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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114. 7544
Quoting TampaSpin:
Tropical Update
Posted by TampaSpin on July 12, 2010 at 12:30 PM




The blue circles are areas of Interest by me and not by the NHC!!!


looks right with the cmc showing is tyhe africa wave the one the cmc shows for so fla at 144 tia tampa

Link
Member Since: May 6, 2007 Posts: 0 Comments: 6617
113. IKE
12Z parallel GFS run through July 28th shows a system affecting the Yucatan and northern Mexico in 8-10 days.

Problem is...last week it showed a system affecting the same areas in the same time period. Now today it's doing the same thing. I know time waits for no one.

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting WatchingThisOne:


Click on the "Table" tab. The quakes seem to be clustered around two depths ... 1 km and 5 km. They are all very low mag and I'm not sure how concerned we should be.


If they aren't getting more shallow then there may be nothing to be concerned about. Katla is under a glacier and seasonal melt will likely cause some seismic activity as the crust relaxes. Now, the recent clustering is a possible cause of concern, but again if they are not getting more shallow through time it may be nothing important.
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Tropical Update
Posted by TampaSpin on July 12, 2010 at 12:30 PM




The blue circles are areas of Interest by me and not by the NHC!!!
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Quoting WatchingThisOne:


Click on the "Table" tab. The quakes seem to be clustered around two depths ... 1 km and 5 km. They are all very low mag and I'm not sure how concerned we should be.


My stupid question of the day - I realize that we're supposed to have earthquake kits like folks have hurricane kits. But where exactly are you supposed to KEEP them. If your house falls in, it would be kind of hard to get it out of the house and I'm not sure keeping bottled water outside in the sunshine is such a great idea either. Any tips?
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Quoting BFG308:
For Reference purposes, the Mississippi River outputs about 3.3 Million Gallons of water every second, and the spill is (see asceptre) ~1.3 Million gallons per day. The gulf contains 643 quadrillion gallons.
I guess, someone will now determine, calculate or estimate how many parts per billion, million perhaps thousand, the spill is in comparison to the GOM.
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Welcome back Jeff. Being in New Hampshire, I can attest to those really hot and humid days last week. Now you should try Maine in February and experience the -20's or even a good Nor'easter. Now that's my favorite time.
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Quoting angiest:


I really wish they would show the depth.


Click on the "Table" tab. The quakes seem to be clustered around two depths ... 1 km and 5 km. They are all very low mag and I'm not sure how concerned we should be.
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Quoting AussieStorm:

Karen???
It was from a joke in 2007.
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Quoting NttyGrtty:
10 year average: 16 named storms, 9 hurricanes, 4 major. Looks like the science folks are downscaling their predictions toward the statistics folks...
Averaging 4 majors a year. Wow
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What the CMC appears to threaten FL with looks very much like it is associated with the current Cape Verde wave.

That said, I'm more intrigued by the random development in the Caribbean toward the last.
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Quoting thewindman:
We Better Get a move on if we will be anywhere CLOSE to those predications. Already had 5 by todays date NAMED in 2005 and 7 by the end of JULY. This year 1 (with no new one in site)


As I mentioned this morning, 2005 will probably not be repeated anytime soon, and, the Pros get a second bite at the apple when they update their numbers again in August based upon then current conditions.......As has been said on here every year, it only takes one bad storm in the right place.........It's really not about the ultimate numbers; it's all about trajectory and landfall.
Member Since: August 8, 2006 Posts: 0 Comments: 8269
Quoting thewindman:
We Better Get a move on if we will be anywhere CLOSE to those predications. Already had 5 by todays date NAMED in 2005 and 7 by the end of JULY. This year 1 (with no new one in site)

i for one do NOT want this season to get a move on.
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2010 Hurricane Preparation


With the Lil break in the 2010 action and the meat of the season to come still,
Now is a good time to buff up ones action plan for a Storm.


Hurricane Preparation is a Family oriented project that can and should include every member for input.


Also,review ones evac plan and destination too.

