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* Severe thunderstorm watch until 11 p.m. | Heat advisory Saturday from noon to 8 p.m., for the District and points east of Interstate 95 | Flash flood watch this afternoon into the overnight *

4:20 p.m. update — Follow our PM Update for the latest on the storms

3:10 p.m. update — Storms approaching from the southwest

A new batch of storms that formed to the south and west is encroaching on us as additional storms develop locally. Several severe thunderstorm warnings are up for our far south and west suburbs, mainly for a strong wind risk. This activity is moving northeast and will overtake the area the next few hours.

1:30 p.m. update: A severe thunderstorm watch has been issued by the National Weather Service for the entire D.C.-Baltimore region until 11 p.m., mainly for the potential that storms this afternoon into evening could produce damaging winds. This is in addition to the flash flood watch also in effect. A few isolated storms have started to pop up in the D.C. metro area, with more storms expected this afternoon into evening.

Original post

Today’s daily digit

A somewhat subjective rating of the day’s weather, on a scale of 0 to 10.

3/10: Perhaps the least comfortable day of summer so far. If you’re out and about — water. Keep an eye to the sky for late-day storms.

Express forecast

  • Today: Heat indexes near 105. Partly cloudy. Showers/storms late. Highs: Mid-90s.
  • Tonight: Showers and storms may continue, then some clearing. Lows: Upper 60s and lower 70s.
  • Tomorrow: Partly cloudy. Less humid. Slight chance of a shower. Highs: Mid-80s.

Forecast in detail

Our week-long heat wave tries to peak on its final day. And if temperatures don’t make that mark, then heat indexes will give it a try. As is often the case, the day before a cold front can be brutal. Near and east of the Interstate 95 corridor, “feels like” values past 105 are possible throughout the afternoon. Showers and storms that become likelier with time signal change on the way.

Today (Saturday): Our one-day break in disgusting humidity was nice. Today we’re back into the soup. With high temperatures similar to Friday’s, or temperatures mainly heading into the mid-90s, the heat index is set to slam us. We could be talking values of 105 or higher during the afternoon, especially D.C. and eastward. Clouds increase with time, and showers or storms become likely heading into mid-to-late afternoon or early evening. Winds are from the southwest around five to 10 mph, with stronger gusts. Confidence: Medium-High

Tonight: Showers and storms are likely during the evening and potentially into the night. It’s probably a situation where the storms are a bit hit-or-miss, but some places get slammed in a short period. As much as two or three inches may fall in the heaviest activity, potentially leading to localized flash flooding. Otherwise, a general quarter-inch to an inch where it rains, and some spots don’t see much at all. It’s humid through the night, with the front passing sometime near dawn. Lows reach the upper 60s and lower 70s. Confidence: Medium-High

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Tomorrow (Sunday): The forecast for the end of the weekend is considerably improved, although it might be tenuous. At this point it seems the front will sink far enough south that most of the rain risk is south of us. I wouldn’t rule out a few showers, but it’s mainly partly cloudy skies and somewhat pleasant northwest breezes blowing drier air in. Dew points in the mid-60s by afternoon, coupled with highs in the mid-80s, might almost feel pleasant after the heat wave we’ve endured. If the front shifts back north, rain chances rise. Confidence: Medium-High

Tomorrow night: Skies stay partly cloudy. A shower or two could pass, especially south or east of the city. Lows are in the mid-60s to near 70, with humidity down somewhat compared with recent nights. Patchy late-night fog may form as well. Confidence: Medium

A look ahead

On Monday we’ve still got the meandering and dissipating frontal zone to watch. Newer weather modeling continues to suggest it will stay farther south than it once appeared, which means rain chances are much diminished. As you head south, odds of raindrops or some storminess grow. Highs reach the mid- to upper 80s. Confidence: Medium

The front is more fully dissipated by Tuesday, which should lead to increased sunshine locally. When you’ve got lots of sun in July, it tends to be hot. This one fits the bill as highs rise to around 90. An isolated storm may pop up in the afternoon. Confidence: Medium