FORECAST DISCUSSION
MONDAY 11th MAY 2026 PM SHIFT
TONIGHT:
Fine weather apart from a few showers were observed at the main headquarters in the late afternoon as the dominant Easterlies prevail at the lower atmosphere. However, there were observations of short-lived cumulonimbus from METAR reports southwest of the Faleolo Aerodrome which were also captured over the satellite visible channel. CIMMS upper level analysis indicate upper convergence persisting over the past 9 hours which restrained duration of convective activities during the late afternoon. Drier mid-level atmosphere conditions were obtained from the sounding profile with upper westerlies dominating aloft driving polar airmass over the AOR. Models suggest a slight increase in cloud cover for tonight as a speed convergence enter the forecast zone.
TUESDAY THROUGH MONDAY:
Upper westerlies are forecasted to tend more southerly through the latter days of this week whilst the lower levels will dominated by Easterlies. The steering level may swerve more Northwest during the weekend as a 25 knots surge relocates over Tonga and Niue group. The high-pressure system centered over the Tasman Sea is predicted to intensify and drifts eastward directing fresh southeasterlies over the southern marine waters allowing the SPCZ to reestablish over the island chain for the start of the upcoming week. Model and ensemble products updated at 00Z hints increasing precipitation for the last days of this outlook period as the aforementioned surge maintains the aforementioned rain-maker system across the islands.
MARINE OUTLOOK:
The latest marine observations from Aunu’u and King Poloa wave buoys, as well as altimeter data, indicate that wave heights continue to fluctuate well below 2 metres. However, a southeasterly swell event is anticipated to enter our southern seas for the end of the week into the weekend as a high-pressure system stationed over Tasman Sea advances eastward. JMA predictions are hinting a 30% chance of elevated swells and waves of more than 3 metres during the aforementioned period and will issue an advisory to cover these severe weather conditions in the next 2-3 days before its arrival.
ADVISORIES/WARNINGS:
NONE
Weather Duty Team:
Gafa, Kalolo, Uili & Baker