CSU and TSR continue to predict a near-average hurricane season

By: Dr. Jeff Masters , 3:18 PM GMT on August 04, 2009

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A tropical disturbance embedded in the Intertropical Convergence Zone (ITCZ), near 9N 35W, is moving west at about 15 mph. The heavy thunderstorm activity associated with this tropical wave has changed little over the past 24 hours, and remains disorganized. This morning's QuikSCAT pass showed a moderate wind shift, but nothing resembling an organized surface circulation. Top winds were in the 20 - 30 mph range. Strong easterly winds are creating about 20 knots of wind shear over the wave, which is marginally conducive for development. The disturbance is about 300 miles south of the Saharan Air Layer (SAL), so dust and dry air should not hinder development over the next few days.

Given the disturbance's current lack of organization, combined with the presence of 20 knots of wind shear, any development should be slow to occur. The forecast wind shear along the storm's path over the next five days is predicted to remain at or below 20 knots, which should allow some slow development. Sea surface temperatures (SSTs) will warm from about 28°C to 29°C as the storm progresses westward. The GFS model has been indicating some development is possible in several of its runs over the past few days, but has not been consistent with this prediction. None of the other models show any development of the system. NHC is giving the disturbance a low (less than 30% chance) of developing into a tropical depression over the next two days, which is a good forecast. The GFS and ECMWF models predict the system will be approaching the northern Lesser Antilles Islands by Sunday. Both models forecast the development of a band of very high wind shear just to the north of the islands at that time, so the long-range survival of anything that might manage to develop is in doubt.

CSU forecast team continues to predict an average hurricane season
A near-average Atlantic hurricane season is on tap for 2009, according to the seasonal hurricane forecast issued August 4 by Dr. Phil Klotzbach and Dr. Bill Gray of Colorado State University (CSU). The CSU team is calling for 10 named storms, 4 hurricanes, and 2 intense hurricanes, and an Accumulated Cyclone Energy (ACE) 83% of average. Between 1950 - 2000, the average season had 10 named storms, 6 hurricanes, and 2 intense hurricanes. But since 1995, the beginning of an active hurricane period in the Atlantic, we've averaged 15 named storms, 8 hurricanes, and 4 intense hurricanes per year. The new forecast is a step down from their June forecast, which called for 11 named storms, 5 hurricanes, and 2 intense hurricanes. Their April forecast called for 12 named storms, 6 hurricanes, and 2 intense hurricanes. The new forecast calls for a near-average chance of a major hurricane hitting the U.S., both along the East Coast (27% chance, 31% chance is average) and the Gulf Coast (26% chance, 30% chance is average). The Caribbean is also forecast to have an average risk of a major hurricane (37%; 42% is average).

The forecasters noted that while sea surface temperature anomalies have increased in the tropical Atlantic and surface pressures have fallen in recent weeks, which normally would favor higher hurricane activity, the presence of El Niño conditions in the Eastern Pacific should counteract these influences. They forecast that the current weak El Niño event will strengthen to a moderate event by September:

El Niño events tend to be associated with increased levels of vertical wind shear and decreased levels of Atlantic hurricane activity. Tropical Atlantic sea surface temperatures anomalies have warmed somewhat since our early June prediction and surface pressures have fallen somewhat. But, the negative influences of El Niño-induced strong Caribbean Basin and Main Development Region vertical wind shear typically dominate over surface pressure and sea surface temperature in the tropical Atlantic.



Figure 1. Change in Sea Surface Temperature anomaly (in °C) between July 2009 and May 2009. Most of the tropical Atlantic has warmed, relative to normal, over the past 2 months. Image credit: NOAA/ESRL.

Analogue years
The CSU team picked four previous years when atmospheric and oceanic conditions were similar to what we are seeing this year: weak to moderate El Niño conditions, and average tropical Atlantic and far northern Atlantic SSTs. Those four years were 2002, which featured Hurricane Lili that hit Louisiana as a Category 1 storm; 1965, which had Category 3 Betsy that hit New Orleans; 1963, which had Category 4 Hurricane Flora that devastated Cuba; and 1957, which didn't have any hurricanes that hit hit land during the peak part of hurricane season. The mean activity for these four years was 9 named storms, 4 hurricanes, and 2 intense hurricanes--almost the same as the 2009 CSU forecast.

