CSU leaves their hurricane forecast unchanged; 92L and Colin's remains worth watching

By: Dr. Jeff Masters , 2:38 PM GMT on August 04, 2010

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Tropical Storm Colin was ripped apart by wind shear yesterday, and the storm's remnants are passing just north of the northernmost Lesser Antilles Islands today. Most of the heaviest thunderstorms are passing north of the islands, as seen on Guadeloupe radar. Long range radar out of Puerto Rico also shows this. Colin's remains are in a rather unfavorable environment for re-development, since the disturbance is passing beneath an upper-level low pressure system with dry air and high wind shear. Wind shear is a high 20 - 25 knots over Colin's remains this morning. Recent satellite imagery shows that heavy thunderstorm activity has increased in intensity and areal coverage over the past few hours, though, and Colin's remnants will need to be monitored for re-development.

Forecast for Colin's remains
The latest SHIPS model forecast predicts that wind shear will drop from 15 - 25 knots today to a moderate 15 - 20 knots on Thursday. Wind shear will continue to decline over the weekend, and this relaxation of shear prompts most of the major models to predict re-development of Colin sometime in the next four days. NHC is giving Colin's remain a 20% chance of developing into a tropical depression by Friday morning. A major trough of low pressure is expected to move off the U.S. East Coast on Friday, and this trough will pull Colin to the northwest and cause it to slow down. By Friday, Colin will be moving at half of its current speed. All of the major forecast models are predicting that the trough of low pressure will be strong enough to fully recurve Colin out to sea early next week. Colin's remains may pass close to Bermuda on Saturday, with the latest 06Z (2am EDT) run of the GFDL model predicting that Bermuda will experience tropical storm force winds on Saturday as Colin passes to the west of the island. The Hurricane Hunters are scheduled to investigate Colin's remains at 8pm EDT tonight. It currently appears that Colin will only be a threat to Bermuda and Canada.


Figure 1. Morning satellite image of Colin's remains and Invest 92L.

92L
A tropical wave (Invest 92) in the south-central Caribbean is moving west at 15 - 20 mph. This wave is over warm water and is experiencing low wind shear of 5 - 10 knots, and could show some development over the next two days. However, the wave's rapid westward motion should bring it ashore over Nicaragua and Honduras on Friday, or the Yucatan Peninsula on Saturday, and 92L probably does not have enough time over water to develop into a tropical depression. NHC is giving a 20% chance of this disturbance developing into a tropical depression by Friday morning. This storm was being tagged as 98L yesterday; I'm not sure why it is being called 92L today.

CSU's forecast numbers for the coming hurricane season remain unchanged
A very active Atlantic hurricane season is on tap for 2010, according to the seasonal hurricane forecast issued today, August 4, by Dr. Phil Klotzbach and Dr. Bill Gray of Colorado State University (CSU). The CSU team continues to call for 18 named storms, 10 hurricanes, 5 intense hurricanes, and an Accumulated Cyclone Energy (ACE) index 185% of average. These are the same numbers as their June 2 forecast. 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 14 named storms, 8 hurricanes, and 4 intense hurricanes per year. The new forecast continues to call for a much above-average chance of a major hurricane hitting the U.S., both along the East Coast (50% chance, 31% chance is average) and the Gulf Coast (49% chance, 30% chance is average). The risk of a major hurricane in the Caribbean is also high, at 64% (42% is average.)

The forecasters cited four main reasons for an active season:

1) Moderate La Niña conditions should be present during the most active portion of this year's hurricane season (August - October). This should lead to reduced levels of vertical wind shear compared with what was witnessed in 2009.

2) Current SST anomalies are running at near-record warm levels. These very warm waters are associated with dynamic and thermodynamic factors that are very conducive for an active Atlantic hurricane season.

3) Very low sea level pressures prevailed during June and July over the tropical Atlantic. Weaker high pressure typically results in weaker trade winds that are commonly associated with more active hurricane seasons.

4) We are in the midst of a multi-decadal era of major hurricane activity, which began in 1995. Major hurricanes cause 80 - 85 percent of normalized hurricane damage.

Analogue years
The CSU team picked four previous years when atmospheric and oceanic conditions were similar to what we are seeing this summer. Those four years were 2005, the worst hurricane season of all time; 1998, which featured 3 major hurricanes, including Category 5 Hurricane Mitch; 1952, a relatively average year that featured just 7 named storms, but 3 major hurricanes; and 1958, a severe season with 5 major hurricanes. The mean activity for these five years was 17 named storms, 11 hurricanes, and 5 intense hurricanes, almost the same as the 2010 CSU forecast.

