by Steve Goddard
The Atlantic Hurricane Basin remains dead quiet, and is now falling below the 1944-2005 average.
http://www.weatherstreet.com/hurricane/2010/Hurricane-Atlantic-2010.htm
I have not spent a lot of time studying hurricanes, but I have read that the “purpose” of hurricanes is to move heat quickly from the tropics to higher latitudes. Heat flow is always driven by differences in temperature. If two places were at the same temperature, there would be no heat flow.
Suppose that temperatures at higher latitudes (60N) were very warm – as they have been. What motivation would there be for hurricanes to form? The video and stil below shows UNISYS SST anomalies, with all anomalies between -1.0°C and +1.0°C removed.
Note that the Atlantic hurricane basin has very few places which are warmer than 1.0°C above normal. This agrees with Bob Tisdale’s graph.
By contrast, SST anomalies in the North Atlantic are far above normal. The difference in temperature between the tropical and north Atlantic is far below normal. Supposedly, it is that difference which gives hurricanes their raison d’être .
Things can change quickly. 1950 was the second most active hurricane season on record, and the first hurricane didn’t form until August 12.
Does it make sense that the heat engine which drives hurricane formation is basically shut down? What do you think?
Just a couple of weeks ago on July 29, Phoenix had a dew point temp of 75.2. Their highest was 79 back in 1957. I don’t care if the temperature was only 90, a dew point in the 70s is ugly. This is rather irrelevant to this post however, but, it looks as if TD #5 may become the fourth named storm once it gets back out over the Gulf again tomorrow.
Would anyone care to comment on the low pressure just off the coast of Alabama which is now judged at 50% of becoming a TD or greater?
They say it’s a remnant of TD5 which died off the evening of Aug 11 around 150 miles due south of Pensacola and which NOAA, as of 8PM EDT, says is located over the central panhandle. and moving south.
1. It seems to me it’s further west than that, but no matter.
2. It’s appears to be both strengthening and getting more organized, very quickly.
3. This TD5, IMO, inexpert though it is, originated/came out of the eastern US as a part of the rather long running clockwise flow that doubles back further south, most of the portions of which sweep SW and have been blowing the Gulf and Caribbean clean of any Cape Verde origin stuff.
4. The thing is that that long running pattern I mentioned in 3, above had been very oblong longitudinally running from west of Texas to, oh, just short of Bermuda, and this has tightened into a lot more of a circular pattern.
Anyway, any thoughts?
As others have mentioned it looks like upper level shear has a large effect on whether the thunderstorm activity can organize into a tropical storm or hurricane.
On another note, why to we not see equivalent activity in the South Atlantic?
The South Atlantic is (almost always) not warm enough to sustain development. 2004 was an exception.
http://www.hurricaneville.com/brazilian_hurricane.html
Dusty says:
August 15, 2010 at 5:24 pm
Reply;
Bonnie, td3, and now td4 have all been squall lines at best, hundreds of mile East of the real center of atmospheric circulation, in what would like to be the outer rain bands of a real hurricane.
Both td3 and td4 had their area of origination as a result of the continental outflows coming off of the Eastern seaboard, then after clearing most of Florida, they attempted to name them. I don’t see where they get off on calling these little disturbances as “Tropical storms”
With td5 the building effects seen are due to the secondary tidal effects as the moon goes toward maximum South declination on the 19th August 2010, at which time it will collapse completely, like the others. All three of these attempted named areas of precipitation show up in the forecast maps on my site. (see name link above)
Stifling dew points?
http://www.intelliweather.net/imagery/intelliweather/dewpt_nat_640x480.jpg
I guess it’s all relative to what one is used to.
BarryW says:
August 15, 2010 at 6:31 pm
On another note, why to we not see equivalent activity in the South Atlantic?
