Category 3 Cyclone Evan leaves Samoa, heads for Fiji
Category 3 Tropical Cyclone Evan is finally done pounding Samoa and American Samoa, after spending two days meandering over the islands. Evan made landfall on the north shore of Samoa near the capital of Apia on Thursday as a Category 1 cyclone with 90 mph winds, and intensified into a Category 3 storm with 115 mph winds after the eye wandered back offshore late Thursday. Media reports indicate that Evan has killed two and brought heavy damage to Samoa. "Power is off for the whole country... Tanugamanono power plant is completely destroyed and we might not have power for at least two weeks," the Disaster Management Office (DMO) said in a statement. Satellite loops show a well-organized storm with plenty of intense heavy thunderstorm activity. The storm will be a region with light wind shear of 10 - 15 knots and very warm ocean waters that extend to great depth, and could intensify into a Category 4 cyclone by Saturday, as it passes through the Wallis and Futuna Islands. On Sunday, Evan is expected to pass just north of Fiji. The GFS model shows that Fiji should experience heavy rains from Evan, but miss the core eyewall region with the strongest winds and highest storm surge. The storm will encounter decreasing ocean heat content on Monday, after it passes Fiji, and should weaken to a Category 1 cyclone. Evan is one of Samoa's most destructive tropical cyclones on record, as discussed by wunderground's weather historian, Christopher C. Burt. The most famous and deadliest tropical storm to strike Samoa (in modern records) was that of March 1889, which influenced the balance of Western imperial power in the Southern Pacific.
Figure 1. People walk over a destroyed bridge in Samoa's capital Apia, Friday, Dec. 14, 2012, after cyclone Evan ripped through the South Pacific island nation. Phone lines, Internet service and electricity were down across the country, and the airport was closed. (AP Photo/Seti Afoa.)
Figure 2. The German corvette ‘Olga’ lies beached on Samoa following the cyclone of 1889. Photographer unknown.
Jeff Masters
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"This close to landfall, the TRMM satellite saw what could only be described as the 'full catastrophe' in terms of the eyewall indicators of a potentially destructive tropical cyclone," said Owen Kelley of the TRMM science team at Nasa's Goddard Space Flight Center, Greenbelt, Md., in a report online on hurricanes and tropical cyclones.
Defined as a cyclone's most destructive region, an eyewall is located just outside the eye where the most damaging winds and intense rainfall is found.
The eyewall around Pablo had six devastating features.
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1) First, noon of December 3, just hours before the pre-dawn landfall, the TRMM radar saw two hot towers "simultaneously reaching a 15.5 kilometers altitude on the northeast side of the eyewall where the storm's forward motion is added to the counterclockwise winds circling under the eyewall."
A hot tower is a cloud that penetrates the tropopause, or that which reached to the lowest later of the atmosphere into the stratosphere. The tropopuase is usually around 15 kilometers above sea level.
The presence of hot towers in a typhoon's eyewall indicates strengthening in the next six hours.
From past records of TRMM images, one hot tower higher than 14.5 kilometers or nine miles already indicates intensification is ongoing. More than that, at the base of these two hot towers were heavy rainfall.
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2)Second, Pablo not just had one but two eyewalls. This indicates "rapid intensification."
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3) Worse, the inner eyewall had only a ~20 km radius, which is smaller than the average cyclone, which again says a lot of the typhoon's "fearsome potential."
"A compact eyewall means that the typhoon's eye contains only a relatively small volume of air that would need to be heated in order to lower the storm's ocean-surface central pressure, which in turn, would make it easier to increase the speed of the circling surface winds that determine the storm's 'headline' intensity," the report said.
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4)
As if that's not enough, Pablo just before landfall had two lightning flashes in the inner edge of one of the eyewall hot towers, a relatively rare occurrence in tropical cyclones.
"Lightning tends to occur where updrafts are strong enough to suspend in mid-air a mix of supercooled water and grauple or hail-sized chunks of ice," the report said.
This ice can only be formed when updrafts "repeatedly bob ice particles up and down through a lower cloud layer with liquid water droplets and then a higher cloud layer cold enough to promote freezing." Meaning, Pablo was not just gathering a very strong rain and wind, it was also playing around with ice.
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5)As a fifth indicator that typhoon Pablo was brewing something really, really big, the TRMM observed "cloud-top temperatures."
The coldest cloud tops had temperatures as cold a -90C. The report said this shows that Pablo was sucking up a great deal of energy from the ocean surface and turning this into strong updrafts that were punching through the troposphere and into what lies between the troposphere and stratosphere.
From relative heat to very beyond freezing cold means very strong updrafts indicating the typhoon was going on an overdrive that has yet to be witnessed again.
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6) To top it off, these same cloud-top temperatures show that the circling wind of the typhoon were contained and prevented from simply dissipating from the eye to the outside drafts.
"Specifically, the cloud-top temperatures show gravity waves propagating around the eyewall instead of spreading away from the inner core like ripples in a pond," the report said.
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Thus, while the Pagasa had earlier announced that it does not use the term super typhoon and that such a term is only used by the media, Pablo was indeed a super typhoon for lack of any other word to describe it.
To add to its record-breaking dimensions, Pablo broke a long-held belief that tropical cyclones can only form at least five or eight degrees of latitude away from the equator.
"Tropical Cyclone Bopha (international codename of Pablo) has just broken this rule, with the TRMM satellite radar catching Bopha in the act of rapidly intensifying from category 3 to category 5 when approximately six degrees north of the equator," the Nasa report said.
There were very few such tropical storms or typhoons near the equator. These include Washi or Sendong, which hit Iligan and Cagayan de Oro Cities last year, Tropical Storm Agni that fell on Somalia on December 5, 2004, and Vamie which hit Singapore on December 27, 2001.
"In the past half century, the two tropical storms with the most similar landfall locations in the southern Philippines may be Kate (Typhoon Titang in 1970) that made landfall at category 4 and caused over 600 deaths and Washi (Sendong in 2011) that make landfall as a tropical storm and caused over 1,000 deaths," the report said.
It was Titang that hit Davao Region and at that time it was listed as the deadliest typhoon to hit the country with 631 dead, 284 missing and $50-million in damage. This has since been surpassed by nearly 20 typhoons throughout the 42-year span, the worst of which so far is Pablo.
"The physical mechanisms contributing to such an event (Pablo) will take scientists time to unravel," the report said.
As of Sunday, the death toll from Pablo has reached 1,020, while 844 people remained missing.
In its update, the National Disaster Risk Reduction and Management Council (NDRRMC) said the number of injured persons also rose to 2,662.
The highest number of dead totaling 962 was reported from Region 11 (Davao Region). The rest included 21 in the Caraga Region, 15 in Region 10 (Northern Mindanao), 10 in Region 7 (Central Visayas), four in Region 12 (Soccsksargen), three in Region 8 (Eastern Visayas), three in Region 4-B (Mimaropa) and one each in Region 9 (Zamboanga Peninsula) and Region 6 (Western Visayas).
The typhoon also affected 701,224 families, or 6,203,826 people in 2,910 villages in 271 towns and 38 cities in 32 provinces. Of these, 230,453 families or 987,349 people are staying in 60 evacuation centers.
Damage caused by Pablo was estimated at P24,160,920,528.05 -- P7,761,431,310 in infrastructure, P16,350,529,805.05 in agriculture, and P48,959,413 in private properties.
At least 63,040 houses were destroyed while 95,544 were partially damaged, said the NDRRMC
SPC has my area marked, I'm hoping for some 70 mph winds.
Forced line in low CAPE environment
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