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.

2.5-minute rapid scan #Himawari8 Infrared images of Category 5 (as of 0000 UTC) Cyclone #Yasa northwest of Fiji: https://t.co/CcSMlqeInA pic.twitter.com/zZ4Vl4DalM

— Scott Bachmeier (@CIMSS_Satellite) December 16, 2020

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.

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As was seen 2 days earlier, a plume of blowing dust developed across the Texas Panhandle in the wake of a cold frontal passage, and was transported southeastward across western Texas on 15 December 2020 — GOES-16 (GOES-East) Dust RGB images (above) displayed signatures of this airborne dust (brighter shades of pink).

GOES-16 True Color RGB images created using Geo2Grid (below) showed the tan-colored signature of blowing dust increase during the afternoon hours leading up to sunset. A few of the point sources of the dust appeared to beds lake beds near the Texas/New Mexico border, areas which were experiencing extreme to exceptional drought conditions.

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1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed the passage of a total solar eclipse shadow across parts of Chile and Argentina, along with the land surface thermal response due to the interruption of incoming solar radiation. In areas of Argentina beneath the path of totality, the infrared brightness temperature of the land surface decreased by as much as 20-30ºC within the umbral shadow.

A larger-scale view of the path of the eclipse shadow was provided by GOES-16 CIMSS Natural Color RGB images (below).

GOES-16 Near-Infrared “Vegetaton” (0.86 µm) images (below) highlighted an advantage of that spectral band — namely, brighter surface values over land (due to the higher reflectivity of vegetation at that wavelength), providing more contrast between the land surface and the darker eclipse shadow. The 0.86 µm band is also used to simulate a “green” component for RGB images such as the CIMSS “Natural Color” product.

A closer look at the eclipse shadow passage using 1-minute 0.86 µm imagery is shown below (with the corresponding CIMSS Natural Color RGB images here).

In a comparison of GOES-16 “Blue” Visible (0.47 µm), “Red” Visible (0.64 µm), Near-infrared “Vegetation” (0.86 µm), CIMSS “Natural Color” RGB and Rayleigh-corrected “True Color” RGB images (below), it can be seen that the Rayleigh-corrected “True Color” is not optimal for displaying features such as solar eclipse shadows (due to over-saturation).

Incidentally, although the path of totality passed to the north, some reduction of incoming sunlight was apparent over the A68a iceberg (located just southwest of South Georgia island) on GOES-16 Visible images created using Geo2Grid (below).

NOAA-20 VIIRS True Color RGB images viewed using RealEarth (below) showed views before and during the time of closest passage of the eclipse shadow.

Other blog posts that show solar eclipse shadows can be seen here.

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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)

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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.

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.

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