Interesting question! It might be that the ocean surface is warmer in the North Atlantic.
http://en.wikipedia.org/wiki/Thermohaline_circulation
Notice how the surface circulation is south-to-north in the Atlantic. So, in the South Atlantic, the surface current has just been around the Cape of Good Hope but in the North Atlantic, the surface current has just been across the equator.
This is just a guess but it makes sense.
Tom in Florida…
It looks as if the legend on that map belongs on a relative humidity map. Saturation has nothing to do with dew point. However, you are right to a degree. It does depend a lot on what you are used to. In Phoenix, average summertime dew points are in the 40s and 50s. Also, I know several people who live in Florida full time and they all describe summer there as “stifling” when temps are in the 90s and dew points in the 70s.
I wish I had kept notes, but a couple of times already this season, depressions that the NHC gave probabilities of 40%+ of developing into a TS not only failed to strengthen, but fizzled out into remnant lows while still over water (“while still over water” is the interesting thing). I started following the NHC off and on several years prior to Katrina, and much more closely thereafter. I just don’t remember that happening before.
I’ve also notice that the discussions now contain little or no description of what the various models are projecting – just a single, summarized prediction that attempts to merge the differing model projections. Makes the discussions, er, dry.
There’s has been, and still is, a large area of Saharan dust over the tropical Atlantic. Reading between the lines on the NHC indicates this dry air just snuffs out storm development. I know zilch about normal conditions (wind, rain, etc) of Africa. Does anyone know if this is a typical condition for this time of year?
Tom In Florida
The highest dew points on your map are 70 degrees. I lived in Houston for a long time, and 70 degree dew points are not pleasant.
jtom says:
August 15, 2010 at 7:57 pm
Reply;
If you want a more open detailed discussion of the total process here is a link to a board where hundreds of pro mets and amateurs from across the country participate in the gory details with their own learned opinions included.
http://www.storm2k.org/wx/
you might need to sign up to post questions…I have been lurking there for most of a year….
What’s the connection between the pleasantness of dew points and hurricane formation?
Frederick Michael says:
August 15, 2010 at 8:51 pm
“What’s the connection between the pleasantness of dew points and hurricane formation?”
Reply;
long term contributors to WUWT babysitting me to make sure “my pseudo-science here to fore unproven conjectures” don’t tarnish the site’s pure science reputation. I thank them for their concerns, and applaud their efforts, I am old enough to stand or fall on my own.
Advances in science come from the fringes, not from the center of the mainstream, but so do the classic flops, and scams, and are due watching carefully.
I have stated the complete detailed forecast for the rest of 2010 hurricane season, in the face of “nobody else can do it, so it can’t be done” gatekeepers who have been shutting out “Lunar”, “planetary”, and “Moon” studies from NSF or any other form of grant funding since they started the peer review process, and pushed for models instead of cycles study in the mid 1950’s, 30 years before they thought about AGW.
So here I am playing Russian roulette with hurricanes, and they don’t want anybody else here to get shot.
stevengoddard says:{August 15, 2010 at 8:20 pm}
“Tom In Florida
The highest dew points on your map are 70 degrees. I lived in Houston for a long time, and 70 degree dew points are not pleasant.”
These are not my maps, they are from links on the right side of this blog.
Dew points last night in my area were 76 degrees. I would also think that Houston is a different environment than Phoenix.
Now as I understand it, the main issue with dew point is the difference between it and the actual temperature. The greater the difference the less relative humidity. That affects the evaporation of perspiration/moisture on the skin which is, as we all know, how the body cools itself. So in a situation where the dew point is 70 degrees with a temperature of 100 degrees evaporation can still take place and the body can still cool itself. It is still very hot and may feel unpleasant if you are not used to it. When the dew point is 76 degrees and the temperature is 88 degrees (as it was early last night) the relative humidity is very high and little evaporation takes place leaving the body sopping wet with very little ability to cool itself. That can be very unpleasant, even if you are used to it.
My (ignorant) two cents worth.
