The last (and my favorite) of the major hurricane seasonal forecasts came out yesterday. Phil Klotzbach and Bill Gray from Colorado State are sticking with their April forecast. Rather anti-climactic, but perhaps it’s a measure of the confidence in the forecast. I didn’t have a chance to write up something in April, so I’ll do it now before normalcy, if it sets in, brings six weeks of inactivity.
http://hurricane.atmos.colostate.edu/Forecasts is used in most of the following. My comments are in italics.
EXTENDED RANGE FORECAST OF ATLANTIC SEASONAL HURRICANE ACTIVITY AND LANDFALL STRIKE PROBABILITY FOR 2011
We continue to foresee well above-average activity for the 2011 Atlantic hurricane season. We are predicting the same levels of activity that were forecast in early April due to the combination of expected neutral ENSO conditions and very favorable atmospheric and oceanic conditions in the tropical Atlantic. We continue to anticipate an above-average probability of United States and Caribbean major hurricane landfall.
Note – in the table below, I changed K&G’s June numbers to the range that include ±1 standard deviation of their hindcast error and added a column with NOAA’s forecast.
| Forecast Parameter and 1950-2000
Climatology (in parentheses) |
Issue Date
8 December 2010 |
Issue Date
6 April 2011 |
Issue Date
1 June 2011 |
NOAA |
| Named Storms (NS) (9.6) | 17 | 16 | 12.3 – 19.7 | 12-18 |
| Named Storm Days (NSD) (49.1) | 85 | 80 | 59.9 – 101.1 | |
| Hurricanes (H) (5.9) | 9 | 9 | 6.9 – 11.1 | 6-10 |
| Hurricane Days (HD) (24.5) | 40 | 35 | 24.8 – 45.2 | |
| Major Hurricanes (MH) (2.3) | 5 | 5 | 3.4 – 6.6 | 3-6 |
| Major Hurricane Days (MHD) (5.0) | 10 | 10 | 4.7 – 15.3 | |
| Accumulated Cyclone Energy (ACE) (96.1) | 165 | 160 | 112 – 212 | |
| Net Tropical Cyclone Activity (NTC) (100%) | 180 | 175 | 127 – 223 |
PROBABILITIES FOR AT LEAST ONE MAJOR (CATEGORY 3-4-5) HURRICANE LANDFALL ON EACH OF THE FOLLOWING COASTAL AREAS:
- Entire U.S. coastline – 72% (average for last century is 52%)
- U.S. East Coast Including Peninsula Florida – 48% (average for last century is 31%)
- Gulf Coast from the Florida Panhandle westward to Brownsville – 47% (average for
last century is 30%)
PROBABILITY FOR AT LEAST ONE MAJOR (CATEGORY 3-4-5) HURRICANE TRACKING INTO THE CARIBBEAN (10-20°N, 60-88°W)
- 61% (average for last century is 42%)
Acknowledgment
This year’s forecasts are funded by private and personal funds. We thank the GeoGraphics Laboratory at Bridgewater State College (MA) for their assistance in developing the United States Landfalling Hurricane Probability Webpage (available online at http://www.e-transit.org/hurricane).
The forecast is a blend of a statistical analysis, a search for analog years with similarities to April-May conditions and the expected August-October conditions, and “qualitative adjustments for other factors not explicitly contained in any of these schemes.”
As they often do, the June forecast is based on a new June statistical model and uses just four predictors (the geographic ranges are in the image at the top):
| Predictor | 2011 Forecast Value |
| 1) April-May SST (15-55°N, 15-35°W) (+) | +0.3 SD |
| 2) April-May 200 MB U (0-15°S, 150°E-20°W) (+) | +1.6 SD |
| 3) ECMWF 1 May SST Forecast for September Nino 3 (5°S-5°N, 90-150°W) (-) | +0.3 SD |
| 4) May SLP (20-40°N, 30-50°W) (-) | -0.9 SD |
Decoding key: SST: Sea Surface Temperature; SLP: Sea Level Pressure, SD: Standard deviation; 200 MB U: zonal wind at atmospheric pressure 200 mb, an altitude of about 40,000 feet.
