Tropical Storm Karen forms; south La. watches

Updated at 9:02 a.m. — South Louisiana will be watching an old-fashioned horse race in the next few days to see if a cold front from the northwest beats out Tropical Storm Karen coming from the southeast.

Forecasters for the U.S. National Hurricane Center in Miami on Thursday announced that data from an Air Force Reserve Hurricane Hunter aircraft shows that “the area of low pressure located over the southeastern Gulf of Mexico has become a tropical storm and is producing winds of up to 60 miles per hour.” It could be at or near hurricane strength by Friday.

A hurricane watch is in effect from Grand Isle, La., to Indian Pass, Fla., and a tropical storm watch is in effect for parts of the Louisiana coast west of Grand Isle, including the metro New Orleans area and Lake Pontchartrain, the Associated Press reported.

Karen was about 500 miles south of the mouth of the Mississippi River and moving north-northwest at 13 mph.

Forecasters have also been monitoring a cold front expected to arrive in south Louisiana sometime between Saturday afternoon and Sunday afternoon. That front could push Karen to the east if the front arrives in time, forecasters have said.

The faster the cold front moves, the farther east that storm would end up, National Weather Service meteorologist Danielle Manning said on Wednesday.

The storm in the Gulf of Mexico is expected to make landfall this weekend.

Computer models Wednesday afternoon were showing possible landfalls anywhere from central Louisiana to Florida.

“Right now, there’s still a lot of uncertainty on track and impacts,” Manning said.

There’s also uncertainty about how strong the storm could get.

Intensity forecast models are notoriously poor but as of Wednesday afternoon most models were suggesting the storm would remain fairly weak, state climatologist Barry Keim said.

Although there is plenty of warm water for the storm to feed off of in the Gulf of Mexico right now, there is also a healthy amount of wind shear that could hamper any major strengthening of the storm, he said.

“So hopefully that will keep it in check,” Keim said.

However, he cautioned the intensity forecast can change. “Bottom line is anything can happen with a storm like this.”

The combination of the weather system with the cold front is expected to bring a good amount of rain to south Louisiana along with rough coastal waters and above average tides.

The cold front will at least bring in the first breath of fall weather with lows Sunday night in the mid-50s in Lafayette and Baton Rouge and in the mid-60s for New Orleans.

The Associated Press contributed to this report.