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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2612. hcubed
Quoting Ossqss:


Do you know how foolish that comment is? This is about two different (official) sources for the same info. Not your perception of such. Quite telling for sure. Does your opinion change it? No, realize that and grow up. Gheeze,

I am outta here! Consider the source is all I will say, the data and the opinion are two different things.


Is he still on that?

He STILL hasn't provided his source of the "busting" of Watts.

His arguement of Watts and "no peer-reviewed articles" is questionable, too.

And as far as the "Goddard" issue, is he saying that if a person posts anonomously, we can't believe them?

That would knock out a few warmist web sites as well.
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Quoting MiamiHurricanes09:
If the entire run of the 06z GFS would verify we would be by the "G" storm in 16 days. That obviously means nothing since it is very highly unlikely that it will, but as you can tell we are getting to that time of the season that storms start forming left and right.

06z GFS still calls for Danielle to form within the next 3 days.

Wow. But it's highly unlikely 16 days out. But it sounds interesting.
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15 trees hit the house and fence. A very long day...
Quoting IKE:


Nice area to do that in. City I live in is growing. We're getting our 8th and 9th traffic lights!
Defuniak now has 9 traffic lights? I need to get up there more often...
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2607. FLDART1
Am curious as to where exactly all of the oil has supposedly gone... hmmmmm.....Dont get me wrong, I hope it really is gone, but I just cant wrap my mind around what they are trying to tell us...
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2605. IKE
Quoting tkeith:
I love the Emerald Coast...tryin to make enough money to retire there.


Nice area to do that in. City I live in is growing. We're getting our 8th and 9th traffic lights!
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Looking at the models for 92L, they seem pretty direct. I don't see any of the models showing it hitting the Yucatan After Honduras. Is there one model showing it passing the Ycatan and hitting Honduras on Friday and another saying it is going much slower and taking till Saturday to cover half the distance to the Yucatan? The days just seem backward to my geographic mind.
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2603. IKE
Quoting RipplinH2O:
Let's not forget Erin either...


Here she is....




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Quoting earthlydragonfly:


Why thank you very much! I am excited! I am still void of pictures over the ocean where you can see the whole bolt.

Dfly they say the best place for lighning pictures is Tarpon Springs just thought you might want to know. I have seen some great shots of lightning and they all came from that area.
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If the entire run of the 06z GFS would verify we would be by the "G" storm in 16 days. That obviously means nothing since it is very highly unlikely that it will, but as you can tell we are getting to that time of the season that storms start forming left and right.

06z GFS still calls for Danielle to form within the next 3 days.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
2599. tkeith
Quoting IKE:


Hope you have a great time.
I love the Emerald Coast...tryin to make enough money to retire there.
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Quoting IKE:


We burned ours off. It took awhile. Having a lot of trees in the yard can be nice, until....hurricane conditions.


Ha - can't burn here in VaBeach - city has to make it's money one way or the other,LOL. Actually - 7x13x6 dumpster was only 25 bucks back then - gone up to 35 now.
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Looks good to me!
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2596. Gearsts
Link
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Quoting severstorm:

I live in zephyrhills and yes we have had a few great storms over here on the west side. Good luck with getting your pics.


Why thank you very much! I am excited! I am still void of pictures over the ocean where you can see the whole bolt.
Member Since: July 1, 2005 Posts: 10 Comments: 1683
2594. IKE
Quoting tkeith:
will be there the week before Labor Day...cant wait.


Hope you have a great time.
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Colin has never looked better
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2592. tkeith
2590. DestinJeff 7:10 AM CDT on August 05, 2010

I'll be a frequent visitor at Harry T's...

Love that Jetty Juice :)
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Quoting earthlydragonfly:


I have 3 daughters and dont think that will be the first pain I get from them... Mostly the broken Hearts I get for them..

Not enough rain... They keep on slipping over to the west.(Tampa) Im going to tampa next week so hopefully this weather pattern will hold up and I get some good lightning shots on the coast!!!


I live in zephyrhills and yes we have had a few great storms over here on the west side. Good luck with getting your pics.
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Quoting biff4ugo:
Good Morning

If ex-Colin is worthy of monitoring, as Dr. Masters says it is, and its development is being modeled, then why aren't the models available on the severe weather T&H page?


I am no MET but I think it has to do with the Low pressure system of a tropical storm.. I believe however, they do forecast and model other storms. Frankly, all of the models I look at do predict all the weather that it expects to happen. I mean I see other types of systems being modeled while Im watching the Tropical weather on the model..
Member Since: July 1, 2005 Posts: 10 Comments: 1683
Quoting GeoffreyWPB:


Just give credit when credit is due.
Your correct, I was just agreeing with this synopsis from Central Florida Hurricane Site--opps
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2587. FLDART1
I see Opal is being revisited this AM. While she still did a good deal of damage, we really dodged a bullet withe her. The systems rapid intensification caught most of us off-guard. Had she not weakened considerably just before landfall the Death Toll would have been bad. Many of those trying to EVAC were still on the roadways...
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Let's not forget Erin either...
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2584. tkeith
Quoting IKE:
GOM deserves a break in 2010 in the tropics. It's great news that BP is finishing that oil-volcano off for good.

Come on back vacationers...to Destin,FL. area!!!

will be there the week before Labor Day...cant wait.
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Good Morning

If ex-Colin is worthy of monitoring, as Dr. Masters says it is, and its development is being modeled, then why aren't the models available on the severe weather T&H page?
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2581. IKE
Ivan was no slouch...at all...and meant business.
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With the AB high being so week it appears anything coming off Africa will eventually curve out to sea. 2010 could be a fishy season.
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2579. IKE
Quoting CoopsWife:
2569.

