Beta drifting; Wilma revisited

Beta remains a tropical storm this morning, drifting slowly north off of the coast of Nicaragua. Its rise to hurricane strength has been thwarted by a large tropical disturbance that has developed about 300 miles to the northeast. This disturbance has created a layer of easterly winds on its south side at mid and upper levels. These winds are now generating about 10 knots of wind shear on Beta's east side. The shear disrupted the small eyewall that was forming early this morning, and Beta decreased in strength for a time. Deep convection has made a bit of a comeback this morning, but Beta continues to struggle with the shear, and has a long way to go before making hurricane status. The shear over Beta is expected to increase to 15 knots by tomorrow morning, then decrease back down to the favorable 5 knots we saw yesterday. Since Beta is a very small system, this relatively high shear may keep the storm from attaining hurricane status until Saturday afternoon or evening. We'll know better this afternoon at about 4 pm EDT, when the first hurricane hunter flight is scheduled to arrive.

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. The computer models are now more divided. The GFS, NOGAPS, and GFDL models 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. The UKMET model, plus some of the less reliable models we usually don't mention, like the Canadian, LBAR, and NHC98 models--favor a more northerly track, with Beta entering the western Caribbean after brushing northeastern Nicaragua. As we can see from the plot of historical tracks of October tropical storms in a similar location, this is the prefered track taken by similar storms in the past, and it would not surprise me if Beta ended up taking a similar path.


Figure 1. Historical tracks of October tropical storms near Beta's location. Only one out of seven of these storms hit Nicaragua.

If Beta does make landfall in Central America, it is unlikely to make it all the way across the rugged mountains of Nicaragua and arrive intact into the Pacific. Beta is a very small storm, and probably will not be intense enough or moving fast enough to survive the crossing. Crossing the flat Florida peninsula is no problem for a hurricane, but the high mountains of Central America can block a hurricane's low level circulation from the surface to 5000 feet, seriously disrupting it. Hurricane Joan of October 1998 did successfully make the crossing, to be reborn as Hurricane Miriam in eastern Pacific. However, Joan was a large and fast-moving Category 4 hurricane.

Although a small storm, Beta will bring 10-20 inches of rain over the regions of Nicaragua and Honduras it crosses, creating serious flooding situations. However, since Beta is a small storm, these rains will be confined to a realtively small area. If Beta hits the northeast corner of Nicaragua or Honduras, the terrain there is relatively flat, and major loss of life from flash flooding and mudslides will not result. Beta is small enough that it is not expected to affect Costa Rica and Panama, and shipping through the Panama Canal should be unaffected.

I know I said this in yesterday's blog, but it bears repeating since I get asked this question all the time: 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.

Elsewhere in the tropics
The large tropical disturbance in the central Caribbean that is interfering with Beta's circulation has increased in organization this morning. Wind shear is a light 5 knots over the disturbance, and some development of this system is possible today. The disturbance is very close to Tropical Storm Beta, though, and Beta may end up absorbing the disturbance.

Elsewhere, tropical storm formation is not expected.

Wilma revisited
I will continue to link to wunderphotos that members in South Florida post this weekend as power is being restored, allowing people to at last turn on their computers and upload photos. As most of the media attention has been focused on Florida for this storm, I want to go back along Wilma's path and draw attention to some of the other areas affected.

Wilma's effect on Mexico
Officials analyzing the damage to Mexico now agree that Hurricane Wilma is the most destructive hurricane ever to hit Mexico, surpassing the $1.2 billion in insured property damage done by Hurricane Gilbert in 1988. Most tourist facilities in Cancun and surrounding areas are expected to be closed through mid-December, and economic losses from this closure alone will approach $1 billion. Officials estimate that 98 percent of the tourist infrastructure and 75 percent of the population of the state of Quintana Roo, which includes the resorts of Canc�n, Cozumel, Playa del Carmen and Isla Mujeres, have been damaged. Over 90 percent of the 17.4 miles of sand in Canc�n has been washed away, and a multi-million dollar beach replenishment project will begin in December. Cruise ships scheduled to dock at Cozumel are finding alternate ports of call, as one of that island's three piers for cruise ships was completely destroyed, and another heavily damaged. Cozumel also suffered "significant damage" to its famous coral reefs, the Environment Department said in a report. Over a million acres of forests were also damaged by Wilma, according to the report.

On a hopeful note, Mexico has shown a remarkable ability to bounce back quickly from severe hurricanes, as we saw after Hurricane Gilbert in 1988 and Hurricane Emily earlier this year. The bulldozers are already out on the beaches of Cancun, clearing away debris. President Fox's goal of having 80% of Cancun's hotels open for business by December 15 is ambitious, but doable. A full recovery by Easter seems probable. Cozumel may recover faster; officials there have set a November 15 date for resuming tourist traffic, and Carnival Cruise lines has agreed to change their return date for cruise ship visits from December 15 to November 15.

Wilma's effect on the Bahamas
The western end of Grand Bahama Island received the full force of Wilma's southeast eyewall when she was a Category 3 storm, and suffered significant damage. Up to 7,000 of the island's population of 47,000 were affected. Grand Bahama was also hard hit by September 2004's Hurricane Frances and Jeanne, and was not recovered from those storms. The communities of Eight Mile Rock, Hepburn Town, Hunters, Martin Town, and Pinder's Point suffered major destruction to homes and utilities from a 15-20 foot storm surge. The island of Bimini, which has a population of 1,717, also suffered significant damages to homes, trees and utility poles from heavy rains and storm surge.

Wilma's effects elsewhere
Torrential rains in southwest Haiti triggered flooding that killed 11 people there. Severe flooding in Jamaica caused millions in damages to roads and buildings and killed one person. Wilma's storm surge and 20-foot foot waves pushed flood waters six feet deep up to 700 meters inland in Havana, Cuba, flooding thousands of buildings and destroying portions of the famed Malecon seawall. Including the damage done by a week of heavy rains to both ends of the islands, Wilma damaged or destroyed over 5000 buildings in Cuba. Over 700,000 people were evacuated in Cuba at various times during Wilma's passage. Honduras, Belize, and the Cayman Islands all received flooding and wave damage from Wilma.

Tropical Storm Alpha
More people may have been killed by Tropical Storm Alpha than by Wilma. The death toll in Haiti stands at 17, and nine people were killed in the Dominican Republic, which shares the island of Hispaniola with Haiti. Most of the victims in the Dominican Republic were swept away when a river broke its banks in the northern province of Puerto Plata. In Haiti, the Interior Ministry said that four people were still missing, bringing the likely total death toll to 30. Wilma is being blamed for 27 deaths so far, 10 in Florida, and 17 people in Mexico, Haiti and Jamaica.

I'll be back with an update if Beta attains hurricane status today, otherwise I'll see you in the morning.

Jeff Masters