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Recent trends in the forecasts indicate that the May/June/July average ENSO SST anomalies are not going to be anything close to the previous outlooks, with a current strong La Nina slowly evolving into a neutral state or even a weak El Nino by the end of the hurricane season. The M/J/J average ENSO Region 3.4 anomaly now looks more like -0.6C - quite a change from the earlier forecast of about -1.3C. Although the La Nina six month forecast is now hinting at a slight intensification (cooling) during May and June, a warming again occurs over the next three months (July - September). The Gulf of Mexico forecast is still expected to be slightly below normal from June through September, however, the northern tropical Atlantic is now expected to be slightly above normal - especially during July and August. While the details of a particular month may be insignificant, the trend is still worth monitoring over the next couple of months. These new trends suggested that it was time to revisit SST climatology to determine analog years that had similar trends and values. 1999 was dropped from the analog list because in that year the La Nina actually restrengthened during the season. That recooling could certainly happen this year but right now that doesn't seem to be a likely scenario. With the anticipation of a less significant pre-season La Nina, a few other years were added to the analog list. In priority order, here is the restructured list of analog years for this season: 1985 - 11/7/3 (quite similar to the current and expected pattern) 1974 - 11/4/2 (similar) 2000 - 15/8/3 (2008 not expected to be quite as weak as 2000) 1971 - 13/6/1 (2008 not expected to increase like 1971) 1950 - 13/11/8 (2008 overall La Nina not as strong as 1950) 1989 - 11/7/2 (strength and flow pattern not likely to be similar) It is worth noting that in 1985 there were 7 hurricanes - and 6 of them made landfall in the United States. The high risk forecast by CSU et al for U.S. hurricane landfall this season seems to be realistic. The analogs still don't suggest a hyperactive season, but they do suggest the possibility of a more dangerous one. No change from my earlier outlook for 12/7/3. ED |