Summer arrived in Maryland Monday with temperatures already well into the 90s, and forecasters advised residents and public health officials to expect the heat, humidity and bad air quality to persist all week with sweltering numbers more typical of mid-July.
Health authorities grappling with the first extended heat wave of the year stood ready to reopen cooling centers in Baltimore. The power company braced for rising demand as air conditioners spun up across the region. And anyone who had to be outdoors just sweated it out and wished for something better.
There was no relief in sight for Ian Cuthbert, a construction worker drilling through a sidewalk at Baltimore's Inner Harbor.
"It gets pretty hot. I gotta wear pants, of course," he said. "If we luck out, we'll get some inside work."
The mercury at BWI-Marshall Airport hit 94 degrees Monday, topping 90 degrees for the third straight day and the eighth time this month. Forecasters said airport temperatures were likely to top 90 degrees nearly all week, threatening some records.
"Summer officially starts today, but it's definitely felt like summer for a while now," said Jared Klein, a forecaster at the National Weather Service office in Sterling, Va.
It was a really warm spring that ended Monday morning, the second-warmest on record for both Baltimore and Washington, Klein said. Temperatures at BWI-Marshall Airport averaged 64.1 degrees, just short of the record high 64.2 degrees in 1991.
Marylanders praying that this early hot weather doesn't signal a summer trend may be disappointed. NOAA's Climate Prediction Center said the outlook for July, August and September shows we're likely to experience above-average temperatures, along with most of the Southwest, Southeast and the Atlantic Coast states.
The recent high temperatures have triggered health warnings from local officials.
Baltimore declared a Code Red heat alert as temperatures reached 95 degrees on Sunday, opening 11 cooling centers for residents unable to find relief elsewhere. "We called it … because we knew we had a significant number of outdoor festivities, so we wanted to make sure people were alerted and protecting themselves," said Olivia Farrow, the interim health commissioner.
A second Code Red alert Monday was judged unnecessary, but all of Central Maryland remained under a Code Orange air pollution alert, a warning of unhealthy conditions for vulnerable people. The bad air was expected to persist with the heat and sunshine into Tuesday.
And as residents cranked up their fans and air conditioners, Baltimore Gas and Electric Co. braced for electric power demands of 6,000 to 6,500 megawatts. A more typical summer day sees demand at about 5,500 megawatts, company spokeswoman Linda Foy said.
"As we always do, we're monitoring usage very closely. BGE doesn't anticipate any problems in order to meet our customer demand," she said. Last year's demand peaked at 6,588 megawatts on Aug. 10. The record summertime peak was 7,198 megawatts in August 2003.
Forecasters at the National Weather Service's Baltimore-Washington office had not yet issued any heat advisories for the region. NWS forecaster Heather Sheffield said forecasters want to see at least a 30 percent chance that heat index values will exceed 105 degrees before issuing a heat advisory.
The heat index is a combined measure of heat and humidity. Humidity levels were not quite high enough Monday to meet criteria for a heat advisory, but Sheffield said forecasters "have been discussing it."
Monday's high of 94 degrees at BWI was a degree short of Sunday's high. But it was well below the 100-degree record set in 1931.
Tuesday's forecast for BWI was for a 91-degree high, rising to 94 again on Wednesday. That's a bit more of a threat to the record — 97 degrees, set on June 23, 1894. Heat index numbers — a measure of heat and humidity — were expected to top 100 degrees.
But airport temperatures were likely to top 90 degrees nearly all week, with peaks of 93 forecast for Thursday, near 90 on Friday and Saturday, and 94 degrees on Sunday.
The extended heat could make a busy week for the area's cooling centers.
The city's Northern Community Action Center, at 5225 York Road, already has seen plenty of traffic this week.
"We had 118 people [Sunday] who received bottles of water, not counting the number who came back for two bottles," said the center's director, David Smith. About 20 showed up just to drink the water and cool off.
Baltimore County has three cooling centers open daily for residents. But Monique Lyle, spokeswoman for the county Health Department, said that with so many air-conditioned public spaces available in the county, the cooling centers are rarely used. "It's not as big of a deal as it is in the city."
Klein said global weather patterns have shifted since last year's relatively mild summer in Baltimore. The El Nino pattern in tropical sea surface temperatures in the Pacific has since given way to neutral or developing La Nina conditions, affecting weather patterns in many distant locations.
Closer to home, the jet stream that separates colder weather to the north from warmer temperatures in the south has retreated deep into northern Canada.
"And, we've got a Bermuda high sitting off the coast, pumping warm, moist air up the coast," Klein said. "It's a classic setup we get for D.C.'s and Baltimore's warm summers."
As the humidity levels rise this week, the chance for showers and storms also increase. From just 30 percent Tuesday and Wednesday, they're forecast to rise a bit to 40 percent on Thursday and Friday before skies clear again for the weekend.
Already this year, BWI-Marshall has recorded 13 days of 90-degree-plus temperatures, including eight in June.
Klein said it is only the sixth time that has happened by June 21 in 139 years of record-keeping. The most recent was in 1994. The most was 18 days, by June 21, 1991.
Last year the airport recorded just 13 days of 90-degree weather all year, and only three through June.
But few people sweltering at the Inner Harbor Monday were thinking about statistics.
"Most people are trying to find someplace air-conditioned," said Watermark cruise guide Sheila Peterson. "You don't see too many people sitting outside eating lunch. It's really hot."
Forecast: Record high for date (year)
Tuesday: 91 degrees. 100 degrees (1988)
Wednesday: 94 degrees. 97 degrees (1894)
Thursday: 93 degrees. 98 degrees (1966)
Friday: 89 degrees. 99 degrees (1997)
Saturday: 90 degrees. 99 degrees (1954)
Sunday: 94 degrees. 99 degrees (1952)
Monday: 92 degree. 98 degrees (1969)
Years with 13 or more 90+ days by June 21, Baltimore.
2010: 13
1994: 13
1991: 18
1941: 14
1933: 13
1925: 14
Source: National Weather Service