The weather world has been closely tracking Hurricane Erin. The system underwent a period of remarkable intensification late last week — exploding in strength from a Category 1 hurricane with 75 m.p.h. winds on Friday evening into a Category 5 hurricane with sustained winds of 160 m.p.h. by Saturday morning.
Erin’s central pressure fell all the way down to 915 millibars (27.02 inches on the typical home barometer), rivaling some of the more historic Atlantic hurricanes. Thankfully, the worst of the storm remained well north of the Lesser Antilles, sparing that region a catastrophe.
Erin has continued to chug along, tracking west and northwest early this week and fluctuating in strength but remaining strong as it moves through the Atlantic. The system is forecast to parallel the Eastern Seaboard this week, remaining offshore but brushing the Outer Banks of North Carolina. From there, Erin is expected to turn seaward and track well south and east of Cape Cod Thursday and Friday.
While the core of the storm is expected to remain far out to sea, we are likely to experience some fringe effects from the system as it nears and passes the area. Rough seas are a guarantee along our oceanside beaches from Provincetown to Chatham. Erin has been generating large waves out over the open ocean and those swells will propagate westward and hit the East Coast this week.
Long-period, high-energy swells from offshore hurricanes often cause dangerous rip currents, and Erin will be no exception. Wave heights will peak locally Thursday and Friday when offshore heights approach 15 to 20 feet. That will result in large nearshore waves and dangerous conditions for boaters and swimmers. Those large waves could also cause some pockets of beach erosion during high tide.
The other effect to monitor is the potential for a period of strong, gusty onshore winds Thursday night and Friday. While the “real” wind associated with Erin will be far to our southeast, a tightening pressure gradient between higher surface pressure to our northwest and Erin passing offshore will yield some very busy northeast winds here. While this doesn’t look like a major windstorm by Cape Cod standards, some gusts in excess of 40 m.p.h. are possible. With trees fully leafed out, 40-m.p.h. winds can be enough to cause limb damage, which could, of course, lead to some (probably brief) power disruptions.
Quieter and warmer weather is expected to take over Saturday and Sunday as Erin pushes far out to sea and onshore winds dissipate.
