Hurricane tracks, changes in hurricane clustering, and other notes from Tucson
I'm in Tucson for the American Meteorological Society's 29th Conference on Hurricanes and Tropical Meteorology. This is the premier scientific conference on hurricanes, and is held only once every two years, so pretty much all of the world's greatest hurricane experts are here. Below are some quick snapshots of four of the talks I attended yesterday; I hope to more more snapshots each day this week.
Angela Colbert of the University of Miami/RSMAS showed how different weather and climate patterns affect the Azores-Bermuda High, and thus the tracks of Atlantic hurricanes. She divided storms into straight-moving storms that move straight west-northwest through the Caribbean, recurving landfalling hurricane that hit the east coast of the U.S., and recurving ocean storms that miss land. Roughly 1/3 of all hurricanes between 1950 - 2009 fell into each of these three categories. These proportions stayed pretty constant during La Niña and neutral years, but El Niño caused a weakening of the high, resulting in far fewer hurricanes hitting the U.S. East Coast. These storms instead recurved out to sea.
Jim Kossin of the University of Wisconsin separated all Atlantic storms from 1950 - 2007 into 4 clusters, based on genesis location. Two of the clusters were more northerly-forming storms that tended to be less tropical in nature--Gulf of Mexico storms, and storms off the U.S. East Coast that tended to recurve. The other two clusters were more southerly tropical-origin systems--ones that tended to form in the Caribbean, and storms that form near the Cape Verde Island region off the coast of Africa. The more tropical Cape Verde and Caribbean storms dominated major hurricane frequency by a factor of four. In mid-1980s, there was an abrupt shift to more of these more dangerous tropical type storms--ten years prior to the active hurricane period that began in 1995. It is unknown what caused this shift. The shift is unlikely to be a result of measurement error, since we had good satellite imagery then. Independent of any trends in frequency, this shift caused an increase in intensity metrics of Atlantic hurricanes. A doubling of these tropical systems has also occurred since 1950. Interestingly, there has been no change in the number of Gulf of Mexico storms, and a slight increase in storms forming off of the U.S. East Coast. Since slight changes in track can make a big difference in what SSTs and atmospheric environment a storm sees, there is a lot of natural "noise" in the system that will make it difficult to get a clear sense of when climate change is having a substantial impact on hurricane intensity.
Bin Wang of the University of Miami studied the global number of storm days from 1965 - 2008, which should be a less sensitive quantity to data problems than the number of storms or their intensity. Storm days were defined as any day when a tropical cyclone of tropical depression strength or greater existed. However, there are still some data problems, as evidenced by a sharp drop in storm days observed in the North Indian Ocean beginning in 1978. Dr. Wang found that there was no global trend in storm days. The Atlantic was the only individual basin that showed an increase in storm days.
Greg Holland of NCAR looked at the distribution of the strongest hurricanes over time by using a mathematical description of the historical hurricane data. His analysis showed that during the period 1995 - 2008, we probably had about a 30% increase in Category 5 storms in the Atlantic, and an 18% increase in Category 4 hurricanes. Using a climate model, he predicted that by the years 2045 - 2055, we should see a 60% increase in Cat 5s, 32% increase in Cat 4s, and 16% increase in Cat 3s in the Atlantic.
Jeff Masters
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Did you notice? :)
Is that a closed low?
heres one with you included on it pottery
This is illustrating that this is not a situation where we should expect development. While impressive for May and interesting to watch, it is more a sign of potential things to come later in the season, when tropical waves will likely tend to strengthen over the central-eastern Atlantic under favorable conditions. Right now the overall environment is still too hostile and the wave too far south, to expect much development.
HYPE!
REQUIREMENTS FOR Tropical Cyclone Formation Alert
If a system gets 35 to 38 points, a TCFA may be issued depending on Dvorak trends, and if a system gets 39 points or more a TCFA should be issued.
Surface
Condition Points
A circulation is evident using visible satellite, shortwave infrared, microwave imagery or QuikSCAT/Windsat ambiguities 3 points
A circulation has been evident for at least 24 hours 5 points
A westerly surface- or gradient-level wind of 5 kt that is within 200 nm (370 km, 230 mi) south of the centre of the disturbance 5 points
Any wind associated with the system is at least 20 kt 2 points
Any wind associated with the system is at least 25 kt 3 points
Any wind associated with the system is at least 30 kt 4 points
A weather station within 200 nm of the system has reported had a pressure drop of 2 mb over 24 hours 3 points
A weather station within 200 nm of the system has had a pressure drop of 3 mb over 24 hours 4 points
The estimated MSLP of the system is less than 1010 to 1009 mb 3 points
The estimated MSLP of the system is 1008 mb or less 4 points
500 mb height
Condition Points
There is evidence of at least an inverted trough 2 points
There is evidence of a closed circulation in the system 4 points
200 mb height
Condition Points
Westerly flow of at least 15 kt over the disturbance -4 points
There is evidence of anticyclonic outflow over the centre of the disturbance 4 points
Easterly flow of at most 20 kt over the disturbance 3 points
Sea surface temperature
Condition Points
The sea surface temperature is 26 Celsius (78.8 Fahrenheit) or higher 3 points
Satellite data
Condition Points
The system has persisted for at least 24 hours 3 points
The system has persisted for at least 48 hours 4 points
The system has persisted for at least 72 hours 5 points
The system has a Dvorak classification of T1.0 to T1.5 from all three agencies (TAFB, SAB, AFWA) 3 points
The system has a Dvorak classification of T1.5 to T2.0 from all three agencies 5 points
The Dvorak final-T number has decreased by T0.5 to T1.0 from two or more agencies -2 points
Miscellaneous
Condition Points
The cloud system is north (or south) of 5 degrees latitude 3 points
The tropical system is within 72 hours of reaching a Department of Defense resource 3 points
The cloud system center and the satellite centre fixes for the system are within 2 degrees of each other 2 points
**********************************************************
Actually it does. Odd.
