Long Island weather: Cloudy and warm

Drier air, increasing clouds and smoke from the fires out West are what Long Islanders can anticipate on Thursday — but the haze from the fires "is expected to remain aloft so ground visibilities are not forecast to be affected," the National Weather Service said.

A high of 82 degrees is also predicted for Thursday.

A high pressure system, in which falling air dries and cools, is helping to lower the humidity that was so strikingly high last month.

And it should control much of the weather over the next seven days, the weather service said, aside from a couple of fronts that might usher in afternoon storms.

Daytime highs should top out in the low to mid-80s during this period. At night, thermometers will slip to the low 70s and mid-60s.

Heat wave, heavy rain, wildfire smoke

In contrast, a triple-digit heat wave is spreading to the Midwest from the Northern and Central Plains with potentially severe thunderstorms, while the Southwest again risks "monsoon intensity" rain and possible flash flooding, the weather service’s Weather Prediction Center said.

And, it added, "From the northern Sierra Nevada to northwest Montana, wildfires are expected to be most likely to spread uncontrollably."

All that pollution has prompted states from Minnesota to North Carolina to issue air quality alerts, the prediction center said.

"Smoke is forecast to be thickest across the Carolinas, Ohio/Tennessee Valleys, Great Lakes, and Upper Midwest today," it said.

Minor flooding possible

On Long Island, the arrival of the full moon later this week is raising astronomical tides, possibly causing "isolated minor coastal flooding along the western South Shore bays" during the early evening through Saturday, said the weather service, which issued a coastal flood statement for Nassau and Queens for Thursday evening.

Friday should be mostly sunny and quite delightful.

"With calm winds, lows Friday morning are forecast to be a few degrees cooler than Thursday morning," the weather service said, predicting another daytime high of 82 degrees.

There may be some late-in-the-day sprinkles: "Another passing disturbance can spark afternoon showers and thunderstorms on Friday, with slightly higher instability than the previous day," the weather service said.

Saturday should also be sunny with a high in the low 80s, and a chance of showers overnight.

On Sunday, there is 50% chance that showers and thunderstorms may arrive, mostly after 2 p.m., as a warm front comes in from the eastern Great Lakes, the weather service advised.

And partly due to a southerly wind, look for the humidity to rise.

Monday to Wednesday should be sunny, with daytime highs in the low 80s.