An ocean storm taking shape southeast of Cape Cod will become nearly-stationary for the next 36 to 48 hours, spinning in place about 150 to 175 miles from the region.
This storm system – which is in its infancy stages Wednesday morning – will organize and strengthen through the day today and into tonight…reaching its peak intensity on Thursday and Thursday night…and then slowly weaken through the day on Friday.
As the ocean storm sits and spins to our south and east and it will transport copious amounts of moisture north and westward from the Atlantic and send it right into eastern parts of Southern New England.
A combination of meteorological factors coming together will produce a substantial rainfall event for us here on the Cape: a nearly stationary system, a prolonged onshore flow, a tap to the warm, moist ocean waters of the sub-tropical Atlantic and a strong low level jet stream aimed due west into SE New England.
Model guidance is in very good agreement on a widespread 3 inches of rainfall over the area with multiple products signaling the potential for 5 to 6 inches of rain. In fact, some available weather guidance has occasionally shown even higher amounts in spots. Whether we end up with 3 to 4 inches of rain or upwards of 7 inches will be determined by the evolution of the storm center and where the heaviest bands of precipitation rotate through.
Regardless, it is safe to anticipate some street and basement type flooding around the area and as such the National Weather Service has posted a Flood Watch.