By Dr. Roy Spencer from his website
Atlantic hurricane activity is notoriously variable, not only from year to year, but decade to decade.
In fact, based upon studies of overwash sediments in coastal lakes stretching from the Florida panhandle to eastern Louisiana, it appears that the period from 1,000 to 3,800 years ago had a considerably higher incidence of Category 4 & 5 hurricanes than in the last 1,000 years. These are admittedly indirect, proxy estimates, but if you read this American Scientist article, it sounds like the researchers have pretty strong evidence.
Why would major hurricane activity vary so much? No one knows. Our climate is a nonlinear dynamical system, capable of undergoing unforced changes both locally and globally. Atmospheric steering currents, wind shear, and African easterly wave activity all play a role in hurricane formation. Tropical Atlantic sea surface temperatures (SSTs) in the late summer are always sufficiently warm to support a major hurricane and are, in my opinion, overrated as a controlling factor. Factors other than SST tend to largely determine hurricane activity and strength.
More direct measurements of hurricane landfalls in Florida have only been possible in the last 120 years or so since prior to 1900 very few people lived there. Before 1900, the intensities of these storms at landfall were quite uncertain. It could be some even went unreported.
If we examine the record of major (Category 3 or greater) hurricanes at landfall in Florida since 1900, and assume that Hurricane Dorian strikes Florida as a 115 kt Category 4 storm, we see that there will still be no long-term trends in either the intensity or number of major landfalling hurricanes. (In fact, both trends are slightly downward, but not significantly so.)
This is not to say there won’t be potentially catastrophic damage. For example, the population of Miami in 1900 was less than 1,700 people. It is now 2.74 million. Needless to say, vast expanses of storm-vulnerable infrastructure has been built over the last 120 years across the Miami-Ft. Lauderdale-West Palm Beach metroplex, and northward along most of the Florida coastline.
But increasing storm damage does not mean increasing storminess.
Friday morning 8:00 am EST. Dorian peak sustained wind speeds currently @ur momisugly 10m are 57 mph. (NOAA)
That is barely a tropical storm. The press is reporting Cat 2 with sustained winds at 124 mph.
Those wind speeds are not being seen at any altitude currently (peak gusts are only at 87mph). What’s going on?
Where are you getting that info?
Keep in mid that even for powerful hurricanes, the strongest winds are in a small core around the eye, and sometimes only in one part of the eye wall.
If there are no buoys near there, how can a measurement be made.
I have no doubt that exaggerations are now routine, but that does not mean that strong hurricanes do not happen, or that an area of powerful winds does not exist.
One reason it is dangerous for the people disseminating data to exaggerate storm intensity, is that when a bad one does hit, people will think they can ride it out. If Michael was a cat 5, well, we see that some houses right on the beach were undamaged.
The whole situation is very aggravating.
It means we do not know what is coming and cannot trust the people doing the reporting.
Adding BS to the uncertainty.
Anywho…central pressure as of 8AM is 972 millibars. This corresponds to Saffir-Simpson Cat 2 96-110 mph, 965-978 mb.
http://4.bp.blogspot.com/-J2cOLewnr6A/TslIDFySuqI/AAAAAAAAAGI/xiU2rlhAe38/s1600/saffir-simpson_scale.jpg
So the official report of 110 mph sustained could be correct and inferred from the barometric pressure.
If it is not measured it is bull crap. Show me a wind speed reading taken near ground level or STFU.
If they are flying into the storm, then they have dropsondes in the eyewall which measure winds all the way to the surface. Since they have a limited number of dropsondes to use, they have to sort of guess where the highest winds might be, based upon where the strongest convection is and SFMR (microwave radiometer) measurements of where there is the most surface foam being generated.
Right back at ya, pal.
So nice to hear from a psychopathic troll.
I am guessing you are not employed in the field of public safety.
We rely on the computer too much, because it is easy, even though it is usually always wrong. The width of the forecast cone shows you the limitations. You can’t model something if you don’t understand the system. Dropsondes are the way, not computer generated crap from high level winds. The hype in this forcast has almost the entire state freaking out.
“The CIMSS Satellite Consensus (SATCON) product blends tropical cyclone intensity estimates derived from multiple objective algorithms to produce an ensemble estimate of intensity for current tropical cyclones worldwide. The algorithm uses individual ADT, CIMSS AMSU, CIMSS SSMIS, CIMSS and CIRA ATMS intensity estimates utilizing a statistically-derived weighting scheme which maximizes/minimizes the strength/weaknesses of each technique to produce a consensus estimate of the current tropical cyclone intensity. The goal of this work is to produce an estimate of intensity that is superior to the individual components. Statistical verification of the method has shown it to be comparable in skill to the Dvorak Technique used by tropical cyclone warnings agencies. In some situations the algorithm can outfperform the Dvorak Technique.
A statistical analysis of each of the member algorithms was used to determine the individual member performance in a variety of TC structures. Each algorithm has strengths and weaknesses that are a function of the algorithm limitations, scanning geometry, instrument resolution or a combination of these factors. For example the ADT algorithm assigns a scene type to each IR image of a TC. ADT performance is strongly dependent on scene type with the best performance for scenes when a clear eye is present and decreased algorithm performance for other scenes. Because of this dependence the ADT is weighted according to scene type.
