The sweltering heat and muggy weather isn't expected to lift fully until Wednesday, making today the fifth straight day of 90-degree temperatures that have sent kids and adults alike diving into pools, seeking refuge in air conditioning and chasing after ice cream and lemonade trucks.

The thermometer today is expected to hit 94 degrees and feel like 103, with more humidity, but afternoon and evening thunderstorms should cool things off a bit, AccuWeather said. High temps the rest of the week are forecast to be in the 80s, with a chance of showers or thunderstorms Thursday and Friday.

Monday's high temperature of 98 degrees was the highest this year, and just missed by 1 degree the record for the date set in 1999. It was still 97 degrees at 6 p.m., according to the Attleboro Water Department.

It also appeared to be the most humid day of the summer season.

With Monday the fourth consecutive day of temperatures of at least 90 degrees, the region is well into a heat wave. Three such days constitute a heat wave, and this is the third one since June. July is shaping up to be one hot one in general, with today expected to be the 10th of 18 days so far this month with temps in the 90s.

`` It isn't just a heat wave. This is a disaster,'' remarked a water department employee. `` It is just humid and wet.''

The employee, who declined to give his name, said he cut his front yard Monday morning but was unable to do his back yard as the thermometer already was hitting 80 degrees. While he said he drank a liter of water, he was `` melting'' and sought refuge inside his home.

Area police and fire departments reported no serious problems from the hot and humid weather.

However, the federal Environmental Protection Agency's New England office predicted unhealthy air quality in Southern New England Monday and today because of elevated levels of ground-level ozone.

During such days, the EPA and the medical community suggest people limit strenuous outdoor activity to avoid respiratory problems. The poor air quality especially impacts children, the elderly and those with respiratory ailments.

The public can help reduce ozone-smog by using public transportation or car pooling and/or combining trips, refueling vehicles at night, and avoiding the use of gasoline-powered engines such as lawn mowers, chain saws, and leaf blowers, the EPA said.

The forecast of hot weather is also expected to cause the demand for electricity in New England to reach high levels. Businesses and individuals can help reduce demand by keeping air conditioning thermostats a few degrees warmer and turning off unnecessary lights, computers and appliances when not in use, officials say.

Most of the country is in the midst of broiling temperatures, sending people scrambling for the shade and prompting officials to open air-conditioned buildings and take to the streets to rescue the homeless and elderly.

Scores of communities reported temperatures of more than 100. Parts of Kansas and Oklahoma hit 108, and temperatures in some areas were likely to exceed 105 through the middle of the week. The heat pushed power consumption to a record in some states, and calls also went out for electricity conservation.

The heat may have caused a New York subway train to lose power, stranding commuters for about 2 1/2 hours. About 70 people had to be evacuated. Transit spokesman Charles Seaton said the power loss may have been caused when the `` third rail'' -- which powers the train -- buckled.

In Illinois, state officials made more than 130 office buildings available as cooling centers. Detroit cranked up the air conditioning in 11 of its libraries and invited the public inside. In Kentucky, Louisville officials offered free fans or air conditioners to those in immediate need.

Arkansas authorities reported one heat-related death but did not release any details.

The federal government reported last week that the first half of 2006 was the warmest in the United States since record keeping began in 1895. The average temperature for the 48 contiguous United States from January through June was 51.8 degrees, or 3.4 degrees above the 20th century average.

With Associated Press reports