textproduct: WSO Pago Pago

DISCUSSION

Upper air observations (RAOB) from this afternoon (11/00Z) together with the latest satellite imageries and model data show dry conditions over the area. These dry conditions was anticipated as the strong trades with higher gusts hold a trough to the north of the area. Any brief showers passing from time to time is embedded within the wind flow, with no deep convections. Both the GFS (American) and EC (European) model data agree on a strong high pressure system to the south, holding the trough to the north as it also continues to produce fresh to strong trades for the short term forecast period.

However, model data also show the trough moving closer to the territory as the high pressure system drifts further east- southeast by midweek. Trade winds will still remain breezy as tight pressure gradients keeps the strong winds over the area. By late Tuesday into Wednesday, model data show the trough line as an embedded low pressure system remains just north of the area. This will likely bring flash flooding conditions over the area. Model projections continue to hold the low pressure system to the north of the area as it tracks east-southeast for the rest of the new week. In summary, expect the threat of strong trade winds and flash flooding conditions to remain over the area for the long term forecast period.

Marine

Observations of a decrease in trade winds throughout the day has also eased seas within the last couple of hours. These winds also align with data of short period waves reported from the PacIOOS buoys (Aunu'u & King-Poloa). While wave data from the King-Poloa buoy show heights well below advisory thresholds, wave heights from the Aunu'u buoy remains elevated. The short wave periods are a clear indication of wind-driven waves. As model projections hold breezy conditions for this forecast period, peaking around midweek, seas are also expected to remain hazardous, especially for the south to southeast to east facing shores of all islands. Addtionally, as the aforementioned trough is expected to move closer to the territory, there is a possibility for thunderstorms to be in the area. Therefore, expect the threat of rough and chopy seas, surfs to remain high and dangerous, and a low to moderate risk of rip currents within the exposed south to southeast to east facing coastal areas.

PPG WATCHES/WARNINGS/ADVISORIES

Wind Advisory High Surf Advisory Small Craft Advisory Hydrologic Outlook