Signatures of fresh snowfall in the Dakotas

March 17th, 2019 |

GOES-16 Near-Infrared

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm) images [click to play animation | MP4]

GOES-16 (GOES-East) Near-Infrared “Snow/Ice” (1.61 µm) images (above) depicted the signature of northwest-to-southeast oriented swaths of fresh snowfall (lighter gray shades) which had recently fallen on top of the aged snow pack across North Dakota on 17 March 2019. As discussed here, the surface of the preexisting snow cover had experienced rapid melting several days earlier, which increased its “water to ice crystal” ratio — making it appear darker, since water is a stronger absorber of radiation at the 1.61 µm wavelength.

A similar (albeit broader and more continuous) northwest-southeast swath of fresh snowfall was seen across South Dakota (below).

GOES-16 Near-Infrared "Snow/Ice" (1.61 µm) images [click to play animation | MP4]

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm) images [click to play animation | MP4]

The radar-derived 24 hour precipitation ending at 12 UTC on 17 March is shown below.

24-hour precipitation ending at 12 UTC on 17 March [click to enlarge]

24-hour precipitation ending at 12 UTC on 17 March [click to enlarge]

Gas explosion and fire in Los Angeles, California

March 17th, 2019 |

GOES-17

GOES-17 “Red” Visible (0.64 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) images (above) revealed the southwestward motion of a dark smoke cloud resulting from a gas explosion and fire in South Los Angeles, California on the morning of 17 March 2019.

A sequence of 5-minute “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images from both GOES-17 and GOES-16 (GOES-East) is shown below. It’s interesting to note that a distinct thermal anomaly (or fire “hot spot”) of 21.8ºC (darker orange enhancement) was apparent at 1502 UTC  and 1512 UTC in the GOES-16 Shortwave Infrared imagery — but not in the corresponding 3.9 µm images from GOES-17 (GOES-16 vs GOES-17: 1502 UTC | 1512 UTC).

In addition, the underlying mostly-urban landscape appeared a bit brighter in the GOES-16 Visible images, further enhancing the contrast between the dark smoke cloud and the surface (GOES-16 vs GOES-17 at 1517 UTC).

"Red" Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images from GOES-17 and GOES-16 [click to play animation | MP4]

“Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images from GOES-17 and GOES-16 [click to play animation | MP4]