Flash flood threat looms ahead of dramatic cool-down in Northeast
While not all locations in the Northeast will experience torrential downpours and strong thunderstorms into Friday, areas that do may receive several inches of rain could have to deal with flash flooding, AccuWeather meteorologists warn.
Noticeably cooler and less humid air is expected to arrive, offering relief to residents and visitors exhausted by recent heat.
There is a significant amount of moisture in the atmosphere in the Northeast, and that has contributed to flash flooding through the summer, when it has been released in the form of torrential downpours.
For parts of the Northeast, a one-two punch of an approaching cool front and a corresponding ripple in the jet stream will produce heavy rainfall into Friday and late this week to early next week in the Southeast.
The first heavy rain and flash flood threat will be an eastward extension of downpours from the Midwest. This band of downpours is forecast to expand from northern Indiana and southern Michigan to northern Ohio, northwestern Pennsylvania and southwestern New York late Wednesday night to Thursday, before weakening and moving out of the region.
At the same time, spotty severe thunderstorms are forecast for parts of the Northeast, but they will not be as widespread as previous severe weather episodes in prior weeks and more recently in the central states.
A flash flood risk will exist along a significant portion of the mid-Atlantic region to southern New England into Friday as the front and jet stream dip begin to join together. This joint effort will unleash a swath of heavy rain.
The zone from eastern Pennsylvania, northeastern Maryland and northern Delaware to the lower Hudson Valley of New York, including New York City, Connecticut and parts of Massachusetts and Rhode Island is expected to receive 2-4 inches of rain.
Rainfall of this intensity can easily overwhelm storm drains and flood city streets, subways and poor drainage areas along highways. Major travel disruptions are possible for both I-95 commutes on Thursday evening, as well as on Friday morning. It can also lead to rapid rises on small streams and a surge of water on rivers, posing risks to campers near creeks and low-lying areas.
A greater concentration of severe thunderstorms packing strong wind gusts is foreseen on Friday from southeastern Pennsylvania and southern New Jersey to the Carolinas.
As torrential downpours, flash flooding and severe thunderstorms focus on the southeastern corner of the U.S. this weekend, much cooler and less humid air will move into the Northeast, resulting in more comfortable air for many. Energy demands will ease, air conditioners can be turned off, and open windows in urban areas will let in cool air for a change.
High pressure from central Canada will take control of the weekend in the Northeast in what is usually the muggiest part of the summer.
Typical highs range from the 80s to the low 90s, while nighttime lows range from the low 60s to the low 70s this time of the year. However, as the cool air takes root this weekend, daytime highs will range from the 60s in the mountains to the low 80s in many I-95, mid-Atlantic cities.
Lows will mainly range from 40s in the mountains to the refreshing 60s in most I-95 cities. A few spots may even dip into the 30s over the coldest mountain spots during the weekend.
With the much cooler air heading in, humidity levels will drop significantly, which has been relentless in coastal areas since early June.
"The difference in pressure between the high building into the north and a developing area of storminess along the southern Atlantic coast will create a stiff breeze in some coastal areas of New England and the mid-Atlantic this weekend," AccuWeather Senior Meteorologist Dave Dombek warned.
A steady or gusty northeast wind can stir up the surf and lead to a higher risk of rip currents. While astronomical tides are unremarkable this weekend, the persistent onshore breeze can push water levels to 1-2 feet above typical levels and may lead to minor flooding at times of high tide in low-lying areas.
Next week, the effects of Canadian high pressure will slowly erode, but Monday and Tuesday should continue to provide cooler and more comfortable conditions for, outdoor activities and general relief from recent humidity.