Ike - we moved in here about 6 months post Isabel. Front yard was nice and tidy. Back yard was full of leaves - and UNDER the leaves were all the branches and debris. First time I walked down the hill I stepped into a mess of branches to mid thigh! Took us nearly a month of clean up and 3 city dumpsters to get it all taken away!


We burned ours off. It took awhile. Having a lot of trees in the yard can be nice, until....hurricane conditions.
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Quoting KoritheMan:


Ivan remains my favorite storm (fascination wise, before anyone reads too deeply into that) because of its eventual regeneration in the Gulf.
I agree... What an incredible (minus the destruction) event and anomaly it truly was from a scientific perspective!
Member Since: July 1, 2005 Posts: 10 Comments: 1683
Quoting SAINTHURRIFAN:
sebastian thats a good point. But listenening not just to people on this blog which we know requires a lot of filtering out lol we have heard wait to july, wait to late july wait to august.Trust me i hope the season continues ths way.My theory is thier is something missing that no mortal is capable of putting a finger on.Something ive never seen posted on this blog that ive always been curious about is this! The 70's and 80's thru the early 90's were relatively quiet for hurricane seasons.Ever since 95 active seasons were projected on lanina or neutral forecast.Weak season were explained due to elnino factoring in.Now my question is in approximately 20 or so years of minimal activity did we have el nino every year lol.That tells me something else was going on and maybe its coming back into play and we are not smart enough yet to figure it out.
Agree, I think. Overall I just think that most land areas don't gett affected by storms often, it is kind of random, and if your towns in the way you could be doomed, but not too often. As far as storms, most blobs never turn into much, but sometimes when everything in the environment is correct, then all bets are off, and God forbid your town is in the way of a Cat 3 or higher. Sometimes the prior will happen, but more often than not, all variables are not there to make that scenario come to fuition, thank goodness, I say anyway.
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Quoting severstorm:

Well then i should of said a 6 yr old daughter instead of a 4x4. lol You getting any rain in your area over in orlando?


I have 3 daughters and dont think that will be the first pain I get from them... Mostly the broken Hearts I get for them..

Not enough rain... They keep on slipping over to the west.(Tampa) Im going to tampa next week so hopefully this weather pattern will hold up and I get some good lightning shots on the coast!!!

Member Since: July 1, 2005 Posts: 10 Comments: 1683
2575. FLDART1
Good Morning everyone...
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2569.

Ike - we moved in here about 6 months post Isabel. Front yard was nice and tidy. Back yard was full of leaves - and UNDER the leaves were all the branches and debris. First time I walked down the hill I stepped into a mess of branches to mid thigh! Took us nearly a month of clean up and 3 city dumpsters to get it all taken away!
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2573. IKE
I've give an honorable mention to this bad girl.....well respected by IKE/the downcaster.....

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Quoting RotorYacht:
Interesting.. What do you make of this CMC run?

Link


Not the expert on interpretation but does it develop that wave currently around 35-40 west? It certainly looks a little bit foreboding this morning but not yet mentioned by NHC in their TWO and no vorticity at the moment per the latest CIMSS charts..
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Quoting RotorYacht:
Interesting.. What do you make of this CMC run?

Link


I looked at CMC, GFS, NOGAPS and all show the bermuda high breaking down next week setting up for a 'fishy' track for any mid-august atlantic storms.
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2570. Hhunter
accuweather professional free trial today. go to accuweather.com
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2569. IKE
Quoting KoritheMan:


I can imagine. Opal was horrific. That one, along with 2000's Gordon, should be decent reminders that just because tropical cyclones develop over the Yucatan Peninsula, does not mean that they will be destroyed and unable to intensify when hit water.

The Yucatan isn't a very mountainous or rugged area.


That hit the October before I bought this house(spring of 1996). The house had been empty for a few months. I'm not making this up...there was a pile of limbs/branches...in the front yard about 10 feet wide and several feet tall from Opal's furry. This place was a total mess.

I've had branches down from Ivan and Dennis, but it wasn't that bad and it was tropical storm conditions. Opal was hurricane conditions.
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Interesting.. What do you make of this CMC run?

Link
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Quoting earthlydragonfly:


I wish.... My youngest daughter likes to play punch buggy but still doesnt understand all the rules that you must punch the person in the arm/ shoulder.. (she is 6) we where walking Im 6'6" and she is about 3 foot tall and I was facing here... (that would put her at a very precarious height compared to me) and WHAMMMmmmm I was doubled up in the Target parking lot.. Poor thing didnt understand but Im still feeling the "sensitivity" of the whole ordeal...

Well then i should of said a 6 yr old daughter instead of a 4x4. lol You getting any rain in your area over in orlando?
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re 2541 -

Ah - great song, though I prefer McKuen's version of that great Jacques Brel piece
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Quoting KoritheMan:


It said northwest.


My bad; need to put my reading glasses back on.... :)
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2564. IKE
Quoting BenBIogger:


Earl?



I was on the west/NW side of it. The winds weren't that strong here. Maybe 35-45/50 mph.
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Quoting weathermanwannabe:
The TWO does not mention movement as to the remnats but it "looks" to me like they are moving in the direction of Bermuda at the moment.


It said northwest.
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Ex-Colin: 50%
SW Caribbean: 10%
Seems reasonable.
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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.