Leeside cold frontal gravity wave across the central and southern Plains

October 11th, 2020 |

GOES-16 Upper-level Water Vapor (6.2 µm) images, with plots of hourly surface wind barbs and gusts [click to play animation | MP4]

GOES-16 Upper-level Water Vapor (6.2 µm) images, with plots of hourly surface wind barbs and gusts [click to play animation | MP4]

GOES-16 (GOES-East) Upper-level Water Vapor (6.2 µm) (above) and Mid-level Water Vapor (6.9 µm) images (below) displayed a well defined leeside cold frontal gravity wave (reference) as it began to propagate southward from Colorado/Kansas late in the day on 11 October 2020. A bore structure eventually developed near the leading edge of the cold frontal gravity wave as it continued moving south over New Mexico/Texas/Oklahoma during the subsequent overnight hours.

GOES-16 Mid-level Water Vapor (6.9 µm) images, with plots of hourly surface wind barbs and gusts [click to play animation | MP4]

GOES-16 Mid-level Water Vapor (6.9 µm) images, with plots of hourly surface wind barbs and gusts [click to play animation | MP4]

As the surface cold front moved southward across the drought-impacted plains of eastern Colorado, 1-minute Mesoscale Domain Sector GOES-16 “Red” Visible (0.64 µm) and CIMSS Natural Color Red-Green-Blue (RGB) images (below) revealed the hazy signature of blowing dust lofted by post-frontal northerly winds with peak gusts in the 60-80 knot range. Blowing dust reduced the surface visibility to 1-2 miles at several reporting stations, falling to near zero at some locations (causing a multi-vehicle accident along Interstate 70 in Kansas).

GOES-16 “Red” Visible (0.64 µm) and CIMSS Natural Color RGB images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) and CIMSS Natural Color RGB images [click to play animation | MP4]

GOES-16 True Color images created using Geo2Grid (below) provided a clearer view of the blowing dust along and immediately behind the cold front across the Colorado/Kansas border region.

GOES-16 True Color images [click to play animation | MP4]

GOES-16 True Color images [click to play animation | MP4]

Wildfire smoke in Colorado

October 1st, 2020 |

GOES-16 True Color RGB images [click to play animation | MP4]

GOES-16 True Color RGB images [click to play animation | MP4]

GOES-16 (GOES-East) True Color Red-Green-Blue (RGB) images created using Geo2Grid (above) showed plumes of smoke drifting across parts of Colorado on 30 September 2020. The most smoke prominent plume originated from the Mullen Fire in far southern Wyoming — which produced a pyroCb cloud on 19 September.

On the following morning, the hazy signature of low-altitude smoke that had settled overnight into the North Park and Middle Park plateau areas of north-central Colorado was evident in CIMSS Natural Color RGB images (below). During the morning hours, this smoke restricted the surface visibility to 1-3/4 mile at Walden and 5 miles at Kremmling, before gradually beginning to disperse in the afternoon hours.

CIMSS Natural Color RGB images [click to play animation | MP4]

CIMSS Natural Color RGB images [click to play animation | MP4]

The signature of North Park and Middle Park plateau smoke was more vivid using GOES-16 True Color imagery which includes a correction for Rayleigh scattering (below).

GOES-16 True Color RGB images [click to play animation | MP4]

GOES-16 True Color RGB images [click to play animation | MP4]

2 pyrocumulonimbus events in Northern California

September 8th, 2020 |

GOES-17 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), Fire Temperature RGB + GLM Flash Extent Density (bottom left) and “Clean” Infrared Window (10.35 µm, bottom right) [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), Fire Temperature RGB + GLM Flash Extent Density (bottom left) and “Clean” Infrared Window (10.35 µm, bottom right) [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm), GOES-17 Shortwave Infrared (3.9 µm), Fire Temperature Red-Green-Blue (RGB) + GLM Flash Extent Density (FED) and “Clean” Infrared Window (10.35 µm) images (above) showed the formation of a pyrocumulonimbus (pyroCb) cloud over the Hopkins Fire in Northern California on 08 September 2020.

The vertical extent of the pyroCb cloud tower was even more apparent when viewed in Visible imagery from GOES-16 (GOES-East), displayed in the top left panel of the animation below.

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), Fire Temperature RGB + GLM Flash Extent Density (bottom left) and “Clean” Infrared Window (10.35 µm, bottom right) [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), Fire Temperature RGB + GLM Flash Extent Density (bottom left) and “Clean” Infrared Window (10.35 µm, bottom right) [click to play animation | MP4]

Later in the day and farther to the east, 1-minute GOES-17 imagery (below) showed the development of another pyroCb cloud over the North  Complex. Unfortunately, there was a ~1-hour gap in images (from 2034 to 2130 UTC) when a yaw flip maneuver was performed on the satellite.

GOES-17 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), Fire Temperature RGB + GLM Flash Extent Density (bottom left) and “Clean” Infrared Window (10.35 µm, bottom right) [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), Fire Temperature RGB + GLM Flash Extent Density (bottom left) and “Clean” Infrared Window (10.35 µm, bottom right) [click to play animation | MP4]

However, during this yaw flip maneuver the pyroCb formation and propagation could be followed using 5-minute imagery from GOES-16 (below). As the lower-latitude portion of the smoke plume associated with this fire flare-up drifted south-southwestward, it restricted the surface visibility to 2.5 miles at Beale Air Force Base (KBAB).

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), Fire Temperature RGB + GLM Flash Extent Density (bottom left) and “Clean” Infrared Window (10.35 µm, bottom right) [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), Fire Temperature RGB + GLM Flash Extent Density (bottom left) and “Clean” Infrared Window (10.35 µm, bottom right) [click to play animation | MP4]

Fast-moving wildfires in Washington State

September 7th, 2020 |

GOES-17 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), Fire Temperature RGB + GLM Flash Extent Density (bottom left) and “Clean” Infrared Window (10.35 µm, bottom right) [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), Fire Temperature RGB + GLM Flash Extent Density (bottom left) and “Clean” Infrared Window (10.35 µm, bottom right) [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm), Fire Temperature Red-Green-Blue (RGB) + GLM Flash Extent Density (FED) and “Clean” Infrared Window (10.35 µm) images (above) showed the smoke plume and thermal signature of the Pearl Hill Fire — which made a rapid ~50-mile run south-southwestward across northern Washington State on 07 September 2020. During this time, northwesterly winds gusted to 40 knots (46 mph) at Omak (KOMK) near the source of the fire. Downwind of the fire, smoke reduced the visibility to 1.5 miles at times in Wenatchee (KEAT).

Later in the day, smaller fires which started burning farther to the east exhibited similar (albeit much shorter-distance) southwestward runs.