***Significant coastal storm to impact the Carolinas, Mid-Atlantic, and Northeast US from later Saturday into late Monday...prolonged period of onshore flow leads to coastal flooding/beach erosion***
Paul Dorian
Low-level winds will be very strong during this upcoming storm event; especially, along coastal sections from the Carolinas to southern New England. Map courtesy ECMWF, Pivotal Weather
Overview
Low pressure is going to intensify significantly this weekend near the Southeast US coastline, induced by a frontal boundary zone that slides into the region and energized by an upper-level trough that drops southeast across the Great Lakes. It appears increasingly likely that this strong coastal storm will then push far enough to the north to have an impact on the Carolinas, Mid-Atlantic, and Northeast US all the way from later Saturday into late Monday. The worst impact will be along coastal sections where rain will be heaviest, winds will be strongest, and the threat of coastal flooding/beach erosion will be high due to a prolonged period of onshore flow.
A band of clouds can be seen on the latest satellite image extending from the southeastern states to the western Atlantic Ocean. This band of clouds is associated with a frontal boundary zone that is sliding southeast towards the southwestern Atlantic. Meanwhile, just to the east of the Bahama Islands, there is a solid patch of clouds associated with an area of showers and thunderstorms. Once the frontal boundary zone interacts with this wave to the east of the Bahamas, surface low pressure will develop and the process will begin for a significant weekend coastal storm. Image courtesy NOAA (GOES-East)
Details
Strong low-pressure will develop near the Southeast US coastline this weekend, and it is likely that this coastal storm will have an impact all the way from the Carolinas to the Mid-Atlantic and to the Northeast US. One of the key players involved in this setup for the weekend/early week event is a frontal boundary zone that is now sliding towards the southwestern Atlantic Ocean. Once in this location, this frontal boundary zone will interact with an area of showers and thunderstorms just east of the Bahama Islands, and increase low-level convergence which, in turn, will help to generate surface low pressure. This low-pressure system will then push slowly northward, likely reaching the coastal sections of the Carolinas by Saturday night, and intensify as an upper-level trough over the Great Lakes – a second key player in this unfolding scenario - begins to interact with the coastal storm and provide a boost. This coastal storm will produce heavy rain and strong winds by later Saturday across the coastal Carolinas – another impactful event for the Outer Banks of North Carolina during this tropical season.
An upper-level trough will help to energize surface low pressure near the SE US coastline later this weekend and a very strong ridge of high pressure over eastern Canada will slow down its northward advance…all resulting in a prolonged rain and wind event for the Mid-Atlantic region. Map courtesy ECMWF, Pivotal Weather
By later Saturday night/early Sunday, rain and wind associated with the significant coastal storm will extend up to the Mid-Atlantic region and Northeast US as the low pressure edges northward. It is at this point that another key player – very strong high pressure ridging over southeastern Canada – will play an important role and act as a “block” in the atmosphere forcing the storm to grind to a halt in its northward progression, and perhaps even take a loop somewhere near the Mid-Atlantic coastline.
Rainfall will be significant during this upcoming storm event along coastal sections from the Carolinas to southern New England. Map courtesy ECMWF, Pivotal Weather
The bottom line here is that the “blocking” pattern in the atmosphere will lead to an extended period of rain and wind in the Mid-Atlantic region likely lasting all the way from later Saturday to late Monday. This prolonged period of strong onshore flow will lead to a high chance of significant coastal flooding and beach erosion from the coastal Carolinas to the coastal sections of the Northeast US. Winds should be quite persistent from an east-to-northeast direction during this long event likely gusting to 50+ mph along coastal sections, and in the 30-50 mph range at most inland locations.
Meteorologist Paul Dorian
Arcfield
arcfieldweather.com
Follow us on Facebook, Twitter, YouTube
Video discussion: