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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Quoting alaina1085:
My how things have changed with this storm. Havent been on the blog since yesterday morning.
Good Evening to You and to All.
Member Since: July 5, 2009 Posts: 0 Comments: 1348
ex Colin is bumped up to code Orange!
Member Since: May 16, 2009 Posts: 0 Comments: 684
Looking at the LATEST steering layers map from CIMMS, trends favor a WNW motion then a NW or NNW motion. We'll see what happens, but I'm not buying the models, nor did I ever for this storm.
Member Since: July 1, 2008 Posts: 13 Comments: 7340
If the wave off africa forms would it turn fishy or track toward the lesser antilles ???
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Quoting Vero1:


Same Here. Just turned SouthEast over the Gulf.


If I had to guess... I would say untasked, en route to 92L
Member Since: October 1, 2007 Posts: 81 Comments: 26505
1357. palmpt
Quoting Tazmanian:



doom i say where all doom


Taz... For years you have cracked me up!
Member Since: Posts: Comments:
The real JFV signed up on my site today. UGH. We'll see how long that lasts before I 86 him.
Should be good for laughs...
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I've got google EArth data showing a mission out of Keesler. Was 120 m SE of NOLA at 7:20 EDT....

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My how things have changed with this storm. Havent been on the blog since yesterday morning.
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Hey Reed,
I'm with you as well. Got a new forecast? I didn't see one today...
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1352. HadesGodWyvern (Mod)
There is Gale Force Winds (Tropical Storm winds) with "Colin" though according to the Tropical Weather Outlook. The system is just missing the close circulation to be classified as a cyclone.
Member Since: May 24, 2006 Posts: 50 Comments: 44424
1350. Vero1
Quoting muddertracker:
On Google Earth I clicked on non-tasked mission, and I can see data.


Same Here. Just turned SouthEast over the Gulf.
Member Since: July 21, 2008 Posts: 4 Comments: 2233
Quoting muddertracker:
On Google Earth I clicked on non-tasked mission, and I can see data.


Yes, but that is not for AL04 (Colin) that is in the northern Gulf of Mexico.
Member Since: September 23, 2005 Posts: 14 Comments: 10831
1347. jeebsa
(lets try one more time), If a recon is on the way and they find a closed circulation than its a T.S again. The 8:00 report will be out before that so if Ex Colin is getting better organizes wouldn't they bump the % points until it is reclassified again?
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On Google Earth I clicked on non-tasked mission, and I can see data.
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Quoting 7544:
its been a ts on the navy site over 4 hours usally if its there first ty=hen the nhc upgrades on thier next two we shall see . they may just put what they see on the sats before the plane goes in at that time the hh may find a strongr sysstem than the nhc sees on the sats



its not a TS
Member Since: May 21, 2006 Posts: 5091 Comments: 114649
1344. 7544
its been a ts on the navy site over 4 hours usally if its there first ty=hen the nhc upgrades on thier next two we shall see . they may just put what they see on the sats before the plane goes in at that time the hh may find a strongr sysstem than the nhc sees on the sats
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Quoting nrtiwlnvragn:


If we get Recon, no data yet that they are currently flying. I know it was scheduled, but no data yet.
Oh. Interesting.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting NoNamePub:
ALoha Gang?

Is colin back????



nop
Member Since: May 21, 2006 Posts: 5091 Comments: 114649
ALoha Gang?

Is colin back????
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Reed, I don't think ex-Colin's new center will get sheared unless the ULL slows down and ex-Colin speeds up. The shear axis looks to be moving northward allowing convection to build on the northern side of the CDO.
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Quoting MiamiHurricanes09:
If we get Colin re-designated it will be at 11P.M after Recon investigates.


If we get Recon, no data yet that they are currently flying. I know it was scheduled, but no data yet.
Member Since: September 23, 2005 Posts: 14 Comments: 10831
Quoting HadesGodWyvern:


don't the hurricane hunters still have to find a closed circulation center?
yes but people are speculating what may happen
Member Since: July 14, 2009 Posts: 0 Comments: 2990
1336. xcool
wait for recon
Member Since: September 26, 2009 Posts: 2 Comments: 15618
Quoting 7544:
hmm colin looks like its 45 or 50 mph ts right upgrade at 8pm ?
If we get Colin re-designated it will be at 11P.M after Recon investigates.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
1334. HadesGodWyvern (Mod)
1328. 7544 11:23 PM GMT on August 04, 2010
hmm colin looks like its 45 or 50 mph ts right upgrade at 8pm ?


