We expect that the next two weeks will be characterized by above-average amounts of activity (greater than 130 percent of climatology.)
So starts the latest two week forecast from Philip Klotzbach and William Gray at Colorado State University.
As you can see in the graphic, the most intense part of the hurricane season should be behind us, and 130% of “climatology” means we can expect less activity than we had in September. (Note that they are talking about ACE – Accumulated Cyclone Energy, the sum of the squares of the estimated wind speed at each 6 hour report by the National Hurricane Center.
The graph above is just the number of storms observed on the date over 100 years.) They base their prediction “primarily to the heightened amount of activity being called for by most of the global models.” This includes both tropical depression 16 which may bring tropical storm force winds to Cuba, Florida, and North Carolina, and one or two more systems predicted by some models.
That’s about it for this forecast.
Storm development this time of year shifts from the Cape Verde area to the Caribbean. As such, the number of long-lived intense storms declines quickly. On the other hand, storms that form in the Caribbean don’t have the room to recurve away from the US mainland as the Cape Verde hurricanes often do, and hence have a better chance of landfall somewhere. Don’t let down your guard.
The forecast for the previous two weeks verified quite well, as Igor, Julia and Karl were existed at the start of the period. Klozbach and Gray only choose one of three broad ranges in these forecasts, and the forecast of 130% or more was readily exceeded – about 220% of climatology was recorded. Not a very hard forecast when you have two Cat 4 storms around.
For an interesting counterpoint, see Joe Bastardi’s video The Reason for the Season and Why I Wasn’t Teasin’. He puts forth his case why he expects the Caribbean to be the focus of hurricane development and why he thinks that
“The US may still have the worst part of the season, as far as impact goes, ahead of us.”
I don’t agree with (or is it I don’t understand?) everything he says, but he has an engaging style and offers some good insights.
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Ryan Maue says: “Here is a comparison mouseover set of plots for 1982-2009 using the NOAA AVHRR 0.25 degree SST data … SST Comparison Plots .”
Thanks for the link.
Being able to see not only anomalies but the actual temps as well puts things in perspective.
Ric Werme says:
September 29, 2010 at 11:28 am
Ryan Maue says:
September 29, 2010 at 9:12 am
“”[ryanm: it’s clear that Santa Ana wind events, i.e. offshore flow are becoming more intense, consistent with what is expected/predicted by climate models. those 2.5×2.5 grid cells resolve those mountain passes perfectly]””
____________Reply;
(I hope you are being sarcastic?) If the Santa Ana winds are being produced by the lunar tidal process, and enhanced by the outer planetary conjunctions, then the number and intensity should drop off as the total of these two effects will not be combining to produces an event as large as this one until Saturn or Jupiter comes close to a conjunction with either Neptune or Uranus, while the earth is in the area, in boreal Autumn.
The potential for this to happen again, IF it is the driving factor in increasing the intensity can be calculated by the use of a heliocentric ephemeris, and similar weather patterns forecast to be expected.
http://ssd.jpl.nasa.gov/horizons.cgi
would be my place to start.
Today the moon is Maximum North declinational culmination @ur momisugly ~23.7 degrees, the enhanced primary tidal bulge in the atmosphere just East of the Rocky Mountains is centered over Huntsville, Alabama, where it has been pioviting around for two days. With the polar air to the west of Huntsville and the equatorial air mass East to the middle of the North Atlantic Ocean.
For the next six days we should continue to see the high precip rates move North along the eastern seaboard. Starting early yesterday the 28th those two areas of tropical moisture off the west coast of Africa now at 12.5 deg N and 50 deg W being the “dig daddy” with his “little sister” to the east, should become active with real circulation and eyes like a normal TS, like Igor and Julie or Earl and Fiona, did earlier.
With a large swath of Precipitation up along the Eastern seaboard starting on October the 7th. (see the daily maps on my site) being off of the coast of Maine and Newfoundland by the 12th or 13th October 2010, when the Moon will be maximum South.
I expect a large flow or tropical moisture to come into the Western side of the Gulf of Mexico, starting on the 10th. and running until the 14th or 15th of October 2010, with a general return flow of much more moisture up into the Central plains from Texas, Mexico, and the gulf states for the whole 27.32 day cycle.
I don’t mean to be antagonistic, just sticking my neck out of my shell, the truth will be the axe wielder.
George E. Smith says:
September 29, 2010 at 9:13 am
“Well maybe I’m just dumber than most; but I would appreciate a formal explanation of just exactly what is mean by 130% of Climatology ?”
That use of “climatology” made me scratch my head the first time I saw it. Later context made it clear it refers to historically derived climate statistics. So when they say 130% of climatology they mean to say 30% above average hurricane activity.
As JB says don’t just take my word for it .Do your own observation
Hey, if the climatologists in charge of weather want to send a tropical storm to Louisiana, it’s ok with me. No hurricanes though please. I hate picking up limbs.