Dr. Jeff Masters on Tornadoes and Cyclones

By: Dr. Jeff Masters, 2:55 AM GMT on January 13, 2014 +39

The year 2014 has just begun, but the tropical cyclone seasons in both the Northern and Southern Hemispheres have already claimed victims. Summer is in full bloom in the Southern Hemisphere, where two Category 4 storms formed last week: Tropical Cyclone Colin, which reached sustained winds of 135 mph midway between Madagascar and Australia on January 11, and Tropical Cyclone Ian, which intensified into a powerful Category 4 storm with 145 mph winds before roaring through the South Pacific islands of Tonga over the weekend. At least one death is being blamed on the storm in the northern Ha’apai Islands of Tonga, home to 8,000 people, and 70% of the buildings were damaged or destroyed, according to the Australia Network News. Tonga is an archipelago of 176 islands, with 100,000 people living on the 36 most populated islands. The economy relies on fish exports, tourism, and money from Tongans living overseas. About 40% of the population lives in poverty.

In the Philippines, heavy rains from tropical disturbance 91W have triggered flash floods and mudslides that are being blamed for six deaths on the southern island of Mindanao on Saturday, with eight other people missing. Twenty-four hour rainfall amounts in excess of 300 mm (11.81″) fell in northeast Mindanao, according to Project NOAH. The disturbance will move slowly north over the islands through Tuesday, and bring torrential rains in excess of 5″ to the islands of Leyte and Samar, ravaged by Super Typhoon Haiyan in November.

Figure 1. MODIS image of Tropical Cyclone Ian as its eye passed over Tonga at approximately 00 UTC on January 11, 2014. At the time, Ian was a Category 4 storm with winds of 145 mph. Image credit: NASA.

First U.S. Tornadoes of 2014 hit Virginia and Georgia
A modest severe weather outbreak over the Southeast U.S. on Saturday, January 11, brought the first tornadoes of 2014: three to Virginia, and one to Georgia:

1. EF-0 tornado near Waleska in Cherokee Co, GA, 3 mile path length, downed trees, damaged fence.

2. EF-0 in Isle of Wight Co., VA, 70-75 mph, 2 mile path, 50 yards wide, trees down, roof damage to homes, no injuries.

3. EF-0 near Smithfield, VA, EF-0, 75-80 mph, 1.4 mile path, 100 yards wide, trees down onto homes, no injuries.

4. EF-0 tornado in Hampton, VA, 80 mph, 1.25 mile path, 75 yards wide; trees snapped, shingles off homes, roof off City of Hampton school maintenance compound; Fox Hill Athletic Association building destroyed.

The strongest wind gust ever recorded at Raleigh-Durham International Airport, 86 mph, occurred at 1:57 PM Saturday, when a line of thunderstorms roared through central North Carolina.

from:    http://www.wunderground.com/blog/JeffMasters/show.html