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Yahoo
31 minutes ago
- Yahoo
National Hurricane Center tracks Tropical Storm Dexter and 2 more systems
Tropical activity exploded over the weekend as the National Hurricane Center now finds itself monitoring Tropical Storm Dexter, a tropical wave and a low-pressure system with the potential for tropical development near Florida's northeastern coast. Tropical Storm Dexter, which formed Sunday night, doesn't pose any threat to the United States and is expected to become post-tropical by Wednesday. The storm is moving east-northeast, away from the U.S., according to the NHC. Elsewhere in the Atlantic, the NHC is tracking a tropical wave that is moving into more favorable conditions for development over the latter portion of the week. A low-pressure area is also forecast to develop in a couple of days, a few hundred miles off the coast of the southeastern U.S.—an area that is becoming a hot spot this season. Here is the latest info on Tropical Storm Dexter and the two Atlantic systems. Where is Tropical Storm Dexter now? Location: About 250 miles northwest of Bermuda (35.2N 67.4W) Maximum sustained winds: 45 mph Movement: East-northeast at 14 mph Minimum central pressure: 1002 mb (29.59 inches) Tropical Storm Dexter was located about 250 miles northwest of Bermuda around 10 a.m. on Monday. The storm is moving east-northeast around 12 mph. Dexter is expected to speed up through early Tuesday before slowing down later Tuesday into Wednesday. Will the US see any impacts from Tropical Storm Dexter? Dexter will, fortunately, stay ocean-bound for the duration of its lifespan. Tropical-storm-force winds are extended outward about 115 miles from the center. There are currently no hazards affecting land, according to the NHC. Tropical Storm Dexter spaghetti models and path Here's a current look at where Tropical Storm Dexter is headed and where it could end up before becoming post-tropical on Wednesday. System off Florida's northeast coast could cause flash flooding, downpours The U.S. managed to dodge Tropical Storm Dexter, but there are two more areas of interest that could see tropical development, and one is sitting just a few hundred miles off Florida's northeastern coast. A broad area of low pressure is expected to develop over the next couple of days, originating in the same spot that eventually brought us Tropical Storm Andrea in early July. The NHC currently places the system's odds of development around 30% over the next seven days. After seeing the same weather pattern multiple times already this year, most residents probably know what to expect: Flash flooding and heavy downpours. Southeastern Georgia and coastal South Carolina are likely to see the largest impacts over the weekend, according to AccuWeather. "A general 4-8 inches of rain could fall over this area over the course of several days, causing street and highway flooding in low-lying areas around cities such as Savannah, Georgia," AccuWeather Senior Meteorologist Dan Pydynowski said. Tropical wave has medium chance of becoming a tropical depression this week Looking further ahead, a tropical wave moving off Africa's west coast has a 50% chance of development over the next week. Environmental conditions near the wave are forecast to become more favorable for gradual development, according to the NHC. There is a 50% chance the wave forms into a tropical depression toward the latter half of the week as it moves west. This article originally appeared on Pensacola News Journal: National Hurricane Center tracks Tropical Storm Dexter, 2 more systems
UPI
an hour ago
- UPI
SpaceX lifts 28 Starlink satellites in landmark reusable booster mission
1 of 3 | Poor weather conditions early Monday forced SpaceX to postpone the launch of its Falcon 9 rocket from Launch Complex 40 at the Cape Canaveral Space Force Station in Florida. The booster launched with 28 Starlink satellites on board at 3:57 a.m. local time. Photo by Joe Marino/UPI | License Photo Aug. 4 (UPI) -- SpaceX launched dozens of new Starlink satellites into orbit overnight after initial delays over weather in the company's 69th liftoff this year. The Starlink 10-30 mission saw liftoff at 3:57 a.m. EDT from pad 40 at Cape Canaveral Space Force Station in Florida after its original 2:01 a.m. time slot had to be changed due to persistent storms. The Falcon 9 and its joint Falcon Heavy rocket carried 28 Starlink satellites to its growing constellation of Internet-ready satellite devices. But it marked a milestones for SpaceX with the 450th launch of its flight-proven booster 1080, which flew for its 21st time. Initially there was an 85% chance for favorable weather in the forecast, according to the 45th Weather Squadron. But strong thunderstorms via a low-pressure system hung over the region and temporarily delayed the launch as Tropical Storm Dexter gains strength. A little over 8 minutes after liftoff the B1080 landed on SpaceX's drone ship "Just Read the Instructions" in the Atlantic Ocean in the 131st landing on the drone ship vessel. So far this year SpaceX has launched over 1,650 Starlink satellites in the Elon Musk-run company's bid to expand global Internet access.
