Area Forecast Discussion
Issued by NWS Pago Pago
Issued by NWS Pago Pago
792 FXZS60 NSTU 180053 AFDPPG Area Forecast Discussion National Weather Service Pago Pago AS 153 PM SST Fri May 17 2024 .DISCUSSION... Satellite imageries shows part of the stationary front moving through the area throughout the day, bringing afternoon showers and increasing the potential for thunderstorms over the islands. Also shown on the satellite imageries are heavily convective areas to the east of the territory. Upper air data from this afternoon (18/00Z) shows a very moist surface to mid-levels and a drier mid to upper air levels. This upper air profile coincides with thunderstorm activity in the AOR. Upper air values also are nearing the threshold levels, indicating an unstable atmosphere. However, model data is showing the latter portion of the stationary front moving south of the territory by the next 4 to 6 hours. Once the front migrates south, an easterly flow with embedded passing showers will prevail for the rest of the short term forecast. By Sunday, the bulk of the moisture will have moved away from the area. This will bring scattered showers with a prevailing moderate to fresh easterly flow. Expect scattered to numerous showers with embedded thunderstorms and moderate to fresh easterlies for tonight, decreasing to scattered showers on Saturday through Sunday. Long term model projections show a broad high pressure system to the south migrating east. This high pressure will continue to produce moderate east-southeast winds throughout the new week. Therefore, expect brief passing showers with moderate east- southeast winds for the rest of the forecast period. && .Marine... Rough and choppy conditions will remain across the territory through the new week. Model data shows combined seas of 7 to 9 feet remaining across the coastal waters through the end of the forecast period. Moreover, the south swell is expected to produce long periods on Sunday through the rest of the period. Long periods combined with high seas will enhance surfs as it nears the shoreline. Additionally, long period swells can generate strong rip currents. Thus, advisories for small crafts and high surfs will remain in effect through the new week. && .PPG WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory High Surf Advisory && $$ JTAllen