Washington-area heat wave is just beginning and could last at least two weeks

Prepare for a prolonged period of heat that will reach intense and record levels at times in the Washington region.

Although still rather calm, the warm weather at the start of the week is only the beginning. If weather models are to be believed, there’s a good chance that most days over the next two weeks will reach or exceed 90 degrees. Some of them could even flirt with the 100.

Friday through Sunday could be the warmest period, when daytime readings could approach the century mark and lows will barely fall below 80 in the city. These temperatures are approximately 10 to 15 degrees above average for this time of year.

This warm spell will be accompanied by very sunny skies and little to no rain throughout the weekend, bringing drought concerns back.

Humidity will be moderate at the start of the week, but will increase as temperatures rise, potentially sending heat index values ​​– a measure of how hot one feels taking into account humidity – to near 105 degrees by Friday.

Monday likely marked the first in a long string of consecutive days of 90 degrees or higher. Technically, a heat wave is considered any period lasting at least three days with high temperatures of 90 or higher (although some argue for a higher bar in the Washington area, as reaching 90 is so common in the middle of summer).

The first few days of this heat wave will be fairly unremarkable, as high temperatures in the 90s aren’t that much above normal. But the heat will gradually intensify.

Models project temperatures between 95 and 103 Friday through Sunday. These longer-term forecasts have tended to be a little warmer than reality in recent weeks, so hitting 100 is not a lock. But if the District manages to reach triple digits, it would be the first time since 2016, when it happened four times.

Records could be at risk

Starting Tuesday, dozens of heat records could fall across the Ohio Valley, Northeast and Mid-Atlantic.

For records to fall in the Washington region, temperatures will need to reach around 100°C, which is possible between Friday and Sunday but unlikely before then. Here are the predicted highs in Washington between Tuesday and Sunday and the current records:

  • Highest forecast for Tuesday: 93; record: 97.
  • Highest forecast for Wednesday: 91; record: 99.
  • Highest forecast for Thursday: 93; record: 99.
  • Highest forecast for Friday: 97; record: 99.
  • The maximum forecast for Saturday: 99; record: 102.
  • The maximum forecast for Sunday: 97; record of 98.

Records are more likely to occur at Dulles Airport (where the sighting history is shorter than for the District). It could challenge records Tuesday, Friday, Saturday and Sunday.

Record low temperatures will also become increasingly possible as nighttime temperatures rise this week. Lows could only dip to the mid 70s to around 80 this weekend.

The heat will likely extend beyond this week

With temperatures of at least 90 degrees expected to continue into next week, this heat wave has the chance to become notable for its longevity. A typical summer sees at least a streak of eight or nine consecutive days at or above 90. The streak starting this week could easily exceed this value if certain model predictions are correct.

The longest streak of days recorded at 90 years or more is 21, recorded in 1980 and 1988.

It is also possible that we will string together a significant series of days at 95 or above at the end of this week and next week. The longest such streak in an average year is about three or four days, and the streak later this week has a chance of at least matching that. The longest such streak, of 12 days, occurred in June and July 2012.

It’s time to start pleading for rain

The prolonged period of heat expected; an intense sun, as the summer solstice approaches; and the lack of precipitation could revive drought problems.

Although some places were flooded a few times by severe storms in May and early June, the month was drier than normal, and April was also dry. As a result, “abnormally dry” conditions have returned to many parts of the region, after last year’s drought ended during the winter, according to the US Drought Monitor.

Lower than normal soil moisture during a powerful heat wave near the solstice is a recipe for parched vegetation.

There is little to no rain forecast through the end of this weekend or early next week, as the first in a series of weather disturbances spread across the Great Lakes and northward. East. Such disruptions could trigger thunderstorms, but it is impossible to predict their timing and location that far in advance.

Long-term forecasts call for drier and warmer than normal weather through July.

Jason Samenow contributed to this report.

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