Guam under tropical storm watch as Tropical Depression Atsani passes south of island


The heavy showers and gusty winds Guam is experiencing Friday morning will continue into early Saturday morning, as Tropical Depression Atsani passes south of the Island.

Landon Aydlett with the National Weather Service (NWS) says Guam is not expecting a typhoon from the weather system although the Island is “just shy of a tropical storm conditions and really feeling maximum weather conditions as far as winds and rain, just below tropical storm thresholds.”

At 8 a.m., NWS issued a tropical storm watch for Guam, meaning tropical storm conditions, including destructive winds of 39 mph or more, are possible Friday evening.

As of 7 a.m., Tropical Depression Atsani was located 9.8 degrees north latitude and 146.8 degrees east longitude, about 375 miles south of Saipan and 290 miles south southeast of Guam. The system is moving north northwest at 14 mph with maximum sustained winds of 30 mph.

Atsani is forecast to intensify steadily the next couple of days, becoming a tropical storm later today and a typhoon on Sunday.

NWS advised, on its current track, the system is expected to pass about 140 miles southwest of Guam late this evening. Showers and thunderstorms are expected across the Marianas this morning with heavy showers and winds gusting up to 40 mph. Additional showers and thunderstorms are possible tonight and Saturday.

Aydlett says wind gusts Friday morning are upwards of 35-40 MPH.

“We’ll be dealing with that probably over the next 18 hours as this tropical depression continues to move in,” said Aydlett at around 6:30am Friday.

The system was upgraded to a tropical depression overnight Friday around 2am. Aydlett says it’s centered around 350 miles southeast of Guam.

“It was tracking north this morning. We are expecting it to turn NW and then WNW, keeping south of Guam and that’s the concern we’re looking at – the eventual turn NW and WNW thus keeping it south of Guam.”

Aydlett says we can expect stormy, down pouring and “sloppy” conditions all day Friday and into Saturday morning. The bulk of the showers will be Friday and Friday night, according to NWS.

“The key for us is we want this thing to stay south of us to keep those winds south of Guam tonight as it moves through.”

Aydlett says NWS is working with Guam Homeland Security Friday morning on “how to handle this [weather system].” He says they want to make sure the Island is prepared for the weather.

“But regardless it’s going to be bumpy this afternoon, evening, tonight and into early Saturday morning,” said Aydlett.

Aydlett says ultimately Guam should buckle in for wet and windy conditions over the next 18 hours into Saturday morning.

“It looks like by Saturday evening, things should be improved. We were earlier looking at Saturday afternoon and evening which would have ruined a lot of Halloween plans. But, it looks like things could start moving out and clearing by Saturday afternoon.”

A small craft advisory is also in effect until 6 p.m. Saturday for the coastal waters of Guam, Rota, Tinian, and Saipan. Southeast winds of 15 to 25 kt with gusts of 30 to 35 kt and seas of 7 to 9 feet are expected. Inexperienced mariners, especially those operating smaller vessels, should avoid navigating in hazardous conditions.

NWS is reminding the community that any northward deviation from the current forecast track, or faster intensification, could bring stronger winds to Guam and the southern coastal waters.

Due to the uncertainty of exactly how close to Guam the disturbance will pass and the strength, NWS advises residents to take the following basic precautionary actions:

•         Stay up to date with the latest information. The system’s track or intensity may change and advisories regarding flash flooding or dangerous seas may be issued.

•         Locate or prepare your emergency preparedness kits for your household; stock up on non-perishable food items and water for your household, flashlights, first-aid kits, batteries, matches or lighters, portable stove, toiletries, etc. Visit for more information on what to include in your supplies list.

•         Secure important documents such as birth certificates, tax papers, and insurance documents and keep copies in a water-proof bag.

•         Clear loose debris around your yard and store any items such as canopies and trampolines that may become airborne with heavy winds, before inclement weather arrives.

•         Gas your vehicles and get fuel for your generators now while the weather is clear.

•         Those living in areas prone to flooding should be prepared to take action: Clear drainage areas and un-block clogged storm drains in your area to minimize the chance of flooding

The Offices of Guam Homeland Security and Civil Defense (GHS/OCD) will continue to monitor the system closely with guidance from NWS and provide updates as needed. The community is advised to heed any additional advisories in the coming days and be prepared to take action, if needed.

Stay up to date with the latest advisory information in the coming days:

·      NWS Website:

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·      GHS/OCD Website:

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