Other notes:
ENSO
The moderate-to-strong La Niña conditions of this past winter have continued to weaken since early April. According to the Climate Prediction Center (CPC), SST anomalies in the central and eastern tropical Pacific have now warmed to the point where ENSO is in its neutral state. While the moderation of tropical Pacific SSTs have continued over the past couple of months, we do not expect to see a transition to El Niño conditions during the next several months.
Current Atlantic Basin Conditions
Conditions in the Atlantic remain favorable for an active season. May SSTs across the tropical Atlantic remain at above-average levels (Figure 17). The anomalously strong trades during the latter part of the winter that caused some anomalous cooling in the tropical Atlantic have now weakened (Figure 18). Sea level pressure anomalies during the month of May were also well below-average throughout the tropical Atlantic (Figure 19). Altogether, tropical Atlantic conditions currently reflect an environment conducive for an active hurricane season.
Forthcoming Updated Forecasts of 2011 Hurricane Activity
We will be issuing a final seasonal updates of our 2011 Atlantic basin hurricane forecast on Wednesday, 3 August. We will also be issuing two-week forecasts for Atlantic TC activity during the climatological peak of the season from August-October. A late-season forecast for the Caribbean will be issued in early October. A verification and discussion of all 2011 forecasts will be issued in late November 2011. All of these forecasts will be available on the web at: http://hurricane.atmos.colostate.edu/Forecasts.
I will likely report on the Aug. 3rd update, but will probably not cover the two-week forecasts. Last year, several were dominated by current activity, low or high.

Sadly anything close to prediction will be touted as confirmation of model. Anything above will also be used to promote agenda. This is a set up for false positives.
Isn’t one of he more succesful indicators for Atlantic hurricane prediction 6 months out use dust levels in the subSaharen Sahel region? I thought I remembered reading about something like that.
Probability that the probabilities can be proven wrong 0%. These thing will either will happen or not in which case the probabilities are 100% or 0%.
I’m predicting 1 hurricane in the Atlantic.
If get 5, I’ll contact the media and report we got 5 times as many hurricanes as expected. The end is near!
My guess is we will have an active season. We have tropical Atlantic sea surface temperatures at or slightly below normal but we have air aloft that is much colder than normal. This will make for much more vigorous convection. What powers these storms is a difference in temperature. The greater the difference, the more powerful the storm. You can have warmer water or you can have colder air, as long as that difference in temperature is there, you will have powerful convection.
Air temperatures above 25,000 feet are the coldest we have recorded since they have been measured by satellites. Warm, wet air will rise quickly in that cold air resulting it a stronger updraft which should get things spinning nicely.
I am personally getting sick and tired of the snide comments written so far and some before, the scoffs at probability forecasting for tropical cyclones.
Dr. Gray has made a career of being quite successful in forecasting the seasons.
The eastern seaboard states (and this does not include the gulf coast states) of the USA contain 112 MILLION people, most of them in rather close proximity to the coast.
Put another way, even though the Eastern Seaboard is only 11.8% percent of the area of the United States…it contains 37% of its total population.
The largest mega-region in the USA, some 50 million people, includes New York City, one of the largest cities in the world, and one that could be quite vulnerable to the (indeed if rare) direct hit from a tropical cyclone.
And I will not even begin to start talking about very densely populated South Florida…
True, tropical cyclones don’t usually bring the instantaneous and apocalyptic destruction that say, tsunamis do (on a large scale) or that of an EF5 tornado (on a small scale.)
But they can be extremely disruptive to commerce, destructive to infrastructure and property, not to mention a major, major threat to life and safety.
In light of the fact that these beasts are the largest storms on earth…and have been responsible for catastrophically huge losses to life and property across the globe…
…I am mystified why some individuals on here, cowardly hiding behind their little computer keyboards in their climate-controlled rooms and insulated from Nature’s dangers, would make light of hurricane forecasting, with cheap, uncalled-for, below-the-belt, class A bull****.
