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How strong was Monica?

By: Dr. Jeff Masters, 4:48 AM GMT on April 25, 2006

Cyclone Monica has come and gone. Fortunately, the storm hit a very sparsely populated area. There no reports of deaths or injuries, and damage was light. Darwin, the capital of the Northern Territory, received just tropical storm-force winds. With Monica's departure, we are left puzzling over an important question--how strong was she? The Navy Research Lab, using a satellite intensity estimation technique called the "Dvorak Technique", rated Monica as the strongest cyclone ever recorded in the Southern Hemisphere, with a central pressure of 879 mb and 180 mph sustained winds. However, the Australian Bureau of Meteorology (BOM) rated Monica a much weaker storm, with a central pressure of 915 mb at that time. Curiously, the BOM give Monica a 905 mb pressure 12 hours earlier, at a time when the Navy Research Lab had her much weaker--892 mb.


Figure 1. Cyclone Monica at peak intensity at 0130 GMT April 24, 2006, the strongest storm in Southern Hemisphere history--180 mph sustatined winds, and a 879 mb pressure. Or was she 915 mb?? Image credit: Navy Research Lab.

So who's right? Well, today I was in the right place to find out! I am attending the American Meteorological Society's 27th annual conference on hurricanes in Monterey, California all week, and I had the opportunity to talk to an Australian hurricane expert. Bruce Harper of Systems Engineering Australia Pty Ltd in Brisbane, Australia, gave a talk titled, "On the importance of reviewing historical tropical cyclone intensities," and I had the opportunity after his talk to ask him about Monica. He told me that hurricane forecasters in eastern Australia, the North Pacific, and Atlantic all use a uniform technique for estimating pressure of tropical cyclones from satellite imagery, but the western Australian forecasters use a different set of equations for that ocean region. These region-specific equations were developed to better model the small and intense cyclones that typically affect the area, such as Tropical Cyclone Tracy of 1974. The equations were not developed with much data from large and intense Category 5 storms, and so the 915 mb pressure estimate for Monica is suspect.

In reality, we will never know just how strong Monica was. There are no hurricane hunter airplanes anywhere but the Atlantic. Satellite estimation techniques are getting better each year, but are still subject to large errors. Scientists who are researching the link between hurricanes and global warming are free to use either intensity estimate for Monica's lowest pressure. This underscores the difficulty of assigning much credence to the reported 80% increase in Category 4 and 5 hurricanes globally since 1970 reported by Peter Webster and Greg Holland last year in their controversial article in Science. While I do believe there has been some increase in these storms, the estimation of maximum cyclone intensities is so fraught with uncertainties that I do not believe a reliable estimate of how significant this increase can be done until a full re-analysis of all historical tropical cyclones is completed. Even then, I think we need at least another ten years of data, since our data set covers such a short period of time.

Jeff Masters

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Dr. Masters: I noticed that the maximum wind gusts given by JTWC (190 kts) and Australia (350 kmph) are the same when converted - 220 mph. Does this mean that Australia was just using a different wind-pressure relationship (155 kts would give a pressure of 906 mb in the Atlantic but 879 elsewhere; Link)?
Also, I wonder how accurate the T8.0/170 kt/868 mb reading from CIMSS was?
Dr. Masters,
Thanks for explaining the various techniques for estimating tropical cyclone intensity in that part of the world. I was getting confused for a while. Like you say, we need more data from that area before we can come to a conclusion about an increase in intensity of tropical cyclones there.
The Royal Australian Air Force has plenty of money for a hurricane hunter aircraft if they want one:

Well........
another cat 5 storm for the global statistics.
Sure seems to me they are on the rise!!!!!!!!!!!!
Without the atmospheric measurements taken by aircraft within a tropical cyclone I suspect it would be nearly impossible to come up with a valid formula to estimate intensity from just satellite photos. How would you know if you got it right?
Dr. Masters:
Do you know how the Dvorak Intensity values were developed? What actual wind and pressure measurements were used during the development?


