Are the Tropics Cooking up an October Surprise? Don’t Look now, but Something’s Gaining on us…
October 24, 2012
The majority of the possible tracks now head into the Northeast, New England, or Atlantic Canada.
Could it really be a strong hurricane, as the European model predicts? We know that, occasionally, hurricanes do occur at these high latitudes at the end of October. Famously, the “Perfect Storm”, otherwise known as the Halloween Hurricane battered New England in 1991. Also, Category 2 Hurricane Ginny hit Nova Scotia in late October 1963. But, neither were of a scale and impact like the Euro is showing.
With the influence of the jet stream, you would think any storm that comes ashore would be subtropical in nature – part tropical and part like a nor’easter – but the NHC doesn’t allow for subtropical hurricanes in their naming scheme. It’s considered to be such a rare and nearly impossible event.
The spectacularly unusual confluence of events is the shape and orientation of the dip in the jet stream that is forecast to develop over eastern North America over the weekend – oriented in such a way to pull Sandy inland instead of pushing it out to sea, and the presence of a strong tropical or subtropical system where it can get pulled in. That’s so bizarrely unusual that I can’t think of another event like it.
This kind of thing occasionally happens with nor’easters, notably the Great Appalachian Storm of November 1950 which curved in off the Atlantic and dumped 20 to 30 inches of snow over a wide area in the Mid-Atlantic and Midwest, but the odds of it happening with a system that originated in the tropics – with all of the moisture that that implies – are extremely low.
A knowledgeable correspondent adds more:
Models are split on whether Sandy will hit New England (and New York City) Sunday night – Monday timeframe, but many of the more reliable weather models, including ECMWF & NOGAPS, continue to hook Sandy inland early next week, sucked up in a larger-scale trough approaching the east coast.
Yesterday the NHC GFDL was sweeping Sandy out to sea, now it looks like a much closer track to the east coast. Only GFS whisks Sandy out into the Atlantic.
No idea how this might impact the election, but expect a fair amount of finger-pointing if there’s major damage from the Carolinas and Mid Atlantic coast to New England.
Models are hinting at a Category 3 storm or stronger. This brings back memories of “Grace” in 1991, which helped to fuel “The Perfect Storm” over New England.
This could get very interesting, a potentially unpleasant October Surprise
Sandy: a potential billion-dollar storm for the mid-Atlantic and New England
On Friday, a very complicated meteorological situation unfolds, as Sandy interacts with a trough of low pressure approaching the U.S. East Coast and trough of low pressure over the Central Atlantic. The Central Atlantic trough may be strong enough to pull Sandy northeastwards, out to sea, as predicted by the official NHC forecast, and the 06Z GFS, 00Z UKMET, 00Z Canadian, and 06Z HWRF models (00Z is 8 pm EDT, and 06Z is 2 am EDT.) However, an alternative solution, shown by the 00Z ECMWF, 06Z GFDL, and 06Z NOGAPS models, is for Sandy to get caught up by the trough approaching the Eastern U.S., which will inject a large amount of energy into Sandy, converting it to a powerful subtropical storm that hits the mid-Atlantic or New England early next week with a central pressure below 960 mb and sustained winds of 60 – 70 mph. Such a storm would likely cause massive power outages and over a billion dollars in damage, as trees still in leaf take out power grids, and heavy rains and coastal storm surges create damaging flooding. The full moon is on Monday, which means astronomical tides will be at their peak for the month, increasing potential storm surge flooding. A similar meteorological situation occurred in October 1991, when Hurricane Grace became absorbed by a Nor’easter, becoming the so-called “Perfect Storm” that killed 13 people and did over $200 million in damage in the Northeast U.S.