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Record quiet tropical cyclone activity in the Pacific

By: Dr. Jeff Masters, 1:37 PM GMT on November 16, 2010

An area of disturbed weather (Invest 94L) in the southern Caribbean a few hundred miles east of the coast of Nicaragua has lost most of its heavy thunderstorm activity, thanks to dry air at middle levels of the atmosphere. Satellite images show just a few clumps of heavy thunderstorms, and no sign of a surface circulation. Water vapor satellite images show a large amount of dry air lies to the north over the northern Caribbean, which is greatly hampering development. NHC is giving 94L just a 20% chance of developing into a tropical depression by Thursday. Wind shear as analyzed by the University of Wisconsin CIMSS group is a moderate 10 - 15 knots, but the dry air surrounding 94L is probably too great too allow development. 94L may bring heavy rains to Honduras on Wednesday, and Belize on Thursday.

Figure 1. Morning satellite image of 94L.

A record quiet typhoon season
While the Atlantic has had its third busiest season on record this year, it has been a record quiet year for tropical cyclones in both the Eastern and Western Pacific. In the Western Pacific, it is currently the quietest typhoon season on record, according to statistics computed by forecaster Paul Stanko at the NWS office on Guam. On average, by this point in the season, there should have been 24.5 named storms, 16 typhoons, and 4 supertyphoons (storms with 150+ mph winds.) So far in 2010, there have been just 14 named storms, 8 typhoons, and 1 supertyphoon. The record lows for the Western Pacific (since 1951) are 18 named storms, 9 typhoons, and 0 supertyphoons. We have a good chance of beating or tying the records for fewest named storms and fewest typhoons, since there are no current threat areas, and none of the models is predicting tropical cyclone development over the next ten days.

A record quiet Eastern Pacific hurricane season
In the Eastern Pacific, it has also been a record-quiet season. On average, the Eastern Pacific has 15 named storms, 8 hurricanes, and 3 intense hurricanes in a season. So far in 2010, there have been 7 named storms, 3 hurricanes, and 2 intense hurricanes. The record quietest season since 1966 was the year 1977, when the Eastern Pacific had 8 named storms, 4 hurricanes, and 0 intense hurricanes. There is a good chance that the 2010 Eastern Pacific hurricane season is over, since we are already into mid-November, and November storms are quite rare in the Eastern Pacific. La Niña is largely responsible to the quiet Eastern Pacific hurricane season, due in part to the cool sea surface temperatures it brought. La Niña also commonly causes less active Western Pacific typhoon seasons, since the warmest waters there shift closer to Asia, reducing the amount of time storms have over water. Still, it is quite remarkable that both of these ocean basins are having record quiet seasons in the same year--there is no historical precedent for such an occurrence.

I'll have an update Wednesday morning.

Jeff Masters


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