Guest Post by Willis Eschenbach
As at 2 PM Pacific time, here’s the current position of Sandy and the projected path.
SOURCE: National Data Buoy Center
I had said a couple of days ago, when Sandy was a hurricane, that it would not be a hurricane when it hit the coast. How did that go?
Well, as of the time that this location and projection of the path was done, the NDBC has shown all the nearest stations. Not one of the actual observations is showing sustained winds over 50 knots, and that’s a long ways from the 72 63 knots that marks a hurricane.
Please note that the big damage from such storms is the flooding, so I am not minimizing the likely extent of the damage. It will be widespread. However … not a hurricane.
w.
Addition by Anthony:
Harold Ambler has a photo of storm surge in Rhode Island here
Flooding in the subway in Newark, NJ (via FirstHand Weather on Facebook)
Matt G. – was not – was directed at Theo …
http://tidesandcurrents.noaa.gov/data_menu.shtml?bdate=20121028&edate=20121030&datum=6&unit=1&shift=g&stn=8518750+The+Battery%2C+NY&type=Tide+Data&format=View+Data
Following up on what Willis just posted, the above link takes you to the tabular data for Battery. Row 1 is predicted, row two is measured. 9.23 was the surge at the ‘peak’, and Battery held an 8ft or greater surge (over 13 feet total tidal level) for some 2 hours and 20 minutes.
List of station extremes:
http://tidesandcurrents.noaa.gov/data_menu.shtml?extremetype=station&bdate=18000101&edate=20121031&unit=1&format=Apply+Change&stn=8518750+The+Battery%2C+NY&type=Extremes
Rank Highest Highest Date Zone Lowest Lowest Date Zone
—- ——- ————– —- ——- ————– —-
1 13.30 19600912 13:00 LST -1.00 19760202 16:30 LST
2 12.99 19921211 14:00 GMT -0.91 19780110 16:12 LST
3 12.80 20110828 12:42 GMT -0.50 19660109 04:24 LST
4 12.09 20100313 23:42 GMT -0.24 19800316 02:06 LST
5 12.01 19911031 03:36 LST -0.23 19800316 00:00 LST
6 11.81 19840329 08:12 LST -0.19 19850208 17:24 LST
7 11.73 19921212 02:18 GMT -0.15 19710127 15:36 LST
8 11.66 19870102 10:30 LST -0.13 19690102 01:12 LST
9 11.64 19930314 05:00 GMT -0.10 19760317 15:42 LST
10 11.62 19681112 10:42 LST -0.01 19800315 13:36 LST
I’d seen numbers bandied about all over the place (for the record I don’t think the 13.88 is verified yet, so its not in the above list) but the previous record was indeed 1960 @ur momisugly 13.30 (of which the actual surge number is somewhat lower than that but I’ve been unable at this point to located the data for that time frame), so that shows us that this storm didn’t beat 1960 (Hurricane Donna) by much, and Donna had 105MPH sustained winds with 115MPH gusts.
What this tells us is location and direction are much more important, to some extent, for a surge event than raw wind speed. A Donna type event hitting exactly where Sandy did would have been significantly more devastating, I’d guess. What made this event special is location, not that sandy was some sort of ‘superstorm’.
A. Scott says:
October 31, 2012 at 2:55 pm
Warm and cold cores don’t determine whether a given storm is considered a hurricane. All that counts is sustained wind speed. If the wind in a cyclonic storm is over 63 knots sustained, you have a hurricane.
Finally, hurricanes have made landfall along the Northeast Coast in the past, including in New York. Sandy might have been one of them. From listening to the media beforehand, you’d have thought it would be a hurricane at landfall. I thought not, and I made a public prediction to that effect. Hey, I took a chance. Easy for you to look back now and claim it was obvious … I didn’t see your prediction at the time, although I might have missed it.
w.
Interesting to see how many commenters here have put on the record how they no idea at all about integral calculus.
Willis,
When there is a typo in the first line, I could tell it was …… rushed ?
So, here we are days later.
You have obviously been missed 🙂
A Scott, I’m still here, just not responding with regards to Sandy. Good for you.
Willis – I didn’t need to make a “prediction” – I already knew what to expect. I had followed the progress all along and kept up on advisory’s and information.
