Sunday 19THNOVEMBER 2017 pm
A ridge of high-pressure system building from far Southeast continues to direct Northeast to East wind flow over Samoa. A short-wave trough located Northwest of the group associated with a cloud band extended from Tokelau to Wallis while scattered mid-low level clouds streaming over the Islands along the Easterly flow with cloud tops shearing from South, due to strong upper-level Southwesterly wind aloft as shown by CIMMS upper-level winds observations. Moderate winds were observed throughout the day as well as the ASCAT passes as of this afternoon. The sounding profile reveals a conditionally unstable atmosphere. The aforementioned short-wave trough is forecast to drift Westward. Therefore partly cloudy with brief showers for the Northern portion of the Islands while cloudy condition with some showers for the Southern Districts and a chance of a few thunderstorms.
Monday THROUGH SaturDAY:
Global models predicted minimum showers with moderate Northeast to East winds to persist in the early part of the outlook period. Another high-pressure system far Southwest ridging Northeastward is forecast to migrate Eastward pushing a trough over the Islands by Wednesday morning, bringing some scattered showers and remain nearly stationary throughout the rest of the long-term forecast. It will again materialize by Saturday morning with an active convergence zone just South of it.
Aunu’u wave buoy recorded swells of 4-6 feet this afternoon. Global models and SWFDDP guidance predicted these swells to remain below the advisory threshold for the rest of the outlook period.