Another PyroCb in Russia near Lake Baikal

On 25 August there was another pyroCb east of Lake Baikal in Russia. The first at 53.9N 109.8 E. Himawari-8 detected the smoke plume and clouds around the fires, as well as the fire hot spot. Starting at 02:00 UTC on August 25, the animation below shows visible (.64 μm) on the left and shortwave IR (3.9 μm) on the right (click image to play animation). In the shortwave IR images the darker black to red pixels indicate very hot IR brightness temperatures exhibited by the fire source region.

Himawari-8 0.64 μm visible (left) and 3.9 μm shortwave IR (right) images (click to play animation)

Himawari-8 0.64 μm visible (left) and 3.9 μm shortwave IR (right) images (click to play animation)

Himawari-8 10.4 μm IR channel imagery the minimum cloud-top IR brightness temperatures could be found. The animation below, starting at 02:00 UTC on 25 August, shows that the pyroCb reached around -52.8 ºC (yellow color enhancement) at 04:30 UTC.

Himawari-8 10.4 μm IR images (click to play animation)

Himawari-8 10.4 μm IR images (click to play animation)

OMPS AI index images (courtesy of Colin Seftor) shows the transport of smoke. There are high AI Index values northeast of the lake, which is consistent of the smoke trajectory in the animations above.

OMPS Aerosol Index image on 26 August (click to enlarge)

OMPS Aerosol Index image on 26 August (click to enlarge)

Below is an animation of the convergence at 250 mb shown by a color fill, the the 250 mb geopotential height contoured every 30 meters and the wind barbs.It has been investigated that upper level divergence is associated with the ability for pyroCu to turn into a pyroCb (Peterson et al., BAMS, Feb. 2015, 229-247). Starting at 0 UTC on 25 August the spots of the pyroCbs are indicated by the white dots. These pyroCbs are in an area of divergence indicated by the light blue and dark green color. This is conducive to the strengthening of the pyroCb. If there is divergence at upper levels there is rising air below that area of divergence. These conditions are favorable to the pyroCb developing.


250 mb Convergence(color fill), Geopotential Height (contoured every 30 m) and wind barbs every 6 hours starting on 25 August 0 UTC.

This Skew-T taken at 06 UTC on 25 August after the pyroCb located at 52.6 N 109.5 E. From the Skew-T it is apparent that there is a good amount of CAPE which is favorable for convective development. Furthermore, this Skew-T shows a very moist atmosphere favorable for convective activity. This will help turn pyroconvection into a pyroCb. Furthermore, from the Skew-T the winds are veering indicating a cyclonic motion.
newer825skewtSkew-T at 06 UTC (click to enlarge) Green line is dew point and red line is temperature.

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