Satellite detection of blowing snow

December 23rd, 2020 |

Day Snow Fog RGB, 1416 – 1751 UTC, 23 December 2020 (Click to animate)

Strong winds behind a storm moving along the United States/Canada border on 23 December 2020 led to blizzard warnings over much of the Northern Plains (link). How easily was the blowing snow detected by satellite?

The animation above shows the Day Snow Fog RGB from 1416 through 1751 UTC on 23 December 2020. During this time over North Dakota, low clouds (bright whitish/periwinkle) and mid/high-level clouds (transparent violet) masked the surface from the satellite view. However, blowing snow is suggested to the south of Lake Manitoba. The RGB has a slightly different, brighter color than the adjacent snow-cover — that is red — and the texture in the image, and the linear features aligned with the wind both suggest lofted blowing snow.

The VIIRS instruments on board Suomi-NPP and NOAA-20 also viewed this scene, once at 1759 UTC (from NOAA-20) and once at 1850 UTC (from Suomi-NPP), with much higher spatial resolution. There is a region of enhanced reflectance (i.e., whiter shades of grey) in the 1.61 µm imagery to the south-southeast of Lake Manitoba in the top center of the image.  These are lofted, fractured ice crystals that are more reflective of solar radiation than surrounding snow cover.  The signal shows up in the False Color imagery as well, but not in the true color imagery that does not incorporate information from the 1.61 µm channel.  A similar signal appears in extreme northeast North Dakota at 1759 UTC.  VIIRS imagery does not suggest widespread blowing snow.  Indeed, snow depths over North Dakota suggest little snow on the ground to blow around (snow depth analysis, from this site)!  Snow depths over Manitoba are a bit larger.

NOAA-20 VIIRS I03 (1.61 µm), False and True Color imagery, 1759 UTC 23 December 2020 (Click to enlarge)

Suomi-NPP VIIRS I03 (1.61 µm), False and True Color imagery, 1850 UTC on 23 December 2020 (Click to enlarge)

The animation from 1751 UTC to 2106 UTC on 23 December, below, which animation includes the times of the VIIRS overpasses above, also captures the snow plume downwind of Lake Manitoba, extending to the North Dakota/Minnesota border and, perhaps, into northwestern Minnesota. However, clouds over Minnesota (and the Red River of the North) make definitive blowing snow detection difficult. Traffic webcams as a supplement to the satellite data source will create a better feel for the horizontal extent of the blowing snow.

Day Snow Fog RGB, 1751 – 2106 UTC, 23 December 2020 (Click to animate)


This 11-minute training video discusses this RGB’s abilities in blowing snow detection in a bit more depth.  You can view a longer presentation concerning othis RGB here.

VIIRS views a winter storm

December 17th, 2020 |

NOAA-20 VIIRS True-Color imagery from 1814 UTC on 17 December 2020 (Click to enlarge)

A storm dropped historic snow amounts over parts of northern Pennsylvania, upstate New York and New England on 16-17 December 2020 (Places around Binghamton NY, for example, received more than 40″ of snow as shown in this map from this site.  Click here to see the Binghamton Radar loop during the storm).  The VIIRS True-Color image from ~1800 UTC on 17 December, above (created at the Direct Broadcast site at CIMSS, and available via LDM feed to NWS Forecast offices), shows the storm south of Cape Cod, and snow on the ground in the Mid-Atlantic states (the Great Valley in Virginia, Maryland and Pennsylvania is particularly apparent)

Cyclone Yasa strengthens rapidly in the South Pacific

December 16th, 2020 |


Himawari-8 Clean Window Infrared (10.41 µm) imagery, 0000 UTC 14 December to 0000 UTC 16 December 2020 (Click to animate)


Himawari-8 Clean Window Infrared (10.41 µm) imagery (courtesy the Japanese Meteorological Agency, JMA) from 14-15 December 2020 (click here for an animated gif) show the development of a potent storm with an obvious clear and large eye by 0000 UTC on 16 December. The Joint Typhoon Warning Center notes: ” TC 05P HAS RAPIDLY INTENSIFIED 50 KNOTS OVER THE PAST 24 HOURS, FROM 85 KNOTS AT 14/18Z TO 135 KNOTS AT 15/18Z.” Yasa further intensified to a Category 5 tropical cyclone at 0000 UTC on 16 December.


Visible imagery from GOES-17 and Himawari-8, (mp4 animation below, click here for an animated gif, and here for a full-sized mp4), during the day on 16 December show a well-developed storm with a clear eye.


Stereoscopic view of Cyclone Yasa, 1800 UTC 15 December to 0550 UTC 16 December 2020. Click to animate. GOES-17 Visible imagery on the left, Himawari imagery on the right

A storm-centered view of the storm is shown below. Click here for the full-sized mp4, and here for an animated gif.


Storm-centered stereoscopic view of Cyclone Yasa, 1800 UTC 15 December to 0550 UTC 16 December 2020. Click to animate. GOES-17 Visible imagery on the left, Himawari imagery on the right

The animation below is also storm-centered, but zoomed in on the eye of the storm.  Click here for a full-sized mp4, and here for an animated gif


Storm-centered stereoscopic view of the eye of Cyclone Yasa, 1800 UTC 15 December to 0550 UTC 16 December 2020. Click to animate. GOES-17 Visible imagery on the left, Himawari imagery on the right

Forecast models take this strong cyclone over Fiji later this week. Refer to the JTWC, to the RSMC in Fiji or the SSEC Tropical web site for more information.

Stereoscopic views of Cyclones Yasa and Zazu

December 14th, 2020 |



GOES-17 (left) and Himawari-8 (right) visible (0.64 µm) imagery over Fiji, 2100 UTC on 13 December through 0500 UTC on 14 December (Click to animate)

An active area of tropical weather has spawned two tropical cyclones that bracketed the islands of Fiji early on 14 December. Himawari-8 (data courtesy the Japanese Meteorological Agency, JMA) and GOES-17 both viewed the two storms, with Yasa on the left and Zazu on the right, and stereoscopic views are shown above. (To view the imagery in three dimensions, relax/cross your eyes until three images are present, and focus on the image in the center). Click here for a full-sized mp4, and here for an animated gif.

The storms had an interesting development, as shown below in a 3-day Himawari-8 Clean Window infrared imagery mp4 animation (Click here for a large animated gif of the same scene) from 10-13 December 2020. Yasa in particular developed in a region of considerable shear and initially followed a circuitous route (shown in this graphic from RSMC Fiji), but it has since moved into a more favorable environment.  Yasa also absorbed the remains of Tropical Storm #4.



Himawari-8 Clean window infrared (10.41 µm) imagery, 0000 UTC on 10 December – 2350 UTC on 13 December (Click to animate;  data courtesy JMA)


GOES-17 (left) and Himawari-8 (right) visible (0.64 µm) imagery over Fiji, 1900 UTC on 14 December 2020 (Click to enlarge)

Added:  The morning view of the storms, above, from 1900 UTC on 14 December reveals that Zazu is becoming sheared.  The low-level center is exposed with convection shifted to the east.  This is consistent with shear analyses from the SSEC Tropical website, below, that shows westerly shear over the storm.

850-200 mb shear analysis, 1500 UTC on 14 December 2020 (Click to enlarge)

For more information on these storms, refer to the SSEC tropical website (link), or to the RSMC in Fiji (link). At present, Yasa is forecast to make landfall in Fiji later this week as a very strong storm. Interests there should monitor this storm closely.