The potential continues to increase for a dangerous, possibly historic, storm in the Mid-Atlantic and Northeast portions of the country for the early and middle portions of next week. There are still some disagreements amongst the many computer forecast models, but the main holdout for the “harmless, out to sea” solution, the US Global Forecast System (GFS), is now evolving to the more threatening “coastal” scenario first proposed by the EWMWF (aka EURO) model. Indeed there were signs in last night’s GFS model run that it would begin to adjust its next solution and we talked about them in detail during this morning’s video. I expect that this GFS model adjustment, away from the “out to sea” solution, will continue over the next couple of days until it is pretty close to the EURO forecast solution.
Two main features will play a role in this upcoming weather event: 1) Hurricane Sandy which now has 80 mph sustained winds and 2) a deep upper atmosphere trough of low pressure with lots of cold air associated with it. It appears that these two features will interact early next week to create a powerful storm off the Mid-Atlantic coast that will then retrograde and get “pulled in” to the Northeast US coast. This storm at some point during this interaction will lose its tropical characteristics and become a major nor'easter on steroids. The storm will move quite slowly inland and will still have an effect on the weather in the Mid-Atlantic and Northeast US into the middle of next week.
The bottom line, we’re looking at the increasing possibility for a long-lasting (early to mid week) weather event in the Mid-Atlantic and Northeast containing torrential rainfall, hurricane-force wind gusts, coastal and inland flooding, power outages, and accumulating snow in inland higher elevation locations across the Appalachians from NC to PA. It is even not out of the question that as cold air wraps around the southwest side of this storm (not the usual northwest side) the rain changes to snow in the DC metro region and perhaps even near Philly. Stay tuned.