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Summer Blizzards 2008 Hurricane Forecast


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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet

    This people is my 2008 Atlantic Hurricane season forecast...

    This forecast will be updated on or before September 10th...

    This forecast will be split into four main areas...

    1) ENSO (El Nino Southern Oscillation)

    2) QBO (Quasi-Biennial Oscillation)

    3) Sea Surface Temperature anomalies

    4) Conclusions

    Each section will contain some information about the topic and its relevance to this forecast, as well as the analogues and expected state this season...

    ENSO (El Nino Southern Oscillation)

    http://www.cdc.noaa.gov/people/klaus.wolter/MEI/#discussion

    El Niño/Southern Oscillation (ENSO) is the most important coupled ocean-atmosphere phenomenon to cause global climate variability on interannual time scales.

    There are many different ways to measure the state of the ENSO, however I think that the best way to measure it is by the MEI index (Multivariate ENSO Index), because it takes into account six variables, these are:

    1) Sea-level pressure

    2) Zonal and meridional equatorial winds

    3) Components of the surface wind

    4) Sea surface temperature

    5) Surface air temperature

    6) Total cloudiness fraction of the sky

    http://iri.columbia.edu/climate/ENSO/curre.../technical.html

    This is also a very important link; it is the latest update on the ENSO from IRI, and points to a 75% chance of neutral conditions developing this summer. Also on the IRI site is this link, which gives details on what each model expects to happen and the previous La Nina and El Nino event and how the models handled that.

    http://iri.columbia.edu/climate/ENSO/curre.../SST_table.html

    This table shows that how the models handled the other two events the best, however the models were not progressive enough in bringing in or exiting the La Nina events.

    The only analogues which matched the March-April period were:

    1999

    1989

    1976

    1967

    1963

    QBO (Quasi-Biennial zonal wind Oscillation)

    http://ugamp.nerc.ac.uk/hot/ajh/qbo.htm

    http://en.wikipedia.org/wiki/Quasi-biennial_oscillation

    The QBO is a quasi-periodic oscillation of the equatorial zonal wind between easterlies and westerly’s in the tropical stratosphere with a mean period of 28 to 29 months. The alternating wind regimes develop at the top of the lower stratosphere and propagate downwards at about 1 km per month until they are dissipated at the tropical tropopause. Downward motion of the easterlies is usually more irregular than that of the westerlies. The amplitude of the easterly phase is about twice as strong as that of the westerly phase. At the top of the vertical QBO domain, easterlies dominate, while at the bottom, westerlies are more likely to be found.

    For a hot summer, no state is preferred; therefore neutral values would be best to allow another teleconnection to dominate.

    The only analogues which matched the March-April period were:

    2006

    1997

    1990

    Sea surface temperature anomolies

    sst_anom.gif

    As you can see, across the Tropical Atlantic, anomolies are above average aside from the far east and west, indicating a more active than average ITCZ (Inter-Tropical Convergance Zone).

    Conclusions

    Based on the anologues below, and the fact that sea surface temperature anomolies are supportive of development, here are the statistics and maps relevant to this forecast...

    2006

    1999

    1997

    1990

    1989

    1976

    1967

    1963

    9 to 11 named storms...

    5 to 7 hurricanes...

    1 to 3 major hurricanes...

    Average number and how this season will compare...

    9 to 11 named storms... (+/-0)

    5 to 7 hurricanes... (+/-0)

    2 to 4 major hurricanes... (-1)

    Below average ACE value is favoured...

    post-1806-1214094059_thumb.jpg

    post-1806-1214094068_thumb.jpg

    As you can see, throughout the 2008 hurricane season, recurviture is favoured with the north east of the USA most at risk.

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    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    tks for that, KW? your view?

    and for another view see this link from the UK Met O

    http://www.metoffice.gov.uk/corporate/pres...pr20080618.html

    they suggest 15

    70% chance between 10 and 20.

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    Posted
  • Location: Liphook
  • Location: Liphook

    Well its an interesting forecast I'll say that much because its going rather against what IMO alot of the conditions are suggesting but still I always say never rule out anything because you just don't know.

    The problem is you've used years which just can't be used in this set-up. For example 1997 had one of the fastest and strongest El Nino ever develop that year and its hardly fair to use that as a comprasion to this one which will likely be neutral. 2006 also had a El Nino developing, 1976 the same.

    Anyway in terms of ACE I've got a sneaky feeling your going to be too low, even if we get the numbers you suggest this is very likely to be a cape Verde season given the above normal moisture levels in central Africa the last couple of months and above normal SST's that have sustained themself just off-shore from Africa. Shear is below normal in the Atlantic overall a trademark of the legacy of La nina we had in the Spring. It'd only take 3 majors that can sustain themselves for most of the journey across the Atlantic from Cape Verde to push us close to average on thier own. Thats how alot of seasons get such huge ACE totals depsite only having what looks like normal storm numbers.

    I do somewhat agree with you though with track recurveature is favored. I've said that IMO main risk zones are central America/Mexico, Lesser Antilles, Florida, Bahamas and also the Carolinas, however obviously thats just a best guess though Arthur did hit central America so thats one of the zones thats been hit by a tropical system already. Also I should add that there is a small window of chance probably in Mid-July for a system to form but we probably won't see major development till in August I think.

    Anyway all this is just my own veiw, you just can't say exactly how a season will go its just a case of wait and see.

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