Seasonal allergies will be in full swing this week in the Northeast as seasonable temperatures take hold.

After a slow start to spring, more consistent, higher temperatures have finally migrated northward.

However, with these warmer temperatures comes the return of seasonal allergies.

With milder conditions starting in the beginning of April, the growing season has really started up. Plants and flowers all over the region are blooming or are ready to bust out. However, it is not the bright, showy flowers that cause most problems for allergy sufferers.

This sudden boom in tree blossoms could have allergy sufferers seeing symptoms more abruptly than usual.

As per this time of year, the tree pollen is the main allergy threat, especially from the less conspicuous oak, maple, pine and elm varieties.

Higher levels of these allergens started in the Southeast several weeks ago. However, as the warm weather has expanded northward into Maryland, Pennsylvania and even southeastern New England, so has the allergy threat.

What seems to have awakened the trees was the sudden warmth early last week, followed by drenching rain in many areas. Even though temperatures slipped back following the rain, they have averaged about 10 degrees higher than the first week of the month.

Consistent warmth is expected through this week, along with occasional rainfall. The combination of the two will continue to spur on blossoming and pollen release.

Even though rain temporarily removes some of the pollen from the air, it promotes a new round of blossoming this time of the year.

In Philadelphia, temperatures will remain at least a few degrees above average with temperatures in the 70s. New York City also looks to experience warmer-than-normal temperatures, reaching the middle to upper 60s this week. Overall, the same trend will reach Boston, with the temperature above the normal middle 50s most days.

So far in April, temperatures have been slightly above normal in both the mid-Atlantic and southern New England. In Philadelphia, temperatures have averaged 2.1 degrees above normal, while Washington D.C., has reached an average of 3.8 degrees above the norm.

The changes in New England are a bit less extreme. After finishing March slightly below average, cities like Boston and Providence have rebounded to about 0.3 degrees above normal for this time in April.


By Courtney Spamer, Meteorologist
April 19, 2013