Warm weather hints at record pollen counts

Conditions likely to worsen after reprieve starting today

April 08, 2010|By Frank D. Roylance | Baltimore Sun reporter

Eyes itchy? Throat a little sore? Car turning a sickly, dusty green? The spring pollen season has arrived ahead of schedule, and allergists say it looks like another bad one.

Unseasonably high temperatures, low humidity, gusty winds and scarce rainfall in recent days have combined to send tree pollen counts soaring to record levels for early April - which will not be news to allergy sufferers.

"The high levels we're seeing now are unusual for this time of year, and we fully expect it will be worse two to three weeks from now," said Baltimore allergist Dr. David Golden.

The same weather has turned Maryland's fields and woods into dry kindling. On Tuesday, the National Weather Service posted red flag warnings from Carroll County west, with cautions for those in the rest of the state to be careful with outdoor fires.

There is some relief ahead for both allergy patients and firefighters, as a cold front and thunderstorms approach today to wet down the landscape and drop temperatures to more seasonable levels. But the relief will be temporary.

The temperature Wednesday at Baltimore-Washington International Thurgood Marshall Airport reached 90 degrees for the second day in a row. Highs of 84 on Monday and 90 on Tuesday broke or tied records for the dates, but Wednesday's high fell short of the 93-degree mark set in 1929.

Meteorologist Kevin Witt of the National Weather Service forecast office in Sterling, Va., said the average temperature this time of year is in the low 60s.

He said a high-pressure system parked off the Carolinas is drawing dry air out of the Southwest, while clear skies have allowed lots of solar heating.

At the same time, the northern jet stream, flowing from the Southern Plains to the Great Lakes, has held storms at bay to our north and west.

The heat and sunshine have spurred the region's trees - especially maples and, increasingly, oaks - to flower and throw off prodigious volumes of pollen, Golden said. Dry air, gusty winds and the lack of rain have kept the pollen airborne.

"This is shaping up to be the fourth year in a row of record-high tree pollen," Golden said.

The spring pollen season in Maryland tends to peak between April 25 and May 2 as trees (mostly oaks) overlap with the start of grass pollination.

Pollen counts typically climb to between 1,200 and 1,500 grains per cubic meter of air, but in recent years have reached as high as 4,000.

We might now be approaching an all-time high. Wednesday's count in Baltimore reached 1,391, Golden said, "a record for this early in April."

"There have been years when we barely got to that level late in April," he said. "I am loath to predict what the season is going to be like. ... We're still three or four weeks away from the peak."

Patients are already reacting.

"This week we're starting to get people calling and coming in, saying they're miserable, and their allergies, their sinuses, their asthma is acting up," Golden said.

Rain would wash pollen from the trees and the air, offering temporary relief.

Beyond that, allergy sufferers "need to keep their windows and doors closed; don't even open them at night, even though it's nice and cool. They should wash their hands when they come in, and their hair, especially if they spend some time outside."

Medical remedies include immune therapy - allergy shots - or whatever pills, eyedrops or nose sprays their doctors recommend.

Meanwhile, the State Fire Service, which responds when local fire companies ask for help with larger wildfires, assisted with four fires in Anne Arundel and three western counties on Tuesday. One was a 10-acre blaze in the Wolfsville section of Frederick County that was caused by debris burning.

Maryland has not yet banned outdoor fires, but State Fire Service supervisor Monte Mitchell urged residents to hold off anyway: "Don't be doing any open-air burning right now while we've got these conditions. Be careful with cigarettes and campfires and use common sense."

Witt, at the weather service, said the high-pressure system off the coast will begin to move east today, and moisture will begin moving in from the Gulf of Mexico and the Atlantic.

"It looks like everybody's going to get into the showers and thunderstorm activity," he said. "We could see a quarter to a third of an inch of rain. Heavier thunderstorms along the front are capable of producing lots of rain in a short period of time."

High temperatures on Friday might stall out in the 50s, Witt said, falling into the 30s and 40s overnight. By next week, he said, "we get above normal once again, but it may not be as extreme."


> Read Frank Roylance's blog on MarylandWeather.com

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