How accurate are the August forecasts?
The August forecasts by the CSU team over the past 12 years have had a skill 21% - 44% higher than a "no-skill" climatology forecast for number of named storms, hurricanes, intense hurricanes, and the ACE index (Figure 2). This is a good amount of skill for a seasonal forecast, and these August forecasts can be useful to businesses such as the insurance industry and oil and gas industry that need to make bets on how active the coming hurricane season will be. This year's August forecast uses a new formula, so we don't have any history on how the technique has behaved in the past. An Excel spreadsheet of their forecast skill (expressed as a mathematical correlation coefficient) show values from 0.61 to 0.65 for their previous August forecasts using different techniques, which is respectable.


Figure 2. Comparison of the percent improvement over climatology for May and August seasonal hurricane forecasts for the Atlantic from NOAA, CSU and TSR from 1999-2009 (May) and 1998-2009 (August), using the Mean Squared Error. The British firm Tropical Storm Risk (TSR) will issue their outlook for the 2010 Atlantic hurricane season on June 4. Image credit: Verification of 12 years of NOAA seasonal hurricane forecasts, National Hurricane Center.

The British private forecasting firm Tropical Storm Risk, Inc. (TSR) is scheduled to release their August forecast later today. NOAA will also be issuing their August forecast sometime in the next week.

This season has had three named storms so far (Alex, Bonnie, and Colin.) It will be difficult to have a season with 19 or more named storms, since the four seasons that had at least 19 named storms all had at least five named storms by this point (August 4.) These four seasons were 1887, 1933, 1995, and 2005.

Next update
I'll have an update on Thursday morning.

Jeff Masters

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1912. robj144
Quoting AussieStorm:

It's a croc not a gator That one was eating cows and goats before it was caught and shot. By there is another 1 similar size out and about up in the top end.


Why did they shoot it? They don't relocate them?
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miami09 post that mjo chart again bro...it didnt show up on my screen...thanks
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Quoting aquak9:
hi jupiter, no not pot-stirring. Not at all. If I can't add something weather-related, or at least a little humorous, I usually just lurk.


Without humor this blog would pretty much be the worst experience ever.
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Quoting Orcasystems:
What would be nice is if we had some function that would allow us to see how long a user has been a member ;)
Good idea. LOL

I know some sites have a feature like that, but they're more list / group sites than blogs IIRC....

Member Since: October 25, 2005 Posts: 19 Comments: 22143
Keen obs there Cyclonic! You are right


Quoting CyclonicVoyage:
You can even see the leading edge of the convection TRYING to wrap. Shear isn't having it. Persistence is the key as always, shear could kill it again.
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1907. txjac
Quoting AussieStorm:
that one 6.5m or 21 feet, age, between 80-100years, weight not known but took 2 landcruisers/toyota 4x4's to pull it.


Wow! Didnt realize that they could live that long
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Quoting BDAwx:


The end of July saw huge amounts of rain over our Cup Match (3-6"). There was some low-lying flooding but it wasn't too bad. The heat is back on now and heat indices are back into the 100*F range.

A good rainstorm from the remnants would be a blessing for some right now: still 9" down on the year.

Do you think that "cool" weather where you are will have any impact on the hurricane season?
I've been speculating about this, and wondering if the lower than average pressure in the area is causing stronger easterlies. But I'm not seeing huge amounts of evidence to support that. I do know we've been in the vicinity of either a passing trough or the TUTT zone for most of July, making it rainier than usual here. I guess that's kept it cool. I suspect it will be much hotter - more like normal - during the rest of Aug-Sep-Oct....
Member Since: October 25, 2005 Posts: 19 Comments: 22143
Quoting stormhank:
When the MJO returns to the atlantic basin region will that mena more ridging and less storms recurving??? meaning more US threats??


Possibly.
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Quoting txjac:


And just how big are these? Like length and weight please?
that one 6.5m or 21 feet, age, between 80-100years, weight not known but took 2 landcruisers/toyota 4x4's to pull it.
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1902. aquak9
hi jupiter, no not pot-stirring. Not at all. If I can't add something weather-related, or at least a little humorous, I usually just lurk.
Member Since: August 13, 2005 Posts: 166 Comments: 25941
Quoting 7544:
is he moving at all

is the hh in it last 10 pages of garbage secchhhhh get with it gang

anyhow colin is lookin better now but still dont see him moving much did he stall?


Drifting around looks like.
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Quoting aquak9:


thanks MH09. Believe me, after the bashing I got? The COON will be back!!!
Lol, I don't think anyone reported you, maybe an admin or something was on here and just removed the comment because of the off-tropic image. Oh well. Good luck with da' COONS!
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1899. SWMIWX
Quoting pottery:
Good Evening...
First evening in a long time when I can see the Stars in a Clear sky.

Probably a Sign that all is well with Ebony, our Black Lab, who we put down today.
She was a Good Companion for 13 years, and will be truly missed.
Wife is Sad, so I am in Comforting Mode.

Keep well, All.


