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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462. BA
Quoting hurricanejunky:


Don't think you can go on without JB's expert analysis? He isn't any better than any of the other experts. I'll take Dr. Masters over JB any day of the week. Which is why I pay for a WU sub not an inaccuweather sub.


accuweather pro has a lot more resources than just JB, it is worth the cost imo, especially with all the model data (including the ecmwf now)

I pay here and for accuweather pro...in addition, I think JB is one of the best, simple as that :)
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Quoting StormW:
MJO being stubborn:



C'mon MJO! You can do it! A little more omph and you're in Octant 1!
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460. SLU
...INITIAL CONDITIONS...

LATCUR = 19.4N LONCUR = 61.2W DIRCUR = 300DEG SPDCUR = 23KT
LATM12 = 17.0N LONM12 = 57.0W DIRM12 = 289DEG SPDM12 = 24KT
LATM24 = 15.4N LONM24 = 52.4W
WNDCUR = 35KT RMAXWD = 30NM WNDM12 = 30KT
CENPRS = 1010MB OUTPRS = 1012MB OUTRAD = 125NM SDEPTH = S
RD34NE = 30NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM
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458. RM706
Quoting StormW:


Cool!

Drak, wanted to pay a compliment...bet when you get to FSU, you'll give them professors a run for their money!


FSU!!! GAH...LOL j/k
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Quoting Drakoen:


That MJO upward motion monstrosity is what some of the computer models want to develop.


How is THAT not an invest?
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ECMWF 12z develops the wave south of the CV islands and takes it out to sea.

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Quoting hurricanejunky:


JB is a highly opinionated pompous wannabe forecaster who sensationalizes every little weather event he can get his hands on. Whew! Feels good to get my real feelings out there...


I'm not saying I like Joe B, but you opinionated your details by saying that Jeff Masters was better than Joe B. That's a matter of someone's opinion! Joe B has his own club on Facebook. Over 70,000 people would disagree with your opinion...
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454. hercj
Quoting StormW:


Why?

Hey Senior, have you heard NASA is getting into the Hurricane Recon game?
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Quoting StormW:


Which one?


the wave just S of CV
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451. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15649
Quoting Drakoen:
The GFS 12z showed a tropical cyclone developing immediately off the African coast in the long-range. Looks like we may be entering the non-stop development period.


HOPEFULLY. I have been insiduously been bored out of my mind with the tropics for the past month.
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Quoting Snowlover123:


Well, that's simply a matter of someone's opinion...


JB is a highly opinionated pompous wannabe forecaster who sensationalizes every little weather event he can get his hands on. Whew! Feels good to get my real feelings out there...
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The GFS 12z showed a tropical cyclone developing immediately off the African coast in the long-range. Looks like we may be entering the non-stop development period.
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Quoting StormChaser81:


Hes a muscle heading body builder, steroids have taken over his ability to forecast.

Here's JB with your local roids-cast. Which he flexes his muscles and then says does that answer your questions.

Then he ask does anybody no where I can find a Pet hospital, "because these babies are sick" (his arms). =)


ROFLMAO!!
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Quoting StormW:


Storm:
could you provide your early thoughts with this one???
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444. viman
Quoting Drakoen:
St. Eustatius, Golden Rock, and Nevis have winds out of westerly directions. Anywhere from W to SW.


Winds SW on St. Croix and out of the north on St. Thomas. very light in the 5-8mph zone but very odd to say the least
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443. xcool
JLPR2 .hey/93L soon. jmo
Member Since: September 26, 2009 Posts: 2 Comments: 15649
Quoting itrackstorms:
This has ben mentioned elsewhere, but the action at ~8N 47W is certainly interesting looking. Wish there was a floater on it.



That MJO upward motion monstrosity is what some of the computer models want to develop.
Quoting Snowlover123:


Drak, could you give us a link? Thank you.


Link
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Quoting MScasinojunkie:
wow - look at the SST's in the Gulf!! Any reason its warmer in the Gulf than the Caribbean and Atlantic?? Now I am a bit more concerned about a potential Katrina 2.0 this summer.


It has been extremely hot along the Gulf Coast. Abnormally hot which I'm sure is contributing to the very high Gulf temps. My pool water hit 94 degrees last weekend. Thankfully it has cooled off a bit here and we had a few thunderstorms. My pool is now a "refreshing" 92 degrees. I think the Gulf near shore is 88 right now.
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Quoting hurricanejunky:


Don't think you can go on without JB's expert analysis? He isn't any better than any of the other experts. I'll take Dr. Masters over JB any day of the week. Which is why I pay for a WU sub not an inaccuweather sub.


Well, that's simply a matter of someone's opinion...
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439. JLPR2
Looking interesting

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438. xcool


anyway.384hr ha
Member Since: September 26, 2009 Posts: 2 Comments: 15649
Quoting Drakoen:


Thanks!


Drak, could you give us a link? Thank you.
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Quoting MiamiHurricanes09:
LOL, I don't, that's why I'll just use my mom's. However, I read that if you cancel it before 30 days they won't charge you...so I'll just cancel it in 29 days.


Don't think you can go on without JB's expert analysis? He isn't any better than any of the other experts. I'll take Dr. Masters over JB any day of the week. Which is why I pay for a WU sub not an inaccuweather sub.
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This has ben mentioned elsewhere, but the action at ~8N 47W is certainly interesting looking. Wish there was a floater on it.

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Quoting StormW:


Cool!

Drak, wanted to pay a compliment...bet when you get to FSU, you'll give them professors a run for their money!


Thanks!
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Quoting StormChaser81:


Hes a muscle heading body builder, steroids have taken over his ability to forecast.

Here's JB with your local roids-cast. Which he flexes his muscles and then says does that answer your questions.

Then he ask does anybody no where I can find a Pet hospital, "because these babies are sick" (his arms). =)


Can we stop talking about Joe B and get back 2 the tropics?
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431. srada
Quoting MiamiHurricanes09:
A system needs to organize before it intensifies. And in reality the remnants of Colin aren't organizing much, the recent blow up of convection is just because of the diffluent flow provided by the TUTT.


Thanks MH09..Im just thinking how the storm will react when it does make it into favorable conditions..
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Looks just like 92L from June:

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Quoting Neapolitan:


I'd waste neither the time nor the money on JB. It's not just that I have an issue with JB's caustic commentary, constant self-congratulation, endless peer-thrashing, or even his whiny and non-funny sarcasm; it's just that he is so very often wrong about things. And I'm not even refering to his non-scientific views on GW; I'm talking just about his weather forecasting "abilities". Yeah, he's right sometimes, often enough to call himself a meteorologist...but he's not accurate nearly often enough to act like the Weather God he too frequently professes to be.


Hes a muscle heading body builder, steroids have taken over his ability to forecast.

Here's JB with your local roids-cast. Which he flexes his muscles and then says does that answer your questions.

Then he ask does anybody no where I can find a Pet hospital, "because these babies are sick" (his arms). =)
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Quoting MScasinojunkie:
wow - look at the SST's in the Gulf!! Any reason its warmer in the Gulf than the Caribbean and Atlantic?? Now I am a bit more concerned about a potential Katrina 2.0 this summer.


The TCHP maps that show up hear would seem to indicate those temps don't go very deep. Think they were higher (TCHP) in 2008 and maybe 2005 as well.
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427. SLU
Quoting Drakoen:


Check the station history from the weather stations in the northern Lesser Antilles.


Those west winds may not be directly associated with Colin. Low level cloud motions indicate a primarily southerly wind flow across the region. The west winds could be as a result of localized sea breeze effects caused by a weakening of the trade wind flow which is normally caused by a by-passing low pressure system disrupting this flow across the islands.
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Good Afternoon!
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425. xcool
Neapolitan .GW talking by jB I HATE IT!.
Member Since: September 26, 2009 Posts: 2 Comments: 15649
423. MahFL
Quoting WeatherNerdPR:

It should have been 30% for both.


Sadly you don't work at the NHC...so it's 20/20.
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how should colin's recent weakening effect its track? also conditions west of 73' west and over the bahamas apear favorable for re development (warm sst's and relativly moist air
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Quoting Neapolitan:


I'd waste neither the time nor the money on JB. It's not just that I have an issue with JB's caustic commentary, constant self-congratulation, endless peer-thrashing, or even his whiny and non-funny sarcasm; it's just that he is so very often wrong about things. And I'm not even refering to his non-scientific views on GW; I'm talking just about his weather forecasting "abilities". Yeah, he's right sometimes, often enough to call himself a meteorologist...but he's not accurate nearly often enough to act like the Weather God he too frequently professes to be.

+1
:D
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The UKMET model is now available for pouch tracking on the Montgomery PREDICT Research page and it goes out to 120 hours!
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419. xcool
Jax82 /thanks i try alot
Member Since: September 26, 2009 Posts: 2 Comments: 15649
Quoting StormW:


Not much, if any, if he keeps moving NW.


thanks, yeah i was thinking the same thing perhaps a bit of the tail end but probably not much it does apear liek its about to "shoot" northward
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417. Jax82
Nice graphic Xcool!
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416. unf97
Good afternoon everyone!
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wow - look at the SST's in the Gulf!! Any reason its warmer in the Gulf than the Caribbean and Atlantic?? Now I am a bit more concerned about a potential Katrina 2.0 this summer.
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414. xcool
Neapolitan .:)
Member Since: September 26, 2009 Posts: 2 Comments: 15649
Quoting Neapolitan:


I'd waste neither the time nor the money on JB. It's not just that I have an issue with JB's caustic commentary, constant self-congratulation, endless peer-thrashing, or even his whiny and non-funny sarcasm; it's just that he is so very often wrong about things. And I'm not even refering to his non-scientific views on GW; I'm talking just about his weather forecasting "abilities". Yeah, he's right sometimes, often enough to call himself a meteorologist...but he's not accurate nearly often enough to act like the Weather God he too frequently professes to be.


+1
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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.

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