Building off of a previous blog post, a simple RGB can be made that allows for the observation of the hot spot, smoke plume, and burn scar associated with a wildfire. The RGB discussed in this post combines the 3.9 um band (RED) to sense the hot spot, the 0.86 um band (GREEN) to highlight the previously burned area, and the 0.64 um band (BLUE) to track the smoke plume. The hot spot (active wildfire) will appear as red, the smoke plume as faded blue or cyan, clouds a bright cyan, and burned area as a locally dark area. Highly vegetated areas will appear as a bright green, and bodies of water very dark. The recipe used in this example is shown in Figure 1. An animation of this RGB with GOES-17 for the Kincade Fire on 27 Oct is found in Figure 2, and the RGB with the three ingredients is shown as a 4-panel in Figure 3. The active large fire is readily apparent, with the associated burn scar extending north of the ongoing fire. The smoke plume is diagnosed extending well to the southwest of the fire. The heavily forested region of northern California is obvious to the west and northwest of the fire. What appears to be lofted dust is also apparent in this example in the southeast part of the scene.

Bill Line, NWS

A late October trough brought significant weather impacts to portions of the western and central United States. The impressive trough was diagnosed in GOES-East water vapor imagery with features readily apparent (Fig 1). The upper jet extended south across the Pacific Northwest, rounded the base of the trough, and stretched northeast across the Great Basin and into the northern US plains. Exceptional shortwave energy near the base of the trough was digging south across northern California, and an associated cold front was racing south down the southern high plains. An overlay of GOES-16 Derived Motion Winds (DMWs) confirms the speed of the jet in areas where winds are available.

In California, extreme fire danger was observed as high pressure built in the wake of the potent shortwave, resulting in strong easterly surface winds and plummeting RH in the presence of very dry fuels. In northern California, rapid expansion and increase in temperature of the Kincade Fire was observed by GOES-West shortwave IR imagery during the overnight hours of the 26th into the early morning hours of the 27th (Fig 2).

Further east, the precise location of the cold front could be tracked as it pushed south across the high plains, with cold air pooling along the Colorado front range and southeast mountains (Fig 3). An overlay of MSAS 3-hr pressure changes and wind barbs shows an expected increasing pressure behind the IR-detected front, along with a shift of winds to a northerly direction.

With sunrise, the extensive shield of low clouds developing within the cold airmass in the wake of the cold front was observed in GOES-East visible satellite imagery (Fig 4). Pikes Peak and other mountain ranges are seen poking through the low cloud layer. Additionally, a multitude of cloud top gravity was are diagnosed atop the cloud layer.

Bill Line, NWS