don't the hurricane hunters still have to find a closed circulation center?
Member Since: May 24, 2006 Posts: 50 Comments: 44424
1333. will45
Quoting 7544:
hmm colin looks like its 45 or 50 mph ts right upgrade at 8pm ?


i may be wrong but i think they will wait to see what recon finds
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Quoting 7544:
hmm colin looks like its 45 or 50 mph ts right upgrade at 8pm ?



it would be at 11pm
Member Since: May 21, 2006 Posts: 5091 Comments: 114649
Here Here! Thank you



Quoting JenniferGirl:


You shouldn't expect a population of meterologists to be talking on a public blog.
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Did anyone just see that kid on TWC? He was a natural! I wonder if he is among us... ;)
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Quoting Seflhurricane:
http://cimss.ssec.wisc.edu/tropic2/predict/predict.php#Link

Here is the link with the new invest near the cape verde islands


That is a pouch that may become an invest in the future, it is not one now.
Member Since: September 23, 2005 Posts: 14 Comments: 10831
1328. 7544
hmm colin looks like its 45 or 50 mph ts right upgrade at 8pm ?
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Quoting earthlydragonfly:


Yes the Happy hour is over and the clowns that like to cause trouble are now in the blog....


My mommies favorite song when I was a kid.... Send in the clowns


I always thought it was "Send in the Clones." Well, I'm the '80s generation. XD
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Quoting JenniferGirl:


I was on here same time yesterday. Yesterday being my first day. I try to keep the peace, and help people to get along. ;)
Welcome to the blog, but you got your work cut out for you girl....LOL
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Quoting Tazmanian:




there is no new invest


thanks TAZ.. I was actually out looking for the info!!!
Member Since: July 8, 2010 Posts: 0 Comments: 345
Quoting ironbark:
this is a free blog. if you dont like the questions being asked,then dont answer them.some of the folks on here are very cold,last time i looked,not every one on here was a meterologist.


You shouldn't expect a population of meterologists to be talking on a public blog.
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Quoting Seflhurricane:
http://cimss.ssec.wisc.edu/tropic2/predict/predict.php#Link

Here is the link with the new invest near the cape verde islands




there is no new invest
Member Since: May 21, 2006 Posts: 5091 Comments: 114649
Quoting CaicosRetiredSailor:
WUblogger LRandyB will be flying into this tonight.

Hey, CRS. Thanks for the heads up on that. I forgot to check his blog when I heard they were flying down to USVI....
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Quoting earthlydragonfly:


Yes the Happy hour is over and the clowns that like to cause trouble are now in the blog....


My mommies favorite song when I was a kid.... Send in the clowns


LOL.. Happy hour over!!!! (in the central time zone they still have another hour!!!
Member Since: July 8, 2010 Posts: 0 Comments: 345
Quoting reedzone:


Thanks Jen, I don't think I've seen you on here before, welcome to the blog!


I was on here same time yesterday. Yesterday being my first day. I try to keep the peace, and help people to get along. ;)
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Quoting earthlydragonfly:


Yes the Happy hour is over and the clowns that like to cause trouble are now in the blog....


My mommies favorite song when I was a kid.... Send in the clowns
Did someone call?
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Quoting Seflhurricane:
the tropical wave off the cape verde islands is now an Invest



where you geting that info from
Member Since: May 21, 2006 Posts: 5091 Comments: 114649
Nothing there to support a new invest 93L on the tpc.ncep page...

Link


Quoting CybrTeddy:


Where?
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http://cimss.ssec.wisc.edu/tropic2/predict/predict.php#Link

Here is the link with the new invest near the cape verde islands
Member Since: July 14, 2009 Posts: 0 Comments: 2990
1312. HadesGodWyvern (Mod)
NO TSUNAMI THREAT TO AUSTRALIA

Issued by the Joint Australian Tsunami Warning Centre (JATWC) at 8:17 AM EST on

Thursday 05 August 2010

********************************************************************************

SUMMARY:

An undersea earthquake of magnitude 7.1 has occurred at 8:01 AM EST on Thursday

05 August 2010 near NEW BRITAIN REGION, P.N.G..

THERE IS NO TSUNAMI THREAT TO THE AUSTRALIAN MAINLAND, ISLANDS OR TERRITORIES.

For further details visit the Bureau web site www.bom.gov.au.

No further updates will be issued unless the situation changes.

********************************************************************************

DETAILS:

An undersea earthquake of magnitude 7.1 has occurred at 8:01 AM EST on Thursday

05 August 2010 near NEW BRITAIN REGION, P.N.G. (latitude 6.060S longitude 150.860E ).
Member Since: May 24, 2006 Posts: 50 Comments: 44424

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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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