Forecasts Call for a String of Hot Days

Washington's hottest period so far this year is expected to start Sunday, and it could last three or four days, according to forecasts.

Predictions call for the mercury to reach 96 or 97 degrees Sunday. A reading of 97 would be the hottest of 2009, and meteorologists expect Monday to be even steamier, with a high of 98 or 99 degrees at Reagan National Airport.

Some forecasts call for at least three consecutive days in the 90s.

"If you thought we might make it through summer without a heat wave, think again," wrote Jason Samenow on The Washington Post's Capital Weather Gang blog.

Heat waves, whether tolerated or deplored, have been recognized through the years as salient facts of Washington's summers.

But so far this year, the longest stretches of temperatures of 90 degrees or more have been a mere two days. Only on July 16 did the mercury at National reach as high as 96, and only twice have there been as many as two consecutive 90-or-above days.

Now, this atmospheric benevolence may show its downside, weather specialists pointed out.

Hot weather takes some getting used to. And most Washington area residents have been deprived of that opportunity this year.

The impact of Monday's searing heat will "be greater" than normal for early August "since full acclimation hasn't yet" happened for most people, a National Weather Service meteorologist wrote in a discussion of the forecast.

On the Web site of AccuWeather, a private forecasting service, senior meteorologist Kristina Pydynowski put it this way:

"The lack of summer heat this year is why residents of the Midwest and Northeast will be more vulnerable to heat-related illnesses during the next few days.

"You may not realize you are exerting too much energy doing seemingly low-strenuous tasks outdoors until you start to feel ill."

Humidity could make it even more unpleasant, specialists said.

The National Weather Service said conditions that include lots of heating by the sun should create readings "near the hottest of the season thus far." Its forecast for the immediate metropolitan area called for highs in the upper 90s Sunday.

Monday is expected to bring "highs around 100," the weather service said. Tuesday? The mid-90s, with Wednesday's highs expected to be "around 90," it said.

Temperatures on Thursday, Friday and Saturday are expected to be in the 80s, the weather service said.

Accuweather called for 96 Sunday, 98 Monday, 94 Tuesday and 90 Wednesday. The Weather Channel's Web site predicted highs of 97, 99, 90 and 89 for those days.