The long holiday weekend is off to a rough start for those across the Northeast and Mid-Atlantic, with severe thunderstorms bubbling from Pennsylvania to southern New York. Even the big cities along the Interstate 95 corridor won`t be spared. The primary concerns will be hail and high winds. A Severe Thunderstorm Watch stretches from eastern Pennsylvania to western Connecticut, including New York City, and Trenton and Newark, N.J. Fresh storms continue to explode in advance of a stalled front draped from eastern Ohio through New England and arcing into the Canadian Maritimes. Out ahead of the front is an unusually hot and humid air mass, while cooler, drier air is flowing out of Canada into the interior Northeast in its wake. The two are creating the perfect recipe for barely-moving severe thunderstorms. The thunderstorms will gradually sink southward across Pennsylvania and northern and northwestern New Jersey, with additional ones likely to build toward the busy Interstate 95 corridor and southeastern Connecticut through this evening. Fortunately, the storms will fade with the loss of their primary fuel source, daytime heating, shortly after sunset. Until then, the most intense thunderstorms will pack a punch with hailstones up to quarter-size and destructive wind gusts reaching up to 75 mph. New York City and Newburgh, N.Y., Newark and Trenton, N.J., Harrisburg and Allentown, Pa., and Danbury and Bridgeport, Conn., could all be impacted by these dangerous thunderstorms through early tonight. In addition to the severe weather aspect, the storms are producing intense lightning as seen on Earth Networks Total Lightning Network and could trigger flash flooding. In fact, the painstakingly slow pace of the thunderstorms will drop 1 to 3 inches of rainfall in a short time. If you approach a flooded roadway, it is best to, "Turn Around, Don`t Drown!" Unfortunately, the same stalled front causing today`s severe weather will retreat northward across the Northeast on Sunday. The net result will be more feisty thunderstorms, though most of them will remain below severe limits. However, a few could contain gusty winds and hail, with the greatest concern close to the higher terrain in Pennsylvania and south-central New York. Be sure to keep WeatherBug active to receive the latest weather in your neighborhood and get the latest updates anywhere on Twitter. What do you think of this story? Click here for comments or suggestions.