A storm system lifting up the Eastern Seaboard tonight and into the day on Saturday will pack quite a punch as it passes near the region.
The surface analysis Friday morning shows low pressure over the northern Gulf Coast, with high pressure situated to its north over the Great Lakes and New England. This low pressure area will gradually deepen today and tonight as it moves northeastward, reaching a position near the Outer Banks of North Carolina overnight tonight and near the Delmarva Peninsula by Saturday morning. At the same time, high pressure will retreat northward into the Canadian maritime regions.
The approach of deepening low pressure to the south of Cape Cod and the position of high pressure to our north and east is a typical coastal storm set-up…and we can expect a storm will all the traditional nor’easter fixings on Saturday.
Heavy Rain: Sprinkles and light rain will overspread the area well after midnight tonight and gradually transition to a steady, wind-driven soaking rain by Saturday morning. Rain, heavy at times, will continue through a good chunk of the daylight hours on Saturday, eventually tapering to drizzle, mist and scattered leftover showers during Saturday afternoon. Rainfall totals of 1 to 2 inches will be common around the Cape and it’s possible that some spots see even a bit more rain that that. The heavy rain may cause some spotty street flooding in the typically prone locations.
High Winds: In advance of the storm system, the pressure gradient will tighten considerably over the area, resulting in a period of strong east and northeast winds from Saturday morning into the first part of Saturday afternoon. Sustained winds of 20 to 40 mph are expected around the area with frequent gusts to 50 mph expected. The highest gusts…on the order of 55 to 65 mph…will be felt during the late morning and midday hours and will cause some pockets of limb and tree damage. The still fully-leafed trees will exacerbate that issue. Expect some localized power outages to develop during the day. Winds will relax during the late afternoon and evening as the storm nears the Cape and the tightest pressure gradient pushes north of the region. The National Weather Service has hoisted a High Wind Watch for the area…and that will likely be converted to a warning later today or tonight.
Beach Erosion and Coastal Flooding: Tides are running a bit higher than normal thanks to the full moon (tides near 11′ in Cape Cod Bay) and that does increase the odds for some pockets of coastal flooding and beach erosion during the time of the midday high tide on Saturday. Thankfully, this storm will be moving along at a good clip and consequently there won’t be a long run-up of onshore flow and building offshore waves. Even so, some erosion is likely on eastern and northern facing beaches and some inundation will occur in the traditionally vulnerable spots – mainly along the outer arm of the Cape and inside of Cape Cod Bay.