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

Share this Blog
4
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1812 - 1762

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56Blog Index

Must be the night for big storms. Here in Tampa the Rays baseball game was postponed by 20 minutes because of severe storms and lightning shutting down the power systems (and they have an indoor stadium!)


Quoting Patrap:
Gust Front just came thru here Uptown,,Gust to 35mph

Mod Lightening

Member Since: Posts: Comments:
1811. IKE
Quoting InTheCone:


IKE is the master of the a.m. downcaster dial, and God Bless him(nobody needs these storms!) I always read his morning posts and info. Don't post much as I am working online at that time, but certainly appreciate his lack of hype! Plus he knows the really great tunes- Thanks Ike!

I'll probably get banned for that:)


You're welcome. I use to DJ at 92.5 WPAP in Panama City...country station...late 70's and WQUH-FM in Defuniak Springs,FL. back in the 80's. They played tunes like....I'm On Fire...Dwight Twilley Band.

The morning crew:)
Member Since: Posts: Comments:
1810. tkeith
Quoting bappit:

Great loop. Feel the breeze, be the breeze.
we spell it Brees in Nawlins :)

Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Blog Update!

August 4, 2010 - 9:15 PM EDT - Tropics Getting Active


Good Post !!!
Member Since: Posts: Comments:
Colin looks pretty good right now.



AOI

AOI

AOI

AOI

AOI

TS BUSTED FORECAST ALIBI
Member Since: Posts: Comments:
Blog Update!

August 4, 2010 - 9:15 PM EDT - Tropics Getting Active
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1805. bappit
Quoting Patrap:
Quoting robj144:


That's a crazy looking radar loop.

Great loop. Feel the breeze, be the breeze.
Member Since: Posts: Comments:
This positive NAO shouldn't last too long. I do expect for the negative NAO to return during the middle-late part of August.
Member Since: Posts: Comments:
Quoting watchingnva:


eastern side of the line is weaker.....the area from louisa southwest needs to come through here...but we will end up getting the weaker side knowing our luck...


by the way watch last thurs we saw a lot of tree damage here at courthouse and lucks lane. nasty though. The storms won't be as bad until you get to petersburg.
Member Since: Posts: Comments:
wow D-MIN took a very big toll on 92L but I belive that D-MAX will fix that problem oh yeah and all of you that 92L is dead it is not I have see the NHC miss to time that they are to post the plots but they will always do it on the next time plots so I see now 00Z plots but I shall wait for the 06Z plots
Member Since: Posts: Comments:
Just a general word to the youngsters and oldsters in here: if u let the shysters run u out of the blog, YOU lose.

Lots of good stuff here if u talk wx and not personalities and learn to use ur tools.
Member Since: Posts: Comments:
1800. Patrap
Gust Front just came thru here Uptown,,Gust to 35mph

Mod Lightening

Member Since: Posts: Comments:
Quoting thelmores:
4-5 years ago, this was the best weather blog hands down!

Now it is nothing but a damned circus with a bunch of immature jackasses!

I almost wish I would get banned permanently so I wouldn't have to worry about coming back myself!

Dr. Masters worked so hard to build this site and this blog into something special....... a real shame what it has ultimately become!

I miss the blog of years ago..... when you could actually have fun, discuss tropical weather, and actually learn something...... and leave the blog in a happy mood.....

Another example of success ruining something!


That deserves more than +1. I think that's the best post i've ever read in my entire time here.
Member Since: Posts: Comments:
1796. angiest
1789 - They probably need more moderators. I don't know how many there really are on here but its probably not enough. And they really need to start issuing more perm. bans and doing something about the people who constantly come on here under different names. I mean, I can't believe they are all sophisticated enough to spoof IP addresses.
Member Since: Posts: Comments:
Quoting Tazmanian:
09 did they drop 92L?
No they have not.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting thelmores:
4-5 years ago, this was the best weather blog hands down!

Now it is nothing but a damned circus with a bunch of immature jackasses!

I almost wish I would get banned permanently so I wouldn't have to worry about coming back myself!

Dr. Masters worked so hard to build this site and this blog into something special....... a real shame what it has ultimately become!

I miss the blog of years ago..... when you could actually have fun, discuss tropical weather, and actually learn something...... and leave the blog in a happy mood.....

Another example of success ruining something!


+1 best post I have read all day on this site :)
Member Since: Posts: Comments:
1791. KEEPEROFTHEGATE (Mod)
XX/XX/XL
MARK
19.93N/62.56W
Member Since: July 15, 2006 Posts: 174 Comments: 54630
1790. angiest
1782 - Noooooooo! I don't want it to be unseasonably warm this winter! I am one of the sensible people who didn't complain about the cold last winter.
Member Since: Posts: Comments:
wave at 32W looks very impressive.It is the first wave to have stayed at 10 deg north. this is an indication that that the A/B ridge is weakening a bit. the area is well to the south of dry air to it's north, and is enbedded in a large area of moisture. although there is good convergence and divergence there is little or no vorticity at the moment. the system is under 20 knots of wind shear, but that is expected to decrese the next few days. some of the global models want to develop this system as it tracks west over the open atlantic. it would not be a surprise if the NHC were to classify his system as 93L during the next 24 hrs
Member Since: Posts: Comments:
1787. angiest
My my, guess I should be glad I had to take my daughter to McDonald's for her birthday dinner tonight instead of being on here.
Member Since: Posts: Comments:
Quoting tropicfreak:


We are about to get a whopping here in Richmond. Straight line winds in excess of 60 mph and lightining is expected.


eastern side of the line is weaker.....the area from louisa southwest needs to come through here...but we will end up getting the weaker side knowing our luck...
Member Since: Posts: Comments:
09 did they drop 92L?






















