Typhoon Surigae has been slowly moving toward the Philippines since it developed earlier this week, but over the past 24 hours the storm has rapidly intensified.
Surigae, known locally in the Philippines as Typhoon Bising, has developed from a tropical storm Thursday to the equivalent of a Category 4 hurricane with winds of 135 mph (215 kph).
This rapid intensification has happened due to the ideal conditions for hurricane/typhoon development: Wind shear, or the changing of wind speed and direction with height in the atmosphere, has been very low. High wind shear can tear storms like this to pieces, but low shear allows them to feed off the extremely warm waters and flourish into a powerful storm.
Continued low shear and excellent outflow will allow Surigae to thrive in the warm water that is running a few degrees above normal for this time of year. In fact, it’s possible that Surigae could reach super typhoon status (winds of 150+ mph, 240+ kph) in the next day or two.
Forecast shifts closer to the Philippines
Earlier in the week, the projections for Surigae were to track to the west toward the Philippines before turning to the northwest and north, comfortably missing the Philippines to the east. However, over the past few days several weather forecast models showed a trend for the storm to track closer to the Central Philippines.
On this current trajectory, the strongest winds of over 100 mph (160 kph) and the worst of the rainfall would remain offshore, but the storm would pass close enough to bring tropical storm-force winds (39-73 mph, 63-117 kph) and four to eight inches (100-200 mm) of rain.
This rain and wind could be enough to cause localized flooding, minor property damage and power outages. PAGASA has already issued warnings as conditions are expected to deteriorate Sunday. If the westward trend continues, the impact will worsen and additional warnings will be issued.
Regardless of the exact track, a storm of this magnitude will generate giant surf and mariners in the region have been advised to use caution.
Even if Surigae remains offshore this weekend, it will need to be monitored into next week as it slowly moves to the northwest and north.
How much the storm curves will determine the impacts for northeastern portions of Luzon. Some weather forecast models show the storm also getting extremely close to this section of the Philippines coast by Tuesday and Wednesday, but other models and official forecasts continue to be farther offshore with limited impacts. Time will tell.