D.C.-area temperatures charge to record highs amid spiking tree pollen.

Cherry blossoms hit first stage in bloom cycle.

Temperatures in the Washington region soared into the upper 70s Thursday afternoon, some 25 degrees above normal, setting record highs. The warm weather came as signs of spring abound, from exploding pollen levels to bursting flower buds.

As crocuses and other early blooming flowers opened up, the green buds of cherry blossoms at the Tidal Basin emerged Thursday, reaching the first of five stages in their development.

Through 4:30 p.m., temperatures at all three D.C. area airports had risen to 79 degrees, topping previous records:

Reagan National Airport broke the March 11 record of 78 from 1967.
Dulles broke the March 11 record of 77 from 1990.
BWI broke the March 11 record of 75 from 1967.
Thursday marked the third-straight day of 70-degree weather in the region, and a fourth is possible Friday.

The surging temperatures caused tree pollen levels to spike. “With the above average temperatures near 70 degrees and sunshine the last several days, our early flowering tree species have released an abundance,” wrote Susan Kosisky, chief of the U.S. Army Centralized Allergen Extract Lab in Silver Spring, Md., in an email.

The tree pollen count climb to 1,470.29 grains per cubic meter of air Thursday, which is in the high range. . .

The cherry blossom blooming was also slowed by the February temperatures, the coldest in six years. Not since 2015 has it taken this long for the blossoms’ green buds to emerge; that year it took until March 18 and peak bloom was pushed back to April 10.

This year, Capital Weather Gang is predicting the cherry blossoms to peak around April 1, while the National Park Service is forecasting the peak a couple days later. . .

Cooler weather should arrive this weekend, with highs in the mid- to upper 50s, which is close to average.

Early next week, the region faces some weather whiplash with high temperatures only in the 40s, and rain may mix with snow Monday night.

https://www.washingtonpost.com/weather/2021/03/11/dc-record-highs-march11/?