Superstorm or Perfect Storm? It doesn’t matter…
Picking up from the end of my previous column a few days ago, a major storm system which is currently impacting southern Florida will strengthen and at times impact points across every state that touches the Atlantic Ocean.
Sandy-Of course one of the main ingredients of the system will be Hurricane Sandy which is currently wreaking havoc over the southeastern Bahamas. This system will trek towards NE Florida and stall out as the steering currents die out.
Blocking -The pattern that makes this even possible is the large blocking mechanism currently setting up over the northwest Atlantic and Davis Strait. This block will extend from the HP at the surface far up into the upper reaches of the atmosphere. This will act as a deflector of sorts, allowing Sandy to become trapped in the western Atlantic. Earlier in the week the routinely wrong American model was showing Sandy being shunted NE out to sea. This never appeared likely given this blocking scenario. An interesting fact, is the blocking placement and strength is very similar to that of the Perfect storm in October of 1991, which featured the forced phasing of three separate tropical and non-tropical systems.
Large CONUS Trough- A large continental US trough is currently tracking east across the plains, this trough is the divider between a current summer time atmosphere over the southeast and plains.
As Sandy tracks towards the Bahamas, she will begin to stall out and wait for the incoming trough to start picking her up. As this happens, she will start to move NNE towards a point 100 to 200 miles off of Cape Hatteras, at this often focal point for all east coast extra-tropical systems, she will begin to phase, this will force Sandy to turn back to the west and WNW and make landfall near Pocomoke City, Md . As this happens, she will start to entrain energy from a 500mb vortmax and begin to congeal into a large upper level low pressure system with tropical characteristics and very low barometric pressures. In some ways, very similar to the spring and winter time characteristics of the Superstorm of 93. The incoming trough from the plains will then act to energize this system even more and deepen it aloft as Sandy makes landfall. 500mb heights could crash as low as sub 510dm’s.
Under this scenario, there will be crippling snowfall over the Appalachians, storm surge and coastal flooding over the mid-atlantic and northeast, as well as heavy flooding rains and widespread inland wind damage. Even backlash snowfall over the piedmont areas of the mid-Atlantic and northeast is possible, with accumulations. Stay tuned for more updates.