Area Forecast Discussion
Issued by NWS Pago Pago
Issued by NWS Pago Pago
178 FXZS60 NSTU 060100 AFDPPG Area Forecast Discussion National Weather Service Pago Pago AS 200 PM SST Sat Jul 5 2025 .DISCUSSION... The latest satellite imageries continues to show a surface trough lingering over the area throughout the day. This trough has continually produced widespread showers, heavy at times with gusty winds, for the last 24 to 48 hours. Total precipitable water (TPW) model data together with upper air observations (RAOB) from this afternoon (06/00Z) continues to show moisture hanging over the area. Also shown on satellite imagery is a convective area with thunderstorm activity to the northeast of the Manu`a Islands. As model data show winds decreasing to a light breeze later tonight, this convection is expected to potentially move over the islands in the next couple of hours through early Sunday morning hours. When this scenario comes to play, more rain with the potential threat of flash flooding and landslides will remain for this time frame. Additionally, possible thunderstorm activity may enhance winds and showers. Hence, the flood watch remains in effect through at least Sunday morning. A brief break from the rain is shown on model data for Sunday, then as winds start to pick up on late Sunday night through Monday, another wave of showers will move through the islands, possibly flash flooding criteria. Model data also shows a high pressure system to the west-southwest moving south of the area as it generates gentle to moderate trade winds on Monday through Thursday night, and peaking at a fresh breeze on Friday through the weekend. Brief passing showers, heavy at times is expected to embed within the trade wind flow from time to time. && .Marine... Manual observations of seas for the last couple of hours have shown a subsiding trend. Data from the PacIOOS buoy near Aunu`u supports the gradual subsidence of seas as it reports heights around 10 to 12 feet with periods hanging around 10 to 12 seconds long. These latest ocean conditions translates to around 11 to 14 feet surfs, which are in the higher end of the high surf advisory threshold. Additionally, models are showing the fresh easterlies decreasing to a light and gentle breeze by tonight through at least Sunday night. Thus, the high surf warning is cancelled and replaced by a high surf advisory for all shores of all islands. Model data also show seas on a decreasing trend through at least Sunday night. By Monday, seas will drop below advisory levels and remain for the rest of the forecast period. However, trade winds will slightly increase to a moderate breeze on Monday afternoon and may enhance white caps and slightly choppy conditions for mariners in the open waters. Will continue to monitor conditions as more data becomes available. && .PPG WATCHES/WARNINGS/ADVISORIES... High Surf Warning is cancelled High Surf Advisory remains in effect Small Craft Advisory remains in effect Flood Watch remains in effect && $$ JTAllen