More pre-season predictions of a very active Atlantic hurricane season

By: Dr. Jeff Masters , 3:02 PM GMT on July 12, 2010

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Hello again, it's Jeff Masters back again after a week away. Well, the past week was a wicked hot time to be in New England, where I was vacationing, and I certainly didn't expect to see 98° temperatures in Maine like I experienced! Fortunately, it's not hard to find cold water to plunge into in New England. Thankfully, the tropics were relatively quiet during my week away, and remain so today. There are no threat areas in the Atlantic to discuss at present, and none of the reliable computer models is forecasting tropical cyclone development over the next seven days. The NOGAPS model does show a strong tropical disturbance developing near the waters offshore of Nicaragua and Honduras this weekend, though. With not much to discuss in the present-day tropics, let's take a look at more pre-season predictions of the coming Atlantic hurricane season.

2010 Atlantic hurricane season forecast from Penn State
Dr. Michael Mann and graduate student Michael Kozar of Penn State University (PSU) issued their 2010 Atlantic hurricane season forecast on May 28. Their forecast utilizes a statistical model to predict storm counts, based on historical activity. Their model is predicting 19 to 28 named storms in the Atlantic, with a best estimate of 23 storms. The forecast assumes that record warm SSTs will continue in the Atlantic Main Development Region for hurricanes. Dr. Mann has issued two previous forecasts, in 2007 and 2009. The 2007 forecast was perfect--15 storms were predicted, and 15 storms occurred. The 2009 forecast called for 11.5 named storms, and 9 occurred (the 2009 forecast also contained the caveat that if a strong El Niño event occurred, only 9.5 named storms were expected; a strong El Niño did indeed occur.) So, the 2009 forecast also did well.


2010 Atlantic hurricane season forecast from the UK GloSea model
A major new player in the seasonal Atlantic hurricane season forecast game is here--the UK Met Office, which issued its first Atlantic hurricane season forecast in 2007. The UK Met Office is the United Kingdom's version of our National Weather Service. Their 2010 Atlantic hurricane season forecast calls for 20 named storms, with a 70% chance the number will range between 13 and 27. They predict an ACE index of 204, which is about double the average ACE index.

I have high hopes for the UK Met Office forecast, since it is based on a promising new method--running a dynamical computer model of the global atmosphere-ocean system. The CSU forecast from Phil Klotzbach is based on statistical patterns of hurricane activity observed from past years. These statistical techniques do not work very well when the atmosphere behaves in ways it has not behaved in the past. The UK Met Office forecast avoids this problem by using a global computer forecast model--the GloSea model (short for GLObal SEAsonal model). GloSea is based on the HadGEM3 model--one of the leading climate models used to formulate the influential UN Intergovernmental Panel on Climate Change (IPCC) report. GloSea subdivides the atmosphere into a 3-dimensional grid 0.86° in longitude, 0.56° in latitude (about 62 km), and up to 85 levels in the vertical. This atmospheric model is coupled to an ocean model of even higher resolution. The initial state of the atmosphere and ocean as of June 1, 2010 were fed into the model, and the mathematical equations governing the motions of the atmosphere and ocean were solved at each grid point every few minutes, progressing out in time until the end of November (yes, this takes a colossal amount of computer power!) It's well-known that slight errors in specifying the initial state of the atmosphere can cause large errors in the forecast. This "sensitivity to initial conditions" is taken into account by making many model runs, each with a slight variation in the starting conditions which reflect the uncertainty in the initial state. This generates an "ensemble" of forecasts and the final forecast is created by analyzing all the member forecasts of this ensemble. Forty-two ensemble members were generated for this year's UK Met Office forecast. The researchers counted how many tropical storms formed during the six months the model ran to arrive at their forecast of twenty named storms for the remainder of this hurricane season. Of course, the exact timing and location of these twenty storms are bound to differ from what the model predicts, since one cannot make accurate forecasts of this nature so far in advance.

The grid used by GloSea is fine enough to see hurricanes form, but is too coarse to properly handle important features of these storms. This lack of resolution results in the model not generating the right number of storms. This discrepancy is corrected by looking back at time for the years 1989-2002, and coming up with correction factors (i.e., "fudge" factors) that give a reasonable forecast.