Not quite....it's still a fairly messy monsoon trough. It's an interesting area, but upper-level conditions are less than ideal and will remain that way for a few days. It is also fighting against large-scale downward motion thanks to the MJO. That's another thing our little wave is dealing with as well.
Sup
Wait. I got an idea. Let's drop a giant steel box over it. It worked for BP.
~X~
Is there any way to figure out how many points it's at now?
We should drop a steel box ON bp
by counting. Dont be lazy
Ha!
in 2008 we had a 'wet' dry season, 'real' rain started around June 1
in 2009 we had plenty rain Jan/Feb, very little M,A,M,AND June. Heavy stuff started in early july. Nov and Dec very low. So 3 months of the 6 were drier than usual.
in 2010 very low J,F,M,A,M (so far). (add Nov dec from last year)
So, basically, nothing to be gleaned from that little exercise. Waste of time, actually.
LOL
I thought it meant that we would see Hurricane strike from Melbourne to Ft. Lauderdale as was suggested yesterday.
*pokemon music*
TROPICS USED DRY AIR!
WILD TROPICAL WAVE USED BURST OF CONVECTION!
It was not very effective...
TROPICS USED DOWNWARD MJO!
WILD TROPICAL WAVE USED BURST OF CONVECTION!
It was not very effective...
TROPICS USED CRAZY HIGH WIND SHEAR!
It was super effective!
WILD TROPICAL WAVE fainted...
hmmmmm. LOL
heres the epac blob
FANTASTIC!
You are suggesting that there is some doubt ? Huh? Bud??
Actually it's very enlightening. You can see the pattern that can indicate what kind of a hurricane season you could have.
2007 sounds like a pretty normal year. Above-normal season overall with 2 bad hurricanes that ran through the Caribbean.
2008's "wet" dry season can be attributed to the La Nina that winter, which reversed to neutral during the summer, still resulting in an above-normal season, but not really bad in the eastern Caribbean and the rest of the deep tropics south of 20N.
2009's wet Jan/Feb can again be attributed to weak La Nina conditions that winter, but these started reversing to neutral in March, and eventually into an El Nino in June, which has continued through today. This would explain nicely the shutdown of the rain in March, with a late start to the rainy season in July. The hurricane season was a dud.
2010's bone-dry and hot winter all the way through can be attributed to the strong El Nino, but with it now reversing, when the rainy season finally begins, expect it to be a big one, and with it a bad hurricane season for the Caribbean and probably everywhere else in the SW Atlantic.
Nah, too violent of an eruption. And nuking it wouldn't make it better either!
Nope not at all. It is very easy to tell where every hurricane will hit before the season starts this early due to rainfall and analog years.
I guess I will have to settle for public outrage and lawsuits
Glad that we read the same stuff. I totally agree.
heheheheh
haha,
JFV- "hey so this rainfall would suggest a South Florida strike, right Do A Barrell Rollster?"
well its call counting if you want
but i have not myself
for expectations for dev are very very low
but i do use it during the season
and once the numbers add up
a T.C.F.A.will be noted
if needed a T.C.F.W. if totals are exceeded
That would be thanks to the MJO currently organizing over the Indian Ocean and maritime continent. There's lots of convection in that whole area of the world right now.
I am going to wait until after hurricane season to browse for houses. The way I feel now I think building a new house above existing hurricane code would be better then trying to get something already built.
I will be an interesting mess if a major hurricane hits an area where a lot of people have underwater mortgages. In normal times you see a construction boom but this may be muted if people walk away from their slabs.
the MJO actually spawned 3 systems.
Probably one argument one can use to justify the formation of TD 1 later this month in the Atlantic or Eastern Pacific, in that case, TD 1-E
yea, it still didnt work but I'll try a bit later.
Thanks
-A weak upward motion MJO to pass over the Caribbean on May 17th.
-Strong upward motion MJO to pass over the Atlantic on May 22nd.
-A strong upward motion MJO to pass over the Caribbean, GOMEX, and Bahamas on May 27th.
All these upward MJOs should really get the ATL going early.
GFS
Link
NOAA rammb has it as 96S & NAVY 97S. I think NOAA is right..
22:45 UTC - 6:45 PM EDT
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