CSU and TSR predict an extremely active 2011 Atlantic hurricane season

By: Dr. Jeff Masters , 12:54 PM GMT on December 09, 2010

Share this Blog
4
+

A continuation of the pattern of much above-average Atlantic hurricane activity we've seen since 1995 is on tap for 2011, according to the latest seasonal forecast issued Wednesday by Dr. Phil Klotzbach and Dr. Bill Gray of Colorado State University (CSU). They are calling for 17 named storms, 9 hurricanes, and 5 intense hurricanes. An average season has 10 - 11 named storms, 6 hurricanes, and 2 intense hurricanes. The new forecast is a very aggressive one, since only six seasons since 1851 have had as many as 17 named storms; 19 seasons have had 9 or more hurricanes. The 2011 forecast calls for a much above-average chance of a major hurricane hitting the U.S., both along the East Coast (49% chance, 31% chance is average) and the Gulf Coast (48% chance, 30% chance is average). The Caribbean is forecast to have a 62% chance of seeing at least one major hurricane (42% is average.) Five years with similar pre-season November atmospheric and oceanic conditions were selected as "analogue" years that the 2011 hurricane season may resemble: 2008, 1999, 1989, 1961, and 1956. The average activity for these years was 12 named storms, 7 hurricanes, and 4 major hurricanes.

The forecasters cited several reasons for their forecast of a much above-average season:

1) Unusually warm sea surface temperatures continue in the tropical Atlantic this fall, an indication that the active hurricane period we have been in since 1995 will continue (in technical terms, the positive phase of the Atlantic Multidecadal Oscillation, AMO, will continue.) SSTs in Atlantic Main Development Region (MDR) for hurricanes, from the Caribbean eastwards to the coast of Africa, were at a record high in October (November data are not yet available.)

2) Hurricane activity in the Atlantic is lowest during El Niño years and highest during La Niña or neutral years. This occurs because El Niño events tend to increase westerly upper-level winds over the tropical Atlantic, bringing high wind shear harmful for hurricanes. The CSU team notes that we are currently experiencing moderate to strong La Niña conditions, with an unusual amount of cool water present in the top 300 meters of the Equatorial Pacific Ocean off the coast of South America. Since 1979, only eight years have had similar amounts of cool water in November. The hurricane seasons that followed each of those eight years were unable to transition to El Niño conditions. Thus, the CSU team expects that we will have neutral or La Niña conditions in place for the Atlantic hurricane season of 2011, which should act to keep wind shear values average to below average, enhancing hurricane activity. Of the 16 El Niño/La Niña computer models that made November predictions for the July-August-September 2011 portion of hurricane season (Figure 1), only 4 (25%) predicted that El Niño would arrive.

How accurate are the December forecasts?
The CSU real-time December forecasts did not shown any skill over the period 1992 - 2007, so the forecast scheme was overhauled and a new scheme implemented for the forecasts made for the 2008 - 2010 hurricane seasons. This new scheme showed some decent skill in those three years, with skill levels 18%, 10%, and 30% above chance for predicting the number of named storms, hurricanes, and intense hurricanes, respectively. Still, three years is too short of a time period to evaluate the skill of these December forecasts, and we should view the latest forecast as an experimental research product. Last year's December forecast for the 2010 hurricane season predicted 13.5 named storms, 7 hurricanes, and 4 intense hurricanes. The actual numbers were 19 named storms, 12 hurricanes, and 5 intense hurricanes.


Figure 1. Forecasts of El Niño conditions by 20 computer models, made in November 2010. The longest range forecasts for July-August-September (JAS) at the right side of the image show that 4 models predict weak El Niño conditions, 7 predict neutral conditions, and 5 predict a weak to moderate La Niña. El Niño conditions are defined as occurring when sea surface temperatures in the Equatorial Pacific off the coast of South America (the "Niño 3.4 region) rise to 0.5°C above average (top red line). La Niña conditions occur when SSTs in this region fall to 0.5°C below average. Image credit: Columbia University.