So sorry, Pottery
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1898. tkeith
Pottery have yoou seen this?
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Any idea where recon. is? Google Earth has not updated in forever.
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Quoting stormhank:
When the MJO returns to the atlantic basin region will that mena more ridging and less storms recurving??? meaning more US threats??
Indeed, upward motion over the Atlantic translates to ridging over the S.E US. As you can see in the graph below, the MJO is well on its way to our octants.

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1894. pottery
Thanks all...
Much Appreciated.
Out for now.........
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Quoting aquak9:


thanks MH09. Believe me, after the bashing I got? The COON will be back!!!


Aquak9
Stirring the pot again?
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1891. angiest
Quoting tkeith:
1851. pottery

wish I could find that Rainbow Bridge post Pottery :(

I'm sad for yall...


Its all over the internet, Google is your friend..
Member Since: August 26, 2006 Posts: 16 Comments: 4766
1890. aquak9
Quoting MiamiHurricanes09:
aquak9,

Hey! I saw the raccoon pictures! LOL, it was pretty cool.


thanks MH09. Believe me, after the bashing I got? The COON will be back!!!
Member Since: August 13, 2005 Posts: 166 Comments: 25941
Quoting pottery:
Good Evening...
First evening in a long time when I can see the Stars in a Clear sky.

Probably a Sign that all is well with Ebony, our Black Lab, who we put down today.
She was a Good Companion for 13 years, and will be truly missed.
Wife is Sad, so I am in Comforting Mode.

Keep well, All.


I know how you guys feel. It sucks to put down a dog. I am sorry for the both of you. Trust me, I am having tears just thinking about Duncan, the Golden Retreiver I had.
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1888. breald
Quoting pvbeachbum:


Condolences on the loss of your pet Pottery - I know the feeling well - lost 2 of my cats in the last two years. But Ebony will be waiting for you and your wife at the Rainbow Bridge!


Pottery, so sorry to hear of your loss. Pets are so special and Ebony will always be a part of your heart. Take care.
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When the MJO returns to the atlantic basin region will that mena more ridging and less storms recurving??? meaning more US threats??
Member Since: Posts: Comments:
1886. Becca36
Quoting pottery:
Good Evening...
First evening in a long time when I can see the Stars in a Clear sky.

Probably a Sign that all is well with Ebony, our Black Lab, who we put down today.
She was a Good Companion for 13 years, and will be truly missed.
Wife is Sad, so I am in Comforting Mode.

Keep well, All.

Sorry to hear of your loss.
Member Since: Posts: Comments:
Maybe before I joined in Oct 05 there was all this sweetness and light going on. But I know in 2006 there was some serious dogfighting in here. Only thing I'm going to say about it is it was mostly about whose forecast was more accurate, but it always degenerated to namecalling and in some instances [rare] swearing and cussing out. This blog has NEVER been a perfect place - that's nostalgia - because its members have never been perfect people. Only things that work consistently here are
1) tolerance to differing views [agree to disagree, eat crow if u are wrong]
2) willingness to ignore / flag / report egregious and flagrant violations of blog policy
3) staying focused on the wx discussions that in the end brought the vast majority of us to the blog.

Whenever we get off track in one of these ways, the blog degenerates. Even the so-called humorists add to the blog, so long as they know when to stop. There's such a thing as overkill, after all.
Member Since: October 25, 2005 Posts: 19 Comments: 22143
Quoting pottery:
Good Evening...
First evening in a long time when I can see the Stars in a Clear sky.

Probably a Sign that all is well with Ebony, our Black Lab, who we put down today.
She was a Good Companion for 13 years, and will be truly missed.
Wife is Sad, so I am in Comforting Mode.

Keep well, All.
Oh man, my condolences.
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1883. tkeith
1851. pottery

wish I could find that Rainbow Bridge post Pottery :(

I'm sad for yall...
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You can even see the leading edge of the convection TRYING to wrap. Shear isn't having it. Persistence is the key as always, shear could kill it again.
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hmmm looking at the steering map and it looks like the wind have fallen greatly from earler today to 00Z

18Z



00Z (now)

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1879. angiest
1868 - The presence of active moderators is about the best thing that can happen to a forum. (Speaking as a mod elsewhere).
Member Since: August 26, 2006 Posts: 16 Comments: 4766
William Dampier on July 4, 1687, in the South China Sea, marks the first record of the passing of the eye of a hurricane (in the Northwest Pacific Ocean basin, a hurricane is called a typhoon).
"When the cloud begins to move apace, you may expect the Wind presently. It comes on fierce, and blows violently at N.E. 12 hours more or less … When the wind begins to abate it dyes (sic) away suddenly, and falling flat calm, it continues for an hour, more or less: then the wind comes about to the S.W. and it blows and rains as fierce from thence, as it did before at N.E. and as long."
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1877. ncstorm
Quoting BDADUDE:

agreed


Signed Up: 2006-08-19 18:07:25 -almost 4 years I have been a member
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Pat did you see that waterspout over the lake ? It was just reported 15 minutes ago
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1875. IKE
Quoting watchingnva:


agreed completely!!!


