Share

Typhoon Threat in the Philippines This Week as Tropical Storm Rammasun Moves West

July 13, 2014

Talking Points

- May to strengthen to a typhoon early in the week

- Will likely affect the Philippines Tuesday and Wednesday

- PAGASA, the national weather agency in the Philippines, has named the storm "Glenda"

Tropical Storm Rammasun (Glenda) is churning in the western Pacific Ocean, not far from where Super Typhoon Neoguri first developed.

(RECAPS: Super Typhoon Neoguri | Photos)

Background

Infrared Satellite

Infrared Satellite

Strengthening Forecast

Tropical Depression Nine strengthened back into a tropical storm on Saturday, after passing Guam, and became Tropical Storm Rammasun (Thai for the God of thunder).

Rammasun is forecast to strengthen Monday and Tuesday as it moves over very warm water in a moderately favorable atmospheric environment.

The national weather agency in the Philippines, PAGASA, has named this system Tropical Storm Glenda. PAGASA uses its own separate list of names for tropical cyclones crossing the Philippines and adjacent waters.

 

This Week: The Philippines, South China, Vietnam

Tropical Storm Rammasun may strengthen into a typhoon (equivalent to hurricane-strength in the Atlantic or eastern Pacific basins, with sustained winds of at least 74 mph) early in the week.

Vertical wind shear (changes in wind speed, direction with height; normally hostile to tropical cyclone development and intensification) increased somewhat near the storm Sunday, putting Rammasun in a less favorable environment for intensification. As a result, its forecast intensity has been reduced from earlier forecasts.

That said, its track westward or west-northwestward over the warm western Pacific Ocean would allow it to strengthen more rapidly if the wind shear were to lessen.

The key to the track is a steering upper-level ridge of high pressure to the north. It appears this ridge will hold firm, keeping Rammasun on a west-northwest path toward the Philippines, while sparing Taiwan.

It is far too early to determine the exact path of the storm. According to the National Hurricane Center, the average forecast track error for Atlantic tropical cyclones four to five days out ranges from 175 to 220 miles. Average errors in the Western Pacific are much larger.

The center of Rammasun may approach the northern or central Philippines by late Tuesday or Wednesday, most likely as a low-end typhoon or high-end tropical storm.

Interaction with land over the Philippines should weaken Rammasun, though it could gain or regain typhoon strength as it moves across the South China Sea in the general direction of southern China and Vietnam late in the week.

Interests in the Philippines, southern China and Vietnam should monitor the progress of this system closely. Taiwan is now outside the cone of uncertainty, but it's a good idea to stay abreast of any possible changes if you live there or have travel plans there.

The Philippines are among the most tropical cyclone-prone countries on Earth. Four typhoons made landfall in the Philippines in 2013, the most destructive of which was Super Typhoon Haiyan (Yolanda). 

(MORE: Philippine Typhoon History | Super Typhoon Haiyan Devastation)

Haiyan was the third Category 5 typhoon to make landfall in the Philippines since 2010, according to Weather Underground's director of meteorology, Dr. Jeff Masters. Conversely, only three hurricanes in recorded history have made a Category 5 U.S landfall.

MORE ON WEATHER.COM: Typhoon Neoguri Photos

People look at a landslide caused by heavy rain in Nago, Japan's southern island of Okinawa on July 9, 2014. (Jiji Press/AFP/Getty Images)

  • Ishigaki, Japan
  • Ishigaki, Japan
  • Okinawa, Japan
  • Ishigaki, Japan
  • Ishiaki, Japan
  • Okinawa, Japan
  • Okinawa, Japan

Featured Blogs

What Do Skyscrapers, Thundersnow, and Jim Cantore Have in Common?

By Dr. Jeff Masters
May 1, 2015

Thundersnow is a rare enough event to get even veteran meteorologists like The Weather Channel’s Jim Cantore excited. New research shows that many cloud-to-ground lightning strikes observed in thundersnow are actually “ground-to-cloud” strikes, initiated by skyscrapers, wind turbines, and other tall objects.

The Great California Storm of April 19-23, 1880

By Christopher C. Burt
April 11, 2015

Could a single big late–season storm have a significant impact on the California drought? A 'Hail Mary' storm event? Normally by this time of the year (April 10th) California would have already received at least 90% of its rainy-season precipitation total and any additional rain or snowfall would have little impact so far as the current drought is concerned. However, back in late April 1880, one of the most intense storms ever to pound the state occurred. Here are the details.

Please check out the new homepage and tell us what you think!

By Shaun Tanner
April 2, 2015

The development team here at Weather Underground has been hard at work producing a new homepage! Please take a look at the sneak peek and tell us what you think!

Meteorological images of the year - 2014

By Stu Ostro
December 30, 2014

My 9th annual edition.

2013-14 - An Interesting Winter From A to Z

By Tom Niziol
May 15, 2014

It was a very interesting winter across a good part of the nation from the Rockies through the Plains to the Northeast. Let's break down the most significant winter storms on a month by month basis.

What the 5th IPCC Assessment Doesn't Include

By Angela Fritz
September 27, 2013

Melting permafrost has the potential to release an additional 1.5 trillion tons of carbon into the atmosphere, and could increase our global average temperature by 1.5°F in addition to our day-to-day human emissions. However, this effect is not included in the IPCC report issued Friday morning, which means the estimates of how Earth's climate will change are likely on the conservative side.