Soggy conditions return to the Northeast
Now that the calendar has officially crossed into astronomical autumn and leaves have started to gain their vibrant colors and fall to the ground, Mother Nature will usher in a notable pattern change across portions of the Northeast.
While the start of meteorological fall is always the first of September, the first day of astronomical fall changes from year to year, and depends on when the sun shines directly on the Equator. This year, the fall equinox was on Sept. 22, at 8:43 a.m. ET.
Slightly cooler conditions, rounds of rain and showers and even thunderstorms will be the theme from the Ohio Valley to parts of Pennsylvania, New York and the mid-Atlantic states, at least for the first half of the week.
A slow-moving storm spanning from southeastern Canada to parts of the Tennessee Valley will kick off the damp workweek, but will be quickly followed up with a separate storm chugging directly behind it.
This will lead to several days featuring rounds of wet weather from parts of the Midwest to mid-Atlantic states with travel concerns possible.
From late last week into the start of the weekend, a coastal storm brought plenty of rain to portions of far southeastern New England, especially along the Cape and islands of Massachusetts.
Over 5 inches of rain fell on Nantucket from Thursday through Saturday, bringing them well above their average rainfall through Sept. 21. There was a sharp gradient of rain totals, however, and the total rain for Boston remains at only 40% of the historical average.
Cities such as Columbus , Ohio, have been parched so far this September, only picking up around 3% of their typical September rainfall as of Sep. 22. Even dating back to the start of June, the city is only collected around 34% of the typical rainfall.
Levels of exceptional drought are still being observed across portions of West Virginia and southern Ohio, but AccuWeather forecasters highlight that this week may provide some much-needed relief for the prolonged dry pattern.
Through at least midweek, between 1-3 inches of much-needed rain can spread across the Ohio Valley and mid-Atlantic states. However, this will come at the risk of nuisance flooding, especially where leaves have already begun to fall. The heavy rain and fallen leaves clog storm drains, which can lead to ponding on roadways and slick travel conditions.
Even for locations farther east, such as Philadelphia and New York City , substantial rain has not been observed throughout the month of September, both standing at less than 10% of the historical average rainfall for the month so far.
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"The prolonged dry stretch in cities such as New York City will finally come to an end later this week, likely Tuesday night or Wednesday. So far, the Big Apple has had only 0.24 of an inch of precipitation this month, while the historical average through Sep. 21 is 3 inches," explained AccuWeather Senior Meteorologist Dan Pydynowski.
"As a slow-moving storm moves out of the Great Lakes and into the Northeast and mid-Atlantic later this week, moisture will be drawn northward and this will finally bring the dry stretch to an end. Currently, New York City could see at least 0.25-0.50 of an inch of rainfall during the midweek period, with the potential for more later in the week if tropical moisture is drawn northward from the Gulf of Mexico," noted Pydynowski.
Not only will the weather pattern turn wetter this week across the Northeast, it will also trend cooler. Temperatures will transition from the 80s Fahrenheit observed at times last week to the the 70s and 60s F this week.
By midweek, highs in New York City will dip into the upper 60s F, closer to typical values observed in early October values than late-September values. While many might welcome the cooler conditions and stretch of wet weather after such a dry month so far, it could also cause headaches for certain outdoor events this week.
"The potential for rain around midweek could cause delays in a key baseball game Wednesday evening as the New York Yankees host the Baltimore Orioles in the Bronx , New York, in an important series," noted Pydynowski.
Chilly and wet conditions can linger into Thursday night, just in time for the football game between the Dallas Cowboys and the New York Giants in East Rutherford, New Jersey.
As the week continues, the prospects for rain and showers will transition eastward into New England and the mid-Atlantic coastline, dampening locations across Vermont, New Hampshire, Massachusetts and eventually Maine.
Conditions will trend drier across areas of the Great Lakes and Upper Ohio Valley, but how long the return of dry weather continues will depend upon the movement of a few features AccuWeather meteorologists are monitoring- such as the storm that may become Tropical Storm Helene .
"There is some risk that the eventual Helene will throw some moisture northward to give quite a wet late-week period to the East Coast, but this is currently not the favored outcome, as it may end up more likely that another storm over the Mississippi Valley can pull the eventual tropical feature and its moisture in that direction instead," AccuWeather Meteorologist La Troy Thornton explained.
Depending on the track of this feature, rounds of moisture can return to the Tennessee and Ohio Valleys later this week, or it could be swept to the east and travel off the Southeast coast. Residents are urged to continue to check back to AccuWeather.com for the latest insights on where this storm is projected to travel.
