tell what, if any, effects the storm will have on the U.S. mainland, but there are several computer models that bring the storm into the Gulf of Mexico, while others move the storm further east.
With roughly 50,000 people headed for Tampa, Florida, for the Republican National Convention August 27-30, there is heightened interest in the future path of the storm.
[Updated at 1:19 p.m. ET] A near-normal Atlantic hurricane season is expected this year, with nine to 15 named storms and four to eight hurricanes, the National Oceanic and Atmospheric Administration announced Thursday.
Of those four to eight hurricanes, NOAA expects one to three to be major. The Atlantic's six-month season begins June 1, although it got off to an early start this year, with Tropical Storm Alberto moving through the Atlantic off the U.S. East Coast last week.
NOAA also said it predicts a near-normal season for the Eastern Pacific, estimating a 70% chance of 12 to 18 named storms - with five to nine hurricanes, of which two to five would be major - for that area. The Eastern Pacific's season is May 15 to November 30.
A major hurricane, designated as Category 3 or greater, has winds of well above 100 mph. The weakest hurricanes have top sustained winds of at least 74 mph, and named storms have top winds of at least 39 mph.
NOAA officials said uncertainty over whether the El Nino weather pattern will form made it difficult to be more precise in predicting the Atlantic storm season.
"If (El Nino) develops by late summer to early fall ... conditions could be less conducive for hurricane formation and intensification during the peak months (August to October) of the season, possibly shifting the activity toward the lower end of the predicted range,” said Gerry Bell, lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center.
The forecasts do not predict how many of the storms will reach land.
Thursday's predictions came as a strengthening Hurricane Bud, churning in the Pacific, appeared poised to bring heavy rain to coastal southwestern Mexico.
It is extremely rare for an Eastern Pacific hurricane to affect the U.S. mainland, though some do have an influence on Hawaii.
Tropical Storm Alberto broke up in the Atlantic this week and another tropical depression was causing heavy rainfall in southern Florida, Bell said. However, he said the early storms were no harbinger of a more active season than normal.
For the Atlantic, a normal season would produce 12 named storms, including six hurricanes and three major hurricanes. Last year saw 19 named storms in the Atlantic.
The Eastern Pacific's average season produces 15 named storms, with eight hurricanes and four major hurricanes, according to NOAA.
What's all the talk about a heat dome causing a heat wave that is blistering the eastern third of the nation? You may have heard your local TV meteorologist talk about a "dome of high pressure" being responsible for this heat wave.
Essentially, a heat dome is just another word for a dome of high pressure that forms south of the polar jet stream, usually during the summer months, in the Northern Hemisphere, said CNN meteorologist Chad Myers.
But why has this heat wave been so severe and deadly?
How many times have you also heard, "It's not the heat, it's the humidity," or, "It's a dry heat"? Believe it or not, the amount of water vapor present in the atmosphere can actually make a huge difference in the severity of a heat wave. The amount of moisture the atmosphere holds affects how severe the heat is to the human body.
Meteorologists use the dew point and the current temperature to calculate the heat index. When a parcel of humid air is cooled at a constant atmospheric pressure, the temperature at which water condenses is called the dew point and the condensed water is called dew. The higher the dew point, the higher the heat index, and the more severe the heat is to the body.
Dew points are downright oppressive when they are over 75 degrees Fahrenheit. By contrast, dew points of 40 to 50 degrees are very comfortable. With dry heat (lower dew point) the body can withstand much higher temperatures because when your body sweats, the sweat evaporates and cools the body. However, if the dew point is high, then the sweat on your body will not evaporate and the body overheats, Myers explained.
The damage to 56 homes and one business in Buford, Georgia, was caused by an EF-2 tornado with winds of 130 mph, according to Steve Nelson, the science and operations officer for the National Weather Service Forecast Office in Peachtree City, Georgia.
Twelve homes were heavily damaged, but no one was hurt, authorities said.
More than 90 record-high temperatures were recorded in the Midwest and Great Lakes yesterday.
And perhaps an even better record came for the residents of Minneapolis-St. Paul in Minnesota - for only the third time in recorded history there was no snow measured during the month of March. (Records date back to 1859).