Chris
Norfolk, VA, USA
Steve R says:
June 2, 2011 at 7:12 pm (Edit)
Yeah, and it’s had a major impact on some seasons. Dust both shades the ocean, slowing down SST warming, and warms the air around the dust, resulting in a more stable atmosphere suppressing the convection vital to a tropical storm.
I don’t think there’s a good service that produces dust storm forecasts. It may be that with wind speeds around the planet weakening, there will be less dust for a while.
crosspatch says:
June 2, 2011 at 8:21 pm
My guess is we will have an active season. We have tropical Atlantic sea surface temperatures at or slightly below normal but we have air aloft that is much colder than normal. This will make for much more vigorous convection. What powers these storms is a difference in temperature. The greater the difference, the more powerful the storm. You can have warmer water or you can have colder air, as long as that difference in temperature is there, you will have powerful convection.
Air temperatures above 25,000 feet are the coldest we have recorded since they have been measured by satellites. Warm, wet air will rise quickly in that cold air resulting it a stronger updraft which should get things spinning nicely.
============================
These are very, very good observations….and in line with Dr. Spencer’s remarks on his website as to the most violent tornadic cyclones being a product of so much cold air aloft.
Chris
Norfolk, VA, USA
Whoops I see I mis-typed my screen name so it published a couple times wrong.
The screen name is savethesharks.
Name is Chris. Sorry about that.
Mods one of my comments may have gone to spam because I typed in my screen name wrong.
Sorry about the trouble of rescuing. I will pay more attention next time.
Chris
Norfolk, VA, USA
svaethesharks says:
June 2, 2011 at 8:37 pm
I went to a lecture at the local university tonight. The speaker noted that scientists are often wrong but there is not anything wrong with that. What is wrong, is when they don’t learn anything from being wrong. The commenters here (and elsewhere) are mostly just having a bit of fun with the early-stage learning curve of hurricane prediction.
Klotzbach and Gray deserve support for their efforts and openness and, my guess is, nearly everyone knows and understands this. Your points about the danger to densely populated areas are also well known. There has been no harm nor none intended from the comments – just a little bit of folks trying to write something that might seem a little witty at the end of a busy week. Right now, if I lived in the South I would go find a nice place to get some good barbeque and a beer. Where I now live the folks think searing a hot dog over charcoal is “barbeque.” Now that’s both mystifying and sad.
What’s with svae?
svaethesharks says:
June 2, 2011 at 8:37 pm
Chris,
It doesn’t appear to me that anyone is diminishing the potential danger of these storms on land or sea. The issue is the integrity of the forecasts. Unfortunately there is an impression that these forecasts are announced intentionally at the high end in probabilities for the forecaster’s own reasons, rather than striving for likely, probable occurrences. Its not as if individual local areas are forecasted to be targeted. Instead everyone is put on the edge of fear. Maybe that’s good so people will be prepared if something happens. But how many times can one credibly say the sky is falling if it isn’t. At this point everyone is watching. Casting the weather is dicey. We’ll see.
Perhaps, in the end, we are all deceived by weather. If the Norse had accurate future forecasts (akin to our great climate models), perhaps Greenland would never have been settled.
Policyguy says:
June 2, 2011 at 10:54 pm
svaethesharks says:
June 2, 2011 at 8:37 pm
Chris,
It doesn’t appear to me that anyone is diminishing the potential danger of these storms on land or sea. The issue is the integrity of the forecasts. Unfortunately there is an impression that these forecasts are announced intentionally at the high end in probabilities for the forecaster’s own reasons, rather than striving for likely, probable occurrences. Its not as if individual local areas are forecasted to be targeted. Instead everyone is put on the edge of fear. Maybe that’s good so people will be prepared if something happens. But how many times can one credibly say the sky is falling if it isn’t. At this point everyone is watching. Casting the weather is dicey. We’ll see.
=====================
Oh really???
Go back and revisit some of the snide, milktoast, climate-controlled, comments.
For people in Sendai Japan and Joplin MO….. the sky DEFINITELY FELL..
http://www.dispatch.com/live/content/national_world/stories/2011/05/23/tornado_video.html?sid=101
Maybe you could make your assessement after that.