The microwave sounder algorithms are sensitive to TC core size as compared to the instrument resolution. Eye size information is provided by the CIMSS ARCHER algorithm, the ADT or the warning agency working Best Track in that order of availability. If the TC eye size is small than the sounder FOV resolution a correction is applied. In addition because of the relatively coarse instrument resolution it is possible that the true TC center may not be co-located with the instrument Field of View (FOV) used for the estimate. This source of under-sampling is addressed in AMSU using information from the AMSU-B moisture sounder. Microwave sounder performance is best when the TC eye is sufficiently large compared to the FOV resolution therefore the sounders are weighted according to whether or not the TC inner core is resolved. In the case of the CIRA ATMS algorithm only estimates where the TC eye size is larger than 40 km are used.
Because the ADT estimates are available for every infrared satellite image it is desireable to have matching microwave sounder estimates. To accomplish this the polar orbiting satellite estimates which are available only at irregular times are interpolated to hourly estimates. These interpolated estimates are then combined with the ADT estimates using the weighting approach. CIMSS ATMS estimates are treated as an SSMIS member because the two instruments have similar resolution/performance and this improves the fidelity of the interpolated values. SSMIS and ATMS sounder estimate weights are adjusted based on the age of the estimate using an exponential decay rate. Thus estimates older than 3 hours have decreasing weight which approaches zero once the estimate is older than 6 hours. This is done because there are currently only two sounders available at this resolution.
In order to account for storm structure differences that relate to TC intensity a Pressure-Wind (P-W) relationship-based SATCON estimate is produced. The P-W SATCON Vmax estimate uses the pressure anomaly derived from the SATCON estimate of MSLP and an estimate of the environmental pressure obtained from the warning agency (NHC or JTWC). This estimate is then corrected to account for bias as a function of latitude, storm size (distance to outer closed isobar also obtained from the warning agency), TC eye size (from ARCHER or ADT only), and intensity. The intensity bias correciton primarily adjusts the SATCON Vmax for a known slight too weak bias for the strongest storms. The final SATCON Vmax estimate is 75% of the SATCON Vmax members estimate and 25% of the SATCON P-W estimate.
The goal of SATCON is to produce an estimate of TC intensity that is superior to both the individual members and a simple average of the members. The tables below show the statistical performance of the algorithms for the 2006-2015 period. Validation consists of warning agency best track estimates of Vmax and MSLP during periods when aircraft ground truth was available within three hours of the intensisty estimate.”
http://tropic.ssec.wisc.edu/misc/satcon/info.html
In the last 3 years NOAA always shows all hurricanes 2 cats higher than they really are. For example Dorian is at 90mph right now – category 1. And no land-point in Florida will probably experience even 60mph…
185mph?? Where? When? Pressure 910? I’ve only seen 955.
http://tropic.ssec.wisc.edu/real-time/satcon/201905L_wind_ssmis.gif
http://tropic.ssec.wisc.edu/real-time/satcon/201905L.html
I’ve updated my blog post to include Hurricane Michael (2018), which was previously excluded. My apologies. The conclusions don’t change.
I stay in Clermont, Florida. Ckermont is west of Orlando. I work at a Publix Supermarket in the area. Yesterday we ran out of a truck load of water. Publix had a purchase restriction, 4 gallons or two 24 bottle cases. Once again, we ran out of water YESTERDAY! Talk about people panicking! Today, (day off work) I was doing errands in 2 counties using buses. Late afternoon/early evening, the majority of gas stations we passed were closed. OUT OF GAS! Talk about people panicking!
Correction: gas stations weren’t closed. The gas pumps were closed. Plastic bags over the handles. Clermont, not Ckermont. (second usage in my post).
…not to mention that Publix is HQ’d in nearby Lakeland, right? It isn’t like Clermont is out on the fringe.
I don’t think technically this storm will hit the USA …. ie, at least the center/eye of the storm
Maybe Cape Hatteras …
JPP
Are you willing to bet your life, or the lives of many thousands, possibly millions, or people on that thought?
Do we suddenly have a consensus of modelling stalwarts here on WUWT?
If those spaghetti plots were not showing that storm curving, when would you think just looking at the strength of it and the path?
Dorian is already ignoring the models and the forecast path.
18-23 foot surge in Bahamas. Huge waves on top of that.
It was moving west at 280° most of last night, now west at 275°. Opposite of what it is supposed to be doing.
Staying in front of that storm is like playing a game of chicken but the other driver is a computer.
Cone of uncertainty does not include the path actually taken 1/3 of the time.
Right now edge of that cone is Boca Raton and Coral Springs, curving north to the shore of Lake O.
But that includes a path that is right now moving north by northwest.
4 PM special advisory…almost exactly due west at 7 mph.
“…Are you willing to bet your life, or the lives of many thousands, possibly millions, or people on that thought?…”
Overly dramatic much? He said he didn’t “think” the eye would make landfall in FL. There are watches, warnings, and mandatory evacuations. JPP isn’t cancelling those or telling people to stay at home and relax because there’s no way in hell that there will be a landfall in FL (not to mention that some evacuations are necessary even if it doesn’t make landfall…it will likely be close enough and strong enough to cause significant damage to the east coast with wind, rain, and storm surge).
“…Do we suddenly have a consensus of modelling stalwarts here on WUWT?
If those spaghetti plots were not showing that storm curving, when would you think just looking at the strength of it and the path?…”
The NHC doesn’t just rely on models. I’ll listen to their expertise over, “OMG what if it just kept going straight west and never turned!!!!”
“…Cone of uncertainty does not include the path actually taken 1/3 of the time…”
That’s across the entire 5 days, and it is usually fast-moving storms which leave the cone. Dorian is currently a slug. Dorian hasn’t hit the meteorological features that will send it north. Stop wetting your pants.
After all the HYPE… !
JPP