A surprise that this Nor’easter could offer us Friday afternoon or Friday night is as the storm is looping, yes looping, off the coast it will produce a vacuum of cold air being sucked out of the atmosphere. It will pull it down all across the area. There will be a pocket where rain changes to snow; however, if you are traveling or flying out of Philadelphia Friday or Friday night to anywhere on the Eastern seaboard marked in the red area than likely you’re going to run into flight delays or cancellations to that destinations because of heavy snow. That’s because of the upper level, closed off low. When you have a closed off low of this vorticity it produces cooling in the atmosphere, or it’s own cold. This is called dynamic cooling. Then it changes everything over to snow. We could see snowflakes or even a period of a heavy burst of snow but no major accumulation. That upper level low would have to dig further south. However, as the storm moves south there is plenty of cold air around. This could touch off a significant period of snow Friday afternoon and early evening.
This is going to be one interesting storm!
Be careful and stay home!!