Is the difference between the Atlantic and Pacific pressure to wind values based on average or "normal" surface pressures for the areas or is there more to it than that?
So why can't they buy 2 or 3 hurricane hunters C-130's or whatever it is they're using now to fly in? It seems that they're getting hit by several Cat 2-3 storms routinely, and it would be a great investment into their force. Then they would have the same advantage we do, along with a couple of nice research planes for the off season.
Ya tey take stattelite information like its fact,that is why it is called "estimation",now matter how hard you try to make a computer it will never be good enough to be accurate enough to take it as fact when it comes to weather.
Without a doubt, a full global-scale reanalysis of modern and historical hurricanes is needed to better understand their natural variability. In some areas, such as the North Atlantic Basin and Northwest Pacific Basin, there are enough documentary records to reconstruct hurricanes back into the early 19th and 18th Centuries. One problem is that many scientists/researchers do not want to spend the time needed to go through archives and reading logbooks to reconstruct past hurricanes. They would rather rely on the short record of the past 40-50 years, which as Dr. Masters stated, is too short for reliable trend assessment.
There is currently a reanalysis program underway for the North Atlantic.

HURDAT Reanalysis Link
And of course these storms (especially the REALLY BIG ONES) become so dynamic in their characteristics that moment to moment changes are being made in size, shape, structure, pressure, etc, etc. "Measuring" becomes quite the fluid exercise...Add to that everyone seems to have their own rubric and the situation is NORMAL--confused. I always think about those who lived hundreds of years ago and they didn't have a clue as to weather conditions in the next county much less on the other side of the globe...and yet they seemed to survive quite nicely in spite of their ignorance. Maybe we are not so smart afterall.
EVERYONE,

The reason that other countries dont have hurricane hunters is BECAUSE THEY DONT WANT THEM. They feel that Sat estimates are reasonable enough to tell them if they are dealing with a strong storm or not, which Sat estimates are. They dont want to spend the money maintaining the planes, paying the pilots, and all the other costs the come with running a hurricane hunter fleet.
Oceanwx2 - this shows you what the Dvorak numbers mean and the wind/pressure values.
MichaelSTL - I know about the scale but was wondering how it was constructed. What data was used since for most area's of the world there would be very few direct measurments of central pressure and wind. In the Atlantic, at least, we have numerous recon flight data to use.
I know that they used to do flights into West Pacific typhoons; they assume that other parts of the world have the same relationships as the West Pacific, except for the East Pacific and Atlantic, which have their own pressure/wind values. I don't know if they ever actually measured the pressure of storms in the Indian Ocean or South Pacific, but it would seem that the W Pacific values can't apply everywhere with great accuracy.
Ah, it is good to be back in Italy again after a year in Afghanistan... It seems to me that this Cat 5 in the land down under can only serve as a harbinger of bad news for the Gulf coast region, just more proof that the days of minimal hurricanes at minimal intensity are about over. But I could be wrong, and probably am.
What would cause there to be a difference in the way storms are measured, Atlantic vs. Pacific? Is the air different in one or the other, is the water not still just H2O?
KansasSoldier: I'm glad you are back in Italy, too...Welcome "home" and thanks for your service...A VN vet
The difference is in ambient pressure, but that does not make much sense; if you look at this chart, you can see that a 35 kt tropical storm in the W. Pacific would have a pressure that is 8 mb lower than the Atlantic and a 170 kt Category 5 (the top of the scale) would have a pressure that is 32 mb lower, which does not make sense (I would expect the scales to be linear).
gcain: It was an Honor, and thank you, sir, for your service.
MichaelSTL, I have to agree, and since the storms that develop in those environments are "native" wouldn't that mean that a 170kt storm, even with the lower pressure would still be just a 170kt storm 32mb lower in the pacific? When looking at storms vs. storms from other regions, we should maybe just look at the wind speeds. It would be alot less confusing.
The thing that does not make much sense is that the difference in pressure is not constant; I would expect the West Pacific to have a presure of 882 mb for 170 kts, not 858 mb if a minimal tropical storm has a pressure that is 8 mb lower in the West Pacific. By the way, this chart suggests that Atlantic storms are more powerful than those in other parts of the world because the lowest pressure of 890 mb in the Atlantic cooresponds to 858 mb in the West Pacific and the most intense storm on record in the West Pacific (and the world) had a pressure of 870 mb, which would be about 895 mb in the Atlantic - this actually suggests that Rita was as powerful as Tip was (the fact that Tip had 190 mph winds and Rita had 180 mph winds does not mean much as I doubt that Tip's is accurate, given that accurate readings have been available for only 10 years or so in the Atlantic)!
I agree STL, and I wonder if the pressure there in the Western Pacific is normaly lower on a daily basis than it is in the Atlantic region. And if it is, then I wonder what causes that, and if we can really say that it would have any effect on overall storm intensity.
I FULLY AND FIRMLY DISAGREE WITH THE IDEA THAT THIS IS CYCLICAL. 7 CATAGORY 5 STORMS IN A 10 MONTH PERIOD HAS NOTHING TO DO WITH A CYCLE AND EVERY THING TO DO WITH THE GREENHOUSE EFFECT. OIL AT $80 BY FRIDAY THE 28TH AND HUMANS STILL CAN'T GET ENOUGH. IF DR JEFF MASTERS OR ANY OTHER SCIENTIST CAN WITH A STRAIGHT FACE TELL US THAT HUMANS AND THE WORLD WIDE INDUSTRIAL REVOLUTION HAVE NOT HAD AN ADDITIVE EFFECT TO THE GREENHOUSE GASSES THAN I AM READY TO LISTEN. BUT THEY CAN'T. MAYBE 7 MORE CAT 5'S IN THE NEXT 10 MONTHS WILL PEEL BACK SOME MORE EYELIDS. I JUST HOPE AND PRAY IT DOES NOT TAKE ANOTHER KATRINA.
The WPAC has lower ambient pressures then the Atlantic, and no the scale is not linear. It has to do with both the inward force of air (linear with pressure diffs), with friction (proportional to windspeed), and with water/air temperatures (it takes less 32C water to run a storm than it does 30C, so less inflow of air is required).
53rd, the all-caps really isn't nessessary.