Member Since: May 21, 2006 Posts: 5091 Comments: 115252
Accuweather predicting the upcoming winter.

STATE COLLEGE, Pennsylvania -- AccuWeather.com has issued its annual winter weather predictions and chief hurricane meteorologist Joe Bastardi said he's forecasting above-normal warmth this winter along the Gulf and Florida coasts.

Bastardi said that should come as welcome news as it could help revive the tourism industry, which was hurt by the Deepwater Horizon oil spill.

It also comes as welcome news for a region that last year experienced the third-coldest winter in 116 years. In metro Birmingham, the National Weather Service said that this past winter was sixth-coldest on record since the late 1890s. The metro area also broke a 1918 record for the coldest first two weeks of the year -- the daily average temperature for Jan. 1-15 this year was 30 degrees.

Bastardi is forecasting that some of the most mild temperatures for the winter of 2010-2011 will occur in Florida and along the Gulf Coast, according to AccuWeather.com. Conditions will be warmer and drier than last winter.

"Florida and the Gulf Coast will be great winter destinations this year," said Bastardi.

Warmer-than-normal temperatures, regularly reaching between 70 and 80 degrees, will pepper the coastal communities along the Gulf coast region all winter long, from Nov. 15 through March 15
Member Since: Posts: Comments:
Quoting reedzone:
BAMM models shifted westward again, if you look at the steering layers map, these models have a point.
BAM's are supposedly pretty good with tracking weaker systems...
BAM info from Wunderground:
Non-global models
The BAMM model (Beta and advection model, medium layer) is included on wunderground.com's computer model page. The BAMM is a simple trajectory model that is very fast to run, and did the best of any individual model at 3-5 day track forecasts in 2005. Since this model is always available, we have included it along with the "big four". In general, one should not trust the BAMM model for the 1-2 day time period when output from "the big four" are available. Interesting stuff.
Member Since: Posts: Comments:
Quoting IKE:


LOL...will do.


IKE is the master of the a.m. downcaster dial, and God Bless him(nobody needs these storms!) I always read his morning posts and info. Don't post much as I am working online at that time, but certainly appreciate his lack of hype! Plus he knows the really great tunes- Thanks Ike!

I'll probably get banned for that:)
Member Since: Posts: Comments:
thats the way ive been doing it just watch read and ask question to hopefully understand things better
Member Since: Posts: Comments:
Well hmmm guess we wont have a hyper active season but we will see alot of junk popping this month and next
Member Since: Posts: Comments:
Quoting FloridaHeat:


i am a new blogger and i agree that it is impossible to fit in here i have had several emails accusing me of being this jfv person and telling me to prove that i am not i dont have to prove anything to anyone
Hey bud, ignore those petty, paranoid ignoramuses. They have nothing better to do than to point fingers and antagonize people. I thought this was a WEATHER blog before... now I'm not so sure.
Member Since: Posts: Comments:
1775. Patrap
Quoting wxvoyeur:


Impressive outflow! nice!



A cooler evening is gonna be sweet.

Member Since: Posts: Comments:
Quoting nyhurricaneboy:
I would like to publicly announce that I am leaving this site forever after some intense thought. Today, it became evident that I am hated here because of my age, inexperience, and immaturity. I just can't fit in. Thanks to all who have supported me and I will make sure to stay in contact with the few friends I have made on here.

Ciao!
You're seriously leaving because JFV got on your nerves? Just ignore him, all he does when he comes here it to bother every single one of us. Hope you stay.
Member Since: September 2, 2009 Posts: 130 Comments: 21194


We are about to get a whopping here in Richmond. Straight line winds in excess of 60 mph and lightining is expected.
Member Since: Posts: Comments:
1771. BDAwx
Quoting BahaHurican:
[ ], BDA, and how r u? I see u may be getting some stormy wx this weekend.... if the forecasts are on track....


I'm good - we're just getting out of a drought, at least in the short term. Back to the summer heat from our High pressure for now.

Yeah but we've had worse than whats forecast so I hope we'll be fine.

How're you doing?
Member Since: Posts: Comments:
Quoting tropicfreak:


same here pat . I am about to see some nasty weather here in richmond VA.


if it holds together....completely that is....not fade as it comes through and blows back up to the south and southeast...
Member Since: Posts: Comments:
00z ATCF Best Track has Ex-Colin with winds of 40mph and a pressure of 1009mb. However it still remains a tropical wave.

AL, 04, 2010080500, , BEST, 0, 202N, 628W, 35, 1009, WV,
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting Patrap:


Gonna get a little wet huh?
Member Since: Posts: Comments:
Quoting TropicalAnalystwx13:


:(


TO JENNIFER: If you want to learn, then lurk and read everything every day, you'll learn a lot and also learn what questions to ask and who to listen to.
Member Since: Posts: Comments:
1762. SWMIWX
Quoting nrtiwlnvragn:


Thanks!
Member Since: Posts: Comments:

Viewing: 1812 - 1762

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56Blog Index

Top of Page

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.

Local Weather

Overcast
56 °F
Overcast