2011 Atlantic hurricane season forecast from Tropical Storm Risk, Inc.
The British private forecasting firm Tropical Storm Risk, Inc. (TSR), issued their 2011 Atlantic hurricane season forecast on Monday. They are also calling for a very active year: 15.6 named storms, 8.4 hurricanes, and 4 intense hurricanes. TSR predicts a 66% chance of an above-average hurricane season, 22% chance of a near-normal season, and only a 12% chance of a below normal season. TSR bases their December forecast on predictions that sea surface temperatures next fall in the tropical Atlantic will be above about 0.3°C above average, and trade wind speeds will be about 0.7 m/s slower than average. The trade wind speed prediction is based on a forecast for a weak La Niña in August-September 2011.

I like how TSR puts their skill level right next to the forecast numbers: 2% skill above chance at forecasting the number of named storms, 1% skill for hurricanes, and 7% skill for intense hurricanes. That's not much skill, and really, we have to wait until the June 1 forecasts by CSU, NOAA, and TSR to get a forecast with reasonable skill.

Comparing 2005 and 2010 steering currents
The U.S. got extremely fortunate during the 2010 hurricane season that the steering currents carried most of the storms out to sea, or forced them to the south. A very graphic way of looking at this is to compare the amount of rain that fell due to tropical cyclones in the Atlantic in 2005 versus 2010 (Figure 2.) The U.S. received a direct hit only from Tropical Storm Bonnie, which hit South Florida as a minimal 40 mph tropical storm and caused no significant damage. TSR is predicting that this luck will not hold in 2010; they project that five named storms will hit the U.S., with two of these being hurricanes.


Figure 2. Rainfall amounts due to all Atlantic tropical cyclones in 2005 and 2010, as measured by NASA's TRMM satellite. Steering currents in 2010 tended to recurve many storms out to sea between the Caribbean and Bermuda, due to a large number of unusually strong troughs of low pressure moving off the U.S. East Coast.

Weekend winter storm for Eastern U.S.
The latest 06Z (1am EST) set of computer model forecasts for this weekend's winter storm over the Midwest and Eastern U.S. point towards a more northerly path for the storm, bringing the axis of heaviest snow through Wisconsin and Michigan. There is still a great deal of uncertainty in the predicted timing and strength of the storm, but a renewed blast of cold air Monday and Tuesday over the Southeast U.S. is still highly likely in the wake of the storm.

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: 81 - 31

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13Blog Index

La nina forecast to strenghen:

Member Since: Posts: Comments:
Question for the experts:

If you go to WolframAlpha.com and type in Weather Greenland, go down to the Temp graph and click on current week and select "All" data.

Why does it show a linear trend since 1983 of minus 1.8 degrees per year?

This isn't intended as an argumenative question, I just can't understand how the melt can increase with the temps declining.
Member Since: Posts: Comments:
Quoting Neapolitan:

Wrong. Just plain wrong.

Yes, we don't have thermometer readings from a thousand or ten thousand or one hundred thousand years ago. But we have proxy data: dendroclimatology, for instance, or isotopic analysis of glacial ice, corals, and stalactites, and so on. And before you dismiss those data, answer this: do you believe there were dinosaurs? Of course you do. And you know this not because you've seen them roaming the earth or because we have videotapes from long ago, but because of fossils. Proxy data is, in effect, looking at the fossils of previous climate paradigms. And if you're willing to believe when science tells you the fossils show there were dinosaurs 100 million years ago, you should certainly be willing to believe those same scientists when they tell you what the temperature was 500 years ago. Any other conclusion is foolishness or denial...
It's still an inference. Take for example, the actual appearance of dinosaurs. We probably don't get the color right. And in many cases we do not know for sure whether a dinosaur had feathers or not because the absence of feather fossils or certain anatomy doesn't rule out feathers. To illustrate, this is what wikipedia says the Velociraptor Mongoliensis looked like:


And they didn't have this evidence before 2007 even though they suspected that it had a lot in common with modern birds (descendants of dinosaurs). So this is only the latest conception of what a raptor looked like. What else will we uncover in the coming years? Maybe it's not perfect. How do we know?

