So the past week it's been pretty warm and we've had a couple pretty good swells in RI, now another polar vortex is sweeping across the EC, and theyre are no major storms on the horizon, and it's dead flat here in RI. Don't know if this is just a trend in the swell, but its happens alot that I see in the winter.
When we get these cold spells, it usually mean storm tracks sweeping down from Canada. That means storms coming in from the NW producing offshore winds.
In comparison, when storms brew up from the south, several, more conducive things occur to help spur on building surf.
1) If south enough, energy from the Gulf of Mexico strengthens the storm
2) If the storm moves off the southern East Coast, the storm strengthens off the coast and as it heads north ward.
3) more wind fetch develops as the storm starts to the south and heads northward.
So, ya, the cold weather systems, produce mainly the strong offshore flow, whereas warm systems moving up from the south have a better opportunity for building wind swell.