Mountain waves over the Sierra Nevada

April 13th, 2017 |

GOES-16 7.3 µm (left), 6.9 µm (center) and 6.2 µm (right) Water Vapor images [click to play animation]

GOES-16 7.3 µm (left), 6.9 µm (center) and 6.2 µm (right) Water Vapor images [click to play animation]

 ** The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. **

A comparison of GOES-16 Lower-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images (above) revealed the presence of numerous mountain waves over parts of California and Nevada on 13 April 2017. The more pronounced of these waves were caused by strong southwesterly winds interacting with  higher terrain of the Sierra Nevada.

A 3-satellite comparison of GOES-15 (GOES-West), GOES-16 and GOES-13 (GOES-East) Water Vapor images (below) highlighted 2 factors that allowed better detection of these mountain waves by GOES-16 — improved spatial resolution (2 km for GOES-16 at satellite sub-point, vs 4 km for GOES-15/13), and a more direct satellite viewing angle (GOES-16 is positioned at 105ºW longitude, while GOES-15 is at 135ºW and GOES-13 is at 75ºW).

OES-15 (6.5 µm, left), GOES-16 (6.9 µm, center) and GOES-13 (6.5 µm, right) Water Vapor images [click to play animation]

GOES-15 (6.5 µm, left), GOES-16 (6.9 µm, center) and GOES-13 (6.5 µm, right) Water Vapor images [click to play animation]

Note that there were no Visible cloud features associated with many of the waves seen on Water Vapor imagery (below); encounters of Clear Air Turbulence (CAT) often occur with these types of mountain waves, as seen by scattered pilot reports of moderate turbulence (plotted as Category 4).

GOES-16 Visible (0.64 µm, left) and Water Vapor (6.9 µm, right) images, with pilot reports of turbulence [click to play animation]

GOES-16 Visible (0.64 µm, left) and Water Vapor (6.9 µm, right) images, with pilot reports of turbulence [click to play animation]

Fires in eastern Kansas and Oklahoma

April 11th, 2017 |

GOES-16 (left) and GOES-13 (right) Shortwave Infrared (3.9 µm) images [click to play animation]

GOES-16 (left) and GOES-13 (right) Shortwave Infrared (3.9 µm) images [click to play animation]

 ** The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. **

A comparison of GOES-16 and GOES-13 Shortwave Infrared (3.9 µm) images (above) showed numerous fire “hot spot” signatures (black to yellow to red pixels, with red being the hottest) from prescribed burning across the Flint Hills region of eastern Kansas and northeastern Oklahoma on 11 April 2017. Such fires are an annual tradition in this area, required to preserve the tallgrass prairies — for example, over 2.7 million acres were burned during Spring 2016. The 2-km spatial resolution (at satellite sub-point) and 5-minute scan interval of GOES-16 allowed for more accurate detection and monitoring of the fires (compared to the 4-km spatial resolution and 15-30 minute scan interval of GOES-13).

The corresponding Visible GOES-16 (0.64 µm) vs GOES-13 (0.63 µm) images (below) tracked the development and transport of smoke from the fires. Hourly reports of surface visibility (in statute miles) are plotted in red; at Fort Riley, Kansas, smoke reduced the visibility from 10.0 miles at 21 UTC to 1.0 mile at 23 UTC, adversely affecting air quality there.

GOES-16 Visible (0.64 µm, left) and GOES-13 Visible (0.63 µm, right) images, with hourly reports of surface visibility (statute miles, red) [click to play animation]

GOES-16 Visible (0.64 µm, left) and GOES-13 Visible (0.63 µm, right) images, with hourly reports of surface visibility (statute miles, red) [click to play animation]

Lake effect cloud plume formation over the Great Salt Lake

April 4th, 2017 |

Visible images from GOES-15 (0.63 µm, left), GOES-16 (0.64 µm, center) and GOES-13 (0.63 µm, right), with hourly surface reports plotted in yellow [click to play animation]

Visible images from GOES-15 (0.63 µm, left), GOES-16 (0.64 µm, center) and GOES-13 (0.63 µm, right), with hourly surface reports plotted in yellow [click to play animation]

** The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. **

As discussed in more detail on the VISIT Meteorological Interpretation Blog, a small lake effect cloud plume formed over the southern portion  of the Great Salt Lake in northern Utah on 04 February 2017. A comparison of early morning Visible images from the GOES-15 (GOES-West), GOES-16 and GOES-13 (GOES-East) satellites (above; also available as an MP4 animation) showed the advantage of improved spatial and temporal resolution provided by the GOES-16 0.64 µm “Red visible” band for depicting the evolution of this feature (which was responsible for some brief inland snow showers). The images are displayed in the native projection of each satellite.

Several hours prior to the formation of the lake effect cloud band, the MODIS Sea Surface Temperature product (below) indicated that mid-lake water temperatures were as warm as 48ºF.

MODIS Sea Surface Temperature product [click to enlarge]

MODIS Sea Surface Temperature product [click to enlarge]

Fog/stratus dissipation: 1-minute GOES-16 vs 15-30 minute GOES-13

April 4th, 2017 |

GOES-16 0.64 µm Visible (left) and GOES-13 0.63 µm Visible (right) images, with surface reports of fog plotted in yellow [click to play animation]

GOES-16 Visible (0.64µm, left) and GOES-13 Visible (0.63 µm, right) images, with surface reports of fog plotted in yellow [click to play animation]

** The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. **

Widespread fog and stratus had developed across southern Alabama and western Georgia during the pre-dawn hours on 04 April 2017. After sunrise, a comparison of 1-minute interval GOES-16 and 15-30 minute interval GOES-13 visible imagery (above) demonstrated the advantage of more frequent scans to monitor the dissipation of fog and stratus. The improved spatial resolution of the GOES-16 0.64 µm “Red visible” band — 0.5 km at satellite sub-point, vs 1 km for GOES-13 — also aided in the detection of smaller-scale river valley fog features.