Through the first week of September 2022, a strong upper Ridge developed across the western US and large wildfires burned across the Pacific Northwest. Increased flow and embedded disturbances across the northern part of the ridge helped to accelerate significant wildfire smoke east across the northern Rockies into the Great Plains and midwest (Fig 1). NWS offices were monitoring the evolution of the smoke, as it was dense enough to reduce visibility, impact temperatures, and reduce Air Quality and threaten the health of certain groups. Satellite imagery is the primary tool forecasters utilize to observe and track the evolution of wildfire smoke. The imagery is supplemented by other observational tools such as ASOS, webcams, air quality sensors, etc in order to better quantify impacts of the smoke. Finally, the HRRR-Smoke model, in which satellite data are vital components, is leveraged to make predictions of where the smoke will evolve over the next few hours to couple of days.
While wildfire smoke can be analyzed in single-band visible satellite imagery, animations of RGB imagery, and specifically True Color Imagery such as in daytime Geocolor, provide the best method for diagnosing and tracking wildfire smoke during the day. Geocolor may not yet be available in all NWS offices, but can be accessed online at the CIRA Slider webpage and GOES Image Viewer. As has been mentioned in past blog posts and is illustrated below, forward scattering plays an important role in the appearance of aerosols, such as smoke, in satellite imagery. In Geocolor imagery from the 6th, Smoke is much more apparent in GOES-West (-East ) imagery during the morning (evening; Fig 2 and 3). Hence, it is important forecasters have access to, and leverage, imagery from both satellites.
A perusal of central US NWS Area Forecast Discussions from the past couple of days indicate widespread discussion of the smoke given its impacts. A few of the discussions specifically mentioning the use of satellite imagery or HRRR Smoke are included below.
First on the 4th, NWS Bismarck, ND analyzed the smoke in Natural Color RGB imagery, available in AWIPS, and its potential impacts: “Natural Color RGB satellite showing nicely wildfire smoke being pulled into the upper low across Montana. Look for this to enter into western North Dakota by this evening.” Note in Figure 4, the smoke becomes most apparent later in the afternoon as it advances east across Montana into North Dakota, from the GOES-East position as the sun sets to the west.
NWS BIS also leveraged satellite imagery on social media to help message smoke impacts.
Later in the evening of the 4th, NWS Aberdeen, SD discussed the earlier appearance of smoke in satellite imagery, as well as the HRRR smoke predicted evolution of smoke for the next two days: “Satellite imagery verifies that there is smoke building into the northern plains region from western CONUS forest fires. The latest available RAP/HRRR smoke model output suggests there is some potential for lofted smoke to be thick/dense enough to affect high temperatures today mainly across the Missouri River valley and west river counties in this CWA. Overspreading more of the CWA overnight and on Tuesday, a larger area of the CWA could see some of that temperature-impacting smoke overhead.”
A HRRR Smoke “Vertically Integrated Smoke” 48 hr forecast animation is shown in Figure 5, predicting smoke to round the northern and eastern periphery of the ridge and fill in across the central US through the evening of the 6th. The predicted location of smoke in this forecast matches well with that in the animations of Fig’s 2 and 3.
On the morning of the 6th, NWS Boulder discussed the state of the smoke as depicted in satellite imagery and the HRRR smoke model, and expected influences on weather for the day: “The huge fire in Idaho is also generating a lot of smoke that is coming south along the periphery of the anticyclone, per the latest HRRR Smoke and GOES-16 imagery. The smoke will not be particularly thick, but should be enough to keep temperatures below 100 across all but the northeast corner of Colorado.” Refer to Figures 2 and 3.
NWS Boulder created a neat social media graphic on the 6th highlighting the satellite depiction of the wildfire hot spots and smoke plumes.
During the afternoon of the 6th, NWS OAX discussed the smoke per Geocolor Imagery and it’s anticipated evolution per HRRR Smoke model: “There is some smoke aloft across the mid CONUS as noted on Geocolor satellite imagery, and the HRRR smoke model indicates this smoke aloft could become more prevalent over our area through Wednesday night. Really not expecting any surface smoke in our coverage area, just most of a hazy sky appearance.” Refer to Figures 2 and 3.
NWS Omaha shared a Geocolor Graphic on Twitter pointing out the location of smoke across the region.
By the morning of the 7th, widespread smoke was present across the middle of the United States, including practically thick smoke over the northern US Rockies and adjacent high plains (Fig 6). NWS offices were already noticing an impact on temperature recovery during the morning, with BIS mentioning: “Temperatures have been slow to warm due to smoke moving in from fires out west. Therefore, high temperatures have been decreased a few degrees and may have to decrease them more with the next
package” and Rapid City writing: “Visible satellite imagery this aftn shows thick mid- to upper-level
smoke across wrn SD drifting ewd with time. This smoke limited incoming solar radiation and associated heating thru the morning hours.”
Other excellent social media posts that messaged the wildfire smoke via satellite imagery and HRRR smoke graphics, along with annotation, include:
- Dodge City leveraging VIS, Fire Temperature RGB, and HRRR Smoke.
- Albuquerque sharing Geocolor from the STAR GOES Image Viewer.
- Goodland using Natural Color imagery.
- Pueblo with HRER Smoke output.
- Des Moines shared a video annotating Geocolor Imagery in CIRA Slider.
Bill Line, NESDIS/STAR
Satellite Liaison Blog 