The Northern Tropics in May 2011

Gradually with the onset of spring in the northern hemisphere  we have seen that tropical band just north of the equator get active with tropical waves, increased sea surface temperatures, rain, thunderstorms, and flaring areas of disturbed weather worldwide. 

Such tropical activity shows clearly within the belt of tropical activitygirddling Earth on the composite satellite view [courtesy of NASA] below:

Full disk composite satellite view of Earth's western hemisphere on 8 May 2011

 On the satellite image two areas are of especial interest to those of us in the United States: (a) One is the eastern-east Pacific just off and west of the coasts of Central America. This region, together with the junction of the isthmus of Panama with South America [Colombia] saw extraordinary rain an storm activity for a good portion of 2010, which was attributed to the effects of La Nina active off the coast of Peru, leading to a number of cyclonic events over Central America, Southern Mexico and the Gulf of Mexico and  above average rainfall over most of Central America, particularly Nicaragua, Costa Rica and Panama as well as portions of northern Colombia and Venezuela with several flooding events.  During the spring of 2011 La Nina is still active, although in a somewhat weaker mode than in 2010, and severe thunderstorms and rain have already affected that Panama – Colombia junction, raising the possibility that we might see more of the same during the summer and fall of 2010. The satellite image below [courtesy of NASA]:

of the Central American region on 8 May 2011″] (b) The other one is the eastern Atlantic, which marks the junction between mainland equatorial Africa and the so-called hurricane alley starting in the neighborhood of the Cape Verde Islands and then west by northwest toward the Antilles and the Caribbean. This area is the terminus for the tropical-wave assembly line that traverses equatorial Africa from east to west and serves as the transport for pulses of disturbed weather often originating over the Indian Ocean, which pick-up heat and moisture over equatorial Africa causing rain and thunderstorms. This activity generates tropical wavesthat emerge over the eastern Atlantic providing fuel fo potential tropical cyclone development. A satellite view of this region on 8 May 2011 already shows plenty of tropical wave activity giving way to cells of rain and thunderstorms south of the Cape Verde Islands moving west along ‘hurricane ‘alley’:

of the eastern Atlantic and western equatorial Africa region on 8 May 2011″]Completing the picture, also on 8 May 2011 a tropical low over the western Pacific became the first tropical cyclone of the the year in northern hemisphere. This is tropicl storm AERE moving toward landfall in the Philippines near the capital city of Manila. The forecast is for the storm to traverse the island and then make way toward Taiwan and possibly Japan under favprable ocean-atmospheric conditions. It would appear then that conditions for cyclogenesis are gradually congealing and becoming more favorable as spring rushes toward summer in Earth’s northern hemisphere. The satellite picture below shows the tropical cyclone on 8 May 2011 just east of the Philippines’ coastline:

showing tropical storm AERE on 8 May 2011 as it approached landfall in the Philippines.”]It is clear the northern tropics are being fueled by warming oceans and atmosphere as the Earth’s axis continues to tilt, bringing the northern hemisphere into full view of the Sun. Conditions are now in place that could soon generate tropical cyclone activity over the eastern Pacific and the eastern Atlantic; if we take into account the continued warming of surface waters in the Atlantic, Caribbean and Gulf, as well as in the eastern east Pacific plus the continuous presence of La Nina off the coast of Peru we may be looking at an active 2011 hurricane season in the Atlantic basin.  Relative to this the Colorado research duo of Bill Gray and Phil Klotzach recently presented their early forecast for the 2011 Atlantic hurricane season, calling for a total of 16 named-storms including 9 hurricanes, of which 5 may reach major hurricane strength (category 3 and above in the Saffir-Simpson scale of hurricane intensity).

Nature is sending us signals through this activity in key regions of the northern tropics. It behooves all of us in vulnerable coastal communities to pay attention to those signals, to be prepared and to practice mitigation to reduce the potential for damage from the impact of hurricanes, which will eventually come our way!