An active weather pattern involving a persistent mid-level jet over US high plains resulting in several days of widespread hazardous blowing dust. As has been captured previously on this blog, NWS offices leverage satellite imagery to detect and track blowing dust, specifically for diagnosing the spatial extent of blowing dust, which is important for the issuance of advisories and warnings, and for including blowing dust in forecast grids. Further, satellite imagery is used to communicate the threat to the public via social media, as well as to partners in decision support service briefings. NWS Area Forecast Discussions provide some insight into how blowing dust appearance in satellite imagery influences forecaster thinking and decision making. This blog post captures some of these applications from 06-07 April 2022.
GOES-East water vapor imagery from 6-7 April capture a very broad upper low meandering over the upper mid-west (Fig 1). It’s western periphery over the high plains resulted in considerable northwesterly upper flow across the region, along with the embedded periodic and subtle shortwaves.
Gusty winds developed early in the day on the 6th, resulting in morning blowing dust and associated considerations by impacted NWS offices:
From NWS Cheyenne, WY at 1609 UTC: Only minor forecast change is related to blowing dust. Latest satellite observations has indicated a few isolated patches of blowing dust in the southern Nebraska Panhandle near Sidney. Nearby locations across central NE and eastern CO have reported areas of blowing dust. Updated the forecast to include patchy blowing dust through the afternoon which could locally reduce visibility at times.
From NWS Goodland, KS at 1600 UTC: Widespread dust developing across the area now. A couple distinct larger areas are showing themselves on satellite… For the moment, issued a blowing dust advisory for the locations of the bigger plumes. However, it’s quite possible that warnings will be needed soon as we’re starting to get a few reports of near zero visibility. And then 1624 UTC: Went ahead with blowing dust warning across SW Nebraska and a large portion of NW Kansas. Started getting several reports of
zero visibility and decided an upgrade to a warning was necessary. Expanded the advisory to include Graham and Norton counties as dust being observed both at Norton AWOS (7 miles) and satellite.
From Dodge City, KS at 1650 UTC: Up to 50-60 mph likely for much of the CWA during peak heating of the afternoon with temperatures in the upper 50s to near 60 degrees. Blowing dust during this time will be an issue as already seen on satellite for western counties in the driest ground conditions.
From NWS Pueblo, CO at 1655 UTC: Blowing Dust Satellite products are showing blowing dust occurring over the far eastern plains, so a blowing dust advisory has been issued until late afternoon for the far eastern counties.
From NWS Boulder, CO at 1710 UTC: The second change was to add in additional blowing dust into the
far northeastern corner of the state. Webcams and surface observations have indicated some areas of reduced visibility due to blowing dust. CIRA’s DEBRA dust product also shows blowing dust has increased quite a bit over the past couple of hours. Have joined our neighbors to the east with a Blowing Dust Advisory for Sedgwick and Phillips counties where dust could impact travel.
As for DSS and social media, NWS Goodland analyzed GOES-East DEBRA Dust imagery in a morning web briefing posted to social media. NWS Dodge City highlighted problem areas in GOES-East Dust RGB imagery in early day social media posts.
NWS offices were confirmed to have used the CIRA DEBRA Dust product (available on CIRA Slider and in some NWS office AWIPS), as well as the AWIPS Dust RGB, shown in Figures 2 and 3, respectively.
One can also easily diagnose the blowing dust in the simple Split Window Difference with grayscale colormap, as regions of relative dark gray to black (Fig 4). The Split Window Difference is a key ingredient to satellite-based blowing dust detection products.
Geocolor imagery with blowing dust highlighted by the SWD is shown in Fig 5, which also overlays wildfires via the Fire/Hot Spot product. Finally, an experimental Blowing Dust RGB highlights lofted dust as dull to bright yellow (Fig 6).
On the 7th, with the same pattern in place, blowing dust developed across much of the same area, again early in the day. One-minute satellite imagery was available to forecasters to help analyze early development of blowing dust
From NWS Goodland, KS at 1513 UTC: Satellite is already indicating dust plumes developing across
portions of the area. The first area is between Sterling, CO, Akron, CO, and Wray, CO with 4 mile visibility already being reported in Yuma, CO. The other area of dust is south of Burlington, CO extending southeast towards Tribune, KS. Decided it was necessary to extend the blowing dust advisory across the rest of the forecast area as a result of the dust plumes viewable on satellite as well as observations. Will be monitoring for and looking for reports of near zero visibility and that will determine if Blowing Dust Warnings are needed once again. And at 1724 UTC: Received a couple reports of near zero visibility, and along with the impressive dust plume observed on satellite imagery, was pushed over the edge to issue the blowing dust warning for eastern Colorado (Yuma, Kit Carson, and Cheyenne Counties) and extreme northwestern Kansas (Cheyenne, Sherman, Wallace, and Greeley counties). This is currently the most impressive signal we’ve seen so far.
From NWS Boulder, CO at 1520 UTC: Blowing dust will be an additional hazard through the afternoon, and current satellite imagery depicts a few dust plumes beginning to surface over Washington County. May consider Blowing Dust Advisories down the line depending on how widespread/persistent the blowing dust looks to be.
A blowing dust advisory was eventually issued for Washington County.
From NWS Hastings, NE at 1544 UTC: The Blowing Dust Advisory has been extended to include more of the forecast area today. This is due in part to expected potential strong winds and suggestions of dust showing up on satellite imagery.
From NWS Pueblo, CO at 1726 UTC: Updated to issue a Dust Advisory for the far Eastern Plains
through this afternoon. Satellite imagery indicates widespread blowing dust moving into the far Eastern Plains.
On social media, NWS offices communicated the blowing dust threat with satellite imagery, including these posts from Goodland, Hastings, Pueblo, and Boulder. Various NWS personnel have commented that DEBRA Dust is a preferred product for public-sharing (blowing dust information) given it’s easy-to-understand nature.
DEBRA Dust imagery for the full day again captured the lofted dust quite well (Fig 7).
Focusing on 1-min imagery over E CO and W KS during the morning, we can analyze the period of blowing dust initiation in detail. The grayscale Split Window Difference can sometimes be difficult to interpret on such fine scales (Fig 8).
Geocolor (and other reflectance imagery) from GOES-East will not highlight lofted dust and other aerosols too well from GOES-East in the morning due to lack of forward scattering (Fig 9). Enhancing the imagery with Split Window Difference helps (Fig 10).
During this time of day from GOES-East, and especially when clouds are present, IR-based products might be best for blowing dust detection, such as with the experimental blowing dust RGB (Fig 11) or traditional Dust RGB.
Viewing the 10-min GOES-West Geocolor, we see how forward scattering helps produce the dust signal in reflectance-based imagery.
Bill Line, NESDIS and CIRA