I do not think the recent past can be relied upon for this years forecast. I think we are seeing a major shift in weather patterns in the northern hemisphere. For example the change in the jet stream last winter giving us very cold weather in the EU, Mongolia, China and the eastern USA and “warmer” weather elsewhere. This summer we saw the same thing with the stalled jet stream in Russia, and very cool weather on the west coast of the USA.
NASA reported A Puzzling Collapse of Earth’s Upper Atmosphere on July 15, 2010 due to the very low solar activity the last few years. That is in contrast to what was happening in the solar cycles before cycle 24.
Solar activity reaches new high – Dec 2, 2003
” Geophysicists in Finland and Germany have calculated that the Sun is more magnetically active now than it has been for over a 1000 years. Ilya Usoskin and colleagues at the University of Oulu and the Max-Planck Institute for Aeronomy say that their technique – which relies on a radioactive dating technique – is the first direct quantitative reconstruction of solar activity based on physical, rather than statistical, models (I G Usoskin et al. 2003 Phys. Rev. Lett. 91 211101)
… the Finnish team was able to extend data on solar activity back to 850 AD. The researchers found that there has been a sharp increase in the number of sunspots since the beginning of the 20th century. They calculated that the average number was about 30 per year between 850 and 1900, and then increased to 60 between 1900 and 1944, and is now at its highest ever value of 76.
“We need to understand this unprecedented level of activity,” Usoskin told PhysicsWeb.”
There is also the changes in albedo from cloud cover as measured by the Earthshine Project
http://www.hindawi.com/journals/aa/2010/963650.html
“…..The earthshine observations reveal a large decadal variability in the Earth’s reflectance, which is yet not fully understood, but which is in line with other satellite and ground-based global radiation data….”
Climate Scientists really do not actually know what is going to happen this year because many are blind to the recent changes. I think that since the sun has not been pumping as much energy into the oceans for the last few years the hurricane season will be at or below normal.
The greater the difference the less relative humidity. That affects the evaporation of perspiration/moisture on the skin which is, as we all know, how the body cools itself.
———–
It’s my sense that perspiration is not the way that we cool until around 75 degrees ambient, absent physical exertion. Below that, dilation of surface blood vessels for radiative cooling seems to be the mechanism.
Most people find sweatiness disagreeable and often conclude that the humidity must be high if their skin is wet.
Although I follw most that is put forth on WUWT, this one cranks up my “illogical hypothesis/theory” alarm. I have no background in this, so much of what I am saying may be complete rubbish. But the bits I know don’t seem to tie in with his arguments here.
When a hurricane or tropical storm forms north of Suriname or a bit east or west of that, I find it hard to believe that the heat accumulation there consults with the northern Atlantic as to whether or not to form. It would seem to be all about convection and Coriolis effect, massaged by the prevailing winds. When it all gets into some kind of “in phase” condition, it is “organized” enough to start rotating as a unit – not necessarily enough to maintain itself, but possibly.
What any of this has to do with temperature differential escapes me.
Steve:
I would argue all three of these sentences, if for no other reason than to see where Steve is coming from.
1. What source does Steve have for the idea that hurricanes move heat quickly away from the tropics? Most of their time is spent IN the tropics, albeit on a slightly poleward path, and then they peter out on reaching the mid-latitudes.
2. The latter two sentences and his map argue that such temperature flow is horizontal (between two “places” [his term]), while my understanding of hurricanes is that it is RISING air that creates hurricanes. I submit that creating a hurricane and moving a hurricane are two essentially separate mechanisms.
At the same time, simply rising hot, moist air would not create any rotation necessarily. One would think that the prevailing wind patterns north of S America play a part in the formation of hurricanes, giving them a kick start on rotation – or not. Winds plowing straight into the center of a mass of rising moist air would tend to rip it to shreds, while wind currents that supplemented the Coriolis effect would tend to increase the rotation.
ALL of the mechanisms I can logically identify with the formation of hurricanes are local.
