For the second consecutive month, Grand Cayman received a record amount of rainfall.
According to statistics provided by the Cayman Islands National Weather Service, a total of 17.7 inches of rain fell in May, breaking the previous record of 16.14 inches – set in 2002 – by more than 1.5 inches.
The new record in May was aided by one particular weather event that occurred on the 21 May, when 8.5 inches of rain fell in one morning.
Typically, Cayman’s rainy season starts around the fourth week of May, although the precipitation started earlier this year than most.
April 2012 also saw a new record when 7.4 inches or rain fell during the month, breaking the previous record of 6.41 inches that occurred in 1985. For the sake of comparison, in 2011 only 0.18 of rain fell in April and 0.90 inches fell in May.
Despite the records this April and May, Grand Cayman would have to receive a lot more rain in order to set a record for the entire year. Through 31 May, 2012, 31.6 inches of rain has fallen, almost 53 inches short of the record of 84.5 inches that fell in 1979. Cayman’s 30-year average for annual rainfall is 56.18 inches.
Updated hurricane forecast
Colorado State University scientists Phil Klotzbach and William Gray issued their updated hurricane forecast on 1 June, increasing their predicted numbers of named storms and hurricanes from their 4 April forecast. The duo now forecasts 13 named storms, up from 10 in their April forecast, and five hurricanes, up from four in their previous forecast. Their forecast number of major hurricanes with sustained winds of 111 miles per hour or more remained at two.
The number of predicted named storms includes the two preseason tropical storms – Alberto and Beryl – so the forecast calls for 11 more after 1 June.
It wasn’t the two preseason storms that caused Klotzbach and Gray to increase their tropical cyclone activity forecast.
“Pre-1 June activity has very little bearing on the rest of the hurricane season,” the scientists stated in their updated forecast report.
“The only two seasons on record with two [tropical storms] prior to 1 June were 1887 and 1908. While 1887 was a very active season, 1908 had average levels of activity.
The last season with a US landfall prior to 1 June was 1976, which was a relatively quiet season.” The change in the forecast was predicated on uncertain climate conditions.
“We have increased our numbers slightly from our early-April forecast due largely to our uncertainty as to whether an El Niño will develop later this summer and to marginal Atlantic basin conditions,” their report stated. El Niño is an anomalous warming of the sea surface temperatures in the equatorial Pacific Ocean.
The cyclical phenomenon is known to cause higher wind shear that hinders the formation and strengthening of tropical cyclones in that Atlantic basin.
Currently, the equatorial Pacific Ocean is in what is called ENSO-neutral conditions, which wouldn’t effect the Atlantic basin hurricane season. However, about half the forecast models predict a transition from ENSO neutral to El Niño sometime during the summer of 2012.
As of 4 June, however, the US National Oceanic and Atmospheric Administration’s Climate Prediction Center predicts that ENSO-neutral conditions are expected to continue through the Northern Hemisphere summer, which would incorporate the peak months of that Atlantic basin hurricane season.
The Atlantic basin hurricane season runs from 1 June through 30 November, peaking around 11 September. However, late season cyclones are common in the Northwest Caribbean. In 2008, Cayman Brac and Little Cayman suffered direct hits from major Hurricane Paloma in early November.