Super typhoon Durian aims for the Philippines; rare tornado hits Wales

Super Typhoon Durian put on a very impressive burst of rapid intensification today, and is now a large and very dangerous Category 4 storm headed towards the Philippines. Durian (named for a tropical fruit) is on track to make landfall on the main island of Luzon later today and pass over the island Thursday. Winds at Catanduanes and Daet, the first major cities that will be hit, had increased to 20 mph at 1am local time Thursday, and will steadily pick up. Durian is in an environment of weak vertical wind shear, warm ocean waters, and favorable upper-level outflow. In the past 24 hours, the storm has intensified from a Category 1 typhoon with winds of 85 mph to a Category 4 super typhoon with 155 mph winds and a central pressure of 916 mb. Durian has a good chance of intensifying into a Category 5 super typhoon later today, before interaction with land and passage over Luzon start to weaken the storm. Unfortunately, Durian is expected to slow down as it passes over the Philippines, and may pass near the heavily populated capital city of Manila, a city of 12 million. The slow motion will make Durian a prodigious rainmaker, and NOAA's Satellite Analysis Branch is predicting rain amounts of up to eight inches in 24 hours (Figure 2). Heavy rains that trigger flash floods and mudslides are the primary hazards of typhoons in the Philippines, and we can expect damage and loss of life similar to what devastating Typhoon Xangsane did to the islands on September 27. Xangsane, a Category 4 typhoon that passed over Manilla, killed 218, did over $100 million in damage, and left tens of thousands homeless. The Philippines have raised its highest alert level, and are moving coastal residents out where a storm surge of up to 15 feet is expected. Schools have been cancelled today and all sea travel suspended.


Figure 1. Latest satellite image of Durian from NOAA.

The Philippines have been hit particularly hard this typhoon season, and Durian will be the 4th major typhoon to wallop the island in the past three months. Typhoon Chebi hit Luzon as a Category 3 typhoon on November 11, but hit the less populated northern portion of the island and moved quickly enough that heavy rains and flooding caused relatively little damage. Super Typhoon Cimaron made landfall October 29 as a Category 5 storm with maximum sustained winds of 160-180 mph. Cimaron killed at least 27, destroyed 2600 homes, and damaged another 18,000.


Figure 2. Latest precipitation forecast for a 24-hour period from NOAA's Satellite Analysis Branch.

Tornado hits Wales
A rare tornado hit Wales in the British Islands yesterday, according to news reports from the BBC. The small tornado, which hit at 1:30 am local time, damaged 20 homes. Tornadoes are rare in the British Islands due to the lack of cold, dry continental air needed to generate severe thunderstorms. Here's the weather discussion put out by the UK Met office before the tornado:


CONVECTIVE DISCUSSION issued at 1045 GMT on Tuesday 28th November 2006 Valid from/until: 1045 - 2359 GMT on Tuesday 28th November for the following regions of the United Kingdom & Eire:

Coastal areas of Wales SW England Southern coastal counties of England Channel Islands

SYNOPSIS: Large upper trough/cold pool is approaching from the west. Cold advection aloft/synoptic lift will cause instability to increase with CAPE values of 2-300 J/Kg expected, with LIs down to -2C or so. Flow is rather unidirectional, and low-level/deep layer shear are not large. However, just ahead of the trough, some increase is 850 hPa winds are forecast by some mesoscale models, especially across northern parts of Wales early-mid afternoon.

THREATS: Heavy showers/a few thunderstorms are expected to affect the areas this afternoon and evening, with the risk shifting east over time. The main effects of these will be hail 15-20mm diameter, gusty winds, briefly torrential rain and a few cloud-ground lightning strikes. However, there is a small risk of tornadic development, especially across northern parts of Wales early-mid afternoon, as 850 hPa wind max moves through. Elsewhere, the risk is lower, but still there. Overall though, the risk is deemed too low for a WATCH to be issued.


Jeff Masters