That the NHC would cease reporting it as a hurricane and refer to it as an extra-tropical – or more officially a “Post-tropical” cyclone – was known days in advance. The NHC educated people thru various sources, including this release 2 days before landfall:
http://www.nhc.noaa.gov/news/20121027_pa_sandyTransition.pdf
The National Hurricane Center noted that when they determine Sandy became post-tropical they would stop reporting on it as a hurricane. Their hurricane advisory’s never extended beyond NC, on 10/27 they were already transitioning to the NWS which does the reporting on non-Hurricane events …
They clearly note the strength may not change, and may even increase, yet they will not report as a hurricane and will transition to the NWS side once it goes post-tropical. They had already started that transition 2 days before expected landfall – acknowledging the confusion that dropping hurricane status, despite that strength may remain the same or increase could cause.
Those NWS advisory’s DID include terms such as “Hurricane Force Winds” to acknowledge the hurricane like strength – but as it stands today, they would not call it a hurricane after it transitioned regardless of the strength.
You may well be correct about the past, but at present once it makes the extra-tropical transition it is no longer reported as a hurricane.
The readings NWS observed and reported even well after landfall – “hurricane force” winds, sustained at 75mph or above – would have been sufficient to call this a hurricane again. But all that would have done is confuse the issue
FWIW I just learned this as well, as I watched and listened to the coverage and did some research into “hybrid” storms.
Here is a reader comment about the transition and naming change that shows the concern quite well:
“I honestly thought the storm had been downgraded when I first read the headline earlier today – but now that I read the whole story I’m glad I did. Nothing has changed about the storm but the name……..”
There are eyesonu.
Willis
Great work. I bracketed & I down loaded the nearest buoy data from the landfall around Atlantic City, NJ, at the following sites and sources:
Station JCRN4 – Jacques Cousteau Reserve (The inland weather station not the buoy)
(www.ndbc.noaa.gov/station_page.php?station=jcrn4)
Station SJSN4 – 8537121 – Ship John Shoal, (www.ndbc.noaa.gov/station_history.php?station=sjsn4)
Station 44009 (LLNR 168) – DELAWARE BAY 26 NM Southeast of Cape May, (www.ndbc.noaa.gov/station_page.php?station=44009)
Station 44065 (LLNR 725) – New York Harbor Entrance – 15 NM SE of Breezy Point , (www.ndbc.noaa.gov/station_page.php?station=44065)
As per your post, none of the historical data showed sustained hurricane force winds over the landfall period. Moreover, the graphs obtained clearly showed Sandy’s eye. So, I managed to capture a fair idea of Sandy’s progress relative to each site.
Note: To get each graph I simply went each websites, looked at the lower end of the web site, and select the graph icon for ” Wind Speed (WSPD)”. This gave me a graph of the historical data.
I also obtained a copy of the NJ Weather and Climate Network’s Atlantic City Marina, NH site at
http://climate.rutgers.edu/njwxnet/images/containerTop.jp
This site did not record sustained winds; but, did to show the maximum winds recorded were 70 mph at 16:52 on Oct 29, 2012.
I can’t say how much I appreciate your efforts. As recent contributor to the U.S. National Climate Assessment, I used data obtained from WUWT to push-back on EPA propaganda in that report. The quality of climate change data I found here was so good that the EPA was forced to delayed publication of their conclusions on the Southeast… for a year… when they were unable to refute the sources cited.
I have no doubt the EPA is using the time to find way to bypass the flood of skeptical opinions they received from a number a independent agencies (including my own). But, again, I would like express my appreciation of the efforts of you and your colleagues… and let you know you are have a positive impact.
Regards, Kforestcat
Kforestcat – check this link:
http://www.weatherflow.com/datascope-open-for-tropical-cyclone-sandy/
There are a number of stations that show sustained speeds in the 60’s and max gusts up to 90mph. This is the data NWS was referencing with some of the specific station comments.
Its normally a premium service but Weatherflow made the Sandy data public
Willis Eschenbach says:
October 31, 2012 at 4:48 pm
Sorry, cold core – not a hurricane, tropical storm, or tropical cyclone. Over 63 knots – hurricane if it’s warm core and not a baroclinic storm with fronts hanging off of it. The NWS will refer to things like “hurricane force winds” in big extratropical storms like nor’easters, they never, ever referred to the Blizzard of ’78 as a hurricane. (They did for the 1991 “Perfect Storm” because a tropical cyclone developed in it, but it was short lived and the NHC didn’t bother to name it. Weird storm, almost as weird as this one but very different.)
The NHC discussion even explained how they were going to share reports with the NWS and (I think) the Hydrological Prediction Center (HPC) after Sandy’s conversion to maintain continuity in reporting the storm. The NHC really doesn’t like to deal with extratropical storms.
