Area Forecast Discussion
Issued by NWS Pago Pago
Issued by NWS Pago Pago
146 FXZS60 NSTU 300207 AFDPPG Area Forecast Discussion National Weather Service Pago Pago AS 307 PM SST Sun Sep 29 2024 .Short term... A trough remained over American Samoa today to give over two and a half inches of rain from 4 AM to 10 AM this morning at WSO Pago Pago. Satellite imagery showed rainfall over Tutuila and Aunu`u while the Manu`a islands received passing showers. However, the trough is anticipated to strengthen throughout the day tomorrow. Precipitable water rates rise along with enough instability over the region to have the chance of heavy rainfall along with the potentional for flash flooding in the region. Therefore, Flood Watch will be in effect starting early Monday morning through at least late in the evening. We will continue to monitor the risk for heavy rainfall into early Tuesday as well. East/southeasterly winds are expected to decrease slightly from around 20 mph to around 10 to 15 by Monday, but higher gusts may accompany heavy rainfall. The trough will lose it`s strength by midweek as a gale well to the southeast will slowly pull moisture currently over the American Samoa islands away from the region. Numerous showers (60% chance) are forecast during this time, but the threat of heavy rainfall decreases thoughout this time. .Long term... By Thursday, a high pressure system to the south will finally strengthen enough to push the trough to the north of Tutuila, Aunu`u and the Manu`a islands, while the Swains island region still has the risk of heavier rainfall. The main weather storyline for late in the week and the upcoming weekend is the breezy east/southeasterly winds, which could reach up to 30 mph throughout this time. && .Marine... Wind driven seas are keeping heights elevated along the American Samoa coastal waters this morning and this afternoon. Seas still remain around 8 feet, but are expected to slowly ease throughout the rest of the day today and tonight. Seas are anticipated to drop below 8 feet, with winds decreasing to below 20 knots by the overnight hours and Monday. However, winds slowly increase in the middle of the week along with incoming southerly swell by Tuesday evening. This will cause seas to start building on Tuesday night. Easterly winds may increase up to a fresh/strong breeze for late in the week and into the weekend to generate rough/choppy seas throughout that time. && .PPG WATCHES/WARNINGS/ADVISORIES... A Small Craft Advisory remains in effect. && $$ LaPlante