Guam, Guam

Partly cloudy skies and isolated to scattered showers are visible on radar and satellite imagery over the Marianas this afternoon. Models and observations indicate combined seas of 5 to 7 feet.

A fairly dry and uneventful week is anticipated. Scattered island effect showers are expected to continue tomorrow afternoon for Guam due to light easterly winds. This will keep showers mainly concentrated to the west side near Agat. By Tuesday, gentle east winds will be too high for island effect showers. However, brief trade wind showers will be possible across the Marianas much of the forecast period as winds increase gradually from tomorrow. However, these will remain weak and isolated to low-end scattered in nature.

Light to gentle trade winds will return from Sunday night onwards. Combined seas of 5 to 7 ft will increase slightly tomorrow with a pulse of long-period, north-northwesterly swell from Typhoon In-fa. Otherwise, sea heights are not expected to change much throughout the week. A secondary east swell may become the dominant swell by late Tuesday. There will be a high risk of rip currents along north and west facing reefs through at least Monday afternoon. There is also a moderate risk of rip currents along east-facing reefs.

Typhoon In-fa is north of the Marianas now, near 22.7N and 144.1E. It is moving east-southeast at 3 mph, and is expected to make a loop and then turn toward the west with an increase in forward speed through Monday. In-fa is forecast to continue to weaken through tonight due to a dry surrounding environment and increasing shear.

For more information on Typhoon In-fa please refer to the Tropical Cyclone Public Advisory, prepared by the National Weather Service, under WMO header WTPQ31 PGUM, or the Tropical Cyclone Warning, prepared by the Joint Typhoon Warning Center under WMO header WTPN31 PGTW.

Drier weather is generally expected to prevail at Pohnpei and Majuro this week as a monsoon-like trough remains in the vicinity, with shower coverage likely remaining only isolated throughout most of the forecast period. Scattered showers and isolated thunderstorms are anticipated at Kosrae for the next couple of days with the trough remaining to the north and convergence continuing in the vicinity of the island. Drier weather is then expected at Kosrae for the remainder of the week. Winds will remain light to gentle at all locations through the week. Combined seas of 4 to 6 feet will continue through the forecast period with seas consisting of a dominant northeast swell at all locations and a small northwest swell at Pohnpei and Kosrae.

The monsoon trough has fragmented across the region, with only patchy showers lingering across parts of Yap and Palau. A plume of drier air looks to shift southward slightly, leading to even drier weather, more so for Yap Monday afternoon through Tuesday night. A segment of the monsoon trough, responsible for a period of showers and a few thunderstorms today at Chuuk, continues to push southwestward, with showers decreasing to isolated over Chuuk Lagoon later this evening. Active weather looks to persist for southern Chuuk State through Monday night along increased convergence on the southern side of the monsoon trough, also linking up with some diffluent flow aloft from an upper-level trough offset to the north. Overall, fairly quiet weather is expected for the main forecast locations through much of the upcoming week due to the lack of significant features across the region. Weak winds and daytime heating at Palau are still expected to bring an uptick in clouds and showers over the islands Monday and Tuesday afternoon.

Combined seas are 4 to 5 feet, with seas increasing to 6 ft at Yap from northeast swell from Typhoon In-fa. Seas will continue to build to 5 to 6 feet across Yap and Palau, possibly reaching 7 feet at Yap Monday night and Tuesday. The long-period swell will also support elevated surf along north-facing reefs over the next few days for Yap and Palau, with seas likely exceeding hazardous levels of 9 feet along north-facing reefs of Yap Monday night and Tuesday. Meanwhile, benign seas and surf continue at Chuuk, with a slight increase in northeast swell increasing seas to 4 to 6 feet around Tuesday.

GU

High Rip Current Risk through Monday afternoon for GUZ001.

High Surf Advisory until 4 PM ChST Monday for GUZ001.

MP

High Rip Current Risk through Monday afternoon for MPZ001>003.

High Surf Advisory until 4 PM ChST Monday for MPZ001>003.

Marianas Waters

None.