Oil at $80? Not likely, stop listening to Ted Kennedy.
And how would your tunnels help Australia? No currents=useless. Logic, cyclone, logic. *flags as spam*
true, $80 not likely, but not impossible.
I don't really like caps; I often use Microsoft Word to convert forecast discussions, etc to sentence case before putting them into my blog because it is harder to read and appears to be shouting.
Friday April 28th is the UN deadline on IRAN to stop there pursuit of NUCLEAR technology. $80 PER BARREL WRITE IT DOWN...
Cyclonebuster - stop your obscene/spam posts - you are the one with the problem, as anybody can tell you. Why can't you talk about something tht is viable - your tunnels have no proof that they work (except for your "formulas").
Was Hurricane Tip flown into ? How did they get accurate readings from 1974?
Now children, can't we all just get along?
cyclonebuster,

Please stop talking about tunnels. Even IF we believed that you had enough evidence to prove that they would work, and wanted to have them built, not one of us could get them built.
I have flagged all posts that have foul language in them as obscene; hopefully, they will be removed.
Posted By: StLucieHurricane at 1:57 PM EDT on April 25, 2006.
Was Hurricane Tip flown into ? How did they get accurate readings from 1974?

This is from Wikipedia's page on Typhoon Tip.

With a minimum central pressure of 870 mbar (hPa), Tip is also the most intense tropical cyclone ever recorded in any basin and holds the record for lowest pressure ever recorded at Earth's surface. Note, however, that since the 1990s, hurricane hunter flights are no longer made into Pacific typhoons, and storm intensity is now estimated from satellite imagery.
Many here are wondering why AU doesn't have hurricane hunters. The simple answer is they dont need them. The US gulf and east coasts do need accurate landfall perdictions of hurricanes.

Why?

Darwin and the Northern Territory only hold 1% of the entire AU population. Darwin itsself is only 120,000 people. Evacuations, even on minimal roads, are not the huge messes they are in the states.

