Friday through Sunday may be the hottest stretch, when daytime readings could near the century mark and lows barely fall below 80 in the city. These temperatures are about 10 to 15 degrees above average for the time of year.
This bout of heat will come with super sunny skies and little to nothing in the way of rain through the weekend, bringing back drought concerns.
Humidity will be moderate to begin the week but will increase as temperatures rise, potentially sending heat index values — a measure of how hot it feels factoring in the humidity — near 105 degrees by Friday.
Monday is poised to mark the first of many consecutive days of 90 degrees or higher. A heat wave is technically considered any period lasting at least three days with highs of 90 or higher (although some argue for a higher bar in the Washington region since hitting 90 is so common in midsummer).
The early days of this heat wave will be rather unremarkable as highs in the low 90s aren’t that much above normal. But the heat will steadily intensify.
Models project highs between 95 and 103 Friday through Sunday. These longer-term predictions have tended to be a little hotter than reality in recent weeks, so hitting 100 isn’t a lock. But if the District manages to reach the triple digits, it would be the first instance since 2016, when it happened four times.
Record highs could be threatened
Beginning Tuesday, dozens of records for heat could fall across the Ohio Valley, Northeast and Mid-Atlantic.
For records to fall in the Washington region, temperatures will need to rise to around 100, which is possible between Friday and Sunday but unlikely before that. Here are the predicted highs in Washington between Tuesday and Sunday and the standing records:
- Tuesday’s predicted high: 93; record high: 97.
- Wednesday’s predicted high: 91; record high: 99.
- Thursday’s predicted high: 93; record high: 99.
- Friday’s predicted high: 97; record high: 99.
- Saturday’s predicted high: 99; record high: 102.
- Sunday’s predicted high: 97; record high 98.
Record highs are more likely to occur at Dulles Airport (where the history of observations is shorter than for the District). It could challenge record highs Tuesday, Friday, Saturday and Sunday.
Record-warm lows will also become increasingly possible as nighttime temperatures rise this week. Lows may dip only into the mid-70s to around 80 this weekend.
The heat will probably extend beyond this week
With highs of at least 90 degrees forecast to continue into next week, this heat wave has the chance to become a notable one for its longevity. A typical summer experiences at least one streak of eight or nine straight days at or above 90. The streak beginning this week could easily exceed that if some model forecasts are correct.
The longest recorded streak of days at 90 or above is 21 set in 1980 and 1988.
It’s also possible we will string together a significant streak of days at 95 or above late this week and into next week. The longest such streak in an average year is around three or four days, and the stretch later this week has chance to at least match that. The longest such streak, of 12 days, occurred in June and July of 2012.
Time to start pleading for rain
The predicted extended period of heat; intense sunshine, as we near the summer solstice; and lack of rainfall could bring back drought concerns.
While some locations were doused on a few occasions by heavy thunderstorms in May and early June, it has been drier than normal this month, and April was dry, too. As such, “abnormally dry” conditions have returned to many parts of the region, after a cessation of last year’s drought over the winter, according to the U.S. Drought Monitor.
Lower-than-usual soil moisture during a powerful heat wave near the solstice is a recipe for desiccated vegetation.
There’s little to no rain in the forecast until late this weekend or early next week as the first of perhaps several atmospheric disturbances scoots through the Great Lakes and into the Northeast. Such disturbances could trigger thunderstorms, but their timing and placement is impossible to predict this far in advance.
Long-range forecasts point to more drier- and hotter-than-normal weather into July.
