****Early season nor’easter to impact much of the Mid-Atlantic and Northeast US...greatest affects along coastal sections where tidal flooding and beach erosion are big concerns****
Paul Dorian
Overview
This forecast map by NOAAs RRFS computer forecast model of precipitable water for late Saturday afternoon clearly defines the circulation center location and “moisture” extends inland back to the I-95 corridor. Map courtesy Dr. Ryan Maue (X), NOAA
An early season nor’easter will impact much of the Mid-Atlantic region and Northeast US and likely have its greatest affects on coastal sections where tidal flooding and beach erosion are big concerns. The time period for impact by this developing storm system for the northeastern states will be from Friday night through Sunday…a prolonged event. The combination of strong high pressure centered over southeastern Canada and intensifying low-pressure over the western Atlantic Ocean will result in a extended period of onshore flow along coastal sections leading to the tidal flooding and beach erosion issues; especially, at times of high tide - and a full moon on Saturday won’t help the situation. As the Atlantic low intensifies and slowly pushes to the north, it will become increasingly under the influence of the strong high pressure ridging to its north, and this will lead to a slowdown and then likely a loop back to the coast. Rain and wind will extend inland back to the big cities in the I-95 corridor during the Friday night through Sunday time period.
Impact began on Thursday morning along the Carolina coastline with intensifying low pressure over the western Atlantic Ocean bringing high (onshore) winds to the Outer Banks (Kill Devil Hills photo).
Details
Low pressure over the western Atlantic Ocean is intensifying and already having an impact on the Outer Banks of North Carolina during Thursday morning with water rises being felt as a result of persistent strong northeast winds. The next several high tide cycles along the Carolina coast and Chesapeake Bay will likely bring gauges close to major flood stage in some locations and problems will then spread farther to the north during the day on Friday.
On Friday, low pressure will continue to intensify as it pushes slowly to the north and will become increasingly under the influence of strong high-pressure ridging centered over southeastern Canada...a key player in this overall pattern. As such, the surface low pressure system will slow down in its northward progression and eventually will likely be “forced” to loop back to coastal sections of the Mid-Atlantic and/or Northeast US.
Low pressure over the western Atlantic Ocean will run into an “atmospheric roadblock” this weekend as deep high pressure over southeastern Canada will halt its northward progress. As such, the storm will slow down and likely loop back to the coast with impact possibly lasting all the way into early next week in some of the northeastern states. This forecast map comes from last night’s run of the “synoptic-scale” European model and verifies at mid-day on Sunday. Map courtesy ECMWF, tropcialtdibits.com
Given the expected lengthy period of northeast winds in the Mid-Atlantic and Northeast US, tidal flooding and beach erosion will become increasing concerns at times of high tide similar to what is already taking place on Thursday along the Carolina coastline - and the full moon on Saturday will only exacerbate tidal issues. Look for rip currents and rough surf throughout the weekend at all of the beaches along the Mid-Atlantic and Northeast US coastlines. Waves of 10 feet or higher are likely to be commonplace in these coastal sections.
Some of the most recent “meso-scale” computer forecast models have shifted westward with their positioning of the surface low pressure system. This forecast map by NOAA’s HRRR model features quite a strong storm system just off the Mid-Atlantic coastline as of Saturday morning. Map courtesy NOAA, tropicaltidbits.com
Impact will likely be greatest along coastal sections during this prolonged weather event; however, rain and wind can certainly make its way inland back to the big cities in the I-95 corridor; especially, from around Baltimore and points to the north and east of there...even the DC metro should get in on some of the action. With the expected slowdown and potential loop, this storm system may linger all the way into the early part of next week with some impact continuing on Monday in portions of the Mid-Atlantic and Northeast US.
Stay tuned...still a day or two to go and the ultimate storm track is not yet set in stone. One final note, if this early season nor’easter is a harbinger of things to come in the upcoming winter season then get ready to buckle up…it would be quite an interesting ride.
Meteorologist Paul Dorian
Arcfield
arcfieldweather.com
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