12.1 million live in metropolitan areas on the Gulf coast. I dont have stats for the Eastern Seaboard. A million people can't move on a dime. As we saw last year with both Katrina and Rita. Evacuate New Orleans and you run out of road to put cars on. Evacuate Houston and you run out of fuel and busses explode on the interstate killing elderly people.

The US is justified in there hurricane expenses because a few mile change in track can mean the difference between a city being destroyed or not. In NWT of Austrila there are few centers of population density to worry about.
so what going on in her
I did a search and found that the errors in using the Dvorak technique in comparison to aircraft measurements taken in the NW Pacific averaged 10 mb with a standard deviation of 9 mb (Martin and Gray 1993).

Source Chris Landsea:Link
What tunnels are you all refering to?? I'm curious to hear this idea.
Here are my thoughts on the link between Global Warming and Atlantic Hurricanes: There isn't one.

It's impossible. Global Warming would be like an El Nino on a global scale. Wouldn't that mean that wind shear would increase in the Atlantic, DECREASING the number of storms, let alone intense hurricanes? The wind shear would rip them apart!

Global warming can't have any connection with 2005. Yes, I know there is a La Nina right now, but that is a COOLING of the Pacific that decreases the wind shear in the Atlantic. Last year was neutral, then a La Nina!

You guys are talking about Global Warming, not Atlantic Warming, right?
The Royal Autralian Air Force has several Lockheed P-3 Orion aircraft based at RAAF Edinburg, which they easily could convert to hurricane duty if they wanted to. These aircraft are used for marine patrol, like submarine hunting.

Do me a favor and cut the bickering.

louastu has a good point. The tunnels topic is probably spent, and any further discussion of it is going to be spammed.

cyclonebuster, if you want to talk more about the tunnels, the best place will be your own blog. Thanks.
WunderYakuza nic to see you pop in by the way mail for you
Hot from CNN...

More warming to come
Whatever the cause, computer projections indicate the warming to date -- about one degree Fahrenheit (half a degree Celsius) in tropical water -- is "the tip of the iceberg" and the water will warm three to four times as much in the next century, said Thomas Knutson, explaining projections from the National Oceanic and Atmospheric Administration's Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey.

Adam Lea, a postdoctoral student at Britain's University College London in Dorking, Surrey, presented research based on British, German, Russian and Canadian studies that concludes half of the increased hurricane activity in the tropics could be attributed to global warming.

Holland, director of the Mesoscale and Microscale Meteorology Division of the federal research center, said tropical storm anomalies in the 1940s and 1950s can be explained by natural variability.

But he said carbon dioxide started changing traceable patterns in the 1970s and by the early 1990s, the atmospheric results were affecting the storm numbers and intensities.

"What we're seeing right now in global climate temperature is a signature of climate change," said Holland, a native of Australia. "The large bulk of the scientific community say what we are seeing now is linked directly to greenhouse gases."

Hurricane Katrina, which tore onto the Louisiana and Mississippi coasts on August 29, was the deadliest Atlantic hurricane in 77 years and the costliest ever, with property damages estimated at $75 billion.

This year, the weather service's Tropical Prediction Center expects more hurricanes than usual, but not as many as last year's record 14.

The complete story here: http://edition.cnn.com/2006/TECH/science/04/25/global.warming.hurricanes.reut/index.html


Hurricane Katrina, which tore onto the Louisiana and Mississippi coasts on August 29, was the deadliest Atlantic hurricane in 77 years and the costliest ever, with property damages estimated at $75 billion.

I think they forgot Hurricane Mitch; it should say "the deadliest U.S. hurricane in 77 years".

Also, there were 15, not 14 hurricanes last year.
hear, hear ..
In my view the global warming due to increased levels of greenhouse gas emissions is contributing to the increased intensity of tropical storms around the world. It is in my view no coincidence that we are seeing one record-setting superstorm after another (Monica being the latest example).

Had a good discussion of this with atmosweather last night, who felt that quite possibly the increased storm intensities are maybe linked to observations that the upper atmosphere is cooler than normal and the lower atmosphere is warmer than normal.

