Mostly in the sense of its maximum wind speed, but not the areal extent of those winds (which has grown), or the storm surge (which is still very strong). People fixate on the category of the storm too much.
The areal coverage of hurricane force winds has remained about the same (70 miles), it's a large storm but it is nothing like Sandy in size. Integrated Kinetic Energy I. K. E. is the measure you're talking about, and Irma's I.K.E., is number 4 on the list, which is up there, but by no means not at the top of the list (Sandy is #1).
Mid- unless a storm forms in tropical waters (or sometimes subtropical waters) by definition it can't be a hurricane. A subtropical storm can become a hurricane, but it has to have a warm core and surrounding thunderstorms concentrated near the center. The storms you are referring to used to be called neutercanes, but now they just refer to them as coastal lows or extratropical cyclones because their "action" is spread away from the center since they are no longer warm core systems (though they can be hybrids if they combined with another storm that actually used to be a hurricane or tropical storm- see October 1991 Halloween Storm in New England and Long Island). Typically these storms are much larger in size than hurricanes and they do not weaken once they hit land (since their strength comes from baroclinic processes.)
We also get something called triple phase systems which are when all three northern hemisphere jet streams combine to create a "superstorm"- normally this happens at higher latitudes like the Canadian Maritimes, but once in awhile it happens pretty far south- the last one was the March 1993 superstorm. Other examples are November 1950 and January 1978. They have very low pressures (similar to a Cat 3 hurricane) and can even have a storm surge (like March 1993 did over the gulf coast of Florida where it had winds of 112 mph.) It dumped about 3-4 feet of snow over a wide area of the interior northeast, just a few months after the 3 day December 1992 noreaster had done the same thing.
By the way I am a big proponent of these storms being named, just like hurricanes are (I think the weather channel does it now.) I know in Europe these kinds of big coastal storms get names!
Hmmm this is interesting https://en.wikipedia.org/wiki/Earthquak ... c_validity
Some recent research has found a correlation between a sudden relative spike in atmospheric temperature 2-5 days before an earthquake. It is speculated that this rise is caused by the movement of ions within the earth's crust, related to an oncoming earthquake. However, the atmospheric changes are caused by the earthquake, rather than the earthquake being caused by any change in atmospheric conditions. Furthermore, this relative temperature change would not cause any single recognizable weather pattern that could be labelled "earthquake weather".
At the 2011 American Geophysical Union Fall Meeting, Shimon Wdowinski announced an apparent temporal connection between tropical cyclones and earthquakes.
In April 2013, a team of seismologists at the Georgia Institute of Technology re-examined data from the 2011 Virginia earthquake using pattern-recognition software and found a correlation between Hurricane Irene's nearby passage and an unexpected rise in the number of aftershocks.https://en.wikipedia.org/wiki/Earthquak ... c_validity
from footnotes this is the original article in Naturehttp://www.nature.com/news/hurricane-ma ... ks-1.12839
Hurricane Irene, a powerful storm that ran north along the US East Coast four days after a magnitude-5.8 earthquake rattled Virginia in 2011, may have triggered some of that earthquake’s aftershocks, scientists reported today at the annual meeting of the Seismological Society of America in Salt Lake City, Utah.
The rate of aftershocks usually decreases with time, says study leader Zhigang Peng, a seismologist at the Georgia Institute of Technology (Georgia Tech) in Atlanta. But instead of declining in a normal pattern, the rate of aftershocks following the 23 August 2011, earthquake near Mineral, Virginia, increased sharply as Irene passed by.http://www.sciencedaily.com/releases/20 ... 121016.htm
University of Miami Rosenstiel School of Marine & Atmospheric Science
A groundbreaking study shows that earthquakes, including the recent 2010 temblors in Haiti and Taiwan, may be triggered by tropical cyclones.https://www.nature.com/news/2009/090610 ... 9.561.html
Now, scientists in the United States and Taiwan have examined slow earthquake events in eastern Taiwan that occurred between 2002 and 2007. They found that 11 out of 20 slow quakes coincided with typhoons — tropical cyclones that originate in the northwest Pacific Ocean. During typhoons, the atmospheric pressure on land is reduced, and at least in the case of eastern Taiwan, this pressure change seems to be enough to unclamp a fault that is under strain and to cause a fault failure.
"The typhoon is nothing but a little hair trigger," says Alan Linde, a geophysicist at the Carnegie Institution of Washington DC. Linde is one of the authors of the study, which is published in Nature this week1. "It requires just the slightest touch of that trigger and the fault will fail."
It is not yet clear whether similar phenomena are occurring elsewhere in the world. In some regions of the Cascadia fault, which reaches from northern Vancouver Island in Canada to northern California, tremors associated with small seismic slips — known as 'episodic tremor and slip' (ETS) events — occur approximately every 15 months2. Previous studies have shown that ETS events can be triggered by remote earthquakes and by tidal variations3,4.
Although the Cascadia region is not affected by typhoons, it does experience extensive low-pressure atmospheric systems that could produce small stress changes within the crust. These might be similar to those occurring in eastern Taiwan, says Herb Dragert, a geophysicist with the Geological Survey of Canada in Sidney, British Columbia, who was not involved in the study. To date, no one has investigated whether atmospheric pressure changes could be triggering ETS events, says Dragert. But the similarity between this latest study and previous ones, he notes, is that "very small stress changes can initiate this kind of slow slip and slow earthquake phenomenon".