Hurricane Dorian – which battered the Bahamas as a torturously slow-moving Category 5 hurricane – is nearing the Carolina coast today and will move parallel to the North Carolina beaches tonight and early Friday morning..entering the waters east of North Carolina during the day on Friday.
From there, the system will track quickly east-northeastward, likely passing about 150-200 miles south of the Cape very late Friday night / first thing Saturday morning…before heading toward Nova Scotia Saturday afternoon and night.
With Dorian expected to pass well southeast of our area, we are assured that we will escape the worst of the system’s weather – as the strongest winds and heaviest rains will stay out over the open ocean waters far south and east of Cape Cod. However, we won’t get off entirely scot-free.
As Dorian continues its journey northward its wind-field will weaken but simultaneously expand outward from its center. Consequently, the areal extent of tropical storm force winds (measuring outward from the center) is expected to increase from about 100 miles to 150 to 180 miles. That puts the Cape right on the edge of some tropical storm force winds or wind gusts (basically 40mph or greater) and that is the going forecast for Friday night and Saturday morning. It should be noted that there is a window of time…between about 6AM and 10AM Saturday morning…when a period of stronger northerly winds are possible. Some model guidance is hitting the Cape with a few hours of sustained 30 to 40 mph winds with gusts over 50 mph during that window. With fully-leafed trees and wet ground, that would be enough to bring down some larger limbs and trees…worth watching over the next 24 hours.
Similarly, a shield of rain – with embedded downpours – is expected to grow in size and that too will likely clip the Cape for a time Friday night and Saturday morning. It remains to be seen whether the truly tropical rains associated with Dorian manage to rotate onto the Cape or stay just barely offshore, leaving us with a steadier moderate to heavy rain as opposed to torrential rains. Most guidance offers 1 to 2 inches of rain across the Cape throughout the event – but if the core of heavier rains can rotate a bit further north and west…totals of 2 to 4 inches would be possible.