A potent jet streak overhead resulted in strong/gusty winds across the high plains on 5 April 2022. The wind combined with dry conditions, resulted in a broad area of elevated to critical fire weather conditions. Further, a shortwave trough rounding the base of a broader upper low to the north sent a cold front south through the high plains, resulting in dramatic wind shifts along it’s path. NWS Dodge City, KS summarized the situation well leveraging GOES water vapor imagery (Fig 1): “Water vapor imagery shows a strong upper level jet moving into the Pacific Northwest and northern Rockies overnight with an upper low starting to close off along the border of Montana and Canada. This low will move out across the Dakotas into Minnesota today into tonight. A cold front will move south across western Kansas today…”
A large wildfire developed in the Oklahoma Panhandle early in the day within gusty westerly winds, but abruptly spread south with the passage of a cold front. An AWIPS procedure captured all aspects of this situation, and is shown in Figure 2. Using the Geocolor as the base layer, we overlay the 10.3 um channel with 10% transparency and a white/cold to black/warm grayscale colormap centered on the brightness temperature range of the pre and post frontal clear sky, and 3.9 um shortwave IR brightness temperature >45 C to capture hot spots. The first part of the animation captures the wildfire hot spot and smoke plume as the cold front approaches. Once the cold front and associated wind shift push through the fire, the hot spot quickly begins to move south, along with the low-level portion of the smoke plume. The shallow nature of the cold airmass is apparent in the smoke plume behavior, with only the low-level portion nearest the fire falling within northerly flow, while further aloft, the plume continues to drift east within the westerly flow.
The location of the wildfire fell within three consecutive VIIRS passes around the time of the frontal passage, allowing for a detailed (spatially) view of the fire and wind shift. The VIIRS Natural Fire Color RGB with a similarly semi-transparent VIIRS LWIR channel overlay is shown in Fig 3.
While surface obs provide the ideal source of quantitative information regarding wind shifts, satellite imagery (especially 1-min as in Fig 2) can be leveraged to analyze frontal movement and associated wind shift with more spatial and temporal detail. In cases of wind shifts at a wildfire, such real-time information is extremely important in the protection of life and property, both for the local public and for emergency personnel working the fire (see example from one year ago here).
For this event, NWS Amarillo, TX (AMA) leveraged GOES Imagery and products in order to illustrate the dramatic fire growth associated with the frontal passage on social media (see post below). NWS/AMA also utilized satellite imagery for their Decision Support Services (DSS) phone briefings supporting the Beaver County fire and other fires in the area. Specifically, the GOES 1-min satellite imagery allowed forecasters to track the front in detail and communicate to emergency personnel the precise timing of the impending change in wind direction at each fire. The Beaver County EM confirmed that they moved personnel based on the NWS briefings of the frontal passage timing, which they got directly from watching the 3.9 um satellite imagery. In particular, forecasters noted their use of the 1-min 3.9 um band (which captured the frontal position and hot spots well) with the Fire/Hot Spot derived product (Fire Temperature) as an overlay (See Figure 4 for grayscale version and wide view of area).
Bill Line, NESDIS and CIRA
Input from NWS/AMA, including Melissa Beat