This is exactly what is expected due to global warming! Put simply - the greenhouse gases keep the sun's heat down in the lower atmosphere (which warms), and thus less of that heat is radiated back out to space through the upper atmosphere (which cools).
If this process is contributing to the observed increased storm intensities, then look out because this process will magnify significantly with each passing year (as we continue to throw up vast amounts of greenhouse gases).
Although I understand the reasons for not having a Hurricane Hunter, isn't learning more about tropical cyclones nothing but a good thing?
I'll say one thing, we already have year long tornado seasons as we have tornadoes every month of year whether it's now or if it was 50 years ago.
Here is a good link regarding the
Objective Dvorak Technique (ODT)
I agree that we do need more data before making big conclusions.
This is interesting: it says that Opal had a pinhole eye as small as 8 km (5 miles) in diameter; this means that they must be more common (not just Wilma, Beta, and Gilbert).
I also saw this sentence:

However, as characterized in many other storms investigated in this study, they generally underestimate the strength of the storm.

Does this apply to Monica? - Imagine if the Dvorak scale went past 8.0!
Monica didn't have a pinhole eye and one estimate placed her as the world's most intense storm, and I think that Wilma was only 6.5 at the highest. Actually, Dvorak estimates will almost never get the intensity of a Wilma-like storm right because the eye cannot be resolved enough for an accurate measurement to be made (maybe we need higher resolution satellites).
Yeah Michael, the CIMSS Dvorak estimates rise considerabky when the eye is clear with no clouds in it. Because Wilma's eye pushed the resolution too far, they thought that she had an incredible CDO but a cloud filled eye that was obscured. If they had a lower resolution, I think Wilma would have exceeded 8.0 by a long way, possibly making it to 8.7-8.9 because of her amazingly cold eyewall temperature and pinhole eye.

For all of you who haven't checked this site out yet...

http://www.ultimatechase.com/Hurricane_Video.htm
Link

Hopefully, this will provide you with a direct link...some good examples of what a hurricane is capable of doing...
Jeff, did you see Greg Holland's presentation on the increase in hurricanes in 2005?

Any idea of whether increased water vapor, which is a greenhouse gas, also contributes to the latent heat which powers hurricanes? Could this be another factor to consider?
I live on the gulf coast. Should I move now??
LOL FUMBLE. I would wait until the market slows down and then sell :)
Sigh I hope this isnt a preview of what we can expect for the Alantic Hurricane season.

Storms that pinhole dring their building stages, like Wilma most famously did, represent a special case. Such storms are typically evolving rapidly, and I find myself wondering whether the usual formulae relating pressure, flight-level winds, surface winds, and other such parameters are even valid in such cases, as they were calibrated with storms with larger eyes and in a more stable, slowly changing state (think Katrina, Rita, or Monica near peak intensity). Are we comparing apples and oranges?
Question about the coral. Pretty astonishing.

How good of track did we keep of coral before now? I'm wondering what the coral looked like after the last AMO cycle we had in the 1960s and if that as well killed of coral. Or is it the warming or the waters due to global warming that is the sole contributer to the killing of this specied?

Educate yourself on global warming and Educate your friends.

GIANTS IN 06
86. Inyo
nah, the planet will be fine. some extinctions will occur, and the animals that suffer the greatest losses will be those highest on the food chain, such as humans. The roaches, coyotes, and rabbits will continue to run around.

That doesnt mean we should cause anthropomorphic greenhouse warming or other forms of pollution. It just means we can't 'kill the earth'
I love this view presented by CNN.com on their homepage as: "2005 hurricanes linked to global warming"

http://www.cnn.com/2006/TECH/science/04/25/global.warming.hurricanes.reut/index.html

Wow... no real mention of the AMO or anything else, it panders to the agenda of the website as we can very well tell by reading the article. You have to love it.

-Ryan
Gotta love the media. They'll do anything to get themselves attention.

Also, if people are just now pandering the agenda of the major media angencies, then what have you been watching and reading? I haven't watched CNN, FOXNEWS, or MSNBC, or any of those in years because all they do is spout non-sense. They never have thier facts straight and always use a quick one liner for a story that makes the story itself seem absolutly abhorable. Then you realize that what the news agency meant by "WOMAN EATS KIDS" is that she ate goat kids(kid is the proper name for a goat baby)

Ok, so done with my rant about the media. There new story about the Global Warming link to the 2005 season is not surprising at all.
Hello everyone.