How accurate are the August forecasts?
The August forecasts by the CSU team have historically offered a skill of 45 -62% higher than a "no-skill" forecast using climatology (Figure 2). However, they are using a new forecast scheme this year, so it is difficult to judge how skillful this year's forecast might be.


Figure 2. Accuracy of long-range forecasts of Atlantic hurricane season activity performed at Colorado State University (CSU) by Dr. Bill Gray's team (colored squares) and Tropical Storm Risk, Inc. (TSR, colored lines). The skill is measured by the Mean Square Skill Score (MSSS), which looks at the error and squares it, then compares the percent improvement the forecast has over a climatological forecast of 10 named storms, 6 hurricanes, and 2 intense hurricanes. TS=Tropical Storms, H=Hurricanes, IH=Intense Hurricanes, ACE=Accumulated Cyclone Energy, NTC=Net Tropical Cyclone Activity. Image credit: TSR.

August 2009 Atlantic hurricane season forecast from Tropical Storm Risk, Inc.
The British private forecasting firm Tropical Storm Risk, Inc. (TSR) also issued a new forecast today, and have increased their numbers by 20% from their June and July forecasts. TSR is also calling for a near-average season, predicting 12.6 named storms, 6.5 hurricanes, 2.8 intense hurricanes, and an Accumulated Cyclone Energy (ACE) 103% of average. Their June forecast called for 10.9 named storms, 5.2 hurricanes, 2.2 intense hurricanes, and an Accumulated Cyclone Energy (ACE) 72% of average. The storm numbers are slightly above the 50-year average of 10 named storms, 6 hurricanes, and 2 intense hurricanes. TSR predicts a 40% chance of an above-average season, 44% chance of a near-average season, and a 19% chance of a below-average season, as defined by ACE index. TSR rates their skill level as 51% above chance at forecasting the number of named storms, 60% skill for hurricanes, and 44% skill for intense hurricanes. These are far higher skill numbers than the June ones: 26% above chance at forecasting the number of named storms, 15% skill for hurricanes, and 19% skill for intense hurricanes.

TSR projects that 3.8 named storms will hit the U.S., with 1.6 of these being hurricanes. The averages from the 1950-2008 climatology are 3.2 named storms and 1.5 hurricanes. Their skill in making these August forecasts for U.S. landfalls is 25% above chance. In the Lesser Antilles Islands of the Caribbean, TSR projects 1.1 named storms, 0.5 of these being hurricanes. Climatology is 1.1 named storms and 0.5 hurricanes.

TSR cites one main factor for their increased forecast: higher sea surface temperatures than expected over the tropical Atlantic, due to the fact that the trade winds over the Atlantic should be slower than originally anticipated. Faster than average trade winds create less spin for developing storms, and allow the oceans to cool down, due to increased mixing of cold water from the depths and enhanced evaporational cooling.

The CSU and TSR groups are done making forecasts for the coming hurricane season, but NOAA is still due to put out an August update.

I'll have an update on Wednesday.
Jeff Masters

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Quoting Patrap:
I do have a occasional moment of sanity press,but it usually passes rather fast.



Good! One can have too much of a good thing...but once in a while is OK...
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I will take a Fresca and extra butter on my popcorn. Oh and is anyone selling candy? I want a candy bar.
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I think there was a blue circle placed over the entire basin this season; we could not see it cause it was the same color of the water. Blue means, less than 1 percent chance of anything forming.
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I do have a occasional moment of sanity press,but it usually passes rather fast.

Member Since: July 3, 2005 Posts: 428 Comments: 129910
Wish this thing could go into the CARIB. but shear to HIGH!!
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Quoting Patrap:
Enjoy the week and weekend,the Atlantic is Quiet except for a AOI,.nothing is imminent nor expected to organise thru the next 48.

