Guam seems to brace as forecasters expect Typhoon Champi to pass just south

Guam’s government told residents on Saturday, Guam time, to finish their storm preparations as Typhoon Champi approached the U.S. territory from the east-southeast, and the National Weather Service (NWS) office in Tiyan, Guam, says the storm seems on course to pass just south of the island as a Category 3 typhoon. In Intermediate Advisory 10A, issued at 10:44 AM ChST Saturday, Oct. 17 (5:44 PM PT Friday, Oct. 16), the NWS placed Champi’s center about 380 miles east-southeast of Guam at 10:00 AM ChST, moving west-northwest at 15 mph with maximum sustained winds of 85 mph. The advisory says Champi should hold that general course and speed through Sunday, and adds: “Champi is forecast to intensify through Monday, becoming a Category 3 typhoon prior to its passage.” Typhoon-force winds reach up to 30 miles from the center and tropical-storm-force winds up to 100 miles, according to the same advisory. Its next full advisory comes at 2:00 PM ChST (9:00 PM PT Friday).

A Typhoon Warning remains in effect for Guam, Rota and the adjacent waters, according to the advisory, which says typhoon conditions, including winds of 74 mph or more, should arrive by Sunday morning, with tropical-storm-force winds arriving Saturday night. Tinian and Saipan in the Northern Marianas remain under a Tropical Storm Warning and a Typhoon Watch. The NWS local statement issued at 9:13 AM ChST adds a Coastal Flood Warning for Guam, Rota, Tinian and Saipan and a Flood Watch for all of Guam and the Northern Marianas. That statement, which reported Champi’s upgrade to a typhoon, says: “Champi is expected to go through a period of rapid intensification shortly, strengthening further as the day goes on.” It also tells residents: “Do not let a false sense of normalcy now dictate your actions tomorrow; prepare NOW!”

Gov. Lourdes A. Leon Guerrero will place Guam in Condition of Readiness (COR) 1 at 1:00 PM ChST Saturday (8:00 PM PT Friday), according to Joint Information Center (JIC) Release No. 5 from Guam Homeland Security and the Office of Civil Defense (GHS/OCD), posted at 9:45 AM ChST. The release says that at COR 1, destructive winds become possible within the next 12 hours, and that on its current track Champi should pass just south of Guam Saturday night into Sunday. It expects damaging winds of 39 mph or more from sunset Saturday through sunrise Monday and typhoon-force winds of 74 mph or more as early as 5:00 AM ChST Sunday (12:00 PM PT Saturday), island-wide, with the most severe impacts in southern Guam, and it tells residents of southern coastal flood-prone areas to move to safer shelter now.

The Pacific Daily News, in a story by Julianne Hernandez, quotes the governor: “According to the tracking of this typhoon, it's heading more towards the south. The south is going to be severely impacted. The coastline is going to be inundated.” The paper reports that she said winds could reach about 130 mph, with gusts up to 164 mph, that she had spoken with all three mayors in southern Guam, and that the Coast Guard has limited resources and might not carry out sea rescues during the typhoon’s peak. She urged residents to stay off the roads after COR 1 takes effect and out of the water, the paper reports, adding: “Stay home, be with your family, and we'll weather this storm together.”

Forecasts of how strong Champi gets differ by source and by hour. The NWS local statement, in its Guam section, forecasts maximum winds “in the 80 to 110 mph range with gusts to 150 mph.” The Joint Typhoon Warning Center (JTWC), in Warning No. 10, issued at 7:00 AM ChST Saturday (2:00 PM PT Friday), forecasts maximum sustained winds of 105 knots with 130-knot gusts at 4:00 AM ChST Sunday (11:00 AM PT Saturday), with the center near 13.0N 145.3E, and 120 knots with 145-knot gusts 12 hours later; JTWC bases its maximum winds on a one-minute average and calls its wind radii valid over open water only. Stars and Stripes, in Dave Ornauer’s Pacific Storm Tracker, reads the JTWC track as taking Champi over southern Guam around 8 a.m. Sunday as a Category 3-equivalent typhoon with 120-mph sustained winds and 145-mph gusts at center. The governor’s 130 mph figure, as the Pacific Daily News reports it, sits above the NWS range. This desk has not reconciled these numbers, which come from different products issued at different hours and, in JTWC’s case, appear to describe the storm’s peak winds rather than a forecast for one island.

Sources also differ slightly on the track. The NWS and the JIC releases describe a pass just south of Guam, while Stars and Stripes says the JTWC track shows Champi clipping the southern edge of the island early Sunday morning. The NWS local statement lays out both cases: a pass just south would keep winds from the northeast, then east and southeast, while a direct crossing would bring winds that shift from the northwest to the west, followed by southerly winds. A crossing would also bring significant wave run-up along western exposures, especially around the inlets of Apra Harbor, the statement says, while a pass to the south would keep impacts on the western coasts significantly lower.

The NWS local statement forecasts severe damage on Guam. It says: “Extremely dangerous winds will cause extensive damage.” It adds: “Most metal roof homes will be destroyed.” It also says: “Near total power loss is expected.” The statement warns that potable water could become scarce as filtration systems begin to fail, that dangerously large breaking waves of 30 to 35 feet seem likely early Sunday at Champi’s closest approach, with coastal inundation of 3 to 5 feet especially along eastern and southern exposures, and that torrential rain could drop 12 to 20 inches on Guam over the event.

The forecast has grown stronger over the past day. On Friday, Oct. 16, at 8:00 AM ChST, GHS/OCD Public Advisory No. 3 relayed an NWS forecast for Champi, then a tropical storm with 40 mph winds about 800 miles east of Guam, to pass very near, or over, Guam late Sunday morning as a Category 2 typhoon, with rain totals of 6 to 12 inches possible. That advisory noted the NWS caution that if rapid intensification came sooner and faster than expected, the Marianas could see a stronger typhoon. By Saturday morning, JIC Release No. 4 reported the Category 3 track and carried a note that “these forecasts can change”.

Shelters opened before the storm’s arrival. The Guam Department of Education opened five emergency evacuation centers at 10:00 AM ChST Saturday with combined room for up to 1,964 people, according to JIC Release No. 4 and the Pacific Daily News; George Washington High School holds the most, 683. The release asks evacuees to bring a seven-day supply of food and water per person, says registration happens on arrival, and bars alcohol, illegal drugs, weapons and pets. The same release says the Coast Guard Captain of the Port set Port Heavy Weather Condition ZULU for the ports of Guam and the Northern Marianas (Saipan, Tinian and Rota) as of 07:00 on Oct. 17.

Islands to the north face less but still damaging weather, according to the NWS local statement. For Rota, it forecasts winds of 35 to 45 mph with gusts to 60 mph, typhoon-force winds to 90 mph if Champi takes a more northwest heading, breaking waves of 20 feet and 10 to 15 inches of rain. For Tinian and Saipan, it forecasts damaging winds of 40 mph with gusts up to 60 mph, possible typhoon-force gusts on the higher terrain of Capitol Hill, and 4 to 6 inches of rain. No source this desk read reported injuries or damage; the storm’s closest approach, early Sunday local time, still lay ahead when these advisories went out.

Reading note: this desk wrote from NWS Guam’s Intermediate Advisory 10A and 9:13 AM ChST local statement, JTWC Warning No. 10, three GHS/OCD releases, two Pacific Daily News stories and the Stars and Stripes Pacific Storm Tracker, not field reporting. Guam runs 17 hours ahead of Pacific time, so Saturday morning in Guam falls on Friday afternoon in California. Forecasts for Champi change with each advisory; residents should follow the NWS in Tiyan and GHS/OCD, not this summary.