Long Island weather: Sunny, breezy start to the weekend; chance of rain Sunday

Friday should be sunny and warm, with the high humidity expected to fall through the day, thanks to a cold front sweeping into the tri-state area ahead of a high pressure system, the forecasters said.

The daytime high should reach 85 degrees — likely the hottest day of the next seven — and it could be windy, especially during the afternoon and evening, when gusts could kick up to 30 mph, the National Weather Service said.

Blowing from the northwest, that wind will help sink dew points — which will begin the day in the oppressive range of 70 — down to much drier and more comfortable levels in the upper 40s and 50s.

Dew points reveal how cool the air must be for vapors to condense. Blue skies result from high pressure systems, in which falling air dries and cools.

While Saturday should also be bright and sunny, temperatures will only rise to 77 degrees during the day, the weather service said.

Sunday likely will begin under clear and sunny skies, though there is a 30% chance of downpours, mainly after 3 p.m., the weather service said.

Any showers could continue on Long Island Sunday night. The chances of rain are 40%, according to the weather service.

Highs near 79 degrees are expected Sunday.

Wildfire smoke

Though much of the Northwest is still trapped under a scorching heat wave that amplifies wildfires, smoke from those fires — which is triggering air quality alerts in parts of Idaho, Montana, Wyoming, Colorado, Minnesota, and Iowa — will probably stay in the upper atmosphere by the time the prevailing westerly winds send it to the New York area by the end of the weekend.

"It looks like as far as air quality, any smoke that does get here on Sunday would likely be in the upper levels, not down here on the surface. It might be more of a problem for the Ohio Valley and the Mississippi Valley," said weather service meteorologist Bill Goodman.

The tri-state area could also escape with just high-level haze because its weather systems are swooping down from central Canada, he explained, versus sailing in from the Northwest, where the wildfires are concentrated.

As the weather service’s Weather Prediction Center explained, "A large dome of cool air behind the low will usher across the Great Lakes and overspread much of the Northeast and down into the Mid-Atlantic during the weekend."

The low it refers to is the system that brought Thursday night’s storms. The warm, rising air in low pressure systems allows vapors to condense into raindrops.

The prediction center added: "This will bring welcome relief to the recent spell of summer heat and humidity across parts of these areas."

In contrast, the Northern Plains are in for a drenching on Friday, which will spread to the Midwest on Saturday. Excessive heat advisories, meanwhile, were issued for the interior Pacific Northwest and the central and southern United States, it said.

Meanwhile, on Long Island...

Monday should start the work week off under sunny skies with a high of 82 degrees. That same daytime high should be matched each day through Thursday, the weather service said.

Showers may possibly arrive Tuesday — the odds of rain were assessed at 30% — and after a partly sunny Wednesday, downpours may dampen Thursday, when the chances of rain are also 30%.