Dr Gray October Update

[MWatkins]

Here it is...read all the way through as there is some very good info on the Florida hurricane problem this season:

Summary: 3 Oct Named Storms, 2 Hurricanes, 0 Majors

http://hurricane.atmos.colostate.edu/fo ... 4/oct2004/

MW

[HURAKAN]

Interesting ...

[Scorpion]

Darn, I wanted at least one or two more majors. Maybe in November.

[Stormsfury]

This is a MUST READ ... explains in-depth of just why, where, what, and how August-September's activity and all the Florida strikes were unusual and devastating "anomalies"

SF

[hibiscushouse]

Good and bad news. But leaning toward reassuring for Floridians.

[rainstorm]

may not get any storms in oct

[Galvestongirl]

didnt really understand it...but, I read it

[Scorpion]

Rainstorm, no that is not possible. Especially in this type of season. I remember you saying earlier that this season was a dud. If not October, November will be an explosive month.

[SouthernWx]

I respect Dr Gray, but must respectfully disagree with his assessment.....in forecasting no major hurricanes in October or November.

I only have to cite the past nine seasons (1995-2003)....when major hurricanes were spawned in 7 of 9 AFTER October 1st; including category 4/5 hurricanes such as Mitch, Iris, Keith, Lenny, and Michelle....as a source of concern.

True, historically, the U.S. has never been impacted by more than three major hurricanes in one season, nor the Florida peninsula more than two...but that doesn't mean is cannot or will not occur.

Both the Caribbean Sea and Bay of Campeche are still extremely warm and posess plenty of fuel (TCHP) to produce another severe hurricane or two. There's no way of knowing, even if they develop if a U.S. landfall will occur at peak intensity....but I wouldn't rule it out, nor ignore the possibility based on Dr Gray's report. As a coastal resident, that would be both unwise and dangerous.

In addition, I've stated since early August that this season's overall pattern reminded me of 1964....the unusually strong troughs for so early in the season, the landfall of a significant hurricane into Florida before August 15th...an event never before observed. In 1964, the Florida peninsula was struck by an early strong hurricane (Cleo). After Dora in September, two additional major hurricanes developed in October 1964.....Hilda, which blasted Louisiana with 120+ mph winds...and later Isbell, which impacted Florida from near Key West to Everglades City and West Palm Beach as a cat-2 hurricane.

I honestly won't be surprised if another strong to severe hurricane impacts southern Florida between now and November. Jeanne was the first landfalling major September hurricane on the Florida peninsula since Betsy....39 years ago. The last major hurricane to impact the peninsula in October was King in 1950. The return period for a major October hurricane in peninsular Florida was once every ten (10) years between 1846 and 1950.....and we've now gone 53 seasons since the last one.

The way this unusual, record breaking season has gone thus far....I'd keep my eyes peeled to the south and southwest if I lived along the U.S. coast...especially if I lived in Florida....just in case my theories are correct and Dr Gray's aren't.

[MSRobi911]

Thanks Mike,

I didn't understand all of the technical talk but got the "just" of the paper. Thanks for posting it for us.

[donsutherland1]

For those who might be starting to think about the coming winter, Dr. Gray's report is revealing in that it notes, "Long period records indicate that active hurricane seasons almost never occur with such high positive values of Atlantic SLPA or when such high anomalous values of sea surface temperature are present in NINO 3.4 (August-September 2004 values were +0.8°C)."

Since 1950 when regular reporting of the global indices has been available, there were two hurricane seasons that saw 10 or more named storms when Region 3.4 had an average temperature at or above 27.5°C (anomaly at or above +0.6°C) for the May-November period:

Code: Select all

Year   R3.4 Temp.   R3.4 Anom.Named Storms   
1969   27.60°C      + 0.64°C   17
2002   28.07°C      + 1.10°C   12
2004   27.76°C      + 0.50°C   12
   



For now, as food for thought, I'll only note that these two years have popped up on other occasions in discussions of possible analogs for Winter 2004-05.

[hibiscushouse]

Oh gosh, you lost me now.

[donsutherland1]

Sorry, Hibiscushouse.

I should have posted this in the "Winter" folder. Briefly, when one is looking to make a seasonal forecast, one relies on a number of factors ranging from computer models to analogs. Analogs are past years that had similar characteristics to the current one, with the idea that such past years might offer some insight into the coming season. At this point in time, the computer guidance alone is not really sufficient for seasonal forecasting.

Analogs proved very helpful in assessing that the 2004 Hurricane Season would be an active one. When one considered such factors as the Multivariate ENSO Index in ranges that were similar to what was expected for 2004, among others, 13-13 past seasons saw 11 or more named storms.

What Dr. Gray noted was a highly unusual situation with water temperature anomalies in a specific location in the Pacific Ocean. In virtually all such years with that characteristic, hurricane seasons were relatively quiet. An active season with that characteristic present has occurred only twice since 1950 when the global indices were regularly reported.

As for Winter 2004-05, at this point in time, there are a number of possible analogs (one can find some discussions of this in the "Winter" folder). This observation by Dr. Gray, if one pursued it further, lent some credence to two that are in the running at the moment. Some reasonable similarities:

1969-70: Weak El Niño, QBO* switched to East, Active hurricane season preceded it, + PDO, etc.

2002-03: Moderate El Niño, QBO switched to East, Active hurricane season preceded it, + PDO etc.

2004-05: Expected: Weak El Niño, QBO switch to East, Follows active hurricane season, + PDO

*-Over the past 12 months (September 2003-August 2004), the QBO has been most similar to that in the September 1968-August 1969 period.

Key:
QBO: Quasi-Biennial Oscillation
PDO: Pacific Decadal Oscillation

[WeatherEmperor]

3 more storms and 2 hurricanes to deal with? Well Dr.Gray knows his word so we are not done until Nov 30 people!

<RICKY>