Airmass RGB imagery every hour from 1000 UTC on 14 December through 1900 UTC on 15 December, below, overlain on top of GOES-18 Level 2 Total Preciptable Water, show strong convection in between Tutuila and the Manu’a islands of American Samoa mostly ending after 0000 UTC on 15 December, but the airmass given the green signal in the RGB (click here for help in interpreting the airmass RGB) remains tropical.

GsMap estimates of 24-h rainfall, below, show that the heaviest rains — a maximum of 150+ mm — occurred in between Tutuila and the Manu’a Islands, but >2″ rains occurred over Tutuila, Ofu and Olosega. Rock slides were reported over western Tutuila (click here for the Local Storm Report).

MIMIC Total Precipitable Water fields, below, (from here) for the 24 hours ending 1900 UTC on 15 December, show abundant moisture over all of Samoa with more arriving from the east. Accordingly, Flood Watches (and a small craft advisory) continue through Saturday.

The MetopB Advanced Scatterometer (ASCAT) winds, below, show the strong winds associated with convection south of the Manu’a Islands at 2100 UTC on 14 December. Note also the cyclonic circulation to the north of Samoa.

GOES-18 Visible Imagery, below, from this site, show strong convection to the north of Samoa at 2000 UTC. Given the moisture shown in both the MIMIC TPW and GOES-18 TPW fields that surround the Samoan islands, however, isolated heavy showers may occur at any time throughout Samoa, and showers were occurring over Tutuila at 2100 UTC on 15th. The small line of clouds responsible is apparent in the imagery below towards the end of the animation.

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