Fresca's are on Sale too.


best, most rational post of the season...
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Ahh.. the typical blog cycles.
Last night through this morning was: 'Why isn't the NHC mentioning this?' to at 8 PM 'Pathetic, should be dropped' tis the season folks! Anyone want some popcorn and a free soda for the game on this here blog?
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Quoting Patrap:
2009 Atlantic Tropical Season

One of these days that poor guy is going to get that mower started.
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wish (wsh)
n.
1. A desire, longing, or strong inclination for a specific thing.
2. An expression of a desire, longing, or strong inclination; a petition.
3. Something desired or longed for.
v. wished, wish·ing, wish·es
v.tr.
1. To long for; want. See Synonyms at desire.
2. To entertain or express wishes for; bid: He wished her good night.
3. To call or invoke upon: I wish them luck.
4. To order or entreat: I wish you to go.
5. To impose or force; foist: They wished a hard job on her.
v.intr.
1. To have or feel a desire: wish for the moon.
2. To express a wish.

--------------------------------------------------------------------------------

[Middle English wissh, from wisshen, to wish, from Old English wscan; see wen-1 in Indo-European roots.]

--------------------------------------------------------------------------------

wisher n.
Usage Note: Wish is widely used as a polite substitute for want with infinitives: Do you wish to sit at a table on the terrace? Anyone who wishes to may leave now. This usage is appropriate for formal style, where it is natural to treat the desires of others with exaggerated deference. The corresponding use of wish with a noun-phrase object is less frequent: Anyone who wishes an aisle seat should see an attendant. Both usages are likely to sound stilted in informal style, however, and want may be substituted for wish. · A traditional rule requires the use of were rather than was in a contrary-to-fact statement that follows wish: I wish I were (not was) lighter on my feet. While many people continue to insist on upholding this rule, the indicative was in such clauses can be found in the works of many well-known writers. See Usage Notes at if, want.
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Purty Images of the Current Atlantic

Atlantic Ocean View (Updated ~3 hours)
Member Since: July 3, 2005 Posts: 428 Comments: 129910
Why would anyone in their right mind wish for a named storm. They can be deadly so why hope for one?
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861. ackee
2009 continue to be slow seasons so far dont think that is going to change its anybody guess if we are going to see Ana anytime soon.
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Enjoy the week and weekend,the Atlantic is Quiet except for a AOI,.nothing is imminent nor expected to organise thru the next 48.

Fresca's are on Sale too.
Member Since: July 3, 2005 Posts: 428 Comments: 129910
Quoting futuremet:
All of this blabber whether this will become Ana or not is futile; some are being overly obstinate because of this. Whenever convection increases or the models invigorate this system, some quickly draw to the conclusion that this is Ana. On the contrary, when convection is fizzling and models are picking up less, downcasters run rampant. The use of satirical language is not beneficial either. This is no different than right-wing and left-winged politics. The fact is, this will not organize substantially until it detaches itself from the ITCZ. It is best to wait until this time tomorrow to draw a valid conclusion. To be honest, I am leaning more toward the ECMWF’s solution. It has proven to be very effective this year.


Very well said

what is the ECMWF solution by the way?
Quoting sebastianflorida:
Red is associated with fiery heat and warmth. It can also mean danger (burning).

Red is the color of blood, and as such has strong symbolism as life and vitality. It brings focus to the essence of life and living with emphasis on survival. Red is also the color of passion and lust.

Put some red in your life when you want:

increased enthusiasm and interest
more energy
action and confidence to go after your dreams
protection from fears and anxieties


And orange, well, in the middle.
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All of this blabber whether this will become Ana or not is futile; some are being overly obstinate because of this. Whenever convection increases or the models invigorate this system, some quickly draw to the conclusion that this is Ana. On the contrary, when convection is fizzling and models are picking up less, downcasters run rampant. The use of satirical language is not beneficial either. This is no different than right-wing and left-winged politics. The fact is, this will not organize substantially until it detaches itself from the ITCZ. It is best to wait until this time tomorrow to draw a valid conclusion. To be honest, I am leaning more toward the ECMWF’s solution. It has proven to be very effective this year.
Member Since: July 19, 2008 Posts: 43 Comments: 4051
Orange is a power color. It is one of the healing colors. It is said to increase the craving for food. It also stimulates enthusiasm and creativity. Orange means vitality with endurance. People who like orange are usually thoughtful and sincere. Lady luck's color is orange. I have been told that if a change of any kind is need in life, just burn an orange candle for 7 nights.

