In early November of 2013 the monster Typhoon Haiyan roared ashore in the Central Philippines claiming over 8,000 souls and rendering many thousands more homeless. It was the strongest storm ever recorded on Earth over land — boasting winds exceeding 190 mph and pressures below 900 mb. It formed over ocean surface waters that were far warmer than normal and whose heat extended much further into the ocean depths than was typical. The kind of powerful storm that many atmospheric scientists say is more likely to occur as humans keep heating the ocean and atmosphere, providing fuel and conditions to make the most intense storms ever stronger.
Today, more than a year later, 15,000 people are still living in tents along a swath that saw more than 4 million homes destroyed as Haiyan made landfall. Climate and extreme weather refugees in a world that is, sadly, seeing more and more dislocated people. People affected by drought, water loss, and by the devastation of storms. From Syria to Brazil to California to the Philippines, the refrain is the same. Bad weather pushed people to the edge or over. It took their homes or made living where they are a nightmare.
And, for a Philippines still reeling from Haiyan’s brutal blow, it may just be happening again.
(December 4 infrared satellite shot of Hagupit as it approaches the central Philippines. Image source: NOAA MTSAT.)
As of yesterday afternoon Hagupit had bombed out into a category 5 monster storm boasting 1 minute sustained winds of 180 mph and a minimum central pressure of 905 mb. This put Hagupit in a tie with super typhoons Vongfong and Nuri as the strongest storms of 2014. Not quite as strong as Haiyan, but still a very dangerous storm. One strong enough to fling out 50 foot waves and bring a storm surge as tall as a two story house to Philippine shores.
Over the next few days Hagupit is expected to steadily weaken, roaring ashore in the Central Philippines as a strong Category 4 or weak Category 5 before slowly churning off toward the WNW toward Manila.
Hagupit is a gradual mover and covers a relatively broad area. The result is that tropical storm and intense typhoon conditions will persist over regions for longer periods than occurred with Haiyan, even if Hagupit is not quite as powerful. As mentioned above, of serious concern is that the currently predicted track of Hagupit will bring it near or over regions that have yet to fully recover from the terrible impacts of Haiyan.
(Predicted track and strength of Hagupit. Image source: Joint Typhoon Warning Center.)
Overall, the predicted track is a bit to the north of Haiyan’s shoreward surge of last year. However, the hardest hit areas are still uncomfortably close to the guidance cone. In addition, the current projected path features more flood prone coastal regions than Haiyan’s path. With many bay features to funnel in and amplify a storm surge.
Along this track, the storm would primarily be a major rainfall concern by the time it reached the capital city of Manila.
Climatology — Very Strong Supertyphoon in December Feature of a Globe in Hot Water
Climatologically, it’s a bit odd for such a strong storm to form in December, even in the warm Western Pacific (at peak intensity, Hagupit was the strongest December cyclone in at least the past 15 years). During recent years and under the apparent influence of a heating climate this region has tended to feature tropical cyclone formation year-round. A phenomena that some atmospheric scientists expect to continue to ramp up with human-caused warming.
(Sea surface temperature anomaly for the Western Pacific in the vicinity of the Philippines. Image source: NOAA Sea Surface Temperature Anomaly Charts.)
Sea surface temperatures for the region remain in a very hot range of 0.5 to 2 degrees Celsius above the 20th Century average. Meanwhile, temperatures at depth are in the slightly above average range. So Hagupit has plenty of energy to feed on, even if conditions aren’t quite as favorable as they were for Haiyan last year.
Perhaps more striking is the persistence and intensity of ocean surface heat on both the regional and global levels. GFS models for the past 8 months have shown positive ocean surface anomalies in the range of +0.6 to +1.4 C above the 20th Century average. A very, very hot world ocean, especially when we consider that the typical major ocean heating event called El Nino was in neutral status throughout this period. In this context, it is also worth noting that January through October of 2014 was the hottest such period for the world surface in all of the 136 year global climate record. Again, occurring without the added heating influence of a declared El Nino.
The Western Pacific, itself, is the hottest ocean zone in the world. And high temperature departures there have been implicated both in increasing storminess at the surface and in a troubling heightening of the troposphere over a warm and warming region.
It is in this context that we should consider the extraordinary storms we’ve recently witnessed and the major potential impacts of Hagupit over the coming days.
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UPDATE: Thursday, Hagupit went through an eye replacement cycle as well as a brief period of weakening. This caused the storm to temporarily dip below super typhoon intensity (150 mph). As of Friday morning (EST), Hagupit had re-strengthened to a 150 mph monster storm with a very low central pressure of 915 mb.
A large and intense storm that is, at least one day ahead of landfall, already pushing seas to the steps of homes, washing out roads in the city of Samar where Hagupit is expected to make landfall, and lashing the Philippine coast with intense squalls.
It is worth noting that many communities in Samar and along the Philippine coast are low-lying and are thus very vulnerable to the effects of Hagupit. A fact the Philippine government appears well aware of as it has already evacuated more than 500,000 people ahead of landfall.
The storm will also race ashore over seas already elevated by human-caused climate change, though the peak of the warm water bulge has shifted east in a broader transition toward more El Nino-like conditions for the Equatorial Pacific.
Wind Shear — Limiting Storm Intensity
Hagupit is feeling the impacts of wind shear to its south and west and this influence is likely to keep the storm below the terrible intensities seen during Haiyan.
(Hagupit feeling the effects of southwest wind shear on December 5, 2014. Despite these influences, Hagupit is maintaining status as a strong category 4 storm. Image source: NOAA MTSAT.)
It is, nonetheless, predicted to be a very powerful storm — raking the Philippine Coast with category 4 winds (135-155 mph), monster waves, storm surges in excess of 10 feet and dumping 10-25 inches of rainfall over very broad regions. Areas along the path of the storm are likely to be heavily impacted by rainfall as the storm weakens and dumps copious moisture. The expected very heavy rainfall has also prompted lahar warnings for mudslides on the flanks of volcanos Mayan and Bulusan — both in Hagupit’s path.
(Updated track of Hagupit from the Joint Typhoon Warning Center)
Hagupit’s current projected track brings its center about 50-100 miles north of Haiyan’s path. This predicted motion would spare regions hardest hit by Haiyan from Hagupit’s worst impacts. However, recent satellite imagery depicts a bit of a southward jog. This recent motion, combined with the storm’s broad size and slow forward speed, mean these regions may still take a substantial beating.
The storm is a slow mover — advancing only at a rate of 5-10 miles per hour. So regions will feel the impacts of Hagupit for much longer than Haiyan. For the Philippines as a whole, it looks like this will be a three day event. A longer duration storm, though somewhat less intense.
Hat tip to Colorado Bob
(Post Edited on December 5)