Following a mellow work week with limited sunshine, minimal rain and below-normal daytime highs, it’s back to the tropics for the Berkshires with typical August heat, humidity, and a chance of thundershowers most days. A trend toward clear, cooler weather is shaping up for the weekend, especially Sunday.

After unrelenting heat through most of June and all-time record rainfall in July, we’re seeing a return to normal heading into late summer. With sunrise just before 6 and sunset around 8, the duration of daylight is down by about an hour and 20 minutes. Average temperatures are beginning their gradual decline, currently 78 for a high, after a pre-dawn low of 57.

Since the atmosphere remains somewhat unstable, afternoon thundershowers are possible through the week, especially with heat and humidity on the rise beginning Tuesday. “The overall severe threat remains low, but locally heavy rainfall will plague a few locations,” according to the National Weather Service in Albany.

From mid-week into the weekend, it will be uncomfortably warm and humid, with little relief expected overnight. Air quality is also declining due to ozone pollution and a potential return of high-altitude smoke from the western wildfires.

The leading edge of cooler air should push through Friday night into Saturday, accompanied by the best chance this week of widespread rainfall and thunderstorms. Next Sunday should be refreshingly clear along with slightly below normal temperatures, by far the best of the upcoming seven days.

The Climate Prediction Center’s outlook for Aug. 15-22 indicates normal rainfall with daytime highs slightly above average.

NATIONAL OVERVIEW

The Pacific Northwest just can’t catch a break. After a brief respite thanks to wet, cool weather, dangerously hot, smoky and gusty conditions are returning this week. A few sprinkles snapped a 51-day streak of no rain in Seattle, AccuWeather.com reported. But extreme to exceptional drought persists from Washington and Oregon, east into Montana.

As of Sunday morning, there were already 24 large active wildfires across Montana, the most of any state, with Idaho right behind it with 21, followed by Oregon, Washington, California and Alaska. Across the region, as far east as Minnesota, South Dakota and Nebraska, the National Interagency Fire Center reports six new outbreaks, with 107 current active fires and 2.2 million acres ablaze across 14 states in all. So far this season, 3.5 million acres have been consumed.

Thick wildfire smoke continue to plague parts of California, the Rockies and High Plains, with air quality alerts expected to continue.

Another in the unrelenting series of record-tying heat domes is setting up over the Northwest, with daily highs 15 to 25 degrees above average from Wednesday through Friday.

Meanwhile, as a result of dry air and dust particles, the Atlantic Ocean, Caribbean Sea and the Gulf of Mexico remain free of tropical storm development, ever since Hurricane Elsa dissipated on July 9.

Heavy rain and severe storms are forecast for the Northern Plains, Midwest and Great Lakes starting Monday, while the Great Plains region remains hot with poor air quality caused by wildlife smoke drifting along the jet stream.

In the Deep South, typical heat and humidity hang on, with tropical rainfall probable over south Florida on Friday through the weekend.

The Outlook is today's look ahead at the week's weather, its impact on the Berkshires and beyond. Clarence Fanto can be reached at cfanto@yahoo.com.