Chris
Norfolk, VA, USA
“”Ric Werme says:
June 2, 2011 at 9:26 pm
– – –
Dust both shades the ocean, slowing down SST warming, and warms the air around the dust, resulting in a more stable atmosphere suppressing the convection vital to a tropical storm.“”
My bold. Is this not what happens in a warming world? Would the good Dr Gray be basing his forecast on a cooling world?
Hurricane or no hurricane, if Houston Texas doesn’t get rain soon, I will be forced to conclude that there is no Republican God.
Of course it does not really matter, all these warmists want is death and destruction by weather. That instantly becomes climate in the minds of these charlatans. One bad hurricane is all they pray for.
I would look at a couple of other indicators:
1. Atlantic trade wind anomalies
2. Strength and location of the Bermuda High
1 and 2 are related. The stronger the Bermuda High, the stronger the trade winds. Strong trades mean a lot of sheer and storms get ripped apart. The location is important because if the high is to the East, storms will go into the Gulf. If it is to the West, the Atlantic seaboard is at risk. Tell me the sea surface temps, temps aloft, location and strength of the Bermuda High, and I will tell you what the hurricane season will be.
A weak high means more storms, strong high means less (greater pressure gradient making for strong trades which cool the ocean surface).
“if the high is to the East, storms will go into the Gulf. If it is to the West, the Atlantic seaboard is at risk.”
That logic is backwards. High to the East means Atlantic seaboard and vice versa. Sorry.
I have no problem with hurricane forecasting, except for the ignorant, worthless, global warming based predicitions.
I don’t care about their forecast, but how do their past forecasts stack up against reality?
Rather like our UK Met. Office and their forecast of a bar-b-cue summer, which was a wash out, and last winter was to be mild but turned out to be the coldest for many years, I have taken all meteorological forecasts for longer than 3 days with a very large pinch of salt.
I don’t know what the hurricane season is going to be like. However, after well over 30 years of ‘man-made’ global warming we have this:
See also Hurricane Intensity
I want to ask Al Gore: What is global warming supposed to do to hurricanes?
After well over 30 years of ‘man-made’ global warming we have this:
Al Gore and the other igNobel prize winners should now step up to the plate and tell us what global warming is supposed to do to hurricanes?
I am in Florida. The hurricane season for the last few years has been very quiet, please check the insurance industry’s profits for conformation. Our local weather people on TV love to play up the dangers of the hurricane season and have appeared petulant for the last few years as there have been no “killer-storms” to send a weather-babe out into for “gripping” footage.
Like most important natural events, the CAGW alarmists/activist crowd will attempt to use any hurricane to trumpet their religion (it is certainly not science) and scare the populace. Since we moved here in ’59 we have seen cycles of hurricane activity as well as cycles of hot/cold winters. Funny how “scientists” have forgotten that cycles are important in climate analysis. Perhaps they can only do linear equations on their computers?
C. DISCUSSION
In a global warming or global cooling world, the atmosphere’s upper air temperatures
will warm or cool in unison with the SSTs. Vertical lapse rates will not be significantly
altered. We have no plausible physical reasons for believing that Atlantic hurricane
frequency or intensity will change significantly if global ocean temperatures were to
continue to rise. For instance, in the quarter-century period from 1945-1969 when the
globe was undergoing a weak cooling trend, the Atlantic basin experienced 80 major (Cat
3-4-5) hurricanes and 201 major hurricane days. By contrast, in a similar 25-year period
from 1970-1994 when the globe was undergoing a general warming trend, there were
only 38 Atlantic major hurricanes (48% as many) and 63 major hurricane days (31% as
many) (Figure 26). Atlantic SSTs and hurricane activity do not follow global mean
temperature trends.
http://hurricane.atmos.colostate.edu/Forecasts/2011/june2011/jun2011.pdf
Richard 111 questioned whether Dr Gray is looking at a cooler world.
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/images3/nino34SSTMonE120.gif
I support the proposition that it will be an intense hurricane season.