The future of seasonal hurricane forecasts using global dynamical computer models is bright. Their first three forecasts have been good. Last year the Met Office forecast was for 6 named storms and an ACE index of 60. The actual number of storms was 9, and the ACE index was 53. Their 2008 forecast called for 15 named storms, and 15 were observed. Their 2007 forecast called for 10 named storms in July - November, and 13 formed. A group using the European Center for Medium Range Weather Forecasting (ECWMF) model is also experimenting with some promising techniques using that model. Models like the GloSea and ECMWF will only get better as increased computer power and better understanding of the atmosphere are incorporated, necessitating less use of "fudge" factors based on historical hurricane patterns. If human-caused climate change amplifies in coming decades, statistical seasonal hurricane forecasts like the CSU's may be limited in how much they can be improved, since the atmosphere may move into new patterns very unlike what we've seen in the past 100 years. It is my expectation that ten years from now, seasonal hurricane forecasts based on global computer models such as the UK Met Office's GloSea will regularly out-perform the statistical forecasts issued by CSU.

2010 Atlantic hurricane season forecast from Florida State University
Last year, another group using dynamical computer forecast models entered the seasonal hurricane prediction fray. A group at Florida State University led by Dr. Tim LaRow introduced a new model called COAPS, which is funded by a 5-year, $6.2 million grant from NOAA. This year, the COAPS model is calling for 17 named storms and 10 hurricanes. Last year's prediction by the COAPS model was for 8 named storms and 4 hurricanes, which was very close to the observed 9 named storms and 3 hurricanes.

Summary of 2010 Atlantic hurricane season forecasts
Here are the number of named storms, hurricanes, and intense hurricanes predicted by the various forecasters:

23 named storms: PSU statistical model
20 named storms: UKMET GloSea dynamical model
18.5 named storms, 11 hurricanes, 5 major hurricanes: NOAA hybrid statistical/dynamical model technique
18 named storms, 10 hurricanes, 5 intense hurricanes: CSU statistical model (Phil Klotzbach/Bill Gray)
17.7 named storms, 9.5 hurricanes, 4.4 intense hurricanes: Tropical Storm Risk (TSR), hybrid statistical/dynamical model technique
17 named storms, 10 hurricanes: FSU dynamical model
10 named storms, 6 hurricanes, 2 intense hurricanes: climatology

Only four hurricane seasons since 1851 have had as many as nineteen named storms, so 5 out of 6 of these pre-season forecasts are calling for a top-five busiest season in history. One thing is for sure, though--this year won't be able to compete with the Hurricane Season of 2005 for early season activity--that year already had five named storm by this point in the season, including two major hurricanes (Dennis and Emily.)

Tropical Storm Conson threatens the Philippines
Weather456 has an interesting post on why the Western Pacific typhoon season has been exceptionally inactive this year. It looks like we'll have out first typhoon of the Western Pacific season later today, since Tropical Storm Conson appears poised to undergo rapid intensification, and should strike the main Philippine island of Luzon as a Category 1 or 2 typhoon.

Next post
I'll have an update Wednesday.

Jeff Masters

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Whats this wave supposed to do this weekend? go into LA/TX??
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2013. IKE
Quoting StSimonsIslandGAGuy:
I wish a tropical wave would move this way and bring me some rain.


Wishcaster!
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2008. Patrap



NASA Drones to Fly Into Hurricanes
Jul 13, 2010 10:44 AM ET
By OurAmazingPlanet Staff


Scientists have no idea why some tropical storms become hurricanes and some do not. NASA is on a mission to get to the bottom of this problem.


NASA scientists will fly three aircraft, including an unmanned drone, over tropical cyclones in the Gulf of Mexico, Atlantic Ocean and Caribbean Sea during the agency's first major United States-based hurricane field campaign since 2001.

One of the major challenges in tropical cyclone forecasting is knowing when a tropical cyclone (the general term that encompasses hurricanes and tropical storms) is going to form. Researchers will try to unravel this mystery during the GRIP mission, which stands for Genesis and Rapid Intensification Processes. The mission will study how tropical storms form and develop into major hurricanes, as well as how they strengthen, weaken and die.

The mission will run from Aug. 15 to Sept. 30 and will feature for the first time in hurricane research an unmanned drone that can peer through cloud tops and measure the internal structure of a storm. Previous hurricane research missions relied solely on piloted aircraft, which can observe a storm for between two to four hours getting only a snapshot of a storm that can spin for days.

