2:15 PM | *Strong-to-severe thunderstorms are popping and downpours are possible…great satellite imagery of an “undular bore” earlier today near the tip of southern NJ*
Severe weather threat, next week's wet pattern
A strong cool front is closing in on the I-95 corridor and strong-to-severe thunderstorms are popping over the past couple of hours. Daytime heating is contributing to increasing instability in the atmosphere and the coverage and intensity of shower and thunderstorm activity should increase through the afternoon hours. Any storm that forms over the next several hours can produce brief downpours, damaging gusty winds and even some hail. There is also the potential for some steadier and heavier rain this evening; especially, in areas north of the PA/MD border.
Any significant rainfall at this point will only increase flash flooding potential as grounds are well saturated throughout the Mid-Atlantic region. Somewhat drier air will move in late tonight and early Saturday and the weekend should turn out to be rather decent in the Mid-Atlantic region although there can be scattered thunderstorms along coastal sections on Saturday afternoon. A wet pattern will resume early next week as a south-to-north flow of moist forms along the eastern seaboard between low pressure to the west and high pressure to the east. Soaking rainfall next week will no doubt continue the threat of flooding in much of the eastern third of the nation.
A strong thunderstorm moved from the Delmarva Peninsula this morning to southern tip of New Jersey and as the storm collapsed an “undular bore” hit the relatively stable ocean air. An undular bore is a wave disturbance in the Earth's atmosphere and can be seen through unique cloud formations. Undular bores are usually formed when two air masses of different temperatures (and density) collide. Like a rock thrown into a pond, the waves propagate outward. When a low level boundary such as a cold front or outflow boundary from a thunderstorm approaches a layer of colder, stable air, it creates a disturbance in the atmosphere producing a wave-like motion, known as a gravity wave, these waves appear as bands of clouds across the sky. The still satellite image (top) shows the band of clouds (circled region) associated with the undular bore and it can be seen in the satellite loop near the southern tip of New Jersey using GOES-16 high resolution imagery.
Meteorologist Paul Dorian
Extended video discussion on the severe weather threat and next week’s wet pattern in the eastern US: