After "Reverse Engineering a Historical Birding Event", and learning more about the associated Great Appalachian Storm of 1950, I was reminded of another remarkable meteorological event, which led to excellent birding, in late Oct - early Nov 2012 - Hurricane Sandy. More specifically, post-tropical Sandy, which underwent transition from a Hurricane (or hybrid system) to a fully extratropical storm prior to making its atypical westward-moving landfall into New Jersey. Here's a surface analysis of post-tropical Sandy as the centre moved into Pennsylvania.
The above image shows a westward-propagating occluded front (purple line), which has a similar structure to the westward-propagating cold front shown on the 1950 Great Appalachian Storm surface analysis:
Interestingly both maps show very large and powerful storms, both have large westward moving fronts passing over the Hamilton area, and both have recently retrograded from east to west, from the Atlantic ocean to inland. Given that our prevailing winds are southwesterly, perhaps the most significant feature here is that both cyclones have gone east to west – a highly unusual direction for a storm to travel in our part of the world. Combined that with the fact that they’re both remarkably strong, it was a one-two punch that displaced many remarkable birds.
While both of these cyclones were atypically directed westward by an area of blocking / high pressure to the north (or northeast), it should also mention that there are some notable differences between them. Hurricane Sandy was a fully tropical cyclone (arguably a hybrid system, and rather unique in size) for most of its life, only transitioning to a Post-Tropical cyclone shortly before impacting our area. This is in contrast to the fully extratropical nature of the Great Appalachian Storm. In meteorological terms this is the equivalent of applies to oranges. It does make me wonder if the Great Appalachian Storm could have had some undetected subtropical characteristics that supported it's incredible strength (but that is not based on anything I have read, just a wild and likely incorrect idea).
Nonetheless I have found the similarities to be another exciting little discovery in my look at the meteorological world and how it relates to the (vagrant) birds we sometimes see!