An active weather pattern across the southern plains resulted in numerous widespread blowing dust events in February-March 2023 (that were observed in NOAA Satellite Imagery), including on Feb 14, 15, 22, 26, 27, 28, and most recently, on Mar 2. As is often the case, the blowing dust event on the 2nd was coincident with a widespread severe weather event (SPC MOD centered over the ArkLaTex region) that resulted in over 100 wind reports, and to a lesser extent, hail and tornadoes. All of the examples in this blog post are created in AWIPS, and can be adapted to any NWS office AWIPS.
The broader forcing for these significant weather phenomena can be diagnosed in GOES-East water vapor imagery, which reveals a compact shortwave quickly advancing east along the SW US/Mexico broader into west Texas throughout the day (Fig 1). Warming on the west/southwest portion of the shortwave represents descending/drying air within the dry conveyor belt of the system, and where downward momentum transfer is aiding the development of strong surface winds and blowing dust. Ahead of this feature, cooling brightness temperatures represent the moist convener belt and where deep moist convection is developing wit the moist/rising air. Overlays of RAP analysis 500 mb height and wind speed help to quantify and trace the location/magnitude of the low and mid-level jet, and aid interpretation of the WV imagery. Over time, such WV+NWP combinations can enhance forecaster confidence in imagery interpretation.
Taking a look at Geocolor+SWD+GLM (or GeoDust+GLM) imagery, we have a easy-to-interpret depiction of weather events during the day, including the widespread blowing dust captured in Geocolor and enhanced by the IR Split Window Difference, and cloud and thunderstorm development shown in Geocolor and GLM FED (Fig 2). Also apparent in the dust portion of the imagery is the broad southwesterly flow lifting the dust from Mexico aloft across southwest Texas, with westerly to northwesterly flow behind a cold front surging east across west Texas. The dust within the southwesterly flow eventually overruns that behind the front.
As has been shared in previous posts, a Color Vision Deficiency (CVD) Dust RGB is being developed, and uses similar ingredients as the traditional Dust RGB (in AWIPS), but in a way that helps Dust to stand out a little better, especially for those who have some degree of CVD. The Dust CVD RGB is compared with the Dust RGB in Fig 3 and 4, respectively. In the CVD version, blowing dust appears as relatively bright yellow compared to an otherwise blue or green background, compared to the pink appearance of dust in a Dust RGB. The Dust CVD RGB also clearly defines the dryline over west Texas as deeper blues within the moist atmosphere to the east, and lighter blues to cyans on the dry side to the west. Convection is observed to develop along that boundary.
This dryline evolution can also be captured in a previously discussed on this blog SWD-IR image combo, which captures the dryline from the SWD (lighter gray is greater low-level moisture), and cloud development in the cold-IR overlay (Fig 5). The advantage of the SWD (raw or in RGBs), is to provide more continuous information about the moisture gradient, both spatially and temporally, as a supplement to the surface obs, which quantify the atmosphere across the boundary. Dust is also apparent as dark gray to black.
One-minute imagery was available across the region to provide forecasters with more continuous satellite information. during this extreme event. Focusing on the development of blowing dust behind the front in west/southwest Texas, GeoDust animations provide excellent detail into the development of the dust plume, in the context of NWS Dust Storm Warning Polygons (Fig 6 and 7).
Further to the east, GOES-East meso-1 and meso-2 overlapped, resulting in a domain of 30-second imagery (Fig 8). A storm developing ahead of the main line of severe storms resulted in large hail falling over north-central Texas. The 30-second storm-relative imagery captures the persistent cooling along the southwest flank of the storm cluster, along with accelerating southeasterly flow in the inflow region as traced by the cumulus field.
Bill Line, NESDIS/STAR
Satellite Liaison Blog 