Your remark below, to which I was responding, implied that I was uninformed about something, but it didn’t spell out what. I made a best-guess about what you had in mind:
Actually, this website often addresses the question of adaptation versus mitigation of CO2. Some adaptive measures are “move away.” Others are sit-tight-and-cope tactics of the sort I proposed. The consensus here is that mitigation is too expensive–and is a hopeless strategy anyway, given the unlikelihood of Asia adopting it, which is a requirement for it to work. But you didn’t explain what that had to do with what I wrote. It doesn’t seem at all relevant. So it seemed to me you were implying something else: that I was uninformed.
If necessary, the hose’s outlet could be positioned on the second floor.
Technically, I should have said, “flood resistant.” But, practically speaking, “flood resistant” means “flood-proof” in NYC, where most future storm surges are unlikely to exceed Sandy’s, which overtopped very few first-floor windows in NYC, AFAIK. Even if the surge did overtop the bottom of the first-floor windows, they wouldn’t necessarily collapse or leak severely, since few would be exposed to battering waves. And the windows in lower Manhattan office buildings are fairly sturdy.
(In Hoboken, NJ, where some buildings are only a couple of feet above sea level, many first floor windows would have been overtopped. But it would still make sense to flood-proof them, given that it would protect against most future storm surges, which will be lower.)
Not necessarily. Power wasn’t lost in most of lower Manhattan until after the flood crest had passed, IIRC. Anyway, it would make sense to provide a back-up generator or battery pack for the pump in an expensive office building, which could afford one. Not so much in a residence, although having one might make sense there too, if other threats to the power supply are considered.
You should have been explicit.
It’s doubtful that there’d be much increased hydrostatic pressure on a basement in NYC, because it would be hard for water to get into the ground around the basement quickly. The surface around the buildings is impermeable. And the office buildings in lower Manhattan have basements whose floors are well below sea level already, and whose walls abut bedrock. They thus presumably are already withstanding considerable hydrostatic pressure. A little more shouldn’t make enough difference to crack them.
This should be easy to determine in the post mortem of Sandy. A survey could be made of a sample of buildings to determine how many basements actually did crack.
The basement is flood-proof even if it has a few leaks and seeps from no longer being water-tight. A pump can keep ahead of them. Or, if the leaks aren’t too bad, the basement can be bailed out later, after the storm surge’s waters have receded. A little water on the basement floor isn’t catastrophic. What’s catastrophic is allowing salt water to get into the electrical equipment higher up.
That’s what you say now. Here’s what you said then:
Nothing about cost-benefit was mentioned in that paragraph. Therefore, the implication of its intemperate fault-finding was that those faults were either insuperable (false, as my response delineated) or that the mere possibility of their existence doomed my proposal. The latter amounted to a demand for unobtainable perfection.
(BTW, if I were mayor, I wouldn’t necessarily have advocated more than a pilot program for a year or two to see how many keys got lost, food got stolen, rats and insects penetrated the locker, etc. I’m a big believer in “try before you buy.” This cautious, testing attitude should have been adopted by the legislatures that “bought” renewable power.)
Other demands for perfection were your implications that my flood-proofing proposal was worthless because 1) it wouldn’t protect against a flood above the first floor windows (how often would that occur, and to how many buildings?), and 2) that it wouldn’t prevent water-incursion into basements (how fast would that be if it occurred, and how likely would it be to occur in Manhattan?). The nuances I just mentioned in these situations were ignored by you and nothing like a balanced cost-versus-benefit approach was taken. Rather, the method was a sneering, sweeping dismissal of my suggestions based on a superficial analysis.
Other sneering, superficial, captious criticisms were:
***********************
You take the cake. FWIW, here’s a look at costs vs. benefits:
The benefit of flood-proofing an office building is immense. Citigroup has just announced that it won’t be able to return to its headquarter building in NYC for at least two weeks, peresumably because the electronics and electrical equipment associated with its elevators and control systems were compromised by being flooded by salt water. That interruption of business is going to cost them tens of millions—and other occupants will be similarly impacted.
On the other hand, the cost of flood-proofing the ground-level openings (and the first-floor windows, too, if need be) of such a skyscraper would (I guess) be well under a million. And it could be amortized against more than one expected storm surge. It would still be a worthwhile expenditure even if there were some chance of total or partial failure, or if it wouldn’t work in a worst-case scenario. If most buildings will be protected against most of the damage from most storm surges, the expense is justified.
