Following a cooler, less humid weekend, typical summer heat and humidity will return to Washington with a vengeance early next week. As a matter of fact, a few record highs will fall by the wayside.
A Canadian high pressure has been supplying the Washington metro area with a cooler Northwest wind that has cleared the air and provided low humidity. The weather pattern will change early next week as the high pressure slides off the coast. A Southwest breeze will pump in much warmer lower 90s on Monday with the humidity creeping back.
A weak upper-low will move from the Midwest into the Upper Ohio Valley and then off the Northeast on Monday afternoon. While Washington will likely stay dry, a brief thunderstorm could develop ahead of this feature north of Interstate 70 during the afternoon.
The atmosphere will get primed for heat Tuesday and Wednesday. Below are two upper-level charts comparing the forecasted mid-level pattern Wednesday with the pattern from a mid-July heat wave that produced a record 102 degrees on July 23, 2011.
Note the similarities in the overall trajectory of the lines on both maps. The difference is that the heat ridge center is displaced farther away from Washington with the upcoming heat wave and the heights are lower this go-around (lower heights yield cooler surface temperatures). Instead of a height of 594 (5,940 meters), the height of the 500 mb level in the atmosphere (which averages 5,500 meters up in the atmosphere) is forecast to be 5,880 meters above mean sea-level.
So, although temperatures won’t likely crack the century mark, based on the analysis above, the pattern favors high temperatures well into the 90s most of next week. As a matter of fact, digging back through the records for early next week indicates the major airports across the Washington-Baltimore area will likely tie or break record highs.
Here’s a table with the records to match or exceed Tuesday through Thursday.
Since the Washington area hasn’t experienced a full heat-wave yet this season (defined as three consecutive days with temperatures at or above 90 degrees), remember to take the following precautions:
• Limit outdoor activity to prior to 10 a.m. and after 6 p.m. This is when temperatures are cooler (although morning is the best time to exercise due to less ground level ozone in place).
•Wear light-colored, loose-fitting clothing. Even better are t-shirts that wick away sweat to keep you cooler than cotton shirts.
•Drink plenty of water. Avoid alcohol as it actually encourages dehydration due to the sodium content.
•Check on the elderly to make sure they are safe in the heat wave.
For your latest 7-day forecast, click here.