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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64. IKE
Quoting DestinJeff:


Meant nothing developed to the point of being named.


I had more rain in a heavy thunderstorm yesterday afternoon(5.23 inches), then Brownsville,TX. had in full, over TD2(3.63 inches).
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Welcome back Dr. Masters! I'm working on updating my website at the CCHS Weather Center for the first time in a month. I'll be in and out throughout the day.
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that wave which I think you guys are talking about is now heading into Central America and looking on the Sat loop it look like a sheared little blob maybe all it will be is some rain for Haiti but still Watch it conditons might change for it

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Before midnight, it will be More Fun Than SEVEN ExxonValdezes Day (assuming the current spill rate of 26,770barrels per day continues. New info and recalculations start about midway down)

"[BritishPetroleum]'s well in the Gulf of Mexico is gushing[...]from 35,000 to 60,000 barrels a day, Energy Secretary Stephen Chu and Interior Secretary Ken Salazar said today [15June2010]..."

35,000barrels equals 1,470,000gallons. 60,000barrels equals 2,520,000gallons.
Cutting the BlowoutPreventer riser on June3rd increased the flow-rate by up to 20% or 1/5th; ie the post-cut flow rate is at most 6/5ths of the pre-cut flow rate.
Conversely, the pre-cut flow rate was at least 5/6ths of the post-cut flow rate, or ~29,167to50,000barrels(1,225,000to2,100,000gallons) per day.

In 43days2hours15minutes from DeepwaterHorizon's explosion&blowout at 9:45pm21April though midnight3June, (temporarily ignoring the RiserInsertionTubeTool) 100% of that flow spilled into the Gulf for a pre-cut minimum spill rate of ~29,167barrels(1,225,000gallons) per day, leading to a subtotal of ~1,256,901barrels(52,789,844gallons) spilled. Subtracting the 22,000barrels(924,000gallons) collected by the RITT, a total minimum of ~1,234,901barrels(51,865,844gallons) of crude had spilled into the Gulf before midnight3June.

In the 30days between midnight3June and midnight3July at the post-cut minimum flow rate of 35,000barrels(1,470,000gallons) per day, a minimum of 1,050,000barrels(44,100,000gallons) of crude had flowed from the wellhead.
NEW INFORMATION: By the midnight3July, the total*volume of crude oil collected or flared was 585,400barrels(24,586,800gallons).
Subtracting the volume collected or flared from the minimum volume that flowed from the wellhead between midnight3June and midnight3July means that a minimum of another 464,600barrels(19,513,200gallons) had spilled into the Gulf before midnight3July.

Added to the volume spilled before midnight3June, that means a combined total minimum of ~1,699,501barrels(71,379,044gallons) had spilled into the Gulf before midnight3July.
ExxonValdez spilled 11,000,000gallons. By midnight3July, DeepwaterHorizon had spilled six ExxonValdezes plus another ~128,072barrels(5,379,044gallons) toward the next one.
Working backwards by dividing that 5,379,044gallons by an averaged^minimum spill rate of 430,815gallons per day, then subtacting the resulting 12.48574 days from midnight3July...
...by 12:21pm21June, DeepwaterHorizon had spilled SIX ExxonValdezes.

* The RITT was emplaced on 16May and removed on 25May.
"On June 5...10,500 barrels...was collected [by the LMRP]... From June 3 through June 5, the [total] volume of oil collected was 16,600 barrels."
Then ~15,000barrels per day until after 16June when a collection&flaring system was added to the LMRP collection system.

^ Averaged minimum spill rate of 10,257.5barrels(430,815gallons) per day equals minimum flow rate of 35,000barrels per day minus the daily collection&flaring rate of 24,752.5barrels per day.
(Averaged by dividing the first subtotal by 6)
.Date collected or flared --> spilled
.On 4July, 24,955barrels --> 10,045barrels
.On 5July, 24,980barrels --> 10,020barrels
.On 6July, 24,760barrels --> 10,240barrels
.On 7July, 24,575barrels .-> 10,425barrels
.On 8July, 24,395barrels --> 10,605barrels
.On 9July, 24,790barrels --> 10,210barrels
.Subtotal 148,455barrels --> 61,545barrels
On 10July 15,195barrels --> 19,805barrels
.Subtotal 163,500barrels --> 81,350barrels
1/2 11July - 4,035barrels --> 13,465barrels (barrels flared subtracted from 17,500, half of 35,000)
.Subtotal 167,535barrels --> 94,815barrels
1/2 11July - 4,195barrels --> 13,305barrels (barrels flared subtracted from 17,500, half of 35,000)
.Subtotal 171,730barrels -> 108,120barrels

