Area Forecast Discussion
Issued by NWS Pago Pago
Issued by NWS Pago Pago
466 FXZS60 NSTU 180042 AFDPPG Area Forecast Discussion National Weather Service Pago Pago AS 142 PM SST Sun Aug 17 2025 .DISCUSSION... A surface trough in the area continues to migrate west as the dominant east-southeast breeze pushes it west-northwest of the Samoa Islands. This scenario will continue throughout the night tonight. Embedded showers within this surface trough will likely pass from time to time through the overnight hours. A drier air mass following the aforementioned trough is expected for the short term forecast period. Also shown on the model data is a mid-level high pressure system hanging over the area throughout the forecast period. However, by midweek, another trough to the east will move over the area, increasing the potential for showers. As the trough passes to the west, a low pressure system embedded within the trough will materialize as it migrates southeast. This low pressure system is expected to pull in moisture from the northeast and enhance showers across the territory over the weekend. East-southeast winds will remain for the rest of the forecast period, peaking at a strong breeze on Thursday night. Therefore, expect numerous showers for tonight becoming scattered in the early morning hours with a fresh east breeze. Scattered showers with a moderate to fresh east breeze is expected for Monday through Wednesday. An increase in showers with a fresh southeast breeze is expected for Wednesday night through at least Friday night. By Saturday, winds will decrease to a gentle to moderate east flow through the end of the period. && .Marine... Current observations at the PacIOOS buoys to the east (Aunu`u) and west (King-Poloa) of Tutuila Island are reporting waves below advisory thresholds. The anticipated arrival of the east-southeast swell for today is likely due to the delayed onset of the fresh east breeze. However, the latest ASCAT swaths from this morning shows the fresh east breeze just east of the Manu`a Islands. This aligns with the latest model data now showing the east waves reaching the American Samoa coastlines by at least tonight. Model data also shows combined seas of 8 to 10 feet with periods more than 10 seconds moving into American Samoa waters by tonight and remain throughout the week. Seas will continue to build as another broad and strong high pressure system to the southwest migrates east. This high pressure will continue to produce fresh trades and generate east- southeast seas for the rest of the forecast period. Therefore, expect rough seas to remain for the week with high surfs and strong rip currents. && .PPG WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory && $$ JTAllen