Capital Weather Gang from The Washington Post

Daily forecast for the Washington area

D.C.-area forecast: Peak summer heat comes roaring in, and it’s going to last a while

* Code orange air quality alert for Friday: Unhealthy for sensitive groups *

'Annapolis Harbor' by Jarrett Hendrix, taken on July 15, 2016.

“Annapolis Harbor” taken July 15 by Jarrett Hendrix via our CWG Flickr page

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

2/10: The heat’s just beginning. Possible “0/10″ to be awarded before it’s all said and done?

EXPRESS FORECAST

Today: Very hot. PM shower/storm? Highs: Mid-to-upper 90s.
Tonight: Shower/storm? Clearing. Lows: 70s to near 80 (downtown).
Tomorrow: Oppressive, dangerous heat. Highs: Mid-90s to near 100.
Sunday: Still hot, and rather steamy. Highs: Mid-to-upper 90s.

FORECAST IN DETAIL

Regardless of whether we set record high temperatures in the coming days, it’s dangerous when the atmosphere brings oppressive humidity while eyeing upper 90s. Perhaps cracking the century mark. Stay well-hydrated and in A/C when not doing those BRIEF outdoor activities.

Today (Friday): Ready to rumble in the heat dome? Mid-to-upper 90s for afternoon high temperatures feel closer to 100+ (even by lunch hour!) thanks to nearly-oppressive dew points near 70 degrees. Any early clouds dissipate quickly, but we could have another batch of clouds during the afternoon give us some natural shade at times. Isolated thunderstorms, especially north of town, can’t be ruled out completely (20 percent chance) before sunset. 5-10 mph southwest breeze may blow at times. Confidence: Medium-High

Tonight: Partly cloudy overall, but we have a slight chance of a few storms through evening. Very warm 70s for low temperatures outside of the Beltway and around 80 degrees downtown is about the best we can do, as the dangerous heat begins. Please check on neighbors who may not have air conditioning. Heat-related issues begin in earnest when overnight low temperatures cannot cool off, and very muggy with humid-feeling dew points above 70 degrees take hold. Southwest winds blow between 5-10 mph. Confidence: Medium-High

For related traffic news, check out Dr. Gridlock. Keep reading for the forecast into next week.

Tomorrow (Saturday): Our heat dome continues to seal us in with a dangerous combination of heat and humidity. We have temperatures in the mid-90s to near 100 degrees on tap, with dew points into the 70s which is terrible humidity any way you describe it. Walk in the shade to avoid infrared beating down on you from the partly to mostly sunny skies. Be very careful with outdoor activities by limiting their duration and stay hydrated and mindful of electrolytes you’re sweating out. West-southwest breezes around 5 mph just feel like a blow torch. Only about a 10 percent chance of a shower or storm. Confidence: Medium-High

Tomorrow night: Thick air continues, as sopping wet dew points continue above the 70-degree mark. Another implication of “the dome” is stagnant air. It’s possible the air quality really won’t be great, so consider that if you have asthma, for instance. 70s for low temperatures are probable outside of the Beltway in the “luckier” spots, with downtown stuck around 80 degrees. A stray thunderstorm is possible — even into the early morning hours — but only about a 30 percent chance. Confidence: Medium-High

A LOOK AHEAD

Sunday: We’re still trapped in this broiling bubble of mid-to-upper 90s but will hold out a tiny bit of hope for a slight possible drop in humidity — hopefully bringing dew points back below the 70-degree oppressive threshold. It’s mainly sunny but it remains to be seen if a weak backdoor cold front can sneak southward down the coast toward us. Because we don’t have high hopes, we believe a 20 percent chance of a cooling shower/storm is about the best we can do. Confidence: Medium

Sunday night: Partly cloudy, with an isolated showers or storm possibly roaming around. Probably about an average July-level of mugginess. NBD! This helps prevent overnight low temperatures from cooling off much (at all) with 70s regionwide. Crank up that A/C! Confidence: Medium

Mid-90s or thereabouts likely continue the fun Monday and into Tuesday with extra humidity added in once again. Dew points above 70 are possible, and we may very well have that oppressive, steamy feeling. Continue to take it easy. Find shade. Drink water. Wear lightweight clothing. Especially given such warm overnight low temperatures near 80 downtown and uncomfortable 70s outside of the Beltway. This contributes to serious, accumulated heat stress on the body. Monday has the higher (40 percent) chance of a shower or storm — perhaps even some clouds — when compared to Tuesday’s sunnier conditions, drier conditions (20 percent chance of rain). Confidence: Medium

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