First time commenter but long time reader. This is a very educational site and one that I visit every day, especially living here in SW LA.

We are understandably a little nervous about the upcoming hurricane season given that many here are still repairing their properties from Rita.

I guess that I sense a bit of global warming frenzy/panic in many of the comments. I believe we are a bit early to make any finite conclusions other than to offer simple opinion. I will agree that the last few years have been extraordinary, especially 2005. Nevertheless, the good earth does tend to have a mind of her own and this isn't the first period of weather phenomena that illustrates her moodiness. It is only the latest and, unfortunately, it comes when the hot topic of debate is global warming and when we have a great deal more media coverage and hype.

As for me, I'll continue to ride the fence(at least the section I have left after last September) and hold my pro/con warming opinion while more data is acquired to truly support any of my future rhetoric.

Thanks for the opportunity to participate.
I would agree that "we can't kill the earth..." but we can alter the enviornment enough decrease our comfort level...For example, gas prices, insurance rates, building costs, immigration, food availability, etc. are all things that take resources out of our collective pocket. The supply of money is not limitless and each time of these factors cost us more, the money must come out of some other place...sooner or later life styles begin to erode. The erosion may not be as dramatic as "Final Days" or "Earthquake" or even "Storm Stories" but the standard of living for our children or grandchildren may be less because of what we do or don't do now...Is that the legacy that our generation wants..."They could have done something, but elected to do nothing because there was no absolute proof." That makes me uncomfortable.
I have 4 questions. Thanks in advance for the answer.

How many hurricane does Australia average in a year?

How many hurricanes does the US average in a year?

What was the ratio of Atlantic catagory 4-5 hurricanes to the number of hurricanes this year?

What was the ratio of Australian catagory 4-5 hurricanes to the number of hurricanes this year?

Thanks
Patrick
What was the ratio of Atlantic catagory 4-5 hurricanes to the number of hurricanes this year?

The answer to this is 1:3 - 5 Category 4-5s and 15 hurricanes. More significant is the fact that there were four Category 5s and the average is only .3 - one every 3 or 4 years - which means that last year had thirteen times the normal number of Category 5 hurricanes!.
Check out the SST loop...really boiling now.
Hurricane Katrina, which tore onto the Louisiana and Mississippi coasts on August 29, was the deadliest Atlantic hurricane in 77 years and the costliest ever, with property damages estimated at $75 billion.

I think they forgot Hurricane Mitch; it should say "the deadliest U.S. hurricane in 77 years".


Your definatly right. Sadly, there's a storm in the Atlantic that kills more than Katrina ever 2 or 3 years it seems.


And it was mentioned above, but that doesn't look like a 879mb storm.

Another thing, I looked at some of the tracking maps from the 1880's and 1890's, and it seemed like alot of the storms were Cape Verde storms. Not many in the Caribbiean.
Randyman wrote:
"Hopefully, this will provide you with a direct link...some good examples of what a hurricane is capable of doing..."


Yeah...that's a cool site...I have that video of Charley dismantling a gas station in Port Charlotte...160+ MPH winds...awesome!
Colby could you post a link to the SST loop you are reffering too?
It is no surprise that hurricane winds can do that kind of damage; after all, the Enhanced Fujita Scale greatly reduces the winds in tornadoes (F5 is 200 mph instead of 300+ mph), and they are measured by gusts.
Heres a link to the SSTs:

http://polar.ncep.noaa.gov/ofs/aofs_3d_images/aofs_sst_nowcast_hurr.png

Image comparing 2006 SST to average:

http://www.bom.gov.au/bmrc/ocean/results/SST_anals/SSTA_NOW.gif



Nice satellite image of Monica:

http://polar.ncep.noaa.gov/ofs/aofs_3d_images/aofs_sst_nowcast_hurr.png
Trouper I have that SST site already but thank you. I was asking which SST loop Colby was referring to.
I noticed that the water is approaching 90 degrees in some areas (see the "Maximum" in the lower-left corner on this map).
Quick question all. In looking at this at the 72 hr frame, I notice blue shadings on the map near Oklahoma. I don't think I have ever seen blue on this map. What does it mean?
Michael the maximum says 30.40 degrees Celsius. That is only just over 86 degrees F.
The blue shade indicates high vorticity; given that a large severe weather outbreak is expected in several days, it is probably from a strong low or the jetstream.
sayhuh that blue represents the strong positive vorticity balancing the strong negative area of vorticity to its west.
30.4 C is more like 87 degrees F (86.72 to be exact). It is approaching 90 degrees and will be 90 degrees (and more) in a couple weeks or so. I wonder if it ever has reached 100 degrees/38 C?
Levi...I will have to research what that actually means..but thank you. I am curious to why I never saw that when looking at canes..seems the vorticity would be enough to create a negative void?
sayhuh I am not sure but I think that hurricanes don't create a negative void because they are not baraclonic storms. They don't run on the same dynamics and they are uniform, that is, there is the most vorticity in the center of the storm and it doesn't need a negative to balance.
So its safe to say that since this is the first I have seen the blue..that the vorticity in this frame is likely stronger than I have seen in the past, or is it due to the proximity of the other vorticity nearby causing a sinking effect?
There are subtropical depressions and subtropical storms. Are subtropical hurricanes possible? If not, why not? If so, have there been any?

I have seen a couple mentions of someone accidentally reporting as spam etc. Clicking on spam etc. should give an option of cancelling or going ahead with the report to avoid this problem.
I wonder what the SSTs were like during the dust bowls when temps as far north as North Dakota were 120 degrees at their peak.

GIANTS IN 06
SSTs during the Dust Bowl were probably not higher than they are now; you cannot validly compare land to water, especially not very dry land (low humidity allows air to get a lot hotter; that is why 120+ in Death Valley is common, and you will never see 120 with 100% humidity).
gippig you can visit the developer's blog and tell Aaron your suggestion on the reporting problem. He is the one that makes changes and upgrades on this site.
Primez sez: "Here are my thoughts on the link between Global Warming and Atlantic Hurricanes: There isn't one.

It's impossible. Global Warming would be like an El Nino on a global scale. Wouldn't that mean that wind shear would increase in the Atlantic, DECREASING the number of storms, let alone intense hurricanes? The wind shear would rip them apart!"

Absolute temps and pressures don't make wind, relative temps and pressures make wind. Same with ocean currents. Its the differences between two places that drives mass.

Pressure differences and temperature differences go towards larger numbers as energy increases in a system.

We don't know what a Carribean or Gulf weather pattern will look like when its 5 degrees warmer in the water. They could set up a semi-permanent high. They could set up a greater variability in highs and lows, making stronger winds and stronger "regular" storms. The could shift around based on what land and water around them does, or whether big polar masses penetrate further south (again because the difference between high and low pressure systems is greater).

You can bet that the effects of global warming will first be seen at the extremes of our climates and weather, because changes at the bounds of systems are almost always the most visible. You can see that now in the loss of cold habitats, and the growth of hot habitats, the deeper penetrations of artic air south, the reciprocal penetrations of warm air into the articm, and the stronger storms.

Global warming naysayers remind me of Bagdad Bob. I imagine them hunkering in their home with 160 mph winds ripping the roof off screaming above the storm "There is no evidence this storm is any stronger than storms 40 years ago! This is a lie perpetrated by fatcat meteorologists trying to dig up more taxpayer money!"
Global warming is also said to decrease shear in the South Atlantic, possibly creating a new "hurricane alley" (where Catarina formed).
Some comments about the latest SST anomalies:

-The Sargasso Sea is still cooler than normal. If this trend continues, it could be unexpected good news for the East Coast. Oddly, a thin ribbon of inshore water from about Jacksonville to the Chesapeake is much cooler than normal. More good news?

-Unless I misinterpret what I see, reports of La Niña's demise may be exaggerated. The area of cold water off equatorial South America seems to be expanding westward, if anything.