Orange Energy
While red is associated with fiery heat, orange is associated with the benign warmth of the sun. A dynamic color to be sure, orange offers a more thoughtful control than explosive red. Curiosity is a driving characteristic of orange, and with it comes exploration of new things.

Put some orange in your life when you want:

to spice things up when you feel time is dragging
to become more involved in something
to increase creativity
relief from things becoming too serious
Member Since: Posts: Comments:
Red is associated with fiery heat and warmth. It can also mean danger (burning).

Red is the color of blood, and as such has strong symbolism as life and vitality. It brings focus to the essence of life and living with emphasis on survival. Red is also the color of passion and lust.

Put some red in your life when you want:

increased enthusiasm and interest
more energy
action and confidence to go after your dreams
protection from fears and anxieties
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000
ABNT20 KNHC 042333
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT TUE AUG 4 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

DISORGANIZED SHOWERS AND THUNDERSTORMS ABOUT 1000 MILES SOUTHWEST OF
THE CAPE VERDE ISLANDS ARE ASSOCIATED WITH A TROPICAL WAVE. ANY
DEVELOPMENT OF THIS SYSTEM WILL BE SLOW TO OCCUR AS IT MOVES
WESTWARD AT ABOUT 15 MPH. THERE IS A LOW CHANCE...LESS THAN 30
PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER SCHAUER CLARK/BRENNAN


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Quoting willdunc79:
the tropical wave/disturbance is actually no longer "just" a "wave" to me IMHO. It's very awfully weak but there is a surface low(broad too) that has maintained & sustained convection so it "should" be an invest actually or declared one by tonight/early Wednesday morning at the latest. This disturbance just needs to gain some latitude and I believe that will help jump start it going.


Gain latitude into that? The dust doesnt seem to be too strong but that may still be enough to choke it or even kill it.

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Color Yellow



The shade of yellow determines the meaning. Pure, bright and sunny yellow is the easiest color to see. People who are blind to other colors can usually see yellow. Yellow is full of creative and intellectual energy. Always use yellow note pads.

Yellow symbolizes wisdom. Yellow means joy and happiness. People of high intellect favor yellow. Yellow daffodils are a symbol of unrequited love. Sunday's color is yellow-gold.

Yellow Energy
Like the energy of a bright sunny day, yellow brings clarity and awareness. The shade of yellow determines its effect: Yellow-green can mean deceit, and creates a disoriented feeling. Orange-yellow imparts a sense of establishment. Clean light yellow clears the mind, making it active and alert.

Put some yellow in your life when you want:

clarity for decision-making
relief from 'burnout', panic, nervousness, exhaustion
sharper memory and concentration skills
protection from lethargy and depression during dull weather
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2009 Atlantic Tropical Season

Member Since: July 3, 2005 Posts: 428 Comments: 129910
YOU GUYS CHOOSE!!!





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the tropical wave/disturbance is actually no longer "just" a "wave" to me IMHO. It's very awfully weak but there is a surface low(broad too) that has maintained & sustained convection so it "should" be an invest actually or declared one by tonight/early Wednesday morning at the latest. This disturbance just needs to gain some latitude and I believe that will help jump start it going.
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circle
Noun
1. a curved line surrounding a central point, every point of the line being the same distance from the centre
2. the figure enclosed by such a curve
3. something formed or arranged in the shape of a circle: they ran round in little circles
4. a group of people sharing an interest, activity, or upbringing: his judgment is well respected in diplomatic circles
5. Theatre the section of seats above the main level of the auditorium
6. a process or chain of events or parts that forms a connected whole; cycle
7. come full circle to arrive back at one's starting point

Well, according to this, "There aint no circle"!
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Quoting kmanislander:


Was it one of the ducks I have been feeding in my yard ??
I think those are mallards.
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mmmm...I think it was THIS duck...

