Northern Islands Municipality, MP Weather

000 FXPQ50 PGUM 261947 AFDGUM

Area Forecast Discussion National Weather Service Tiyan GU 547 AM ChST Tue Oct 27 2026

.Marianas Update: Isolated showers are expected for Guam and Rota for the next couple of days, though given lighter winds island-effect showers will be possible for Guam. An incoming trough will likely promote scattered showers and isolated thunderstorms for Tinian and Saipan through at tonight. Light to gentle north to northeast will continue for the next couple of days with periods of variable winds possible for Guam and Rota. Combined seas of 5 to 6 feet will continue through Thursday. Otherwise, a moderate risk of rip currents will continue through tonight along north, east, and west-facing reefs.

.Tropical Systems Update: Typhoon In-fa is nearly stationary this morning, drifting to the west-northwest around 3 miles per hour, currently located near 14.1N 162.6E. In-fa is expected to maintain the general west to west- northwest movement with a slight increase in forward speed through Wednesday as it continues toward the far northern Marianas. The maximum sustained winds remain at 130 miles per hour this morning. In-fa is forecast to weaken slightly today given the presence of ongoing vertical wind shear and cooler sea surface temperatures due to upwelling. It is then forecast to re-instensify starting late tonight or early Wednesday. Typhoon force winds extend outward from the center up to 30 miles. Tropical storm force winds extend outward from the center up to 80 miles.

For more information on Typhoon In-fa, please refer to bulletins from the Joint Typhoon Warning Center under WMO header WTPN31 PGTW and from the National Weather Service under WMO header WTPQ31 PGUM.

.Eastern Micronesia Update: Mostly scattered showers are expected to persist over the next couple of days at Pohnpei with drier weather likely prevailing at Majuro and Kosrae. Gentle to moderate west-southwest winds will continue through at least Wednesday at Pohnpei while light to gentle winds persist at Kosrae and Majuro. Combined seas of 4 to 6 feet will continue for the next couple of days.

.Western Micronesia Update: Scattered showers and isolated thunderstorms are expected at Yap through tonight with drier weather generally expected at Palau and Chuuk. Light to gentle winds will continue for the next couple of days. Generally benign marine conditions are expected to continue through midweek, with combined of 2 to 4 feet prevailing.

.Prev discussion: /issued 623 PM ChST Mon Oct 26 2026/

Marianas Synopsis: Gentle to moderate east-northeasterlies prevail across the Marianas this evening. Isolated to scattered showers are visible on radar and satellite. Model and observation data indicate combined seas of around 6 feet.

Discussion: Isolated showers tonight across the Marianas are expected to continue for Guam for the whole forecast period with the exception of scattered island effect showers in the afternoon Tuesday and Wednesday. Due to light northeast or north winds, these will likely be concentrated more over central and southern Guam. For the CNMI, a trough is expected to move into the region and bring a period of scattered showers and isolated thunderstorms before returning back to isolated Tuesday night. Showers will likely remain isolated until Friday when coverage changes to scattered upon the passage of Typhoon In-fa somewhere to the north through the far northern CNMI. Current Typhoon In-Fa is expected to make it's closest point of approach sometime Friday or early Saturday which will bring scattered showers for the CNMI and potentially breezy conditions. The current JTWC track puts a 30% chance of tropical storm sustained winds for Tinian and Saipan and only 10% for Rota. This situation remains highly uncertain, though most models show a passage through the remote, far northern CNMI somewhere between just north of Saipan to as far north as Maug island. This will continue to be monitored closely for any potential changes. See the "Tropical Systems" section for more details.

Marine:

..HAZARDOUS SEAS AND SURF LIKELY FRIDAY THROUGH EARLY SATURDAY:

Gentle easterlies will prevail across Tinian and Saipan through at least Wednesday night, becoming light over Rota and Guam Coastal Waters tonight. Scattered showers and isolated thunderstorms will be possible for the CNMI Tuesday as a trough moves into the region. Therefore, there is a moderate risk of lightning for the CNMI Tuesday. There will be a moderate risk of rip currents through at least Tuesday for west-, north-, and east-facing reefs due to a primary east-northeast swell and a secondary west-northwest swell. Combined seas are expected to waver between 5 and 6 feet through Thursday. By late Thursday or Friday, seas are expected to increase significantly and become hazardous ahead of current Typhoon In-Fa. Widespread seas of 10 to 15 feet are expected with seas up to 20 feet possible for Tinian and Saipan if In-fa takes a southern track. Mariners should start to plan now and take any necessary precautions.

Tropical Systems: At 100 PM CHST, the center of Typhoon In-fa was located near 13.9N 163.1E. In-fa was moving west-northwest at 9 mph. Maximum sustained winds were 90 mph. In-fa is expected to maintain this general course with a decrease in forward speed over the next couple of days. The latest forecast track takes In-fa to the north of Saipan, near Pagan late in the weekend or over the weekend. In-fa is also expected to strengthen over the next couple of days, likely becoming a category 2 typhoon later this evening and category 3 around Thursday. Although TY In-fa is expected to move through the far northern CNMI, it is important to remember that the expected track, speed and intensity may, and likely will, change over the next couple of days. Therefore, residents of all islands in the CNMI need to monitor progress and changes to the forecast.

Typhoon force winds extend outward from the center up to 15 miles. Tropical storm force winds extend outward from the center up to 75 miles.

Eastern Micronesia: A pretty dry pattern is in place across eastern Micronesia this afternoon. Little to no showers are present across Kosrae and the Marshall Islands, south of 10N. Pohnpei is seeing a few more showers, though nothing more than isolated. For Kosrae and Majuro, this dry pattern looks to continue for the next several days, with Majuro seeing no showers Tuesday or Tuesday night, with only isolated showers expected for the remainder of the week. Kosrae can expect only isolated showers into the weekend. For Pohnpei, the dry pattern looks to change a bit around Tuesday night. As TY In-fa moves west- northwest, expect a band of convection, associated with a feeder band into the typhoon, to move over Pohnpei. This will produce a couple of days of increased convection over the island, with POPs (Probability of Precipitation) in the 30 to 40 percent range. POPs look to decrease to 20 percent again around Friday.

For the marine forecast, nothing really significant is expected. Combined seas look to remain at or below 6 feet. Gentle to moderate winds will continue at Pohnpei into Thursday as In-fa continues to move farther away from the island. Elsewhere, light to gentle winds will prevail into the weekend.

Western Micronesia: The main focus in the short term (next 48 hours) was rainfall coverage/potential, when periods of scattered showers look probable. Palau saw light showers (island convection) develop this afternoon under light winds, and a repeat performance is anticipated Tuesday. Meanwhile, Yap will see increasing shower potential, as surface convergence increases due to a surface trough to the northeast moving overhead. Then at Chuuk, a monsoon west to southwest flow into Typhoon In-fa has developed, augmented by a weak circulation near Satawal.

Heading into the latter half of the week, a north to northeasterly swell will arrive initally at Chuuk, moving west with time, as In-fa will likely be a strong typhoon or super typhoon as it crosses the far northern CNMI. At this time, given In-fas fast projected forward speed, maximum wave heights look to remain below high surf and small craft criteria. However, depending how things unfold, a headline for elevated surf may be needed at Yap or Chuuk later this week. Winds will generally be light to gentle area-wide for the rest of the week.

Watches, warnings and advisories

GU: None. MP: None. Marianas Waters: None.