Should be one for weather only....tropics...tornado...severe....winter...summer...

GW and weather blog just don't mix well together.
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Quoting MiamiHurricanes09:
Indeed, I agree. I strong believe that Colin has a closed surface circulation. I would upgrade it at 11PM EDT.


And Ex-Colin sure looks like a good circulation on the pics I've seen posted here lately!

Unfortunately, my husband's ship is heading down into it again on their way to PR - they are currently east of the Bahamas and Miami...
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Quoting pottery:
Good Evening...
First evening in a long time when I can see the Stars in a Clear sky.

Probably a Sign that all is well with Ebony, our Black Lab, who we put down today.
She was a Good Companion for 13 years, and will be truly missed.
Wife is Sad, so I am in Comforting Mode.

Keep well, All.
Sorry for the loss Pottery
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1872. txjac
Quoting pottery:
Good Evening...
First evening in a long time when I can see the Stars in a Clear sky.

Probably a Sign that all is well with Ebony, our Black Lab, who we put down today.
She was a Good Companion for 13 years, and will be truly missed.
Wife is Sad, so I am in Comforting Mode.

Keep well, All.


So sorry to hear that pottery ...I used to have a black lab too! loved that dog.
Member Since: Posts: Comments:
Quoting pottery:
Good Evening...
First evening in a long time when I can see the Stars in a Clear sky.

Probably a Sign that all is well with Ebony, our Black Lab, who we put down today.
She was a Good Companion for 13 years, and will be truly missed.
Wife is Sad, so I am in Comforting Mode.

Keep well, All.


Pottery, so sorry. Nothing harder than having to say goodbye to an old friend. My condolences to the wife.
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pottery so sorry to hear! :-(
Member Since: July 8, 2005 Posts: 259 Comments: 24042
Quoting pottery:
Good Evening...
First evening in a long time when I can see the Stars in a Clear sky.

Probably a Sign that all is well with Ebony, our Black Lab, who we put down today.
She was a Good Companion for 13 years, and will be truly missed.
Wife is Sad, so I am in Comforting Mode.

Keep well, All.


Sorry Pottery.. I should have read it all before typing. Sorry for the lose.. its not fun
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Quoting sassisu:
This is my first and last post. Been a lurker for a couple of years.I have lurked quietly and learned from Patrap,Levi,StormW,Drak and many others that I have a great deal of respect for. Where have you all gone? I guess its time to move on. Its been nice and thanks to all and I am not JFV!


This is indeed quite sad - I did notice that the blog was excellent when Dr. M was actively blogging today; and while I do understand that he cannot be here alot, it would be nice if a group of admin posters came on when it was busy.

Just remember folks that they make money here on the # of hits that they get - advertising. I do remember that there were something like 1 million + hits here during a busy time. That = some big money..... Just saying. Might be wrong.
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aquak9,

Hey! I saw the raccoon pictures! LOL, it was pretty cool.
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1866. Greyelf
Quoting pottery:
Good Evening...
First evening in a long time when I can see the Stars in a Clear sky.

Probably a Sign that all is well with Ebony, our Black Lab, who we put down today.
She was a Good Companion for 13 years, and will be truly missed.
Wife is Sad, so I am in Comforting Mode.

Keep well, All.


Sending comforting thoughts your way as well, Pottery. Have been through what you're dealing with today and it's a lot to deal with. Sorry for your loss.
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1865. aquak9
pottery. I am so sorry. Comfort the wife.
Member Since: August 13, 2005 Posts: 166 Comments: 25941
1864. angiest
Quoting pottery:
Good Evening...
First evening in a long time when I can see the Stars in a Clear sky.

Probably a Sign that all is well with Ebony, our Black Lab, who we put down today.
She was a Good Companion for 13 years, and will be truly missed.
Wife is Sad, so I am in Comforting Mode.

Keep well, All.


So sorry to hear that. One of our Yorkies developed lymphoma late last year. Fortunately, with chemo, he is in remission but we know it is likely only a matter of time...
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting pottery:
Good Evening...
First evening in a long time when I can see the Stars in a Clear sky.

Probably a Sign that all is well with Ebony, our Black Lab, who we put down today.
She was a Good Companion for 13 years, and will be truly missed.
Wife is Sad, so I am in Comforting Mode.

Keep well, All.


Condolences on the loss of your pet Pottery - I know the feeling well - lost 2 of my cats in the last two years. But Ebony will be waiting for you and your wife at the Rainbow Bridge!
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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.