Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather
By: Dr. Jeff Masters , 4:18 PM GMT on September 02, 2007
Hurricane Felix grazed the islands of Aruba, Bonaire, and Curacao this morning, passing 50 miles north of the northernmost island in the chain, Aruba. Thus far, top winds reported on Aruba have been 28 mph, gusting to 40 mph. Bonaire's winds peaked at 22 mph, and top winds at Curacao were only 18 mph. Heavy rains were reported on all three islands, but damage should be minimal. Felix missed--but not by much (Figure 1).
Figure 1. Radar image of Felix as it passed 50 miles north of Aruba as a Category 2 hurricane. Image credit: Meteorological Service of the Netherlands Antilles and Aruba.
Felix a possible catastrophe for Honduras
Given the nearly ideal conditions for intensification--low shear and plenty of high-heat content water--Felix is likely to be a Category 4 storm as it approaches Honduras Monday. If the center tracks parallel to the coast within about 100 miles of it, an extremely dangerous situation ensues for Honduras. Hurricane Fifi of 1974 passed along the north coast of Honduras in 1974 as a Category 2 hurricane, and dumped up to 24 inches of rain on the mountainous country. The resulting landslides and floods killed an estimated 8,000 people--the fourth deadliest Atlantic hurricane ever. The town of Choloma in northwestern Honduras suffered the most. A huge mudslide triggered by Fifi's rains plowed into the city at dusk on September 20, 1974. The mudslide then formed a dam that pent Fifi's raging flood waters. When the dam burst, flood waters ravaged the entire city. Half of Choloma's population--about 2,800 people--died in the catastrophe. Fifi also killed at least 200 people in neighboring Guatemala.
Felix will be stronger that Fifi was, but it will be the size of Felix that will be critical in determining if Fifi-like rains hit Honduras. As Fifi approached Honduras between September 17 and 18, 1974 (Figure 2), it grew in size. The increased size allowed Fifi to pull in moisture from the Pacific Ocean, which greatly enhanced the rainfall over Honduras. If Felix grows large enough to tap this Pacific source of moisture, prodigious rains capable of causing major loss of life will result. Currently, Felix is not large enough to tap the Pacific moisture source. Additionally, Felix is moving faster--17 mph, as opposed to Fifi's 11 mph. This won't give Felix as much time to pour torrential rains on the region. These factors may combine to prevent Felix from matching Fifi's deadly rainfall totals. However, once Felix moves clear of the South American coast, there is a good chance the storm will grow in size, due to the additional influx of moisture from the south. If this occurs, not only Honduras is at risk. The nations of Nicaragua, El Salvador, Guatemala, Belize, and Mexico will also be at high risk of life-threatening flash flooding and mudslides.
Figure 2. Satellite photos of Hurricane Fifi of 1974, which killed 8000 people in Central America. Fifi was the fourth deadliest hurricane in Atlantic history. Note how in the right hand photo, taken 24 hours after the left hand photo, Fifi had tapped the Pacific Ocean as a source of moisture, and the storm's spiral bands reach all the way to the Pacific.
Felix's threat to other locales
Felix will be devastating wherever it makes landfall, which currently appears to be the Yucatan Peninsula. There are no troughs of low pressure capable of altering Felix's steady course coming, until the storm emerges into the Gulf of Mexico after crossing the Yucatan. At that point, a trough of low pressure strong enough to bring Felix to the Texas coast may move through. It is too early to guess how strong this trough might be, and what the potential risk to Texas is.
Links to follow today:
Current conditions on Aruba, Bonaire, and Curacao
A tropical wave (98L) in the mid-Atlantic, halfway between Africa and the Lesser Antilles, has the potential to develop into a tropical depression later this week. However, conditions are not as favorable today as they appeared yesterday, and there is a higher likelihood that wind shear and dry air will prevent this disturbance from developing. The system has a closed circulation and a small area of heavy thunderstorm activity on the west side of the center. Wind shear from strong upper-level winds from the east-southeast are preventing thunderstorm activity from building on the east side of the storm. The SHIPS model was forecasting a low shear environment would set up over the path of 98L by Tuesday, but now has reversed itself, calling for shear to remain 15-25 knots for the next five days. If the shear does remain that high, formation of a tropical depression is unlikely. However, 98L has a vigorous circulation, and it may be able to outlast the hostile wind shear until it finds a more favorable environment. Furthermore, other global models, such as the NOGAPS, are not forecasting such hostile wind shear conditions. I believe the SHIPS model shear forecast looks a little fishy, and that the NOGAPS model has the right idea. I'm expecting 98L to be a tropical depression later this week, perhaps as early as Wednesday.
98L moved southwestward for a period last night, but now has resumed its westward motion and slowed down to 10 mph. A strong trough of low pressure will pass north of 98L Tuesday and Wednesday, which could impart a more northwesterly motion to the storm. The GFDL and HWRF models have 98L moving to a position about 800 miles east of Puerto Rico by Thursday. A ridge of high pressure should build in after the trough passes, forcing 98L on a more westward track towards Puerto Rico. This is highly speculative, as both the HWRF and GFDL develop 98L into a 50 mph tropical storm by mid-week, and this is not likely to occur. I expect a weaker 98L may not "feel" the presence of the trough so strongly, and it may not get pulled as far north as the GFDL and HWRF are forecasting. In this case, 98L would stay farther south and move through the Lesser Antilles south of Puerto Rico late this week. None of the other computer models develop 98L.
Elsewhere in the tropical Atlantic
Several computer models develop a tropical depression off the South Carolina coast by Wednesday or Thursday, along an old frontal boundary. An area of disturbed weather has already formed here, and will bear watching over the next few days. You can track this using long range radar out of Jacksonville, Florida. The Cape Verde Islands off the coast of Africa are also predicted to be a genesis region, as early as Tuesday.
Henriette kills six in Acapulco, takes aim at Baja
Tropical Storm Henriette continues to churn along the Pacific coast of Mexico towards Baja this morning, and could bring hurricane conditions to the Baja on Tuesday. Now that Henriette has moved away from the coast, it should be able to organize itself and intensify, possibly into a major Category 3 hurricane by Tuesday. Visible satellite loops show this intensification may be underway. Heavy rains from Henriette triggered two landslides in Acapulco Saturday that killed six residents.
Links to watch for Henriette
Los Cabos radar
San Jose Del Cabo observations
My next update will be Monday by noon EDT.
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