3. In addition, it is TOTALLY known that many N Atlantic hurricanes end up traveling INTO the Gulf of Mexico, which is a VERY warm body of water. This would seem to belie Steve’s assertion that weather systems go from warm to cold and that this is the driving force for hurricanes.
4. In this context looking at temperature ANOMALIES does not make sense. Anomalies are not temperature. HEAT FLOW is from warmer to colder. NOT from how much variation there is from “average”. AIR FLOW is from more dense to less dense. Hence convection. Hence wind currents. Anomaly differences between Point A and Point B geographically have nothing to do with CREATING hurricanes – it is only pressure differences (and the Coriolis effect), plus the Hadley Cell flows.
I may not have made a lot of sense on all of these points, and I don’t tie them together well, but I just don’t think Steve is correct on this. What is going with convection on off the S American coast has NOTHING to do with what temp anomalies in the far north. In addition, MOVEMENT of hurricanes isn’t even tied to temperature gradients (much less anomalies) – otherwise few hurricanes would ever enter the Gulf of Mexico.
See this almost current SST http://www.osdpd.noaa.gov/data/sst/contour/usatlant.fc.gif . I am tryin to insert the image here: If it fails to post, please go see the map at the above link…
Which direction would a hurricane go, if it was driven by temperature differential (much less temp anomalies)? Obviously the ones that didn’t dive into the Caribbean would head NORTH, according to Steve’s premise.
I can’t see any validity to this argument. Hurricanes do not form in one place because of conditions in one of the possible locations that the air mass might travel to in 10 or 15 day’s time. And temp ANOMALIES don’t move systems – air pressures do. The only temperature effect involved has to do with convective RISING, not movement.
If I am wrong, beat on me, guys.
jtom – wouldn’t this Sarahan dust also be an aerosol that tends to cool?
I would logically agree with your point, also. Airborne particulates – don’t they act as nucleating objects for water vapor condensation, which would then increase rainfall locally, removing heat from the developing system?
In support of this (and hoping this doesn’t get me laughed off the site!), Wikipedia summarizes hurricane formation factors thusly:
That seems to generally agree with my points above. NONE of the factors has anything to do with anything that is happening in northern latitudes, whether anomalies or actual temps.
(I seriously wish this site had a PREVIEW function…)
Steve,
This may be helpful to you: http://en.wikipedia.org/wiki/Tropical_cyclogenesis
Feet2theFire
Have you ever looked at SSTs before/after a hurricane moves through?
Temperatures drop several degrees, because of energy transferred from the water to the atmosphere. Higher latitudes are colder than the tropics, so the heat necessarily moves towards the higher latitudes (basic thermodynamics.)
A good paper concerning Effective Temperature can be found at:
http://climate.colostate.edu/pdfs/Denver%20Heat%20Wave_21Nov2005_final.pdf
by Roger Pielke Sr.
Feet2theFire says:{August 16, 2010 at 7:54 am}
” 3. In addition, it is TOTALLY known that many N Atlantic hurricanes end up traveling INTO the Gulf of Mexico, which is a VERY warm body of water”
That is due to the Bermuda high which normally develops each summer near, you guessed it, Bermuda. It is one of the main steering currents for hurricanes. Absent a strong cold front out coming out of the U.S., hurricanes will travel clockwise around the Bermuda high and end up in the Gulf of Mexico. Nothing to do with going from colder to warmer or warmer to colder.
The direction which the hurricane moves is a different issue from the north-south movement of heat.
What Hurricane season is that you are referring to ? I must not have paid my dues or something; because I have not been getting any Huricanes yet !
As an addendum to this “strange” season, TD5 is backing off the continent and heading back over the GoM….
If it continues southward for the next day, it may well become the tropical storm (or even weak hurricane) that was originally expected.
We have been quacking like ducks for 3 days straight now, here in P-cola, and am not looking forward to more of the same. Ivan came back at us eventually, too…I guess we’re well nigh irresistible.