Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 3:46 PM GMT on October 27, 2005
The Hurricane Season of 2005 remains unrelenting. Tropical Storm Beta formed this morning over the warm ocean waters of the southwest Caribbean, just north of Panama. Given the ideal environment for intensification setting up in the southwest Caribbean, this is likely to become Hurricane Beta by tonight, and could grow to major hurricane status before making landfall in Nicaragua on Sunday.
Recent satellite imagery shows a small but rapidly developing system. There is plenty of growing deep convection, good low-level spiral banding, and a Central Dense Overcast (CDO) forming over the center. An eyewall appears to be forming under the CDO, and there is a good chance we'll be talking about Hurricane Beta by this evening. The first hurricane hunter flight is scheduled for Friday afternoon.
Beta is stuck in an area of weak steering currents, and is being slowly pulled northwards by the trough of low pressure that swept Wilma over Florida. All the computer models except the Canadian model forecast that this trough will pull northwards and strand Beta in the southwest Caribbean. A weak ridge of high pressure will then build in and force Beta westward, with a landfall expected in northeastern Nicaragua. With water temperatures 29 - 30C, very light wind shear less than 5 knots, the chances of Beta growing to major hurricane status appear good. Intensification beyond Category 3 status is questionable, since Beta is travelling over relatively shallow water with lower heat content than Wilma had to work with. Additionally, Beta's slow forward speed may cause some upwelling of cold water from the depths that will interfere with the intensification process.
Beta's expected landfall in Central America is likely to be a major disaster. Although a small storm, Beta will bring 10-20 inches of rain over the interior mountainous regions of Nicaragua and Honduras, creating a serious flooding situation. The GFDL model indicates that Beta will survive the crossing of Nicaragua and emerge into the Pacific Ocean, where it will re-intensify into a Category 1 hurricane. The projected path takes the storm northwest along the coast of El Salvador, potentially adding to the destruction caused by Hurricane Stan earlier this month, which killed 69. Beta may also continue on to affect Guatemala, which suffered the cruelest blow of any nation this destructive hurricane season; between 1500 and 2000 Guatemalans died in floods and mudslides spawned by Hurricane Stan. The threat to El Salvador and Guatemala remains highly speculative at this point, since we are talking about events a week or more in the future.
There are no provisions for what to do in the event we have to retire Beta's name and replace it on the list of hurricane names. One possibility is that the storm will be dubbed Beta-2005 and the name Beta will be reused. Another possibilty is that Beta will be skipped over next time the Greek alphabet comes into use.
Figure 1. Current sea surface temperatures show the warmest waters in the North Atlantic are in the region just north of Panama where Beta formed.
Elsewhere in the tropics
The strong tropical wave spreading heavy rains through the Lesser Antilles remains disorganized today. The amount of deep convection has increased some since yesterday, but remains spread out along a long line. A weak circulation center has developed along the south edge of this line, near 12N 60W (the island of Barbados). Wind shear over the wave has decreased to 5 - 10 knots today, and is forecast to decrease further the next few days as the wave pushes into the central Caribbean. Development of a new tropical depression could occur as early as Saturday with this system. Any storm developing from this wave would likely be a threat to Nicaragua, Honduras, Belize, or Mexico later next week.
Another tropical wave, midway between Africa and the Lesser Antilles, remains poorly organized as it moves westward at 15 mph. While a circulation center has developed near 9N 40W, upper level winds are currently unfavorable for development of this system.
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