Category Archives: Tropical Storm


As the Earth’s axis tilts while orbiting the Sun, we are approaching the date when the Sun will be directly above the equator and one of two times during the year when day and night will have equal duration. This time, which will take place this coming Wednesday, September 23, 2010 at 11:09 EST, marks the autumnal equinox and the start of the fall season of 2010.

Worldwide satellite view of Earth identifying all active tropical cyclones on 20 September 2010 at 0740 EST.

 So, we are seeing the last days of summer 2010 and as we take a look at Earth’s oceans and atmosphere we see plenty of actual and potential tropical cyclone activity worldwide. Most of the activity is in the larger Atlantic basin where we have hurricane IGOR and tropical storm JULIA moving toward the southeast over open ocean waters, and a large tropical wave just west of the Cape Verde Islands that appears on the verge of becoming a tropical cyclone, plus several other waves in the Caribbean, near the windward Islands and the eastern Atlantic. There is also a typhoon and a tropical depression in the western Pacific and another tropical wave in the eastern Pacific. Additionally there are several tropical waves and cells of stormy weather over equatorial Africa and the Indian Ocean all moving westward toward the still quite warm waters of the Atlantic.

2010 is shaping-up to be somewhat different than your typical year with respect to tropical cyclone activity. The eastern Pacific basin, which usually averages 50% – 60% more tropical cyclones than the greater Atlantic basin has been somewhat quiet so far, with only five named storms versus eleven already in the Atlantic. The central Pacific region has also been extremely quiet with no named storms so far in 2010. However the southern Pacific and Indian oceans have see plenty of activity so far. It is clear that several factors including the La Nina event now under way off the Pacific coast of Peru, the position of the Bermuda high and water temperatures over the Atlantic, the direction of the Julian-Madden oscillation and the water content in the atmosphere are all contributing to shaping up the 2010 worldwide hurricane season.

Composite satellite view showing precipitable water in the atmosphere on 20 September 2010 at 0740 EST. The band of color ranging from yellows to orange and dark brown represents the highest concentrations of precipitable water in the atmosphere, with the darker browns depicting potential precipitation in the range of 70-80 mm (3.1+ inches) per hour.

 On a worldwide basis we continue to see high levels of moisture in the atmosphere particularly near the equator. In fact satellite observations today show large quantities of precipitable water in the atmosphere, which in some regions is up to 70-80 mm/hr. This high moisture content in the atmosphere creates an environment conducive to wet hurricanes, meaning storms that generate large amounts of rain regardless of the intensity of the cyclone itself. Recent reports from the passage of Hurricane Karl through the Yucatan peninsula as a category 1 hurricane refer to large amounts of intense rain, as the most damaging component of the storm. Other recent storms have also generated vast quantities of rain causing flash flooding and mudslides in affected communities.

Global mosaic showing a satellite view of Earth from the eastern Pacific, through the Caribbean, Atlantic and equatorial Africa to the Indian ocean on 20 September 2010. Solid yellow outlines identify hurricane IGOR and tropical storm JULIA as they move over the open waters of the Atlantic toward the northeast. Several tropical waves or cells of disturbed weather, which could potentially generate tropical cyclones, are shown within dotted yellow outlines. The tropical wave just to the west of the Cape Verde Islands appears to be getting better organized and stronger with a high probability for further development within the next few hours.

Over in the Atlantic conditions appear favorable for continued tropical cyclone activity as the number of tropical waves riding along ‘Hurricane alley” and the ‘assembly line’ over equatorial Africa appears to have no end in sight at least for the next 2 – 3 weeks. Only time will show if all these waves are able to generate tropical cyclones, but for the time being all interests around the greater Atlantic basin, including island nations and countries bordering on the Caribbean and Gulf and USA Atlantic coastal regions must closely monitor all of this activity. We must all pay attention! Be prepared!! And above all always practice MITIGATION!!!


Atlantic-wide satellite view for the aviation industry showing the trio of tropical cyclones, Igor, Julia and Karl, which are currently simultaneously active as we have entered the second half of the 2010 Atlantic hurricane season.

 Three tropical cyclones are active in the Atlantic and Caribbean basins: IGOR, JULIA and KARL. Julia became the 11th  named storm of the 2010 Atlantic hurricane season as it entered the period that historically has been the peak of the annual season, so there is more to come.

We have known this trio of storms for quite some time as they were mere tropical waves or areas of disturbed weather, emerging from equatorial Africa over the warm waters of the Atlantic to ride on Hurricane Alley as Igor and Julia have done or crossing into the Caribbean as just a blob of bad weather generating plenty of rain over the Virgin Islands and Puerto Rico and Hispaniola as what is now Tropical Storm Karl did. You can actually follow this storms from genesis to current stage through earlier postings on this site. All of these storms have been part of the “belt” of tropical activity we have highlighted and illustrated on this blog.

Visible light satellite view of category 4 Hurricane IGOR on 14 September 2010 at 2015 EST
Projected track for hurricane IGOR on 14 September at 2000 EST developed by the Navy Research Laboratory
Visible light satellite view of Hurricane JULIA on 14 September 2010 at 2015 EST as the cyclones was some 400 west of the Cape Verde Islands
Projected track for Hurricane JULIA on 14 September 2010 at 2000 developed by the Navy Research Laboratory; the storm was a category 1 hurricane with sustained winds of 85 mph
Visible light satellite view of Tropical Storm KARL on 14 September 2010 while the storm was in the western Caribbean aiming for the state of Quintana Roo in Mexico
Forecast track for Tropical Storm KARL on 14 September 2010 at 2000 EST developed by the Navy Research Laboratory

As we look eastward toward the Cape Verde Islands, the eastern Atlantic and equatorial Africa, there are more tropical waves being generated above the hot and humid tropical forests in Africa and moving west toward the Atlantic, which continues to be quite warm. What is noticeable already is how these tropical waves are being generated farther south and closer to the equator than say six weeks ago, a sign of the approaching change in seasons; as summer winds down and fall approaches the warmest Atlantic waters and coupled atmosphere are shifting southward.

Color-enhanced infrared satellite view of the Eastern Atlantic and the western region of equatorial Africa showing Hurricane Julia and several tropical waves over the hot and humid equatorial region of AfricaGlobal mosaic, a composite of several satellite views, showing the Atlantic basin, equatorial Africa and the Indian Ocean on 14 September 2010 at 2045 EST. Active tropical cyclones are identified by name and solid yellow outlines, while several tropical waves are identified by dashed-line outlines.
Global mosaic, a composite of several satellite pictures on 14 September 2010 at 2045 EST, showing the three active tropical cyclones in the Atlantic and Caribbean, plus tropical waves over equatorial Africa, and a view of the Indian Ocean.