The airline, which sparked intense fare wars with its arrival at BWI two years ago, traditionally has flown East-West routes while avoiding the heavily traveled North-South routes where competition among airlines is fierce.
Southwest's presence at BWI has kept fares low to the Midwest and other cities westward. But ticket prices to Florida have risen steadily in the past six months after Continental Airlines scrapped its discount CalLite operation, allowing the airport's other major carrier, USAir, to boost its fares.
With competition beginning to wane at BWI, Southwest's long-awaited announcement about the Florida service is critical to Baltimore-Washington International Airport retaining its much-touted reputation as a mecca for discount fares.
"This is going to stir up the fare wars a little on Florida," predicted Jay Hierholzer, associate administrator for marketing at BWI. "It will provide some formidable competition in the Florida market, not just for USAir but for other airlines as well."
Currently, low fares to several Florida cities are being offered at Washington-Dulles International Airport by ValuJet, the upstart Atlanta-based discount carrier. That has driven down prices at both Dulles and National, with fares as low as $69 one-way to Florida.
Southwest said yesterday it would begin service from BWI to Tampa and Fort Lauderdale in January and to Orlando in April. The airline, however, did not say how much the flight will cost or how often it would be offered. An announcement on that is expected within several weeks.
Tom Parsons, editor of Best Fares magazine, said yesterday that Southwest's move could drop leisure travel fares on some routes from 30 percent to 50 percent and business fares even more.
The airline's current fares to cities of comparable distance -- such as St. Louis and Birmingham -- range from $49 to $119 one-way. It is likely that it would fly at least two nonstop flights a day.
Southwest has indicated for months that Florida was its next target for expansion, but yesterday's announcement came unexpectedly early.
"It's always been a hot market we wanted to tap into," said Linda Rutherford, a spokeswoman for Southwest. "The announcement was made to give vacationers plenty of time to make their plans."
Until now, she said, the carrier has been preoccupied with its expansion on the West Coast and with competition from United Airlines' new Shuttle service there. In addition, it has been expanding rapidly at Midway Airport in Chicago.
She said the Florida move was also possible because of 10 aircraft deliveries expected late this year from Boeing.
The airline will also begin flying next winter and spring to the three Florida cities from about a dozen other cities in the South and Midwest that it currently serves. Southwest currently operates more than 1,970 flights a day with an all-jet Boeing 737 fleet of 210 aircraft. It currently serves 45 cities in 22 states.
From BWI, it flies nonstop to six cities.
By the end of 1995, it will lease six gates there, giving it the capacity to operate roughly 72 flights a day.