INFRARED SATELLITE IMAGE - OCTOBER 30, 1991
Hard to believe it's been 20 years since the Perfect Storm. And, just as it represented a meteorological event unique up until that point in the historical record, there has been nothing like it since.
[UPDATE FRI AM: Though amazingly, on the 20th anniversary, even though it'll be of a different nature it looks like there's going to be another wild and highly unusual (for October) storm in the northeast U.S.!]
[ADDENDUM FRI NOV 4: For in-depth scientific analyses of the weather situation in late October and early November 1991, see these papers by Jason Cordeira and Lance Bosart of SUNY Albany, one on the development of the storms and one on the large-scale pattern associated with their formation, which includes not only the two I highlight in my blog, but also one over the northeast Atlantic near Europe.]
This is a repost and update of previous blogs I've written about the 1991 Perfect Storm.
Tropical cyclones have official numbers and names, but not other kinds of weather systems. Sometimes, though, one will be exceptional enough to come to be known informally by name, such as the "Blizzard of 1888" or 1962's "Ash Wednesday Storm" in the Mid-Atlantic and "Big Blow" in the Pacific Northwest.
Until today when TWC severe weather expert Dr. Greg Forbes and I unofficially categorized what happened in late April 2011 as a tornado "superoutbreak," there had only been one outbreak known as that, in April 1974. There still is only one storm that has gained acceptance as a "superstorm," in March 1993. And there is still only one known as the "Perfect Storm." There have been other contendas, but none ended up rivaling the atmospheric process which unfolded this final week of October in 1991.
For a while it was known as the "Halloween Storm" (even though it was past its peak by October 31), until Bob Case of the National Weather Service coined it "The Perfect Storm," and then came the book & movie which chronicled the plight of the Andrea Gail and escalated this weather event's legacy into popular culture.
Mr. Case was not engaging in hyperbole. This was a truly extraordinary confluence of atmospheric ingredients. Although other East Coast cyclones (e.g. hurricanes and snowstorms) have been "worse" in terms of severity of wind and precipitation, and overall impact to people and/or property, this one was unique in its evolution, and per these NCDC and NWS reports it was no slouch in its atmospheric and oceanic statistics either. And of course there were the tragedies at sea for which the storm is [in]famous.
For all of these reasons, the event is more well-known than many of those in recent decades which have made the official billion dollar disaster list (this one's cost was in the hundreds of millions of dollars).
This is a great sequence of satellite images showing the life cycle of the storm; this is an animation of the evolution at the surface and aloft.
And here are a meteorological analysis; a video clip of me on The Weather Channel during the Perfect Storm, showing a rare satellite loop of it; and a look at another lesser known but also whopper storm walloping North America at the same time.
IT ALL BEGAN ...
... on the 28th and 29th of October 1991 with a cold front and burgeoning non-tropical storm over the northwest Atlantic eating Hurricane Grace for breakfast. We'll never know exactly what the outcome would have been without Grace; the situation was already potent, but the hurricane did play a key role by providing extra moisture & energy and influencing the overall configuration of weather systems.
Meanwhile, there was also a strong high pressure system over eastern Canada to the northwest of the developing storm which helped develop a steep "pressure gradient" and long fetch of wind. This already caused waves to build, and it was during this phase that the Andrea Gail met its fate. (The exact time of the vessel's and its crew's loss is unknown but the final reported contact was on the 28th).
Ultimately the developing storm became quite a formidable one in strength and a behemoth in size, and it backed toward the U.S. coast rather than move away as most storms which are already at sea do.
The most significant impacts on land were felt in the northeast U.S. where damage was widespread, including, as you might recall, to then-President George H. W. Bush's house in Kennebunkport, Maine, but effects in the form of high waves were felt all the way from Newfoundland to Florida and Puerto Rico.
Although the storm was officially "extratropical" at its peak and it certainly did have non-tropical aspects, near its center the cyclone also had some characteristics of a tropical or at least subtropical cyclone.
It's not easy to find radar imagery of the Perfect Storm, but I have this screen shot from TWC's coverage, as the cyclone moved westward near southeast New England. Sure looks like an eyewall on the north side of the center, doesn't it? (The south "eyewall" may have been too far away from the radar to show up, or the rain might have not completely surrounded the center.)