5,620,956gallons is equal to 133,832barrels (explanation below)
At midnight3July, 11,000,000gallons minus 5,379,044gallons was the volume remaining toward the 7thExxonValdez.
(133,832 was rounded down from 133,832.2916... as was 5,620,956 from 5,620,956.25,
because 5,379,044 was rounded up from 5,379,043.75)

From BPwebsite (because they overwrite frequently while rounding numbers upward),
"For the last 12 hours on July 10 (noon to midnight), approximately 4,060 barrels of oil and 9.8 million cubic feet of natural gas were flared on the Q4000.
On July 10, total oil recovered was approx. 15,200 barrels: approx. 7,096 barrels of oil were collected, approx. 8,100 barrels of oil were flared, and approx. 35.2 million cubic feet of natural gas were flared."
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Quoting Drakoen:
Strong Tropical Wave


yes, some of the models were predicting a very strong tropical disturbance once it made it to the central atlantic, however i believe the model might have changed, it's still something to keep an eye on.
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Well on his update before he went on vac he said he didnt forsee a TS in the upcomming week. So he did have it right.
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Quoting RitaEvac:


we had 4 circles at one time as soon as he left

certainly and one of those at one time had a 50% chance of developing.
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Quoting Floodman:


Nothing developed? Nothing major, certainly, but the week was hardly uneventful


we had 4 circles at one time as soon as he left
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Quoting DestinJeff:
He's back, and nothing developed during the vacation. Now we can put that Urban Legend to bed.

Welcome back, Dr Masters.


Nothing developed? Nothing major, certainly, but the week was hardly uneventful
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Quoting Drakoen:
Strong Tropical Wave

Quoting jasoniscoolman2010x:
better watching this wave here.

Let's see if both of them are still there by 8 o'clock.
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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.

I'll be watching also, Doc. Many folks (myself included) have trouble getting over the "we can't even predict next year's weather" hurdle when the discussion turns to GW. In any event, it should certainly augment the statistical approach to hurricane prediction.

Thanks for the post. Our future is ahead of us...
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Thanks for the blog update. We needed a new one.
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Quoting SavannahStorm:
I'm liking the FSU forecast of 17 storms and 10 canes. Seems much more reasonable at this point than the other forecasts.



A little Cape Verde twist on the end of that loop?
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Quoting calder:


yeh they could make the site a lot better by providing info on each tremor..


To be fair that information is available in tabular form, but since the area covered is fairly large not all of the seismic activity is related to Katla.

The key is to see if the earthquakes are becoming shallower with time, which could indicate a rising body of magma.
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yes we should jasoniscoolman2010x it has some vort at 850 it has convergence and divergence only factor that is limiting developing is that it has 20-30 kt of shear and has been increasing as well
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Quoting Patrap:
psst,

..95L too.

snicker,ack..


ack? you choke on something?
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Quoting angiest:


I really wish they would show the depth.


yeh they could make the site a lot better by providing info on each tremor..
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Good day everyone. The ground here in mexico is still super saturated and the river has calm down to an extent but rain still persist to fall every 2 hours or so! and power outages aren`t helping the situation.
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Quoting calder:
look at the seismic activity near katla yesterday - prelude to her eruption?

Link


I really wish they would show the depth.
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non-husband makes an early appearance!

:)
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On a side note, I have a visitor here from Tuscon Arizona.
He had heard about 'humidity'. But now he knows what it 'means'.
I think he is having trouble breathing. His gills are not well developed...
LOL
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look at the seismic activity near katla yesterday - prelude to her eruption?

