DC’s warm and wet start to July

 

DC's 7-day forecast (Source: WUSA9)

Rain occurred on 15 of the first 21 days of July in the nation’s capital. Those 15 days saw as little as a trace (too little to measure) to 1.33” on July 14 and has added up to 5.22” at National Airport. It’s also been a warmer than average month-to-date at both National and Dulles Airports. While warmer than average, it hasn’t been exceptionally warm with the hottest temperature of the month having been 94° (July 13).

Warmer and wetter than average July weather isn’t unusual given DC’s tendency to see frequent summertime showers and thunderstorms. However, it is in contrast to the first half of last July that was 1.2° below average through July 16 when it was also wetter than average. The key difference between the start of this July and last July has been the amount of sunlight. Last July got off to rainier start and was commensurately cooler. 

By comparison, this month’s rain has occurred at night on several occasions. That’s allowed temperatures on those days to rebound as skies cleared early in the day without any significant impacts. Ironically, this has been DC’s wettest month since July 2022 (7.61”). That’s excellent news as the nation’s capital has been mired in chronic drought conditions in recent months.

While the 5.22” of rain so far this month is appreciably more than DC’s July average of 4.33”, the significant rainfall totals have been rather localized during scattered thunderstorms. Consequently, the beneficial rainfall hasn’t been widespread enough to put a significant dent in the ongoing drought conditions.

NOAA’s outlook for the rest of July is for warmer than average temperatures in the DC Metro Area. In fact, my colleagues and I on the WUSA9 weather team are tracking what will likely be the hottest weather of the summer later this week with highs in the mid to upper 90s. Aside from scattered showers in the forecast tomorrow, no widespread rainfall is expected during the upcoming week. That means the moderate to severe drought conditions will linger into August. 

It’s increasingly likely, absent a major shift in the weather pattern, that it will take a decaying tropical system to bring enough widespread, significant rainfall to alleviate the drought conditions.