Saturday, October 18, 2014

Category 2 Gonzalo Hits Bemuda; Hurricane Ana Brushing Hawaii; Trudy Drenching Mexico

By: Dr. Jeff Masters , 2:46PM,GMT on October 18,2014





Hurricane Gonzalo made a direct hit on the island of Bermuda near 8:30 pm EDT Friday night rated by NHC as a strong Category 2 storm with sustained 110 mph winds. Sustained winds at the Bermuda Airport peaked at 76 mph, with a gust to 96 mph, as the northern eyewall passed overhead between 8 - 9 pm ADT. After a calm lasting about an hour, when the pressure sank to 953 mb, the southern eyewall hit, with stronger winds than the northern eyewall--93 mph, gusting to 113 mph, at 11:55 pm ADT. An unofficial gust of 144 mph was recorded at Commissioners Point at an elevation of 262', a site notorious for recording strong winds due to local terrain effects. In addition, a sustained wind of 89 mph gusting to 144 mph was reported at an elevation of 159' at St. Davids near the airport (thanks to wunderground member BDAwx for this stat.)


Figure 1. MODIS satellite image of Hurricane Gonzalo taken at approximately 11:00 am EDT October 17, 2014. At the time, Gonzalo had top winds of 125 mph, and was embedded in a cold front whose clouds extended northwards past Cape Cod, Massachusetts and into Nova Scotia, Canada. Image credit: NASA.


Figure 2. Gonzalo as seen by the Bermuda radar at 9:43 pm ADT October 17, 2014, when the eye was over the island. Image credit: Bermuda Weather Service.

Gonzalo's damage not as heavy as Fabian's of 2003
Thankfully, no one was killed on Bermuda from Gonzalo. Damage on the island was considerable, though appears to be much lower than that wrought by Category 3 Hurricane Fabian of 2003, the only hurricane to get its name retired exclusively because of its impact on the island of Bermuda. Fabian did $300 million in damage, making it the most expensive hurricane ever to hit the island. Fabian's storm surge destroyed the causeway connecting the airport to the rest of the island, and this causeway withstood Gonzalo's impact--though divers are scheduled to inspect its footings Saturday afternoon before reopening will occur. Damage at the airport was mostly minor (roof damage and minor flooding), and all the navigational infrastructure seems intact. The storm surge damaged the airport's weather sensors, though, according to the Bermuda Weather Service. According to the island's utility provider, BELCO, about 35,700 of the island's 36,000 metered homes were without power at the height of Gonzalo. Virtually all of the island's major roads were blocked by downed trees and power lines.


Video 1. This time-lapse animation shows the evolution of Gonzalo (viewed in infrared, but overlaid on the Blue Marble) from midday on October 13 to midday on October 17, 2014. Images were acquired by the GOES-East geosynchronous weather satellite, which was built by NASA and is operated by the National Oceanic and Atmospheric Administration.


Video 2. Powerful winds sweep across Bermuda on the evening of October 17, 2014, as Hurricane Gonzalo makes landfall. Video by Nicholas Ferrando.


Figure 3. Bermuda Weather Service Meteorological Technician Wayne Little waiting for the lull to release the 00Z (8 pm EDT) weather balloon/sonde into the eye of Hurricane Gonzalo on October 17, 2014. The balloon was successfully launched, and returned a sounding showing a very moist and warm atmosphere inside the eye--no surprise, since hurricanes are warm-cored low pressure systems. Image credit: Bermuda Weather Service

Gonzalo headed towards Canada
Gonzalo is steadily weakening as it speeds north-northeastwards towards Canada. Infrared and visible satellite loops on Saturday morning showed that Gonzalo had lost its well-defined eye, and the storm had been stretched into an elliptical shape by high wind shear. Gonzalo is still expected to have Category 1 strength winds when it makes its closest pass by Southeast Newfoundland, predicted to occur between 4 am - 6 am EDT Sunday by the 00Z Saturday runs of the GFS and European models. In their 5 am EDT Saturday Wind Probability Forecast, NHC gave Cape Race, Newfoundland a 57% chance of experiencing tropical storm-force winds, and a 1% chance of hurricane-force winds. Heavy rains from ex-Gonzalo are likely to be the main threat to Newfoundland.


Figure 4. MODIS satellite image of Hurricane Ana near the Big Island of Hawaii taken on October 17, 2014. At the time, Ana had top winds of 75 mph. Image credit: NASA.


Figure 5. Radar image of Ana at 10:20 am EDT OCtober 18, 2014, from the Kona radar.

Hurricane Ana bringing heavy rains to Hawaii
Hurricane Ana took advantage of light wind shear and warm Sea Surface Temperatures (SSTs) warm of 27.4°C (81°F) to intensify into a Category 1 hurricane with 85 mph winds as of 5 am EDT on Saturday, but is not a threat to make a direct hit on any of the Hawaiian Islands. Satellite loops on Saturday morning showed that Ana had its most impressive appearance yet, with a large area of heavy thunderstorms, plenty of low level spiral bands, and solid upper-level outflow to the north and east. Heavy rains causing flash floods and mudslides are a major concern. Rainfall amounts of 6 - 8 inches are possible on the Big Island, where a Flash Flood Watch is in effect. Portions of the island had received 2 - 3" of rain as of Saturday morning, according to radar estimates.

Related posts
Climate Change May Increase the Number of Hawaiian Hurricanes, my August 6, 2014 post
Climatic Atlas of Tropical Cyclone Tracks over the Central North Pacific (2008)

Tropical Storm Trudy hits Mexico
In the Eastern Pacific, Tropical Storm Trudy formed Friday night and was making landfall on the Pacific coast of Mexico about 75 miles east-southeast of Acapulco on Saturday morning with sustained winds of 60 mph. Acapulco radar is showing very heavy rains affecting the coast, and Trudy has the potential to dump rains of 6 - 12 inches during the next few days in the states of Guerrero and Oaxaca in southern Mexico. Moisture from Trudy will move northwards across Mexico into the southern Gulf of Mexico's Bay of Campeche by early next week, contributing to the formation of a large area of low pressure that will bring heavy rains to Mexico's Gulf Coast, Western Cuba, and South Florida on Wednesday through Friday.

Jeff Masters
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Pre Gonzalo photos
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image.jpg (Bonn1)
A crate from a container ship lands in Hamilton Harbour.
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