ST. PETERSBURG, Fla Cities in more than a dozen states in the Southeast and Central Plains could top their record highs on Thursday, and southeastern Florida may feel the effects of Tropical Storm Emily this weekend.
Emily currently is expected to pass within 100 miles of Florida's easternmost point on Saturday and could intensify, according to AccuWeather.com.
"A tropical storm watch should be issued for southeast Florida today," said AccuWeather.com's tropical weather and hurricane expert Dan Kottlowski.
"That will be followed by a warning if the storm is projected into the southeast coast of Florida."
As forecasters kept a close eye on Emily's path, the National Oceanic and Atmospheric Administration on Thursday increased the number of expected named storms for the 2011 Atlantic hurricane season.
The weather agency now predicts 14 to 19 named storms, up from 12 to 18, with seven to 10 expected to grow into hurricanes. Three to five storms could be major hurricanes, with winds of at least 111 miles per hour, NOAA said.
The National Weather Service issued excessive heat warnings in Kansas, Missouri, Oklahoma, Arkansas, Tennessee, Mississippi, Louisiana, Alabama, Texas, Florida and Arizona, indicating more dangerously hot temperatures in those states.
Though it is hot across much of the South, the "bull's-eye" of the heat is being felt in Oklahoma, Arkansas, Texas and Louisiana, National Weather Service meteorologist Joe Jurecka said.
The unrelenting drought and heat in Texas already has broken records. State climatologist John Nielson-Gammon said the current drought is now the worst since Texas started keeping records on rainfall in 1895.
"Never before has so little rain been recorded prior to and during the primary growing season for crops, plants, and warm-season grasses," he said on Thursday.
July was the single warmest month ever in Texas, with an average 24-hour temperature of 87.2 degrees, beating the previous warmest month by two full degrees, he said.
"Unfortunately, we're in a vicious cycle of dry weather leading to hot temperatures and a lack of thunderstorms," he said.
Little Rock, Arkansas, which hit an all-time record high of 114 degrees on Wednesday, faced another stifling 108-degree high on Thursday, Jurecka said.
Additional cooling shelters have opened to help the 2,000 customers without power as of mid-Thursday after a breaker malfunction caused by a fire at an Entergy substation in Benton, Arkansas, about 20 miles southwest of Little Rock.
There is little relief expected from the heat wave across the region, even after the sun goes down, Jurecka said.
"One thing that really causes this to stand out is the nighttime lows are much higher in this outbreak," he said, comparing the current hot spell to a similar one in 1980.
"It doesn't cool down. That puts additional overnight strain on everything."
(Additional reporting by Suzi Parker in Little Rock and Jim Forsyth in San Antonio; Editing by Jerry Norton)