CNN
2 hours ago
- CNN
We're entering primetime for hurricane season. Here's what's going on in the Atlantic
Hurricanes StormsFacebookTweetLink Follow Atlantic hurricane season is about to hit its stride. August through mid-September is historically the most active stretch of the season, and while there have been a handful of short-lived named storms, the Atlantic has yet to spawn a hurricane in 2025. That could change soon: Tropical Storm Dexter formed on Sunday night, churning far off the coast of the United States and well northwest of Bermuda. There are two other areas the National Hurricane Center marked for possible tropical development in the coming days, and one is off the coast of the Southeast US. While Dexter is expected to remain a tropical storm as it tracks farther away from the US, it's impossible to know how strong the other potential tropical systems could become before they've even developed, and this flurry of activity is a huge sign that the Atlantic is ready to go. Here's what's going on in the Atlantic and why the next few weeks could be a whole different ballgame as the conditions that fuel hurricanes start to fall into place. The Atlantic served up more of an alphabet appetizer than a full soup through the end of July. Three named storms — Andrea, Barry and Chantal — were all short-lived, disorganized systems that struggled against hostile environmental conditions such as dry air, strong winds higher in the atmosphere and Saharan dust. The Atlantic hasn't had a start this sluggish in over 15 years. Still, the vast majority of hurricanes, including most major, or Category 3 or stronger, ones, form from August toward the mid-September seasonal peak. Many of the most intense and long-tracked hurricanes in history — storms like Irma, Florence and Andrew — developed during this exact window. Tropical Storm Dexter was named on Sunday, but it's more of a drifter than a danger and will remain over open ocean with no impact to land. Dexter is the fourth tropical storm of the season, which typically occurs by mid-August. There are signs tropical development will pick up in earnest over the next one to two weeks as the Atlantic is loaded with potential. Sea surface temperatures across what forecasters call the 'main development region' — the stretch of tropical Atlantic between West Africa and the Caribbean where many hurricanes form — are extremely warm, providing an as-yet-untapped pool of energy for hurricane development. All it could take is a slight shift in the atmosphere to displace the lid that has kept storms at bay thus far in 2025. That shift could be coming soon. Strong winds in the upper-levels of the atmosphere — the kind that tear developing storms apart before they can organize — are expected to weaken across parts of the tropical Atlantic in the coming days. That creates a more favorable environment for storms to form and strengthen. Dry, dusty air from Africa's Sahara almost always makes an early-season appearance and does its best to infiltrate and weaken tropical systems, which feed off clean, moisture-rich ocean air. Dust this year has been more scarce than usual, but has still caused issues, along with dry air. A global weather pattern known as the Madden-Julian Oscillation — which helps boost thunderstorm activity in the tropics — may help push some of the dry air out of the main development region, while nudging the Atlantic into a more active phase later this month. Meanwhile, batches of stormy weather emerging from Africa are becoming feistier, showing signs of better organization and richer moisture. These storms are known as tropical waves and can be the seedlings of many of the most powerful and long-lived Atlantic hurricanes. They're now entering a stretch of ocean and atmosphere that may be more willing to let them grow. Forecast models are beginning to pick up on the signs that the atmosphere is becoming more supportive of tropical development. Over the next one to two weeks, some reliable computer models are hinting at several tropical waves trying to organize as they move across the Atlantic. One of these waves just moved off the coast of Africa Monday and has a medium chance of becoming a tropical depression or tropical storm later this week as it tracks west through the main development region, according to the NHC. There's another spot to watch for tropical trouble right off the southeastern US coast. Low pressure could form in this region later this week and has a low chance to gradually develop into something tropical, according to the NHC. Outside of these areas, there's still too much uncertainty and too many unknowns to make any detailed predictions for the coming weeks. Not every tropical wave that comes off Africa will develop, and even those that do may struggle depending on the environment they encounter. But the broader pattern shift is what's worth watching most closely. The ingredients — warm water, weakening upper-level winds, rising air and more moisture — are starting to come together for sustained tropical development. All it takes is one storm to change everything, so now is the time to start paying attention. CNN Meteorologist Mary Gilbert contributed to this report.