Dear A. Scott
Referring to your comment A. Scott says: October 31, 2012 at 9:21 pm; where you say:
“Kforestcat – check this link:”
Son, I checked your data from prior comments. As many commenter’s have stated above, wind gusts are not the proper metric – sustained winds are. Nor are model simulations based on near real time inputs a proper metric. I deal in policy and prefer to use hard data from weather sites who’s data is readily available and visible to the public.
The buoy data provides enough of a contrast to NOAA’s public statements to start asking tough questions.
Regards, Kforestcat
I dropped by to see if some commenters here had developed the grace to feel a little sheepish about reactions posted here on the 29th, now that it’s clear that Sandy has crippled New York, and that the reported death toll is currently at 74. (Perhaps some have; clearly, not all.)
It will be interesting, in a grim sort of way, to see what the final tab turns out to be. But it’s not too early to say that if we go by the scale of loss inflicted, Sandy well deserves the term “superstorm.”
But it doesn’t deserve the term Frankenstorm, which is what it was being hyped as. We were being warned that it would combine, ala Frankenstein, with other oncoming storms, to wreak havoc in the interior from winds and precipitation. That prediction has been a 90% fizzle, although there’s been lots of snow in WV, and the warnings had the effect of misdirecting attention. Instead, the havoc impacted the shoreline, from the storm surge plus new moon. There’s sheepishness to go around on both sides.
Kevin McKinney says:
November 1, 2012 at 6:53 am
Well, gosh, Kevin, thanks for checking up on us. Now if you’d just have the grace to feel sheepish about not quoting the remarks you are talking about, we could all join in the discussion.
Because as it stands, so far all you’ve done is kvetch and whine about some vague unspecified something that The Great Kevini didn’t like, as if people would just go “well, I don’t know what or who Kevin’s talking about but he must be right” …
Put up or fly away, Kevin. What do you think people should be feeling sheepish about, and which people are you referring to? Because I certainly don’t feel sheepish. I said that Sandy would not be a hurricane at landfall, and it wasn’t. How does the number of deaths affect that at all? Why should I feel sheepish about saying it wouldn’t be a hurricane at landfall?
Of course, you may not be referring to me at all. But that’s the recurring problem with folks like you. You are more than willing to go all moralistic and lecture us for doing what The Great Kevini doesn’t like … but you’re not willing to tell us who has done what to get you all huffy and moralistic, you’d rather just make vague insinuations and data-free claims.
w.
Kforestcat … it would appear then you did not actually check the data at the link I provided you, as you claim..
Since BOTH max gust AND sustained average wind speeds are noted in the Weatherflow data.
Hard data, not models. the same hard data used by the NWS and reported (and specifically identified as from Weatherflow) in their regular advisory’s. NWS advisory’s … which reported sustained winds in excess of 75mph even well after landfall
And when you review that data you can clearly see the relationship between average sustained speeds and wind gusts. It remains fairly uniform across all data and sites You will rarely if ever find 70-90mph gusts when sustained speeds are at low levels.
The link takes you to the Weatherflow Sandy data page.
http://www.weatherflow.com/datascope-open-for-tropical-cyclone-sandy/
Select any station, scroll down and you’ll find the data archive graph, click on 10/29 segment to blow it up. (You’ll also find a map with other stations below the praph).
Here is the Tuckerton Station reading referenced in the NWS advisory I posted above:
http://ds.weatherflow.com/spot/45700
Here is the Image link for the Tuckerton 10/29 data – please note that landfall was appx 4:00PM – and at that point this station had a 90mph gust, 60+mph avg wind speeds and 50+mph “lull” windspeeds. Please also note the relationship between gust wind speeds and sustained wind speed – usually 20-25mph, with max 30mph difference at peak gusts. So it really is quite easy and useful to look at a peak gust map as provided earlier and max a useful and reasonably accurate estimate of sustained speeds :
http://api.weatherflow.com/wxengine/rest/graph/getGraph?spot_id=45700&time_start=2012-10-29%2000:00:00&time_end=2012-10-29%2023:59:59&units_wind=mph&wf_apikey=1d10f490-991c-11e1-a8b0-0800200c9a66&wf_token=29e47310552f9e85e6728a414e5a5d86&wind_speed_floor=30&graph_height=250&graph_width=720&type=line3&fields=wind&format=raw&v=1.1
Dear A. Scott
While I had previously looked at the Weatherflow site, at face value, it looked as if only a limited amount of data was available. Using your detailed instructions I was able to glean the average wind speed data your had previously referred to.