Notice how it looks wildly different than what we saw in jurassic park.

Even the Deinonychus looks different, despite that it's a similar size and is probably dangerous too (just not the same, nor as fast and not as smart as the ones in the movie):


Until we have actual video from that time and actual recordings, it can only be an inference. That doesn't mean it's not reliable, it just will always give deniers an element of doubt to hold onto.
Member Since: Posts: Comments:
Updated yesterday, but a bit long of a read for lunch. Have fun :)

Link
Member Since: Posts: Comments:
Significant lake effect snowfall reports.
-------------------------------------------------------------
==weather event discussion==

The traditional snow belts of Southern Ontario are in the tail end
Of a major multi-day snow squall event. Brisk northwest winds from
Lake Huron and Georgian Bay have produced impressive snowfall
accumulations over the past couple of days. Snow squalls are
continuing to weaken and are expected to end later today. Snow totals
are well over one metre in and around the London area as well as some
locales to the southeast of Georgian Bay.

Lucan has reported receiving a staggering 177 cm as of 5:30 AM and
An additional few cms are still possible this morning.

-------------------------------------------------------------
Location snowfall amounts (cm snow)

London 65-80
London airport 75 (59 cm compacted snow depth)
southeast of London 85-95
Lucan (northwest of London) 177 (as of 5:30 AM today)
Dorchester (east of London) 69 (51 cm compacted snow depth)
Goderich 55 (estimated)
Mount Forest 18 (compacted snow depth)
Lakelet (near Clifford) 40 (as of 4 PM Wednesday)
Paisley (ne of Kincardine) 10 (possibly more)
Beeton (south of Alliston) 105 (to 11:30 AM Tuesday)
Holly (southwest of Barrie) 64 (24 hour total to 7 AM Wednesday)
Alliston 83
Thornbury 61
Barrie 20-30 (higher just west of Barrie)

Please note that this summary contains the observations at the time
of broadcast and does not constitute an official and final report of
the weather events or the high impact events attributed to the
weather events.

END/OSPC
Member Since: July 15, 2006 Posts: 174 Comments: 54639
Not a mention of the record low temps in Europe or the SE US.
Member Since: Posts: Comments:
12:06 PM EST Thursday 09 December 2010
Snow squall warnings ended for ontario regions

Member Since: July 15, 2006 Posts: 174 Comments: 54639
Quoting Seastep:


Give this one a try if you have not.


thanks!

Quoting hurricanejunky:


User CoreFTP...it's free and works great. Let me know if that works...


they are uploading, I created a new folder
Member Since: Posts: Comments:
SQUAWK!!!!
Member Since: Posts: Comments:
Quoting tornadodude:


hmmm, not yet, I can see the folders but Im not sure how to add anything to them. I cant find a free FTP client that works


User CoreFTP...it's free and works great. Let me know if that works...
Member Since: Posts: Comments:
Quoting Neapolitan:

Wrong. Just plain wrong.

Yes, we don't have thermometer readings from a thousand or ten thousand or one hundred thousand years ago. But we have proxy data: dendroclimatology, for instance, or isotopic analysis of glacial ice, corals, and stalactites, and so on. And before you dismiss those data, answer this: do you believe there were dinosaurs? Of course you do. And you know this not because you've seen them roaming the earth or because we have videotapes from long ago, but because of fossils. Proxy data is, in effect, looking at the fossils of previous climate paradigms. And if you're willing to believe when science tells you the fossils show there were dinosaurs 100 million years ago, you should certainly be willing to believe those same scientists when they tell you what the temperature was 500 years ago. Any other conclusion is foolishness or denial...


Ive been staying out of the debate, but I fail to see how finding a fossil is similar to being able to tell what the temperature was by using ice records, etc. A fossil is pretty solid proof of something's existence, and is relatively easy to understand. However, the ice core readings and other terms get thrown around so loosely that a lot of AGW believers probably don't know how they even use ice to find out the temperatures from thousands and thousands of years ago.