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SST are favorable, pressures are dropping,wind shear is low, spin is there. This potential system is not done, thats why the forecast is for SLOW developement.
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Quoting sebastianflorida:
Think I'll go play with my red crayon, since it will be the only red I see this season.


lol
Member Since: March 19, 2009 Posts: 0 Comments: 1421

Link

I think its doing what's called "trundling."
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Quoting sebastianflorida:
Think I'll go play with my red crayon, since it will be the only red I see this season.


dont pout lol, we know you will be the first one jumping in here when we get a named storm
1. DISORGANIZED SHOWERS AND THUNDERSTORMS ABOUT 1000 MILES SOUTHWEST OF
THE CAPE VERDE ISLANDS ARE ASSOCIATED WITH A TROPICAL WAVE. ANY
DEVELOPMENT OF THIS SYSTEM WILL BE SLOW TO OCCUR AS IT MOVES
WESTWARD AT ABOUT 15 MPH. THERE IS A LOW CHANCE...LESS THAN 30
PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS.
Member Since: July 21, 2009 Posts: 0 Comments: 552
Quoting stormpetrol:
This is going be Ana, no question, no doubt, a whistling duck just told me so! :)

Was it this duck? LOL
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It's all an illusion!

heh heh heh
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Think I'll go play with my red crayon, since it will be the only red I see this season.
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Quoting stormpetrol:

Hi Kman , welcome back home, hope you had a great vacation. I got about 45 whistling ducks that has taken over my yard now, 12 young ones , they are just beautiful, I feed them, they have my cars scratched to pieces that why I won't buy a new car but I just adore them, can't help it.


Thanks, great to be back. Nearly every time I pass your home I see them sleeping on your car !. I also feed about 30 in my yard. They eat 50 lbs of scratch feed every 7 days. Thankfully it only costs $14 a bag LOL

Off to feed them now. Back later
Member Since: August 19, 2006 Posts: 0 Comments: 15948
No orange allowed till Aug 15th,sorry they on back order
Member Since: July 3, 2005 Posts: 428 Comments: 129910
If you ask me...it has a pretty good chance of becoming 'ANA':
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The NHC still has not said it has become "less organized"
Member Since: June 29, 2009 Posts: 13 Comments: 5315
Quoting kmanislander:


Was it one of the ducks I have been feeding in my yard ??

Hi Kman , welcome back home, hope you had a great vacation. I got about 45 whistling ducks that has taken over my yard now, 12 young ones , they are just beautiful, I feed them, they have my cars scratched to pieces that why I won't buy a new car but I just adore them, can't help it.
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nice spin, but the moister is being sucked right out of the "feature"!
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Out for a while
Member Since: August 19, 2006 Posts: 0 Comments: 15948
Pat dont you have a orange crayon in your box.
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788. Drakoen
In case you missed it earlier,
I joined the two hi-res QS panels that caught this area. Link
Member Since: October 13, 2005 Posts: 4 Comments: 2156
Phew,,,Im glad that yellow circle is out there,..can we see it on the IR Loop?


GOES-12 IR Ch-4 Loop,large
Member Since: July 3, 2005 Posts: 428 Comments: 129910
Well...still hanging on:
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Quoting Patrap:


No Red? lol

Member Since: March 19, 2009 Posts: 0 Comments: 1421
Member Since: July 3, 2005 Posts: 428 Comments: 129910
Quoting StSimonsIslandGAGuy:
I don't recall any reputable blogger yesterday saying that the Atlantic wave was about to turn into Ana....


I didn't say "reputable"...it was just a general comment.
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Quoting stormpetrol:
This is going be Ana, no question, no doubt, a whistling duck just told me so! :)


Was it one of the ducks I have been feeding in my yard ??
Member Since: August 19, 2006 Posts: 0 Comments: 15948
Quoting StSimonsIslandGAGuy:
I don't recall any reputable blogger yesterday saying that the Atlantic wave was about to turn into Ana....


Key word being "reputable"
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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.

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