PyroCb in Montana

On 28 August there was some discussion on whether there was a pyroCb in Montana. Upon further investigation it was found that there was a pyroCb at 48.2 N 113 W. GOES-15 detected the smoke plume and pyroCb cloud, as well as the fire hot spot. Starting at 21:00 UTC on 28 August, the animation below shows visible (.63 μm) on the left and shortwave IR (3.9 μm) on the right (click image to play animation). In the shortwave IR images the red pixels indicate very hot IR brightness temperatures exhibited by the fire source region.

GOES-15 0.63 µm visible channel (left) and 3.9 µm shortwave IR channel images (right) (click to play animation)

GOES-15 0.63 µm visible channel (left) and 3.9 µm shortwave IR channel images (right) (click to play animation)

In addition, using GOES-15 10.7 μm IR channel the cloud-top IR brightness temperature could be found. From the animation above it can be seen that there were three major convective clouds associated with this pyroCb. The animation below, starting at 21:00 UTC on 28 August, shows the brightness temperature for the pyroCbs associated with this fire. Each pyroCb has a red circle encompassing it. The first pyroCb is -67ºC around 23:00 UTC on 28 August (red color enhancement), the second pyroCb is -68ºC around 00:30 UTC on 29 August (red color enhancement), and the third pyroCb is -70ºC around 02:00 UTC on 29 August (dark red color enhancement).

GOES-15 10.7 µm IR channel images (click to play animation)

GOES-15 10.7 µm IR channel images (click to play animation)

The animation below is from IDEA, it shows the 48 hr forecast of the trajectory of an air parcel, along with wind models and precipitation. The animation starting on 28 August at 18 Z shows the hot spot in the southwestern part of Montana. From there the smoke from this pyroCb moves northeast towards Canada. In addition, the colors of the arrows are important. Since the arrows are a white color that is indicative of upward motion of air flow.

48-hour aerosol trajectory forecast with model winds and precipitation on 28 August

48-hour aerosol trajectory forecast with model winds and precipitation on 28 August

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