It was a very ugly Saturday across parts of the Northeast, and unfortunately this weather will remain in the forecast through midweek as a cut-off low remains almost stagnant through Tuesday over the eastern Great Lakes. A cut-off low is basically a displaced area of the jet stream hovering in the mid level of the atmosphere. This will be the main culprit for the clouds, showers, and storms that are forecast over the next few days.
The precipitation activity definitely won’t be as widespread today as it was yesterday, but large areas in the northeastern US will still be in for a rather ugly day. The worst of the weather will be in New England, as low clouds dominate much of the region through a large duration of the day. Temperatures will be in the 70s and 80s, both in New England and the Mid-Atlantic. The highest concentration of showers and storms will be in the afternoon across southern New England. Farther south, there may actually be a line of thunderstorms developing later in the day east of the Appalachian Mountains in Virginia. Gusty winds and heavy rain will have to be watched this evening in cities like Richmond, Washington, and Baltimore.
The cut-off low won’t budge much heading into Monday, keeping the clouds and unsettled weather around. The good news is that temperatures will remain on the cooler side, with highs into the 70s to mid 80s in urban areas. The precipitation on Monday will remain rather unorganized, a fairly common feature of these stagnant lows. Across most of the Northeast, passing showers and spotty thunderstorms will be in the forecast for really the entire day. However, the day will not be a washout, so some areas may get lucky and avoid the showers throughout the day.
By Tuesday, a developing trough over the central US will begin to budge that low, moving it toward New England. Unfortunately, it won’t progress enough to kick out the dreary weather. Instead, clouds and showers will remain in the forecast for yet another day. Showers should be spotty across New England, keeping the chance for rain at 30-40 percent, while a line of more widespread showers may develop somewhere across the Mid-Atlantic, bringing a higher chance (60-70 percent) of rain.
Most of the wet weather will shift out of New England on Wednesday as the upper-low finally shifts and weakens offshore, allowing for showers over the Mid-Atlantic to move east. Most of the day in New England should be dry, but unfortunately it will be another rather cloudy day. In the Mid-Atlantic, conditions will be improve, with a low chance for rain and partly cloudy skies. This will also allow for temperatures to rise up into the 80s, and possibly the low 90s in a few locales.
Flash flooding will thankfully be not much of a concern through Wednesday, but there will still be heavy rain in some areas as tropical moisture from the Gulf of Mexico streams in. Through Tuesday night, the heaviest of rain in excess of 1 inch will be found across the northeastern Mid-Atlantic and western New England.
Unfortunately, a new storm system will move in late-week, allowing for a few showers and storms to return to parts of the Northeast Thursday. A more widespread line of showers and storms will move in on Friday, which we will detail later this week.