D.C.-area forecast: Warm start to the week, but showers are in the mix
with a big cooldown later in the week.
Rather humid conditions last through Wednesday.
Express forecast
Today: Intermittent showers, maybe some late thunder. Highs: 73 to 78.
Tonight: Evening showers/storms, then mostly cloudy. Lows: 60 to 65.
Tomorrow: Partly sunny, a few p.m. storms. Highs: 84 to 88.
Forecast in detail
The weather is nice and warm through midweek, but it’s rather humid and each day offers possible showers and storms, the highest chances today and Wednesday. The weather turns noticeably cooler for the second half of the week, with highs mostly in the 60s and lows in the 40s. Another shot of rain is possible Friday.
Today (Monday): Showers are possible at any time today, but they may be most numerous between the morning hours and midday. We’ll have dry intervals as well, especially in the afternoon when skies may brighten. On balance, skies are mostly cloudy with highs near 75. It’s moderately humid, with dew points from 60 to 65. Winds are from the south at around 10 mph, with some gusts to 20 mph or so. Rainfall amounts are pretty variable but average between 0.1 and 0.25 inches. Confidence: Medium-High
Tonight: Skies remain mostly cloudy and some hit-or-miss showers or thunderstorms are possible through the evening. Rain chances diminish after midnight, with mild lows from 60 to 65. Confidence: Medium-High
Tomorrow (Tuesday): A summerlike day with very warm temperatures and on the muggy side (dew points near 65). Highs soar into the mid- to upper 80s under partly to mostly sunny skies. Factoring in the humidity, the highest it’s been this year, and we may see heat index values top 90. A few storms could (20 to 30 percent chance) pop up late in the afternoon, especially in our northern areas, but most of us stay dry. Breezes are light to moderate (around 10 mph with some gusts to 20 mph) from the southwest. Confidence: Medium-High
Tomorrow night: Some evening storms are possible (30 percent chance), but coverage may end up being spotty. Otherwise, skies are partly to mostly cloudy with lows in the 60s. Confidence: Medium-High
A look ahead
One more warm day on Wednesday, with highs climbing well into the 70s or even cresting at 80 if we can manage some sun before any rain. A cold front coming through brings showers and storms, their exact timing to be determined. Right now, they seem most likely in the afternoon, but an earlier or later arrival is possible. Clearing and much cooler Wednesday night, with lows in the 40s in our cooler areas to near 50 downtown. Confidence: Medium
Thursday may be one of the week’s nicest days with sunny skies and highs from 65 to 70, not unlike this past Saturday. Gradually increasing clouds Thursday night with a chance of rain toward morning and lows from 45 to 50. Confidence: Medium-High
Friday has the look of a rainy day as a coastal storm attempts to develop in the Mid-Atlantic. The clouds and rain keep it cool, and highs, generously, may reach the 60s, but it could be cooler if the rain is steady and falls throughout the day. Rain should exit by Friday night, with clearing skies and chilly lows in the 40s. Confidence: Medium
Breezy and cool, but dry conditions are most likely by Saturday, with highs in the mid-60s. Milder air starts to return to the region on Saturday night, when lows are in the 50s. Sunday, Mother’s Day, looks like a warmer day, with highs 70 to 75. However, clouds may increase some, and we can’t totally rule out a shower or storm. Confidence: Medium
https://www.washingtonpost.com/weather/2021/05/03/dc-area-forecast-warm-start-week-showers-mix-big-cool-down-late-week/?