September D.C. weather outlook: Warmer and drier than normal


While it’s now meteorological fall (outlined as September by means of November), September generally is a summer time sibling in some ways. Washington can expertise sturdy warmth and humidity at instances in the course of the ninth month.

In the approaching weeks we count on it’ll typically really feel extra like summer time than fall. For September total, we project temperatures will common 1 to 2 levels hotter than the month-to-month norm (which is 72.4 levels — averaging daytime and nighttime temperatures).

Meanwhile, the dry circumstances that commenced in August will in all probability proceed. We’re predicting about one inch much less rainfall than normal in the course of the upcoming month (the 30-year common is 3.93 inches).

Parts of the Washington area are parched, and it’d get even drier

Computer mannequin simulations typically favor close to normal to above-normal temperatures and normal to below-normal rainfall for the primary half of the month:

The projected above-normal temperatures within the Mid-Atlantic are modest, which implies highs primarily within the mid- to higher 80s with reasonably humid circumstances.

Precipitation simulations are extra blended, however the fashions principally lean towards drier-than-normal circumstances within the Mid-Atlantic however above-normal quantities within the Southeast.

September is the height of hurricane season, and it takes simply the remnants from one storm to offer rainfall totals an enormous increase. But to this point this year, the Atlantic hurricane season has been remarkably quiet.

Did forecasts of an extra-busy hurricane season prove lifeless flawed?

The National Weather Service up to date its September outlook Wednesday and tasks warmer-than-normal circumstances over a lot of the United States, together with the D.C. space. Its outlook requires equal possibilities of above-normal, normal or below-normal rainfall.

The presence of La Niña tends to favor heat and dry weather in our area in the course of the fall, however previous occasions have resulted in variable outcomes, notably for precipitation.

Recapping August and meteorological summer time

We’re predicting September to be much like August in plenty of methods. August completed 1 diploma hotter than normal, and it was on the dry aspect.

The common temperature of 80.4 levels ranked because the Twelfth-hottest August on file. The month-to-month rainfall of two.42 inches was 0.83 inches drier than normal, and the fourth-driest on file.

Our August outlook referred to as for a mean temperature between 79 and 80 levels, and so was simply barely off. Our rainfall projection of three.25 to six.25 inches was too aggressive.

Extreme weather took a pause in the course of the month with no information set. Our hottest temperature was 97 levels Aug. 9. Our rainiest day was Aug. 4, when 0.93 inches fell — the identical day because the lethal lightning strike close to the White House.

Washington’s summer time, by the meteorological definition of June by means of August, averaged 79.2 levels, which is 0.3 levels above the current 30-year normal. It marked the Fifteenth-hottest summer time on file, although it was the best since 2017. Rainfall managed to file 1.21 inches extra than normal, regardless of the dry August.

So far, 2022 is monitoring barely drier and cooler than final year, however barely hotter and wetter than the current 30-year common. For now, 2012 continues to be the most popular year ever recorded in Washington.

To this level, Washington has seen 36 days at or above 90 levels, which is strictly normal. In a typical September, we might see 4 extra, although we’ve an honest probability to exceed that this year.

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