Dr. Gray at the Colorado State University released an updated forecast for the remaining season on 10/3/2006.
The forecast reduces the numbers yet again. For the remaining season which ends on November 30th, the forecast calls for 2 Named Storms, 1 Hurricane and no hurricanes of Cat 3 or greater intensity.
The following statement is made on the forecast.
"We have experienced average hurricane activity through September. August was inactive, but September had above-average activity. We expect October to have below-average activity largely due to developing El Niño conditions in the central and eastern Pacific. November activity in El Niño years is very rare."
Listed below are the October and November forecast
October forecast;
"We had previously developed a statistical forecast of October-only activity; however, we did not have an explicit ENSO predictor in this scheme, and therefore we have discontinued its use for this year. Our research over the past couple of years indicates that ENSO is of critical importance in determining October and November activity. We intend to develop a new statistical forecast by next summer for October activity that takes into account El Niño conditions. This forecast will likely be developed using a similar methodology to what was used for our new August seasonal statistical forecast that uses predictors obtained from surface data. Using only surface data, we can develop the scheme on data extending back to 1900. Our new October forecast scheme will be developed on 1949-2005 and then tested on 1900-1948. A forecast scheme that shows skill over 106 years is likely to be quite robust.
It is expected that the currently rapidly developing El Niño in the central and eastern Pacific will likely bring an early end to the Atlantic basin hurricane season. El Niño conditions typically cause a greater suppression of the latter part of the hurricane season than they do in the earlier portion. Table 2 displays average (1950-2000) October TC activity compared with years when the August-September Nino 1+2 and Nino 3 indices average greater than 0.5ºC above average. For our October forecast calculation, this will be our definition of an El Niño. Based on correlation data from 1949-2005, October Atlantic basin hurricane activity is more affected by SSTs in the eastern Pacific than SSTs in the central Pacific.
Table 2 shows that there is typically a marked reduction in October Atlantic hurricane activity in El Niño years. Table 3 gives probabilities of percentage reductions in October TC activity in El Niño years. The probabilities for one or more intense hurricanes, two or more hurricanes and an October NTC value of 20 or greater drops considerably when SSTs in the east-central Pacific (Nino 3 temperatures) are greater than 0.5ºC above normal. These probabilities drop even more when SSTs are above normal in the eastern Pacific (Nino 1+2 temperatures greater than 0.5ºC above normal). We estimate that the Nino 1+2 and Nino 3 indices for August-September will average around 0.7ºC above average. Note the large reduction in October activity, especially for intense hurricane and intense hurricane days in El Niño years. No intense (or major) hurricanes have been observed to form after 1 October in El Niño years since 1950."
November Forecast;
" Tropical cyclone activity in November is not very frequent. Since 1950, 41% of years have witnessed the development of one or more named storms in November, while only 27% of years have witnessed the development of one or more hurricanes. Only four years since 1950 (7%) have had a major hurricane develop in November. The probability of named storm, hurricane and major hurricane development becomes even less likely in El Niño years. For our calculations, we define an El Niño year to be a year where August-September Nino 3 temperatures are 0.5ºC or greater above the long-period average, years where August-September Nino 3 temperatures are 0.5ºC or less below the long-period average are La Niña years, and all other years are classified as neutral. Using this classification, 14 years since 1950 are defined as El Niño years, 22 years are defined as La Niña years, and the other 20 years are classified as neutral. Table 6 displays the probability of development of a named storm, hurricane and major hurricane for all years, La Niña years, neutral years and El Niño years, respectively. Note the large decrease in probability for November tropical cyclone formation with increasing August-September Nino 3 anomalies. We estimate that the August-September average Nino 3 value for 2006 will be approximately 0.7ºC above average which fits our definition of an El Niño year, and therefore we think that development of tropical cyclones in November is unlikely. It should also be noted that none of the ten years with Nino 3 anomalies of 0.7ºC or greater witnessed named storm formation in November. "
Click here for the full forecast.
If you only worked during hurricanes of 2004 and 2005 or rely only on hurricanes for work, Plan accordingly!