"This is really going to be a game-changing hurricane experiment," said GRIP team member Ramesh Kakar of NASA. "For the first time, scientists will be able to study these storms and the conditions that produce them for up to 20 hours straight. GRIP will provide a sustained, continuous look at hurricane behavior at critical times during their formation and evolution."

Spinning storms

From late spring to early fall, the west coast of Africa spits out what are called African easterly waves almost like clockwork every few days. Some of these swirling systems become hurricanes. Most do not.

"The genesis part of this campaign is really focused on under what conditions these waves become tropical storms and hurricanes, and why some fizzle out and become nothing," Kakar said. "And when a tropical storm becomes a hurricane, we are trying to determine whether this will sputter or rapidly intensify."

Hurricane season in the Atlantic Ocean and Gulf of Mexico begins on June 1 and lasts until Nov. 30, with August and September typically being the most active months.

While the 2009 hurricane season was much tamer than many in recent years, with only three hurricanes developing in the Atlantic, the 2010 season could see more than three times as many, hurricane forecasters have projected. One hurricane model predicts that there will be 17 named storms (or those that reach Tropical Storm status with winds of at least 39 mph (63 kph)) this season, with 10 of those developing further into hurricanes, which have winds of at least 74 mph (119 kph).

An average hurricane season, in comparison, has 11 tropical storms with six of them becoming hurricanes.

Eyes in sky

Soaring above the storms will be the Global Hawk the same drone model flown by the U.S. Air Force. This drone can fly up to 65,000 feet (19,800 meters) for up to 20 hours, which would be the longest continuous observation of tropical cyclone development ever recorded by an aircraft.

The aircraft aren't NASA's only eye in the sky for the mission. Three NASA satellites will also observe tropical cyclones and provide rainfall estimates and help pinpoint the locations of what are known as hot towers powerhouse thunderstorms in tropical cyclones. Satellites will also provide infrared, visible and microwave data that reveal such factors as temperature, air pressure, precipitation, cloud ice content, convection and sea surface temperatures.

The NASA scientists can't wait to start playing with their toys.

"Now that the start of the field experiment is almost here, we can hardly contain our excitement," Kakar said.
Member Since: Posts: Comments:
2007. QMiami
Quoting Tazmanian:
JFV likes too drive evere one nuts but he wont last vary long am forcasting he will olny last 12hrs on here be for he ends up geting banned

No you guys are driving everyone nuts by bringing his name up constantly even when he's not around - how annoying- ignore user and move on - let us make up our own minds what we want to do
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As soon as the atmosphere gets its act together, we are in for one hell of a ride. It's coming.
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Quoting cyclonekid:
Man! This blog is really dead.


yep, until it gets busy in the tropics and then we won't be able to keep up with all the posts. :)
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Man! This blog is really dead.
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I'd say between 1900 and 1950 there were some improvements in storm detection, if only because of the increased use of radio, radar, similar developments on ships as they plied the ATL. While they may not have been identified as hurricanes / tropical storms, an increasing number of the storms between 20N and 50N would have been detected and reported as the years progressed.
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Miami NWS:

DISCUSSION...
THE AREA OF CLOUDINESS AND MOISTURE ACROSS THE CENTRAL AND
NORTHERN BAHAMAS CONTINUES TO MOVE SLOWLY WESTWARD. THIS IS
CONSISTENT WITH THE LATEST GUIDANCE...INDICATING THAT THE LEADING
EDGE OF THE LOW LEVEL MOISTURE COULD APPROACH THE ATLANTIC COAST OF THE
SOUTH FLORIDA PENINSULA AROUND 12Z WEDNESDAY. THE LATEST GUIDANCE
ALSO INDICATED MORE NUMEROUS SHOWER AND SCATTERED THUNDERSTORM
ACTIVITY BY WEDNESDAY AFTERNOON WHICH SEEMED REASONABLE WITH THE
INCREASE IN MOISTURE ACROSS THE REGION...WITH A GENERAL INCREASE
IN POPS ACROSS THE PENINSULA FOR WEDNESDAY AFTERNOON. BY THURSDAY AND
FRIDAY SOUTHEASTERLY LOW LEVEL FLOW WILL CONTINUE TO BRING
ADDITIONAL MOISTURE ACROSS THE AREA WITH SCATTERED SHOWERS AND A
CHANCE OF THUNDERSTORMS...MAINLY IN THE AFTERNOON.
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Tropical Storm Conson
5pm EDT
Joint Typhoon Warning Center Advisory #10
*NEW* Graphics Update

