DC's record dry stretch comes to a close

 

A windy fall day in the nation's capital

DC’s record of 38 consecutive days without measurable rain came to an end on November 10 when 0.2” was observed. This fall has been exceptionally dry and the nation’s capital has a growing rainfall deficit that stands at 4.72”, as of September 1. This fall’s warmer and drier than average conditions have combined to produce widespread moderate to severe drought conditions across the Mid-Atlantic Region.

Although some showers are possible Thursday afternoon, no other rainfall is expected over the next week. There are some similarities between DC’s record 38 days without measurable rainfall, from October 3 – November 10, and the second and third longest stretches of dry weather.

The second longest period without measurable rainfall in the nation’s capital is 34 days from September 15 – October 18, 2007. Despite this dry stretch of weather, October 2007 still finished as DC’s 10^th wettest with 6.55” of rain. This was also DC’s warmest October on record, similar to how October 2024 finished 2.2° warmer than average. 

A strong episode of La Nina was in place during the 2007 – 2008 winter season. Consequently, a below average seasonal snowfall total of 4.9” occurred in the nation’s capital. La Nina winters in the United States often feature a more northerly storm track that can lead to drier winters and less snow for the Mid-Atlantic Region. La Nina conditions correlate to above average sea surface temperatures in the tropical Atlantic with below average temperatures in the eastern Pacific, near Central America.

The third longest period without measurable rainfall in the nation’s capital is 33 days from August 7 – September 8 in 1995. A wetter than average fall followed and a moderate-intensity La Nina occurred during the 1995 – 1996 winter season. It was an atypical La Nina winter in the nation’s capital with a seasonal snow total of 46”. Washingtonians experienced measurable snowfall in five consecutive months from November 1995 – March 1996.

NOAA expects a weak La Nina to develop for the upcoming winter season. That’s not good news for local winter weather enthusiasts. There have been 12 weak La Nina winter’s since the 1950s that produced a snowfall average of 9.4” in the nation’s capital. That’s below DC’s seasonal snowfall average of 13.7”. The most recent winter with weak La Nina conditions was the 2022 – 2023 season when DC had only 0.4” of snow.

That’s not to say the upcoming winter will be similar to past winters with La Nina conditions that followed long stretches of dry late-summer or fall weather. It merely illustrates the need to pay attention to your favorite meteorologists, such as those on the WUSA9 weather team, as the right ingredients need to come together only once to produce a memorable winter storm.