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 , 23. lokakuuta 2010 klo 16:14 (GMT)
Tropical Storm Richard suddenly overcame its struggles with dry air and wind shear this morning, took advantage of low wind shear of 5 - 10 knots and warm water temperatures of 29°C, and intensified into a strong tropical storm. An Air Force hurricane hunter aircraft departed Richard late this morning, and found that the storm had managed to develop respectable surface winds of 65 mph. However, they reported no sign of an eyewall forming, and additional intensification will be limited until Richard can develop an eyewall. Recent satellite imagery shows that Richard has a Central Dense Overcast (CDO) of high cirrus clouds expanding and covering the center of circulation, a telltale sign of an intensifying tropical storm. Low-level spiral bands are becomign more prominent, and upper-level outflow is improving on all sides except the west. Water vapor satellite loops show considerable dry air to the west of Richard, and this dry air is still causing some trouble for the storm. The next hurricane hunter aircraft is due in the storm near 8pm EDT tonight.
Figure 1. Forecast radius of tropical storm force winds of 39+ mph (dark green colors), winds of 58+ mph (light green colors) and hurricane force winds of 74+ mph (yellow colors) as predicted by NHC at 11am EDT 10/23/10. Hurricane force winds are predicted to affect just a small region to the northeast of Richard's center, beginning Sunday morning.
Forecast for Richard
The latest set of 2am EDT (6Z) model runs are similar to the previous set of runs. Richard will continue to move just north of west today, in response to a ridge of high pressure that is expected to build in over the Caribbean. This path will bring the center of Richard very close to Guanaja and Roatan Islands off the northern coast of Honduras near 8am EDT Sunday. Residents of those islands can expect tropical storm force winds of 39+ mph to arrive at the islands between 8 pm - midnight EDT tonight. A good way to estimate these arrival times is using the wundermap with the "hurricane" layer turned on and the "wind radius" and "forecast" boxes checked. The coast of Belize can expect tropical storm force winds of 39+ mph to arrive Sunday afternoon, between noon - 4pm EDT. The 11am EDT NHC wind probability forecast is giving the highest odds for tropical storm-force winds at Guanaja in Honduras, at 89%. Belize City is next highest, at 69%. Richard will pass very close to the coast of northern Honduras today, which may limit intensification some. Dry air to the west may also be a problem for the storm, and it is unlikely that Richard will grow stronger than a Category 2 hurricane with 100 mph winds. NHC is currently giving Richard a 4% chance of intensifying into a Category 3 or stronger hurricane before making landfall in Belize on Sunday. The models predict that Richard will dissipate over the Yucatan Peninsula on Monday. If the storm does make it to the Gulf of Mexico, Richard will probably dissipate by Tuesday or Wednesday, due to high wind shear, and the storm is not a threat to the U.S.
A tropical wave (Invest 90L) centered near the Cape Verde Islands off the coast of Africa is encountering 30 knots of wind shear. The shear is predicted to rise over the few days, discouraging further development. NHC is giving 90L a 20% of developing into a tropical depression by Monday.
No news yet on Cyclone Giri's impact on Myanmar
Powerful Cyclone Giri made landfall Friday morning on the coast of Myanmar (Burma) as an upper-end Category 4 storm with 155 mph winds. Giri strengthened from a 60 mph tropical storm at to a 155 mph Category 4 storm in just 24 hours, leaving little time to evacuate the coastal regions in its path. Giri's winds at landfall were 20 mph stronger than those of Cyclone Nargis of 2008, which killed over 138,000 people. However, Giri hit a portion of the Myanmar coast that is not as heavily populated or as low-lying, so this will not be another Nargis catastrophe. Nevertheless, Giri's record strength and remarkably rapid intensification rate undoubtedly surprised an unprepared population, and the potential exists for a significant death toll. Communications with the disaster area are out, and the impacts of the storm are unknown at this time.
Typhoon Megi hits China
Typhoon Megi made landfall on the coast of China opposite from Taiwan near noon local time on Saturday afternoon. Megi was a Category 1 typhoon with 80 mph winds at landfall, and brougt torrential rains to both China and Taiwan. Mudslides and flooding from Megi's rains in Taiwan left 12 people dead and 26 missing, and the typhoon is also killed 36 people and left $176 million in damage earlier this week in the Philippines. The remnants of Megi are bringing only moderate amounts of rain to the coast of China this afternoon, and flooding damage may not be a great as previously feared.
Figure 2. Radar image of Typhoon Megi at 10:30am Taiwan time on Saturday, October 23, 2010, as Megi was making landfall on the coast of China opposite from Taiwan. Image credit: Taiwan Central Weather Bureau.
I'll have an update Sunday.
Our weather extremes expert Christopher C. Burt has a very interesting post today on the hottest temperatures ever measured on Earth.
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