D.C.-area forecast: A humid week with daily downpours possible
Flash flood watch for parts of the region today.
Express forecast
Today: Showers and storms possible at times, some heavy. Highs: Near 80.
Tonight: Scattered showers and storms. Lows: Near 70.
Tomorrow: Partly sunny with a few showers/storms possible. Highs: Near 85.
Forecast in detail
It eclipsed 90 degrees on all but one day last week. This week, it may never hit 90 but it’s so persistently humid that it won’t feel much cooler. All the mugginess fuels almost daily chances of showers and storms, drawing from moisture pumped in from the south, including some from Tropical Storm Fred midweek. Some areas may contend with flooding. Later this week, the rain chances should diminish some, but temperatures are toasty.
Today (Monday): Showers and storms, some with heavy rain, may stream through the area from south to north. How widespread they become is an open question, but a lot of rain could fall in a short amount of time, posing a flood threat. It won’t rain the entire day, and the downpours could miss some areas altogether. Cloudy with muggy (dew points rising above 70), with highs near 80. Winds are light from the east. Confidence: Medium
Tonight: Scattered showers and storms, with potentially heavy downpours, remain possible through the evening. Late at night they probably ease or end, with cloudy skies and lows near 70. Confidence: Medium
Tomorrow (Tuesday): We should have some partial sunshine, which boosts high temperatures toward the mid-80s. However, it remains very humid and we can’t rule out some isolated to widely scattered showers and storms, especially late in the day; overall rain coverage should be less than Monday. Winds are light from the south. Confidence: Medium-High
Tomorrow night: We can’t rule out an evening shower or storm but it’s mostly dry. Toward morning, some showers may redevelop as the remnants of Tropical Storm Fred approach, especially in our western areas. Lows are again near 70. Confidence: Medium-High
A look ahead
The remnants of Tropical Storm Fred probably pass to our west on Wednesday and Thursday, where the bulk of the rain might stay. However, they will draw enough tropical moisture northward for scattered showers and storms both days that could produce locally heavy downpours. Highs are in the low 80s on Wednesday and mid-80s on Thursday. Lows at night are near 70. Confidence: Medium
For Friday into the weekend, we settle into a pretty typical August weather pattern with partly sunny skies, very warm and muggy conditions, and isolated to scattered late-day storm chances. Highs are mostly in the upper 80s with nighttime lows from 70 to 75. Confidence: Medium
https://www.washingtonpost.com/weather/2021/08/16/dc-area-forecast-humid-week-with-daily-downpours-possible/?