Typhoon Hagupit as it intensified on Wednesday, Dec. 3, 2014.
Update: 5:15 p.m. ET: Typhoon Hagupit has been upgraded to super typhoon status, with maximum sustained winds of 150 miles per hour as of 5 p.m. ET. The storm is forecast to intensify further, potentially reaching high-end Category 5 status with maximum sustained winds of 185 miles per hour on Thursday.
The latest storm track forecast from the U.S. Joint Typhoon Warning Center has shifted the storm west compared to the previous forecast, which would take the storm closer to the Philippines, while still turning the storm to the north as it approaches the island nation. However, the Philippines' own forecast agency, in a forecast that is supported by forecast agencies in Japan, Taiwan and other Asian nations, is predicting the storm will make landfall near the island of Leyte on Saturday, local time. This would affect the same area as Super Typhoon Haiyan last year.
However, even if the storm reaches Category 5 intensity on Wednesday night and Thursday, it is likely to slow its forward speed significantly and weaken before it approaches the Philippines. However, it is still forecast to be a typhoon at that point.
Super Typhoon Hagupit is now the sixth super typhoon to form in the Western Pacific Ocean so far this year.
Update: 3:30 p.m. ET: Typhoon Hagupit has intensified significantly since Wednesday morning, and is now nearing super typhoon status, at the border of a Category 4 or 5 storm based on satellite imagery. It is expected to remain a very intense storm through at least Thursday, before it begins weakening as it gets closer to the Philippines.
Typhoon Hagupit is currently intensifying over the western tropical Pacific Ocean, about three days (or 800 miles) away from a potential landfall in the central Philippines. The storm is forecast to intensify to Super Typhoon status, with maximum sustained winds of about 150 miles per hour.
But there's just one major problem with the storm forecast: Computer models are diverging dramatically regarding its projected track, making forecasters sweat this one more than usual.
In an unusually stark instance of computer model inconsistency, the American-made Global Forecast System (or GFS model) is projecting that the storm will head west, toward the Philippines, but at the last minute will turn sharply to the north. This forecast track would spare the Philippines from a direct hit, and the Joint Typhoon Warning Center (JTWC) is forecasting just such a scenario. The GFS model performed well during the North Atlantic hurricane season this year, out-forecasting the European model on both projections of storm track and intensity.
EC ensemble very consistent with track of typhoon #Hagupit toward the Philippines with no recurvature. pic.twitter.com/Xs1q4VEQym— Sam Lillo (@splillo) December 3, 2014
However, the European model is forecasting a far more ominous scenario, and one that needs to be taken seriously: a direct hit on the central Philippines, with an east-to-west track at a slow forward speed, striking the same areas that were nearly wiped off the map last year by Super Typhoon Haiyan. The biggest threat would be heavy rain and high winds, but the storm would likely be far weaker than Super Typhoon Haiyan was when it hit last year.
The European model's scenario is reflected in the public forecasts from the Philippines' own weather agency, known as PAGASA, which shows the potentially deadly east-to-west traverse starting on Saturday night in eastern Samar. Other agencies in the region are forecasting a similar track, including the Japan Meteorological Agency, making the JTWC forecast an outlier.
If the storm is still relatively intense at that point, and moving slowly, it could dump copious amounts of rainfall on steep terrain, leading to mudslides, and would also subject cities to a long-duration high wind and moderate storm surge event. It is likely the storm will be significantly weaker than the monstrous Super Typhoon Haiyan, which roared ashore with sustained winds of about 190 miles per hour, when it hit the city of Tacloban last year, killing more than 6,000.
This storm will not be a repeat of Haiyan in terms of storm intensity, but the potential track is comparable.
The reason for the divergent forecasts concerns broader scale factors that help steer tropical cyclones, including typhoons and hurricanes (both storms are the same thing, meteorologically-speaking, but they are called different things in different parts of the world). Although these storms can be ferocious, with waves higher than 50 feet tall and winds close to 200 miles per hour, they are extremely sensitive to the environment around them. Low pressure systems and high pressure areas can cause a major hurricane to reverse course, and the forecast uncertainty with Hagupit concerns the effects of a significant dip, or trough, in the jet stream over Japan, as well as a series of smaller troughs that are expected to sweep over the East China Sea during the next three days.
While totally different in size/strength, it is amazing how PAGASA's fcst track for #Hagupit compares to #Haiyan.pic.twitter.com/SWaec2biLb— Brandon Miller (@BrandonCNN) December 3, 2014
The JTWC is expecting "a series of migratory midlatitude troughs" moving across the East China Sea to weaken the storm, and pull it northward in time to avoid a landfall in the Philippines. This scenario is supported by the GFS, GFS ensemble models and two other models, but rejected by other reputable computer models.
So, in perhaps the understatement of the year in weather circles, the JTWC's forecast discussion says, "There is overall low confidence in the forecast track."
The ocean heat content that lies in front of Hagupit is not nearly as high as it was last year, when Super Typhoon Haiyan explosively intensified into one of the planet's strongest storms on record.
Tags: CLIMATE, PHILIPPINES, TYPHOON, US & World, WORLD