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1999. scott39
Ive got the no developing, no tracking, nothing goin on in the tropics, blues. LOL
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1998. IKE
SYNOPSIS FOR THE GULF OF MEXICO
430 PM CDT TUE JUL 13 2010

.SYNOPSIS...THE NORTHERN PORTION OF A TROPICAL WAVE WILL MOVE
ACROSS THE BAY OF CAMPECHE TONIGHT. WEAK RIDGE FROM S FLORIDA TO
23N93W WILL SHIFT N TO ALONG 28N WED THROUGH THU AND TO JUST N
OF THE GULF FRI AND SAT AS A TROUGH MOVES FROM E TO W ACROSS
GULF THU THROUGH SAT. THE RIDGE WILL BUILD AGAIN FROM E TO W
ACROSS THE GULF WATERS BY SUN.



SYNOPSIS FOR CARIBBEAN SEA AND TROPICAL N ATLC FROM 07N TO 22N
BETWEEN 55W AND 65W
530 PM EDT TUE JUL 13 2010

.SYNOPSIS...A TROPICAL WAVE ALONG 55W WILL MOVE ACROSS THE
REMAINDER OF THE TROPICAL N ATLC THIS EVENING THROUGH THU BEFORE
ENTERING THE EASTERN CARIBBEAN SEA THU EVENING. THE WAVE WILL
THEN MOVING THROUGH THE REMAINDER OF THE EASTERN CARIBBEAN
OVERNIGHT THU INTO FRI...AND SHOULD REACH NEAR 70W BY SAT.
ANOTHER TROPICAL WAVE IS EXPECTED TO APPROACH THE FAR EASTERN
TROPICAL N ATLC WATERS LATE SAT REACHING THE E CARIBBEAN LATE
SUN.
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1997. angiest
I'm going to change my meridian to around 50 degrees as the cut-off of where storms would be missed before satellite. And estimate perhaps half a dozen storms in 2005 would have been missed, and others that hit Europe and Africa may not have been understood to be tropical.

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I'm Out......Have a Good Afternoon Folks......WW
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Quoting Floodman:


I have 18 on my list...ignore that is (I've given up the whole JVF is back thing)...he comes back in, I detect it;'s him, I ignore him and I move on



you got mail
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1994. sky1989
Quoting StormW:


Looks like almost all of them. LOL!


LOL!
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Quoting Tazmanian:
JFV most have 50 names that got in banned by now he been doing this evere 24hrs evere time hes gets bannd if i was the Admin i would make sure he woukd not get pass a banned you would be banned from the site for evere


I have 18 on my list...ignore that is (I've given up the whole JVF is back thing)...he comes back in, I detect it's him, I ignore him and I move on
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1986. sky1989 5:08 PM EDT on July 13, 2010

The biggest single breakthrough application for weather forecasting, including the tropics, was the sattelite starting in the 60's....We will never know the true extent of past h-seasons before the modern era unless land fall occured in "recorded" populated areas.
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Quoting WeatherNerdPR:

47N 91W is somewhere in North-Central Wisconsin...
OK, I looked it up on Google Earth... some islands nearby, so a little bit like my home...

Quoting 47n91w:


Yeah, my handle brings you pretty close to my home coordinates. Unfortunately, tropical trees wouldn't survive very long on the shores of Lake Superior. My experience with Fragipani (and other tropical trees) is centered around two years near 12 degrees S and 27 degrees E. What I would give to be able to experience that landscape again!
That's a lot closer to where they actually come from... If u can't get back there, u can find frangipani (transported, of course lol) pretty much throughout the Bahamas and Caribbean. I'll bet there are even some in S FL, though I don't recall actually seeing any growing there.

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More rain for Nicaragua and Honduras...
Member Since: July 11, 2006 Posts: 14 Comments: 11272
1987. angiest
Quoting sky1989:


Well, we have already seen more activity than this year did! I'm curious though, on how many storms went undetected that year.


Pretty much anything east of about 40 degrees (give or take) would have been missed before satellite. Same is true of minicanes like Marco.

