A68a Update

December 3rd, 2020 |

A very large iceberg broke off the Larsen-C Ice Shelf on the Antarctic Peninsula in July 2017 (recall this CIMSS Satellite Blog post) or this more recent post. While NOAA’s GOES-16 ABI visible sensors may not be ideal, they can monitor the iceberg’s location if the cloud cover is not too thick, as shown in the “natural color” animation. A similar loop, in the animated gif format. These composite images include information from ABI “blue” and “red” visible bands, along with the near-infrared “vegetation” band. A sample still image from November 21, 2020. More information can be found in the quick guide.

A GOES-16 natural color animation, at 15:30 UTC each day. The first day is November 4 , while the last day is December 2, 2020.

Thanks to a recent tweet by Simon Proud, showing a GOES-16 animation of A68a:

The geo2grid software was used to generate these loops.

Mesoscale bands of snowfall in New Mexico, Oklahoma and Texas

November 29th, 2020 |

GOES-16 Mid-level Water Vapor (6.9 µm) images, with hourly precipitation type plotted in yellow [click to play animation | MP4]

GOES-16 Mid-level Water Vapor (6.9 µm) images, with hourly precipitation type plotted in yellow [click to play animation | MP4]

GOES-16 (GOES-East) Mid-level Water Vapor (6.9 µm) images (above) showed a cutoff low that was moving slowly eastward across eastern New Mexico and the Oklahoma/Texas Panhandle on 28 November – 29 November 2020. This system was helping to produce rain and snow across parts of that region — and some elongated convective elements were evident across the OK/TX Panhandles. Snowfall totals included 2.5 inches in New Mexico and 3.0 inches in Texas, with 4.8 inches at Felt, Oklahoma (NOHRSC).

On the following day, a few north-to-south oriented mesoscale bands of snow cover were evident on GOES-16 “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (below). Since snow is a strong absorber of radiation at the 1.61 µm wavelength, it appeared as darker shades of black on those images. Swaths of lighter snow cover melted rather quickly during the day.

GOES-16 "Red" Visible (0.64 µm) and Near-Infrared "Snow/Ice" (1.61 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images [click to play animation | MP4]

Mesoscale snowband effects on temperature in Kansas

November 25th, 2020 |

Day Snow Fog RGB, 1421 – 1926 UTC on 25 November 2020 (Click to animate)

An extratropical cyclone deposited a mesoscale snowband — a few counties wide — in south-central Kansas late in the day on 24 November 2020 (Click here to see the storm at 0300 UTC on 25 November). As is often the case, such bands have profound impacts on surface temperatures. It is therefore important to monitor their precise location. The animation above shows the Day Snow Cloud RGB; its use of the 1.61 µm band allows the RGB to distinguish easily between snow and clouds, both of which are bright in the visible, as shown in the image below, courtesy Mike Umscheid, NWS ICT, that shows the snow band and the similarly reflective clouds to the east. (Imagery created at this nifty website!)

GOES-16 Visible imagery, 25 November 2020, and morning snow depths over central Kansas (Click to enlarge; imagery courtesy Mike Umscheid, NWS ICT)

GOES-16 Land Surface Temperatures (a baseline level 2 product) shows the effect of the snow on skin temperature, below. Shortly after sunrise, temperatures over the snowband are several degrees (Fahrenheit) cooler, as expected with clear skies and a fresh snowpack. (Warm lakes also shine through!)  Bare land in Kansas warms quickly, with Skin Temperatures reaching into the upper 60s and 70s by 1900 UTC, whereas the snow band remains in the 30s!

GOES-16 Land Surface (skin) Temperature, 1421 – 1916 UTC, 25 November 2020 (Click to animate)

A comparison of GOES-R Land Surface Temperatures with METAR observations, below, underscores the notion that the skin temperature can be much warmer than the temperature 1.5 m above the ground, where METAR thermometers (or thermistors) measure the air temperature. The warmest METAR temperature at 2000 UTC is 57º F at Scott City, KS. Land Surface Temperatures there are in the mid-60s, with 70 just to the northeast.

GOES-16 Land Surface Skin Temperatures with surface METAR plots, 2000 UTC (Click to enlarge)

Note that the default bounds of the colorbar range in Land Surface Temperature have been changed. Default values range from -10º to 110º F; values shown above range from 10º to 80º F. The toggle below compares the two, at 1501 UTC.

GOES-16 Land Surface Temperature with default color bounds (-10 to 100 F) and more useful bounds for this day (10 to 80 F) (Click to enlarge)

Towards sunset, the Day Snow Fog RGB (or any RGB that relies on reflectances from visible, near-Infrared or infrared channels) can become dim. In that event, an AWIPS user can edit the Composite Options, reducing the upper bounds of all three RGB channels o that the image retains brightness and utility (in this case upper bounds were reduced for Red from 100 to 60; for Green from 70 to 40; for Blue from 30 to 19).

GOES-16 Day Snow Fog RGB at 2241 UTC, 25 November 2020, with default bounds (dimmer image: Red 0-100; Green 0-70; Blue 0-30) and adjusted bounds (brighter image: Red 0-70; Green 0-40; Blue 0-19) (Click to enlarge)

Cardboard Container Factory Fire in Niagara Falls, NY

November 20th, 2020 |

GOES-16 Mesoscale Sector-1 Shortwave Infrared (3.9 µm) Imagery, 1440 – 1450 UTC on 20 November 2020 (Click to enlarge)

GOES-16 Mesoscale Sector 1 imagery, in its default position over the metropolitan New York City aviation hub, also views western New York. It was therefore able to view the beginning of a large fire at a cardboard container recycling and manufacturing facility in Niagara Falls (Youtube link) on 20 November 2020. GOES-16 Band 7 shortwave infrared (3.9 µm) imagery, above, first detected the fire hot spot at about 1441 UTC, or 9:41 AM EST (It becomes visually apparent in the imagery at about 1447 UTC). GOES-16 continued to observe the fire until clouds moved into the area around 1600 UTC, or 11 AM EST, as shown in the Fire RGB animation, below, from 1430 – 1630 UTC, and in this visible imagery animation. (Click here to view the Band 7 (3.9 µm) animation from 1430 – 1630)

The warmest GOES-16 Band 7 (3.9 µm) pixel temperature occurred at 1512 UTC: 53.5ºC. Click here to see the image; (here’s the Fire RGB for that time).

GOES-16 Fire RGB, 1430 – 1630 UTC on 20 November 2020 (Click to animate)

Radar observed the fire’s plume (link from 1550 UTC, courtesy Michael Fries, NWS BUF). Thanks also to Michael for alerting us to this event.