This website works best with a newer web browser such as Chrome, Firefox, Safari or Microsoft Edge. Internet Explorer is not supported by this website.

Archive: Jul 2025

Hail in the Samoan Archipelago

In the evening of 28 July 2025, residents of the Samoan island of Upolu experienced an intense thunderstorm which produced hail, a very rare event for maritime tropical Pacific environments. Social media videos show 1 – 2 cm hailstones falling around residents excited to see such novel conditions. The forecasters... Read More

Decaying Mesoscale Convective System’s outflow boundary produces a low-level undular bore, along with a vertically-propagating gravity wave

5-minute CONUS Sector GOES-19 (GOES-East) Nighttime Microphysics RGB images from the CSPP GeoSphere site (above) depicted a nocturnal arc of low-level cloud bands (pale shades of white) associated with an undular bore produced by the outflow boundary from a decaying Mesoscale Convective System (MCS) over northern Iowa on 28 July 2025 — however, the boundary... Read More