After a welcome stretch of summer sunshine this weekend, the Northeast is getting hit by another round of unsettled weather, with heavy rain and flash flooding threatening parts of the region today. Heavy rain and thunderstorms are expected to return this weekend, raising the risk of flash flooding in parts of the region still recovering from this week's historic rainfall. By Sunday afternoon, slow-moving storms may repeatedly track over the same areas, increasing the risk of flash flooding. Flash Flood Threat in the East. By Tuesday, the flash flooding threat lightens up to a Level 1 out of 4, and rain will linger in some areas.