Washington D.C. Forecast: Severe Thunderstorm Watch until 8pm

This Afternoon:Hot and Humid, Storms Possible Temperatures: Mid to Upper 90s Heat Index: 100-105 Tonight:Storms End, Warm and Muggy Lows: 70s Wind: S 5-10 m.p.h. Thursday:Showers and Storms Likely, Heavy Rain Possible Highs: Upper 80s to Near 90 Precipitation: 80%

A Severe Thunderstorm Watch is in effect until 8pm this evening.

A Heat Advisory is in effect until 7pm this evening.

High heat and humidity will lead to dangerous heat index values near 105°F this afternoon and evening which is why the Heat Advisory has been issued. In addition, strong to severe storms will also be possible this afternoon and evening. Tonight will be partly cloudy, warm and muggy with lows in the 70s.

Thursday may feature tropical downpours as Tropical Storm Arthur approaches from the south. Expect partly sunny to mostly cloudy skies with highs in the upper 80s. Friday morning will be breezy with a few showers mainly east of D.C., but skies may experience some clearing by the afternoon and evening as Arthur moves farther out into the Atlantic. Conditions should improve for the weekend with more sunshine and comfortable levels of humidity.