textproduct: WSO Pago Pago

DISCUSSION

Continuous widespread showers, heavy at times, remained throughout the day as the monsoon trough lingers over the area. The latest satellite imageries show the active monsoon trough connected to Tropical Disturbance 08F (TD08F/99P), gradually migrating south of the Samoa Islands as TD08F tracks further south. However, model solutions show a high pressure system near New Zealand, holding the monsoon trough just south of the area through at least Monday night. This will keep the threat of flash flooding conditions over the area through at least this time frame. A break from showers is expected for the overnight hours tonight through Sunday evening. By Sunday night, models are showing more showers moving into the area as the monsoon trough remains in close proximity to the islands. Additionally, the threat of strong winds experienced in the last 8 to 12 hours has decreased significantly. This is further supported by the upper air observations (RAOB) from this afternoon (01/00Z) and the latest ASCAT satellite swaths from earlier in the day. Flash flooding atmospheric conditions remains as the stronger north- northwest winds shifts south, prompting the cancellation of the wind advisory. Therefore, expect numerous to widespread showers with embedded thunderstorms and moderate to fresh north winds for tonight through at least Monday night, with breaks from showers from time to time throughout this period.

Model solutions also show a high pressure system to the east with a building ridge to the north of the islands, keeping or holding the monsoon trough from migrating northward. By Tuesday, the aforementioned ridge is expected to dominate and push the monsoon trough further away from the islands. As this scenario plays out, expect gentle to moderate northeast winds on Monday night turning east on Wednesday with scattered showers to remain for the rest of the new week.

Marine

Seas have been gradually subsiding in the last 12 to 16 hours as observed through the data reported by the PacIOOS buoys. More noticeable are the winds decreasing to a moderate north flow, keeping seas in moderate conditions. The model trend show seas continuing to subside to favorable conditions throughout the forecast period. Heights are slightly higher at the King-Poloa buoy versus conditions at the Aunu'u buoy. This may have to do with the north-northwest winds being a little stronger on the west side of Tutuila Island. As the ridge to the north continues to build, the monsoon trough is expected to move further south, and thus ocean conditions slowly improving. Thus, the high surf advisory is now cancelled while the small craft advisory remains in effect through at least Sunday.

PPG WATCHES/WARNINGS/ADVISORIES

Wind Advisory is cancelled High Surf Advisory is cancelled Small Craft Advisory Flood Watch