After whacking the coast on October 30 -- its estimated lowest pressure of 972 millibars was that day and its closest approach to land was that night -- the storm rapidly wound down on Halloween itself.
However, in a bizarre (yet fitting) final chapter ...
Within the weakening larger overall circulation, a small circulation (see below) that was decidedly "warm-core," indicative of a tropical cyclone, spun up on November 1 and became an unnamed hurricane!
Thus, the "unnamed hurricane" wasn't The Perfect Storm per se, but it was a component of the evolution of the system, one which ironically did not produce the significant damage.
[Click on image for close-up of the unnamed hurricane.]
VISIBLE SATELLITE IMAGE - NOVEMBER 1, 1991
The hurricane was not named because it was feared that would confuse people. Given how bad the original storm was, there was the potential for undue alarm if residents along the coast heard a hurricane with a traditional "name" had now developed. But ironically the hurricane was so tiny that it was relatively harmless, especially given that it was heading away from the U.S. coast, not toward it like the parent storm a couple days prior. Landfall was eventually made, but as a rapidly waning tropical storm in Nova Scotia on November 2 with little impact.
A non-tropical system absorbing a tropical one is not unprecedented, nor is a tropical cyclone developing from a non-tropical system. But for both processes to occur with the same system, not to mention one of this magnitude, is what made the cyclone so amazing. In fact, Grace even started as a subtropical storm. This weather system was an ultimate hybrid!
MEMORIES ...
I have vivid memories of that whole situation as it unfolded. I had been at The Weather Channel for only a couple of years, and was in the midst of a few days off. Upon briefly stopping by the office to attend a meeting, my colleague Tony Fulkerson, who was working the shift on the other side of the week, popped his head in the room and said, "Stu, have you looked at the weather situation?"
Upon doing so shortly thereafter, I thought, "Oh, my!"
Next thing I knew, I found myself on the air the following evening, with Jeff Morrow, whom I've known for -- gasp! we're not as young as we once were! -- 35 years now since our first math class together in our freshman year in college.
This was the second weather event during which I made cameo on-camera appearances. The first was Hurricane Bob a couple months prior. The next ones after The Perfect Storm included Hurricane Andrew and the severe nor'easter in December 1992, then the Superstorm in March 1993 [video clip of that is here]. Ahh, those were the days ...
And, as much as it makes me wince to go back and look (for example, my not-ready-for-primetime eyeglasses!), here is a video of one of my Perfect Storm segments.
I can't definitively lay claim to that being the first time water vapor imagery was ever shown on television because I don't know for sure what else might have taken place before that, but at least to the best of my knowledge it was the first time on TWC and elsewhere. In any event, I couldn't resist displaying and talking about that water vapor loop, as it seemed if ever there was a time to spring it on the masses, this was it -- what a sight! And now that clip is the only easily accessible satellite loop that I know of which shows the development of the storm including the ingestion of Grace.
THE OTHER STORM
Not having received the worldwide notoriety that its cousin to the east did but remembered vividly by those who were in Minnesota and thereabouts at the time was another extreme storm concurrent with the latter part of the Perfect Storm.
Portions of the Upper Midwest were being affected by another powerful cyclone and an unusually cold arctic outbreak for so early in the season, the combination of which resulted in a record early-season snowstorm. It was dubbed by some the "Great Halloween Megastorm" and set the record for the largest single-storm snowfall (28.4") in Minneapolis history for any month of the year! Likewise, the 37.9" snowfall in Duluth was the largest on record at that time for the state of Minnesota, beating any storm in the middle of winter. (It was exceeded in January 1994.) On the southern fringe of the wintry precipitation was a severe ice storm in Iowa.
And the two atmospheric explosions were connected, as can be seen by the pattern aloft (first map below), in an exceptionally "high-amplitude" pattern: a big-time trough over all of western North America with a strong disturbance about to swing from the southwest U.S. toward the Great Lakes, which led to the intense cyclone centered near Lake Superior a few days later (second map below, and note the relatively benign unnamed tropical storm in Nova Scotia); a mammoth cutoff low in the western Atlantic, associated with the Perfect Storm which was blocked from a rapid exit out to sea; and a ridge in between waaay up across eastern Canada.
If you remember either one of these storms, submit a comment!
