11:10 p.m.: The few showers and storms that rolled through the area earlier have dissipated and a heat advisory has been issued for Wednesday. It’s in effect from 11 a.m. to 8 p.m. for areas near and east of Interstate 95, including the District for heat index values near 105 degrees.
The National Weather Service advises: “Take extra precautions if you work or spend time outside. When possible, reschedule strenuous activities to early morning or evening. Know the signs and symptoms of heat exhaustion and heat stroke. Wear light weight and loose fitting clothing when possible and drink plenty of water.”
Original post from late afternoon
There was no trouble getting to 90 degrees today, as temperatures headed up into the low 90s most spots. That’s day six in a row with temperatures of 90 degrees or higher in the city, which ties for the longest heat wave of the season to date. Temperatures are likely to head even higher tomorrow, although we’ll need to see whether showers and storms mess with that risk at all.
Through tonight: Isolated to scattered storms may dot the area through sunset or so, then die off into the night. Any storm can pack a punch, with a small threat of wind damage if they gust out in a rush. Partly cloudy and muggy is the main story for most folks. Lows range from about 70 to perhaps as high as the upper 70s. A patch or two of fog is possible late at night as winds trend light.
View the current weather at The Washington Post.
Tomorrow (Wednesday): Under partly sunny skies, highs range from about 92 in the coolest spots in elevation north and west to as hot as 98 or so in the city and other similar locations. When you add in high humidity and dew points in the low 70s, heat index values are around 100 during the afternoon. With the remnants of Barry passing by, showers and storms are again possible, especially late day. Some could be severe. Winds are from the south-southwest about 10 mph.
Pollen update: Grass pollen is moderate. Weed pollen and mold spores are low/moderate. Tree pollen is low.
Storms: We’ve got a “marginal risk” of severe weather from the Storm Prediction Center through the evening, or level 1 of 5 on its scale. A few storms may roll through, and they could be strong to severe. Supporting storm chances, Capital Weather Gang’s Jeff Halverson notes the “atmosphere is unstable with good low-level lapse rates.” While it is uncertain how much remains organized into the area from the west, Halverson points out “a wet microburst or two” is a risk east of mountains. Heavy rain is also a threat.
Another marginal risk is up for tomorrow as Barry’s remnants move by. The threat would again tend to focus on the afternoon or evening. There is some hint that the most widespread activity may stay west, but with it passing close by it’s hard to bet on that. Any storms could be intense, with heavy rain the main threat, but also risks from lightning, the potential for isolated wind damage and perhaps a quick tornado or two.
Want our 5 a.m. forecast delivered to your email inbox? Subscribe here.