Link
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...................... A lot of clouds in the Western Pacific...Tropical Storm Conson approaching the Philippines.....
Member Since: September 27, 2007 Posts: 1 Comments: 20569
Welcome back Dr.M you were missed by many oh yea you missed TD2

the reason Ameister12 is because it wants to gain more heat and is maybe waiting for that other wave and both become one it block out the SAL oh yea there is a ULH near it the way it is looking this could be the next Bill or Bertha but heads into the Caribbean
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Good Morning!
The weather here is--
temp- 92F
humid- 59%
heat index- 102f
pressure -1012 steady
bodily functions- sweat.

Nice wave in the east atl.
Watching that one, for sure.
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AEJ = africa eastern jet
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Welcome home, Doc.

This is from yesterday - I assume some of this dust is still present over the Atlantic. And the dust that preceded this puff.

Photobucket

Link
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I'm starting to think Conson may be forming an eyewall.

Loop
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31. MTWX
I know this is not tropics related, but since things are slow... Has anyone heard any updates on the status of the oil spill??
Member Since: July 20, 2009 Posts: 23 Comments: 1392
"My word, I've got the vapors..."



Looks like the wave may have lagged behind the dry air and is now somewhat insulated from it. Hmmmm....
Member Since: September 22, 2005 Posts: 18 Comments: 2317
Quoting Drakoen:
Strong Tropical Wave


Wow! That wave still hasn't moved a whole lot.
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26. MTWX
Good morning all!! Welcome back Dr. Masters!
Member Since: July 20, 2009 Posts: 23 Comments: 1392
I'm liking the FSU forecast of 17 storms and 10 canes. Seems much more reasonable at this point than the other forecasts.

Member Since: September 22, 2005 Posts: 18 Comments: 2317
Good post Dr. M!
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Reposting from previous blog. I don't know if this was already discussed over the weekend:

Link

HOUSTON—New laboratory test results released Friday showed that most of the tar balls that washed up on Texas shores during the past week were not from the massive Gulf of Mexico oil spill, the Coast Guard said.

Officials had initially said on Monday that the tar balls that were rolling up over the weekend on Galveston and other Texas Gulf shorelines were from the BP-operated Deepwater Horizon rig that blew up April 20, killing 11 people and causing an oil spill that has yet to be controlled. Now, the Coast Guard said only tar balls found Monday were from the rig.

The tar ball sightings in Texas, and the news that it had originated from the BP well, created a stir because it had been the only Gulf state untouched by the oil spill.

From the beginning, officials were perplexed by what they called "the weathering" of the tar balls, saying it was inconsistent with oil that had traveled 400 miles. They speculated the oil had not arrived with the currents or naturally, but may have been carried in by a vessel.

On Tuesday, National Incident Commander Thad Allen said officials were investigating five vessels that may have carried the oil to Texas.

Coast Guard spokesman Petty Officer Richard Brahm said the confusion resulted from a mistake made at a lab in Houma, La.

"It turns out that almost all the tar balls are not BP," Brahm said.

The more accurate test results arrived Friday from a Coast Guard lab in Virginia, Brahm said.

The tar balls that are from the Gulf oil spill were found Monday on McFaddin Beach, a stretch of coast east of Texas’ Bolivar Peninsula.

All oil has a distinct DNA of chemicals and the government has a database of the different oils in the reservoirs where drilling and production is going on. Further testing should be able to help officials figure out the origin of the tar balls in Texas, Brahm said. If a match is not made, it is likely they are the result of natural seepages from the seabed.
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Def looks Like a Curtain "threater".
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Strong Tropical Wave

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Good morning.

Great to have you back, Dr. Masters!
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As far as the wave emerging off Africa, the SAL does appear to be retro-grading along with it but that is no guarantee of development in the immediate short term (and especially with no model support at the moment). Just have to keep an eye on it as it passes the CV islands and see how it looks in a few days as it nears 35W.
Member Since: August 8, 2006 Posts: 0 Comments: 8868
Carried over from previous blog:

Quoting Drakoen:
It is really amazing how much amplitude these wave have; they are creating large perturbations within the AEJ.

Inquiring minds want to know.....




Okay, I consulted storms blog for the acronym list, and could not find this one listed what is AEJ?
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psst,

..95L too.

snicker,ack..
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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.