Don't put away jackets just yet! Cool wave to interrupt warmth

Alex Sosnowski
·6 min read

A summerlike start to the week may have left warm-weather lovers reaching for shorts and T-shirts and rejoicing in the warm and humid conditions in the Midwest and Northeast. AccuWeather meteorologists are advising people not to put away the jackets and long sleeves just yet though as yet another cooldown is on the way.

High temperatures are expected to be slashed by 20-25 degrees from peak levels during the first part of this week to those on Thursday, Friday and Saturday.

For example, in Washington, D.C., the high temperature of 84 that was reached on Tuesday will be followed by a high in the middle 60s during Thursday, Friday and Saturday. High temperatures may be no higher than the 50s in Pittsburgh each day from Wednesday through Saturday, following a high of 72 on Tuesday.

"The tastes of summer recently might have had many people excited to open up pools, have cookouts or do any number of other outdoor activities," AccuWeather Meteorologist Jake Sojda said, adding that the upcoming weather pattern may disrupt those hopes and plans. "Mother Nature is going to press pause on spring warmth once again, with chillier weather expected to return and spoil things for warm-weather lovers for at least another week or so."

The much cooler air will also sweep into the Southeast states and part of Florida, which is rare feat for cooler air to make that much southward progress once May arrives. High temperatures in the 90s in Orlando, Florida, into midweek will be swapped with highs in the 80s later in the week. Atlanta and Charlotte, North Carolina, can expect highs to be in the lower to middle 70s during the middle and latter part of this week after highs reached the 80s earlier in the week. Highs will be a few degrees below average during late week.

In addition to the temperature dip, a significant drop in humidity levels is predicted later this week when compared to the first part of the week.

Overall, most areas of the Midwest and East are anticipated to experience temperature departures of 5-15 degrees below average for the first to second week of May.

Amid the chillier weather, scattered frost could develop in the traditional cold spots around the central Appalachians and eastern Great Lakes region late in the week, but temperatures are not likely to dip as low over such a broad area as last weekend, when strong winds ushered in much colder air. Temperatures plummeted in the lower 30s and upper 20s across a broad swath of the Midwest and Northeast last weekend. Snow even fell across the interior Northeast, adding to the wintry feel. Not only will frosts and freezes be less widespread, but no wintry precipitation is predicted with the upcoming invasion of cooler air.

"Despite the chilly air, more clouds will help to prevent a widespread threat for frost," Sojda said.

Still, where possible, people may want to take precautions if they live in frost-prone areas during early May in portions of Michigan, Wisconsin, northern Indiana, northern Ohio, Pennsylvania, upstate New York, northwestern New Jersey and northwestern New England.

"Gardeners will still want to pay close attention to their local forecast, as any patches of clear sky overnight can be enough to lead to frost formation," Sojda said.

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Late-week lows in most cold spots will be in the middle to upper 30s with few exceptions. Low temperatures in most major cities should be no lower than the 40s.

Just as the cool weather pattern may have difficulty in producing very cold air at night, it may struggle to keep clouds and rain away for long.

"This will not be a massive sweep of dry air and clear skies that lasts for days, as a single, large area of high pressure is not expected to build in and take over," Sojda explained.

Instead, smaller areas of high pressure will build into the region, but a large pocket of cool air higher in the atmosphere could trigger some unsettled weather at times. Strong sunshine will create some instability in the atmosphere and cause clouds to build up with spotty showers.

"Even without any strong storm systems around, cool air aloft in May alone, without a big sweep of dry air, can lead to pop-up showers, thunder and even incidents of small hail," Sojda said.

In addition to extensive areas of clouds, multiple weak storms systems will swing through from the Midwest to the Northeast states. Each of these systems will tend to enhance the showers and potentially trigger spotty thunderstorms. In some cases, a zone of steady rain may develop and may last for several hours.

The sporadic showers and spotty thunderstorms can occur any time through Mother's Day, but two storm systems bear watching for the potential for steadier rainfall.

One such storm is forecast to develop near the mid-Atlantic coast Friday. The storm is likely to develop fast enough to produce a patch of steady rain in the mid-Atlantic region with spotty showers and thundershowers farther west Friday.

From there, the storm will either speed northeastward and out to sea, taking steady rain with it, or strengthen and turn northward with a potential swath of rain aiming for New England Friday night into Saturday.

The formation and track of a second storm is much more likely to affect a significant stretch of land and population later this weekend.

The storm will first affect parts of the Plains and Midwest from Saturday to Mother's Day, but it may not spread its rain into the central Appalachians until Sunday afternoon and coastal areas of the Northeast until Sunday evening.

Those with flexible plans may want to consider taking mom out on Saturday in parts of Pennsylvania, West Virginia, Maryland and northern Maryland. An early dinner might be a safer option for those who live along mid-Atlantic coast on Sunday.

The exact track would determine the north and south extent of drenching rain versus showers and thunderstorms that would be more brief in nature. The forward speed of the storm is critical for rain for all or part of the day on Mother's Day.

Since the weather will trend more unsettled, people may want to take advantage of any dry breaks when they occur into the weekend.

The AccuWeather app can help people plan outdoor activities, and its MinuteCast feature, which is also available on AccuWeather.com, can aid with the start and stop times of precipitation and intensity over the next four hours.

Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, FuboTV, Philo, and Verizon Fios.