Area Forecast Discussion
Issued by NWS Pago Pago
Issued by NWS Pago Pago
322 FXZS60 NSTU 270103 CCA AFDPPG Area Forecast Discussion...CORRECTED National Weather Service Pago Pago AS 203 PM SST Wed Nov 26 2025 .DISCUSSION... The latest satellite imageries show the main trough to the west migrating closer to the Samoa Islands. Observations throughout the day show a weaker trough to the north and east of the area, producing passing showers over the islands. These observations align well with the latest upper air observations (RAOB) from this afternoon (27/00Z). An increase in moisture content, instability, and the potential for flash flooding conditions is shown on the RAOB. Both the GFS and the European Model (ECMWF) agrees on the trough moving over the area, with an increase in unstable weather patterns. Expect numerous to widespread showers with embedded thunderstorms and light and variable winds with higher gusts from time to time. Hence, a flood watch is now in effect through at least Friday. However, the ECMWF model has the trough lingering over the area through at least Saturday, whereas the GFS model shows the trough moving away from the islands by Friday morning. With the close proximity of the trough compared to the model data, the GFS model seems to be more aligned with the latest satellite imageries. Disagreement between model data will determine daily weather patterns for the short term period. Long term model projections show a high pressure system building from the west-southwest, pushing the aforementioned trough further east on Saturday through the new week. Thus, expect scattered to numerous showers with light and variable winds for the rest of the forecast period. && .Marine... Favorable ocean conditions remains across the American Samoa coastal waters throughout the day. Seas of 5 to 7 feet remains through at least tonight, subsiding to 4 to 6 feet thereafter through the end of the forecast period. However, model data shows a long period north-northwest swell reaching coastal waters on Saturday afternoon with periods peaking at 20 seconds long on Monday. Even though seas will be around 4 to 6 feet, the long periods will likely generate strong currents and enhance surfs closer to shore. Additionally, with the aforementioned trough over the area, embedded thunderstorms will likely elevate seas and winds nearby. Will continue to monitor conditions as more data becomes available. && .PPG WATCHES/WARNINGS/ADVISORIES... Flood Watch through Friday. && $$ JTAllen