I also don't think the database has any depressions (that didn't subsequently become tropical storms or hurricanes) that far back. Therefore, there may have been more "known" tropical cyclones.
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1986. sky1989


Well, we have already seen more activity than this year did! I'm curious though, on how many storms went undetected that year.
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Quoting angiest:


No, its not a weather related forum.



oh
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1984. angiest
Quoting Tazmanian:



you most ues storm2k


No, its not a weather related forum.
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1983. 47n91w
Quoting BahaHurican:
One place I used to work had a pair of frangipani trees outside the windows. When they were in bloom, it was the most heady experience u can imagine.

BTW, are u near / from the location in ur handle? That sounds like US NW somewhere...


Yeah, my handle brings you pretty close to my home coordinates. Unfortunately, tropical trees wouldn't survive very long on the shores of Lake Superior. My experience with Fragipani (and other tropical trees) is centered around two years near 12 degrees S and 27 degrees E. What I would give to be able to experience that landscape again!
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Quoting K8eCane:
You all are Cyber Bullying JFV...you need to stop it


You must not have seen the ugly side of JFV. He's not a cute innocent kid on here that just happens to be annoying. He's a troll.
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Quoting BahaHurican:
One place I used to work had a pair of frangipani trees outside the windows. When they were in bloom, it was the most heady experience u can imagine.

BTW, are u near / from the location in ur handle? That sounds like US NW somewhere...

47N 91W is somewhere in North-Central Wisconsin...
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Quoting angiest:


I don't know what software they use here, but at a forum where I am a mod I use the IP ban fairly frequently. If the code is well-written, you can ban anything from a specific address to an entire block of addresses. Of course, it is not terribly difficult for the determined to spoof an IP address.



you most ues storm2k
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1978. K8eCane
You all are Cyber Bullying JFV...you need to stop it
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This year remainds me of 2004. The western extent and strength of the A/B high kept everyone guessing all year and this year looks to be the same. Even the local mets are having a rough time on their rainfall predictions due to the on again/off again subtle yet persistent ridging and associated dry air intrusions which appear too far south for normal cimatology. I look for an average year starting in mid August when the shear in the Caribbean and dry air and SAL in the Central Atlantic finally let up. JMHO
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1976. angiest
Quoting Tazmanian:
JFV most have 50 names that got in banned by now he been doing this evere 24hrs evere time hes gets bannd i was the Admin i would make sure if you got pass a banned you would be banned from the site for evere


I don't know what software they use here, but at a forum where I am a mod I use the IP ban fairly frequently. If the code is well-written, you can ban anything from a specific address to an entire block of addresses. Of course, it is not terribly difficult for the determined to spoof an IP address.
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Quoting 47n91w:


Hard to put the experience into words. I visited a Fragipani at dusk. In the darkness the white flowers glowed while the thick scent enveloped the entire tree. It's one of those moments where you wish life had a pause-button.
One place I used to work had a pair of frangipani trees outside the windows. When they were in bloom, it was the most heady experience u can imagine.

BTW, are u near / from the location in ur handle? That sounds like US NW somewhere...
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1972. LaCoast
Quoting StormW:


Well, those two, along with the very warm sst's in the Atlantic, and setup of the Atlantic Tripole will ensure upward motion is focused in the Atlantic Basin.


His named storms prediction are pretty low all things considered. His prediction of upwards of 75% of the 12 making landfall are pretty high percentage wise. You would need twice the number of storms to even come close to that percentage, although 5 landfalls could be possible but not with only 12 named storms.
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1971. XLR8
"Banncasting" LOL
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Quoting tkeith:
you must have used the xtrap model for that forecast Taz :)

I like the new Avatar btw...



yup
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The JFV thing is getting old....Just use the ignore button and stay focused on the relevent issues.....Lot's of outside folks will be coming on the Blog this year when the season heats up for information so no need to clog it up with useless banter about one particular person/blogger (even if for comic relief).
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1967. tkeith
Quoting Tazmanian:
JFV likes too drive evere one nuts but he wont last vary long am forcasting he will olny last 12hrs on here be for he ends up geting banned
you must have used the xtrap model for that forecast Taz :)

I like the new Avatar btw...
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I am leaving Biloxi next Thursday, July 22 until Monday, July 26 (going to Illinois). Do you think the tropics will remain quiet until I return? I don't want to be away from home if something is brewing.
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1964. sky1989
Quoting TexasHurricane:


What did he/she do? I only started coming on here last year. Seems like the majority on here don't want him/her here....just curious.


I have been here for 3 years, mostly lurking though, and have still not figured that out! lol.
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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