If I find a footprint in the sand, and it is still wet, is it because it has been wetter than normal due to human-induced warming causing more rainfall? or simply because of a natural reason, such as high tide?
Member Since: Posts: Comments:
Quoting tornadodude:


hmmm, not yet, I can see the folders but Im not sure how to add anything to them. I cant find a free FTP client that works


Give this one a try if you have not.
Member Since: Posts: Comments:
12Z GFS has backed off the East Coast storm idea, I have to dissagree. With the NAO goes negative, a storm should develop just off the East Coast and cold air should run into it and blossom the storm creating havoc in that area. That is my opinion.. I feel the big cities will see a change over to snow eventually.
Member Since: Posts: Comments:
67. XLR8
Hey KOG, keep them circles off my state we dont need any more bad weather here. Thanks ;)
Member Since: Posts: Comments:
Looks like the forecast here in Sarasota Fl has backed off on the intensity of this next system good news and bad news. Good news because because it may not get as cold as originally thought. Bad news because they've dropped the rain chance from 40 percent on Sunday to 30 percent. I don't mind a little cold weather, but this is a bit much.
Member Since: Posts: Comments:
Quoting ncgnto25:
There are a lot of people that believe the current 'warming' that is melting the Arctic icecap will disrupt the Atlantic oscillation and create a mini ice age. Some even believe it could take less than 10 years to effect a change. Are we starting?

Can you please name some of those "lot of people", and tell us how many of them are credible climate scientists?

The planet is getting warmer. The data on that are conclusive, and the evidence overwhelming. And 2010 has been one of the warmest years on record, so a brief cold snap in the US is no more proof that the planet is cooling than a single cough is proof that an otherwise healthy person has inoperable lung cancer.
Member Since: November 8, 2009 Posts: 4 Comments: 13580
Quoting P451:


This logic is lost on most. Intentionally at times it seems.

Not only what you said, but, the collection of such records, using different devices, watching these devices encroached on by urban development undoubtedly skewing the record keeping.

You put it together and it keeps AGW as a theory at present.

Faulty record keeping and faulty science cannot be used to produce facts. I generally ignore the "Hottest ____ on record! We are all DOOM DOOOOOM!" entries no matter who they come from.

*shrug*


Wrong. Just plain wrong.

Yes, we don't have thermometer readings from a thousand or ten thousand or one hundred thousand years ago. But we have proxy data: dendroclimatology, for instance, or isotopic analysis of glacial ice, corals, and stalactites, and so on. And before you dismiss those data, answer this: do you believe there were dinosaurs? Of course you do. And you know this not because you've seen them roaming the earth or because we have videotapes from long ago, but because of fossils. Proxy data is, in effect, looking at the fossils of previous climate paradigms. And if you're willing to believe when science tells you the fossils show there were dinosaurs 100 million years ago, you should certainly be willing to believe those same scientists when they tell you what the temperature was 500 years ago. Any other conclusion is foolishness or denial...
Member Since: November 8, 2009 Posts: 4 Comments: 13580
Member Since: July 15, 2006 Posts: 174 Comments: 54639
people dont listen 2 jeff 9641 he wrong i called the nws and they said next monday will be upper 20 in weston and they said high near 55 in south fla so people get ready for another cold one we will be near freezing temps and there will be frost
Member Since: Posts: Comments:
Quoting seflagamma:
Orca and Scott,

I still have a hard time believe "global warming" is causing all this cold weather in South Florida...

as sad as it is, I think we are going thru a climate change.. I do beleive that... and the Earth will just have to make adjustments.
If Florida keeps getting colder and colder every winter...then we will have to find someplace else to grow food in the winter months...and the tropical animals will have to move further south into the Caribbean...

but I've been brainwashed into thinking the world was getting warmer not colder....

that "sea ice" may melt some every summer but it freezes back every winter...

Yes, sea ice melts every summer, and it freezes back every winter. But for the most part, more melts each summer than the summer before, and less freezes each winter than the winter before.

At any rate, don't be fooled into thinking that dealing with global warming is as simple as finding "...someplace else to grow food in the winter months" or making "...the tropical animals...move further south into the Caribbean". The true costs to man will be infinitely worse.
Member Since: November 8, 2009 Posts: 4 Comments: 13580
Quoting hurricanejunky:
Hey TDude...did you get the uploading issues resolved?


hmmm, not yet, I can see the folders but Im not sure how to add anything to them. I cant find a free FTP client that works
Member Since: Posts: Comments:
I have to dissagree with Dr. Masters on the Winter Storm... 06Z runs actually shows a more likely chance of snow on the Eastern Seaboard, not quite there, but last nights 18Z GFS was lovely for Long Island, showing a swath of moderate snow. I'm still not buying the wacky EURO at this time, it's alone and no other models support a potent Great Lakes Storm at this time. I am buying the GFS run for right now, a change over to snow for the East Coast.
Member Since: Posts: Comments:
Hey TDude...did you get the uploading issues resolved?
Member Since: Posts: Comments:
Quoting Jeff9641:


How much rain have you guys seen so far today?


.28...not alot but better than nothing. We have been terribly dry. It's likely gonna be a crappy fire season...
Member Since: Posts: Comments:
good morning everyone

Member Since: Posts: Comments:
Blame man made global warming for that as well.

Quoting seflagamma:
While we may not be getting Hurricanes we are now getting record break cold temps every winter.. and this year in December ... breaking 150 year old (or older) records every morning!

not good. Our farmers have already lost most of their Dec Green Bean and Sweet Corn crop that would have been in the stores in a few weeks for Christmas... now there will be a shortage and what we have will be very expensive.

The farmers say they ALWAYS get their Dec veggies to market, it is usually the January one they expect to sometimes miss due to cold temps..but not this year.
Member Since: Posts: Comments:
Any educated guesses as to when Northern Delaware might get significant snowfall?
Member Since: Posts: Comments:
Just a reminder: 356days left to the end of the AtlanticHurricaneSeason...
...and not one stinkin' hurricane, not even a measly TropicalDepression.
2011 is a bust.
Member Since: Posts: Comments:
OOps again...2011 doc

TSR is predicting that this luck will not hold in 2010;
Member Since: Posts: Comments:
51. JeffMasters (Admin)
Quoting CaicosRetiredSailor:
OOPS... in Dr. Master's blog above:

TSR is predicting that this luck will not hold in 2005; they project that five named storms will hit the U.S., with two of these being hurricanes.


Time travel errors are things spell checkers don't catch! Fixed, as well as two places I said "2010" instead of "2011".

Jeff Masters
Wonder what they are gonna think when I flip the mitten that has a Canadian Flag on it!
Orca - it's ALL your fault!
Quoting SuperYooper:


You are too funny. We have new driving terms you haven't heard of up here. When driving with mittens on and someone cuts you off, you are allowed to "flip the mitten" since nobody can tell what you are doing anyway.
Member Since: Posts: Comments:
Just NE of Houston this morning it was 29 in Cleveland, TX with freezing fog with 1/4 mile visibility.
Member Since: Posts: Comments:
Quoting Orcasystems:


Ok, that just proves it.. you people from the centre of the universe are nuts. Your starting to make KOG look sane... and thats just wrong


You are correct, the universe does revolve around us. :) I tell you what though.....you do that 3 times and you will sleep like the dead. Snow angels are really fun to make when you do that too.
Member Since: Posts: Comments:
Quoting SuperYooper:


Now you are just being mean. :) We do snow golf up here. And the polar bear club meets on new years for a dip in the lake. That and if the temps get any lower I'll have another notch in the 180 club (stoking a sauna up to 160, then stepping outside to -20).


Ok, that just proves it.. you people from the centre of the universe are nuts. Your starting to make KOG look sane... and thats just wrong
Member Since: Posts: Comments:
Quoting PensacolaDoug:
Bottomed out at 24.6 for me last night. Rebounding nicely now tho.


I wonder how many remember this post.....

