Typhoon Dolphin lashed the U.S. territories of Guam and the Northern Mariana Islands in the western Pacific last night as a strong category two. The storm was initially expected to clear Guam with mild impacts, but a last minute shift in the storm’s track left Andersen Air Force Base with winds gusting over 100 MPH.

Guam Governor Eddie Baza Calvo is doing a pretty good job of keeping territorial citizens up-to-date on the recovery efforts across the island through his Facebook page. It doesn’t seem like there’s too much damage across the island, relative to what could have been, though power outages are widespread and numerous roads are blocked by downed trees and debris. The airport will reopen late Saturday morning for both inbound and outbound flights, and schools might hold classes on Monday, depending on how well they can repair infrastructure over the weekend.

Guam is 14 hours ahead of Eastern Daylight Time, so 5:00 PM Friday in New York is 7:00 AM Saturday in Guam.

For several days, official forecasts by both the National Weather Service in Guam and the U.S. military’s Joint Typhoon Warning Center expected the center of Typhoon Dolphin to head northwest through the Northern Mariana Islands, coming close to or making landfall on the small island of Rota, home to about 2,000 people. The agency wrote a very strong statement on Thursday warning of the devastating impacts Dolphin could have when it made landfall, which was similar in language and tone to the infamous “Katrina Bulletin” issued ahead of Hurricane Katrina’s landfall on the Gulf Coast.

However, as the storm neared the islands, a sudden burst of heavy thunderstorm activity south of Dolphin’s eye dragged the center of the storm farther to the south, allowing the typhoon to track farther to the west than anticipated. I mentioned this possibility in yesterday’s post (“Any leftward wobble in Dolphin’s forward motion from its forecast track would produce much more dire conditions in both Guam and Rota [...]”), and the storm’s effects on Guam were much greater than originally anticipated on Dolphin’s initial forecast track.

In the end, Dolphin’s eye managed to cut a path down the center of the channel separating Guam and Rota, lashing both islands with intense winds in the typhoon’s eyewall. Andersen Air Force Base, located on the northeast tip of Guam, recorded typhoon-strength wind gusts for several hours on Friday, with winds gusting as high as 106 MPH at one point. The storm’s close proximity to the island gave us a great look at its structure on Doppler radar until the radar stopped transmitting data.

Dolphin continues to move away from land, strengthening rapidly in the process. The typhoon quickly cleaned up its appearance and developed a well-defined eye after it passed the islands, and it should reach category five status with winds close to 165 MPH as it recurves to the north and northeast, staying well east of Japan and no longer posing a threat to any landmasses.

The typhoon shows the importance of the cone of uncertainty, which is the historical margin of error in track forecasting for a certain region. Confidence in a storm’s forecast track goes down with time, and storms can and usually do deviate from the forecast. Today is the first day of hurricane season in the eastern Pacific Ocean, and June 1 is the first day over in the Atlantic basin. Remember that anyone in and around the cone of uncertainty is at risk for seeing adverse conditions from a storm, and even if the cone shows the storm moving away from you, things can change in an instant.

[Images: NOAA, Gibson Ridge, NWS Guam]

You can follow the author on Twitter or send him an email.