While it may be winter, unseasonably warm conditions on February 19 were able to support convection across portions of the midwest and into southern Ontario. Convection began firing at multiple locations, including metropolitan St. Louis, Missouri; northeastern Indiana, and southeastern Illinois. To start with, let’s look at the 1500 UTC... Read More
The residents of American Samoa found themselves in the early morning hours of 20 November 2025, as strong maritime convection moved into the region. There is no radar in the area, so satellite observations are critical for operational awareness and nowcasting. The Band 13 infrared view on GOES-18 showed a... Read More
Heavy rains developed overnight over American Samoa, as depicted by the animation above from the CSPP Geosphere site. Low clouds — white/cyan in the RGB — start to show vertical development (that is, they get more and more red) shortly after 1000 UTC with more vigorous vertical growth apparent after 1100 UTC.... Read More
Night Microphysics RGB imagery over the Samoan Islands, above, saved from the CSPP Geosphere site, shows the characteristic color changes in the Night Microphysics RGB imagery from pink/salmon to dark red as lines of cumulus grow to thunderstorms. GREMLIN fields from the CIRA Slider, below, show the satellite-estimated MRMS fields. Rain starts... Read More
