By Kate Bilo
By now, everyone is aware that we’ll be facing the threat of a potent nor’easter on Wednesday, but even as the storm time frame approaches, the models continue to throw curveballs. The European model, which has been fairly consistent in predicting this storm right along the coast since late last week, today shifted the track a little further east. This is only one model run, but this coupled with a much colder GFS run midday throws the threat for snow back into the equation.
Basically, a track further east would bring cold air in around the back edge of the storm Wednesday evening. Boundary layer temperatures in the city of Philadelphia at this time are borderline – mid 30’s – and temperatures at 850 millibars are just slightly below freezing. This implies a high degree of uncertainty – will it stay a cold rain? Will it mix with some wet snowflakes? Will it change over to a period of heavy wet snow? Right now there’s no clear answer but much of our area, especially the north and west suburbs, should be at least prepared for the potential for some snow, even perhaps some accumulation on grassy and unpaved surfaces, later Wednesday. And we still cannot rule out the worst-case scenario, which would be several inches of heavy wet snow in an area that is still reeling from the impacts of Sandy.
So the snow part of the equation remains uncertain, but what seems certain as of now is that this storm will pack a punch at the coast, an area that needs nothing less. The main impacts at the shore will be felt on Wednesday with the potential for 1-2″ of rain, wind gusts to 50-60 mph, moderate tidal flooding, and possible additional power outages. Of course, in the wake of Sandy, the impacts will be felt doubly in this area – there is the risk for re-flooding, increased beach erosion, and further wind damage as the gale-force winds pound the already weakened structures. As far as flooding goes, the high tides of concern are early Wednesday afternoon around 1-2pm and again early Thursday morning around 2-3am. A High Wind Watch and a Coastal Flood Watch have already been posted for the area as the storm looks to be stronger and slower as more information rolls out.
As always, we will continue to monitor this storm as it moves offshore and strengthens, and bring you the latest updates and information.