-The Caribbean is only slightly above normal, so far.

-The Gulf of Mexico has some real hot spots up by the coast, but most of the rest of it looks only slightly above normal.

I don't know how to find last year's map for comparison purposes.
Gippig, probably the closest thing to a subhurricane (that's what I'd call them) would be a warm-cored blizzard. It happens sometimes when they move NE over the Gulf Stream, though it's usually brief.

Epsilon wasn't really totally tropical, nor was Vince, so you might consider them subhurricanes.
Snowfire here is the SST Anomaly and archives back to 1996. Link
Hmm - Sargasso Sea way colder, rest of atl similar, Gulf on FIRE...
Wow we just had a very nice Thunderstorm pass over the area. I didnt get pictures but it was very nice. Several Cloud to groud lightning strikes. I live in Whittier, CA

Scattered thunderstorms...some with brief heavy rain and possible small hail...will affect the Los Angeles County coast...and the San Fernando and San Gabriel valleys through 900 PM. As of 700 PM...Doppler weather radars indicated a thunderstorm near Burbank...and another one near Whittier. These thunderstorms were moving west at 30 mph. Additional showers and thunderstorms are possible through early this evening.
Is the appearance of a tropical cyclone in the North Indian Ocean in April unusual? Is this the 2nd tropical cyclone of the season in that basin? Thanks for any info.
No, April storms in the North Indian are not unusual; in fact, a storm in 1991 that formed at almost the same time (it also had the same number, 2B) was one of the deadliest storms in history.

1991 Bangladesh Cyclone
125. RL3AO
wow, 138,000 dead...
Regarding global warming:
The earth has been warming, more or less, since the end of the last ice age ~10,000 years ago. It is difficult to prove that the arctic melting, earlier springtimes, etc. are anthropegenic. Also, because there is naturally large variability in weather from year to year, the relatively small increases in average temperature (1 degree F)are hard to definitively link to human-induced climate change.
I think the data show the RATE of warming has increased and global, not local, averages appear to be rising. I am personally confident that we are very significantly altering climate and my 5-year-old twins will suffer severe consequences throughout their lifetimes, worsened by slow reaction to a long-awaited threat. I am also confident that some portions of the ecosystem will thrive and that people will use technology to adapt, but not without perhaps significant problems.
I don't know windsurfer. I have spent the week in Madison, WI and, for the end of April, its awfully chilly. It was 31 degrees last night! As for your twins (may God bless them both), what severe consequences do you think they will be facing? Who's to say they will suffer from this. No one knows what these "changes", if that's what they are, will change things for the worse. I also think that we tend to look at our little part of the world and disregard the other parts of the world that have seen incredible cold this past winter. Of course, with that comment comes everyone out of the woodwork to say that the Earth has seen a 1 degree temperature change! WOW! A whole degree. Why do we think that is such a big deal? The hurricanes?...cyclic. And we are in the active cycle. Hmmm...it seems to me that our hurricane count WOULD go up if we're in the active phase.
Are we having an effect on the environment? You betcha we are. Is it going to "ruin" our world?...I don't think so. Hey, who to say these changes...if they ever Do come...won't result in great technological advances....or new species, since all the doomsayers have significant species dying off. Significant species have been dying off since this world began. And new species have always taken their place. Cycles...its what this Earth is all about.

Rule #1 - The Lord giveth...and the Lord taketh away.

Rule #2 - WE are not going to change rule #1.

129. Inyo
Lightning10, when i was driving home from work on the 210 around La Canada Flintridge i saw one massive lightning bold splatter across the sky and apparently hit the ground a few miles in front of me. I didn't see any other lightning, although it did rain a bit.. big drops, wouldnt be surprised if someone got hail. Perhaps we will get more tonight but it doesnt look immediate.
2006APR24 003300 8.0 868.5/ +10.5 /170.0 8.0 8.0 8.0 8.0 NO LIMIT OFF 9.75 -80.54 EYE/C 20 IR -11.46 -135.07 COMBO
Monica was stronger than Tip