Thank you for your detailed instructions on the use of that site. I stand corrected regarding the nature of the data available at that there.
With respect to the Willis original proposition that Sandy was not a hurricane; or more accurately, did not have wind speeds consistent with a hurricane at landfall. The Weatherflow data, at the Tucker site appears to support that Willis conclusion, I’d come back to this in a second.
However, the Weatherflow “average wind speed”, in my view, has an “issue”. A detailed explanation is in order.
My understanding is the Saffir-Simpson hurricane scale is based on wind speed measurements averaged over a 1-minute period at 10 m (33 ft) above the surface. [Noting, as an aside, that the definition of sustained winds recommended by the World Meteorological Organization (WMO) that of a 10-minute average at a height of 10 m (33 ft)]. (See: http://en.wikipedia.org/wiki/Tropical_cyclone_scales)
The Weatherflow site appears to be reporting “average” wind speeds over a five minute period. Consequently, it is not all that clear the Weatherflow “average wind speeds” can be used as an accurate proxy for gauging the “sustained wind speeds” needed for the Saffir-Simpson scale. And I would be reluctance to use Weatherflow figures – particularly in policy setting – without having had a pretty through discussion with a professional meteorologist.
Consider, for example, the data for the Tucker Site you listed. The average winds at that site reached a maximum five-minute average wind speed of 63.8 MPH (55.4 Knots) in the period from 19:30 to 19:35 hours on 10/29/2012.
By the Weatherflow definition of “average wind speed”, the speed did not reach the 74-95 mph (64-82 kt) level required to classify Sandy as a Class I hurricane on the Saffir-Simpson scale. So, Willis proposition is generally supported by both the buoy data set and the data you presented for the Tucker site.
However, with the Tucker site, I still have the issue of the Weatherflow’s “average wind speed” not being the one minute standard upon which the Saffir-Simpson scale is based… I think you can see why I prefer to use NOAA’s buoy data as a starting point.
Please note that I am assuming the NOAA buoy data is reporting one-minute sustained winds. This may or may not be the case. This assumption would require verification before one could come to a firm conclusion.
Regards, Kforestcat
New York Post: Nov. 2, 2012 9:03 am
About the 14th Street substation / co-gen station explosion.
Kforestcat … NWS uses Weatherflow – and specifically notes this, in some of their advisorys.
tThis advisory s- at 11pm EDT 6 hours after landfall – was still reporting “hurricane force” winds – excerpts here.
And this NWS report at 9pm EDT shows max sustained winds at 80mph w/gusts up to 90mph
I don’t think the NWS is in the habit of making up numbers.
I think the 1, 5 or 10 min averaging is really picking nits – the Weatherflow is more conservative at 5 min than the 1 min averaging, which would makes it easier for gusts to affect the avg speed.
Sandy ceased being called a hurricane as noted several times above, regardless of the data on the storm, regardless of whether it met hurricane numbers or not. NWS dropped hurricane status and began reporting as a “post-tropical” storm at a fixed point and time.
They do not revert back to hurricane status regardless of the storm data once designated “post-tropical” … they DID continue to note “hurricane force winds” in their advisories, until well after landfall.
It could, based on the weather service reported numbers, have been reported as a hurricane at landfall. There are important implications to this.
I suspect the loss of life – now approaching 100 in the US – could have been reduced if this had been more actively reported as a hurricane, but we’ll never know. I do think people had more than adequate warnings about the strength and severity. I do not think, in hindsight, the storm was excessively hyped.
There is another short term benefit to residents by not calling it a hurricane – Gov. Cuomo has issued an edict that homeowners do NOT have to pay the “Hurricane Deductible” on their insurance (1-5% of the insured value) becasue it was not technically listed as a hurricane at landfall.
Sounds like a great deal huh – screw those nasty old insurers … and it will be a big benefit to the current policyholders. But it doesn’t reflect the reality – that this damage was from a hurricane event. The insurers must and will recover those lost funds – which were factored into the rates paid. And as a result the premium will skyrocket even further.
And they will go up more yet as the insurers will now realize that even IF they are hurricanes they will not be called so going forward.
But that’s what was done with Irene last year, and as a result we reaped the unintended consequences of that alarmism this year. I.e., in the aftermath of Irene’s failure to justify Bloomberg’s evacuation orders, portions of the public in NYC & nearby were less likely to obey his orders this year.
