textproduct: WSO Pago Pago

DISCUSSION

Mostly cloudy skies with numerous showers, heavy at times with light winds have been observed throughout the day. Also observed is an active area of thunderstorms just south, gradually deepening and moving closer to the islands. These unstable conditions are also shown on the upper air observations (RAOB) from this afternoon (21/00Z) with elevated convective energy, increased precipitable water content, and signals of thunderstorm activity. This instability will continue to linger over the area as a shortwave trough moves across the territory, tonight. Shown on the latest model solutions is a high pressure system anchored southeast, generating gentle to moderate easterlies pushing the trough further west and south of the islands by Tuesday. Once the trough passes, the aforementioned high pressure system will keep the moderate easterlies with embedded showers through at least Friday.

By late Friday, model data is showing another high pressure system to the southwest migrating east as it maintains moderate southeast winds for the rest of the forecast period. These southeasterly winds signals at an early trade-wind season. However, will continue to monitor conditions as more data becomes available.

Thus, expect numerous showers, heavy at times with possible thunderstorms and light east winds for tonight. Much improved conditions with scattered showers and gentle to moderate east- southeast winds is expected for the rest of the forecast period.

Marine

Calm and smooth seas continue to remain over the area. These conditions are further supported by data reported from the PacIOOS buoys (Aunu'u & King-Poloa) with heights lingering in the 3 to 5 feet range. Model data show these heights remaining over the area through at least Tuesday. However, model data also show a southwest swell moving into the area by Tuesday night and remain through Wednesday. This swell coupled with moderate east-southeast winds will produce rough conditions in the coastal waters. Also, with swell periods projected to peak at more than 15 seconds long, expect higher surfs and strong rip currents to impact the west to south facing shores of all islands. By Wednesday night, a downward trend in seas will produce favorable conditions for the rest of the forecast period. There are no other significant swells expected for this period.

PPG WATCHES/WARNINGS/ADVISORIES

NONE