_____________________________

668. PensacolaDoug 1:54 PM GMT on October 08, 2010 Hide this comment.

Quoting Orcasystems:


KOG, PDoug was unhappy with your attempt at snow last year.




Yes I was. So this year I'm putting in my order early for a repeat of Feb 1899!!
Member Since: Posts: Comments:
Quoting Orcasystems:


I am really sorry to hear that.. (snicker snicker). I on the other hand have to go thru the hassles of cleaning the Golf clubs and shoes.. to get ready for the start of the season :)


Now you are just being mean. :) We do snow golf up here. And the polar bear club meets on new years for a dip in the lake. That and if the temps get any lower I'll have another notch in the 180 club (stoking a sauna up to 160, then stepping outside to -20).
Member Since: Posts: Comments:
There are a lot of people that believe the current 'warming' that is melting the Arctic icecap will disrupt the Atlantic oscillation and create a mini ice age. Some even believe it could take less than 10 years to effect a change. Are we starting?
Member Since: Posts: Comments:
Bottomed out at 24.6 for me last night. Rebounding nicely now tho.
Member Since: Posts: Comments:
Quoting Beachfoxx:
I never complain when its hot either!
This cold is miserable! I don't have the clothes for this....
Except for my RED Mitttens! Thank goodness!


You are too funny. We have new driving terms you haven't heard of up here. When driving with mittens on and someone cuts you off, you are allowed to "flip the mitten" since nobody can tell what you are doing anyway.
Member Since: Posts: Comments:
Quoting SuperYooper:


Already over? That isn't fair. If this storm heads the way it should I'm not only going to see snow from the storm but lake effect after it goes by that will dump a foot a day.


I am really sorry to hear that.. (snicker snicker). I on the other hand have to go thru the hassles of cleaning the Golf clubs and shoes.. to get ready for the start of the season :)
Member Since: Posts: Comments:
looking at the central us on wv one can see a classic example of topographic lifting, and how it cools and rides over the mountain. When this parcel reaches its dew point voila a cloud is born. As can be seen in the southern rockies. Seeing as though its freezing there id bet some warnings to be posted.
Member Since: Posts: Comments:
Quoting HaboobsRsweet:

Here is the problem. Our records are really only 100-140 years old. Earth has been around a lot longer so techincally these might not even be records. This could be the norm for all we know.


Good point, i'm now in deep thought :)
Member Since: Posts: Comments:
Quoting Orcasystems:


Actually... KOG is way over dues for winter, and ours started way to early and is already over. So I am actually a happy camper, not to mention... 689 hours till I am in Puerto Vallarta for 2 weeks :)


Already over? That isn't fair. If this storm heads the way it should I'm not only going to see snow from the storm but lake effect after it goes by that will dump a foot a day.
Member Since: Posts: Comments:
looking at the central us on wv one can see a classic example of topographic lifting, and how it cools and rides over the mountain it reaches its dew point and voila a cloud is born. Seeing as though its freezing there id bet some warnings to be posted
Member Since: Posts: Comments:
Heard that the Artic Dip was expect in Mexico in about 14 days.....
Quoting Orcasystems:


Actually... KOG is way over dues for winter, and ours started way to early and is already over. So I am actually a happy camper, not to mention... 689 hours till I am in Puerto Vallarta for 2 weeks :)
Member Since: Posts: Comments:
I never complain when its hot either!
This cold is miserable! I don't have the clothes for this....
Except for my RED Mitttens! Thank goodness!
Quoting SuperYooper:
Keep and Orca, don't you sometimes enjoy reading the whining? I never complain when it is hot.
Member Since: Posts: Comments:
Quoting SuperYooper:
Keep and Orca, don't you sometimes enjoy reading the whining? I never complain when it is hot.


Actually... KOG is way over dues for winter, and ours started way to early and is already over. So I am actually a happy camper, not to mention... 689 hours till I am in Puerto Vallarta for 2 weeks :)
Member Since: Posts: Comments:
Quoting niederwaldboy:


EINSTEIN!!!!!!!
FREUD !!!
Member Since: Posts: Comments:

Viewing: 81 - 31

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13Blog 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.