Time spent wisely now will save one from stress then, and that can affect ones capability to make sound and timely decisions when it counts.
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10 year average: 16 named storms, 9 hurricanes, 4 major. Looks like the science folks are downscaling their predictions toward the statistics folks...
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We Better Get a move on if we will be anywhere CLOSE to those predications. Already had 5 by todays date NAMED in 2005 and 7 by the end of JULY. This year 1 (with no new one in site)
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Most predictions have been for a season with far above-normal Atlantic tropical cyclones. Predicting great departures from normal is always risky, especially when many factors are unknown. I wouldn't forecast snow in Miami no matter how good the indicators. I predict the hurricane season will be a lot closer to normal than most people think. The UK Glo-Sea model isn't very brave: a 70% chance of 13 to 27 named storms. For the record, I give it a 100% chance of having between 1 and 500 named storms this season.
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Climate Prediction Center Weekly update has nino 3.4 down to -0.8C. That number is down from the -0.6C of last week's update. This means La Nina continues to get stronger.

Link
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Quoting BFG308:
For Reference purposes, the Mississippi River outputs about 3.3 Million Gallons of water every second, and the spill is (see asceptre) ~1.3 Million gallons per day. The gulf contains 643 quadrillion gallons.


True that. And for further reference purposes: fish can extract oxygen from water; water doesn't need to be scrubbed off of surfaces with detergent and a brush; water doesn't leave blobs of gooey, sticky tar in and on beach sand; birds can fly with water on their wings; fish and turtle eggs layed in and around water will oftentimes hatch; beaches are seldom closed to visitors due to pollution by water; nobody needs a HazMat suit to work with water...
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Thanks Storm
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Blog Update " Puerto Rico " Weather- Link
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Currently at Homebush, Sydney, Australia.
Temperature 52.3°F rising
Dew Point 49.3°F rising
Feels Like 52.3°F
Relative Humidity 89%
Wind
Wind Gusts -
Pressure -
Fire Danger -
Rain since 9am/last hr 0.0mm / -

Goodnight.
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Quoting btwntx08:
someone quote my post #74 so ike can see i know he still has me on ingore for no reason


I mean this with no malice intended but having someone quote you so someone who ignored will read what you say defeats the purpose of the ignore function. Factual statement. I mean no harm
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Quoting hydrus:
The Caribbean thing is probably the remnant low of Karen.;0

Karen???
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Quoting 7544:
CMC wants to bring something to so fla

and look whats in th carb. lol

Link
The Caribbean thing is probably the remnant low of Karen.;0
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Burst of wind, rain and cold heading east

Residents in southeastern states can expect similar weather to that which has just hit the Perth area, and it's not far away.

Numerous strong wind warnings have been issued for South Australia, Tasmania, Victoria and New South Wales for the coming few days.

Prone areas of these states such as the coasts and ranges are a good chance to cop wind gusts in excess of 90km/h. Generally it won't be quite as windy as it has been in southwest Western Australia but windy enough to cause damage.

Rain will accompanying this burst of wind and it looks substantial. Agricultural areas in each state will have widespread falls of 10 to 20mm worth of rain by next weekend. For areas on and just inland of the ranges, particularly in Victoria and NSW, 20 to 40mm is a chance.

Once most of the rain has passed, cold winds will follow with further showers, some showers with small hail. It will be cold enough for a decent dump of fresh snow over the alpine areas, most likely the best of the snow season so far.

Weatherzone 2010
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79. 7544
CMC wants to bring something to so fla

and look whats in th carb. lol

Link
Member Since: May 6, 2007 Posts: 0 Comments: 6617
For Reference purposes, the Mississippi River outputs about 3.3 Million Gallons of water every second, and the spill is (see asceptre) ~1.3 Million gallons per day. The gulf contains 643 quadrillion gallons.
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and a satellite loop of TD2??
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Good Evening all. Just started a new Blog with Info on TS Conson.
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Does anybody have a saved radar loop of TD2 coming ashore???
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69. MTWX
thank you for the information aspectre. that whole situation is, for lack of a better word, horrible!
Member Since: July 20, 2009 Posts: 23 Comments: 1391
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No storm names, but stuff to watch
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Just trying to understand the good Dr's post:
In 2007 Dr Mann predicted 15 storms and 15 were observed.
In 2007 the UK Met Office predicted 10 Named Storms and 12 actually occurred.

These statements seem a bit contradictory, what am I missing ?
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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

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About JeffMasters

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