Circus arts at the Folklife Festival in Washington Sunday. ( Angela N via Flickr )

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

5/10: Not the worst July day, but heat and humidity are on the upswing and Sunday was so much better.

EXPRESS FORECAST

Today: Partly sunny, shower possible. Highs: Around 90.
Tonight: Partly cloudy, muggy. Lows: 68-75.
Tomorrow: Partly sunny, very hot. Highs: 95-99.

View the current weather conditions at The Washington Post headquarters.

FORECAST IN DETAIL

Sunday’s magnificence was such a tease, as the summer’s most intense heat wave (so far) takes hold this week. High temperatures in the upper 90s are possible Tuesday through Thursday, and that’s not even factoring in the humidity. A cool front sliding south Thursday night into Friday does offer some relief in time for the weekend.

Today (Monday): Winds that had drawn cool, dry air in from the northwest Sunday, becoming southerly today (at around 5 to 10 mph). That means it turns warmer and noticeably more humid, with highs around 90. Skies are generally partly to mostly sunny, though we can’t rule out a brief shower in the morning. Confidence: Medium-High

Tonight: It’s a partly cloudy, typical July evening. The air is humid, there’s a soft, gentle breeze, and it’s warm. Evening temperatures are in the 80s and overnight lows range from the mid-70s downtown to the upper 60s in our cooler areas. Confidence: High

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Tomorrow (Tuesday): This is the first day of fairly brutal heat. The sun beats down, humidity is moderately high and temperatures take aim at the upper 90s. Factoring in the humidity, it feels like 100-105 in the peak afternoon hours. We can’t rule out a late day storm, but mostly we’re all just baking. Winds are from the southwest at around 10 mph. Confidence: Medium-High

Tomorrow night: There could be an evening storm or two lingering; otherwise it’s just a tranquil, muggy, midsummer’s night. Overnight lows range from near 70 in our cool spots to the upper 70s downtown. Confidence: Medium-High

A LOOK AHEAD

The heat wave reaches its peak Wednesday and Thursday, with highs in the upper 90s and we night even spy a triple digit reading or two. The humidity is up there too, producing heat index values up to 105. Late both days, we can’t rule out a brief cooling storm, with the best chance coming perhaps Thursday evening. The overnight hours don’t offer a ton of cooling with lows in the 70s to near 80 downtown. Confidence: Medium-High

Assuming a cold front passes to our east by Friday, it shouldn’t be quite as hot or humid. But even so, behind the front it will take some time for relief to filter in, so we still expect highs near 90 or so. Skies should be partly sunny, with a chance of afternoon storms  highest in our eastern areas. Confidence: Medium

The weekend looks pretty good. High pressure builds in from the west, lowering humidity a bit. Both days should see a good deal of sunshine with highs in the mid-to-upper 80s Saturday and up near 90 Sunday. Lows range from the low 70s downtown to the 60s elsewhere. Confidence: Medium