Sandy’s damage has been concentrated on the coast, the reverse of Irene’s. Now a different portion of the public has been disillusioned with official and media alarmism–those living in the interior. And both coastal and interior residents will have a general distrust of such forecasts, which got it wrong on twice on what the major threat was. (IIRC, the Frankenstorm was supposedly going to be a high-speed merged hurricane ravaging the interior–that was the main warning until the last couple of days.)
Here’s what I posted on August 29 or 30 last year:
====================
I don’t think we critics of the NHC are implicitly calling for less “alarm” on the part of the public. The public could have been warned repeatedly by the media that a large tropical storm will drop lots of rain, leading to flooding, and that its winds can drop lots of trees, particularly since there’s been no similarly large windstorms for years, meaning that weak, vulnerable trees near power lines haven’t been thinned. There could be an in-depth explanation of why evacuation is a good policy, even if ones home isn’t vulnerable to flooding or tree-fall: because electricity and phone service can be lost for many days, causing a crisis situation in unreachable isolated homes if emergency service (e.g., medical, fire) is needed by them.
There is plenty of time available on the media for this sort of educational material—a fraction of the time they spent on Irene. I suggest the government prepare a half-hour educational video for TV stations–and make it available on the Internet as well. (It should contain hints that local power companies should thin trees near their power lines as routine maintenance.)
But it’s very bad for just-the-facts reporters like the NHC to spin their reporting even slightly in order to produce these desired effects, due to the loss of credibility that can result, not just among the public (the crying-wolf effect) but among people who are suspicious of what the government has to say. It gives them a case-study with which to convince others that official predictions and “facts” aren’t trustworthy, but are mostly propaganda.
I think the NHC put its thumb on the scale just before and after landfall in NC:
Shortly before landfall, it predicted it would occur as a Category 2 storm, when it barely qualified as a Category 1.
Just after landfall, it claimed that hurricane force winds (of 75 MPH, maximum) extended for hundreds of miles, when the number couldn’t have been more than half that.
And it predicted at that time that Irene would still be a hurricane as it progressed far to the north–i.e., to NJ, NY, and NE.
It should have been impartial about reporting such matters, regardless of what it perceived their public impact to be (complacency) and regardless of how much it would have made their previous predictions look bad. In the long run, this would have been the better course. If it wanted to make the case for the public’s Taking Precautions, even against a mere tropical storm, it should have done so in a separate section of its Advisories.
But residents of the interior would differ. To many of them it was a fizzle that was excessively hyped in regards to its effect on their area. So next year they may be more complacent than they should be.
PS: Here are a couple of other posts I made last year:
————-
If politicians want to be responsible and precautionary, they should make sure that electricity providers trim back overhanging limbs and cut down weak trees alongside their power lines in advance of storm season. Failure to do so is what causes the widespread power outages just seen. (In Cleveland, when a new owner took over the power company, it cut back sharply on this routine maintenance, resulting in a sharp increase in outages a few years later.)
Bloomberg News, and other MSM outlets, are emphasizing the large number of outages as a way of implying that their alarmism was justified, and that the storm was a monster. What these outages really indicate is that politicians and regulators were asleep at the switch. Outages shouldn’t be used as a proxy for a storm’s destructiveness.
————
I suggest that the NHC categorize storms on two scales: wind speed and damage potential. The latter would take into account factors like:
* Storm surge potential (is it approaching land rapidly? perpendicularly? at high tide?)
* Tree knock-down and electric outage potential (is the ground saturated? does the storm cover a wide area? is it moving slowly? are the trees in full leaf? have there been few recent big windstorms (to thin weak trees)? have the electric utilities been lackadaisical about trimming branches over their power lines?)
* Flood potential (is the ground saturated? does the storm cover a wide area? is it moving slowly? are the rivers high? are the dams full?)
The public should be warned primarily on the basis of the damage potential estimate, not current wind speed. It could easily be educated into taking this figure more seriously than the hurricane category. (For instance, the public already has been educated to take warnings of “black ice” seriously, even though it isn’t something that can be based on any particular number.)
I suggest that the NFC call it the Threat Index, on a scale of 1 to 5, paralleling hurricane categories. An Index like that would not contaminate the wind speed classification; such contamination will lead to cynicism and disregard of their crying-wolf in the future.
Such dual-mode measurement are already commonly used: i.e., the wind-chill factor and the discomfort index (I’m guessing about the name, but it includes both heat and humidity). The public takes these measurements seriously. A third one is needed for these cyclones.