GOES-16 (GOES-East) True Color RGB images created using Geo2Grid (above) revealed dense smoke plumes moving southeastward from wildfires in New Mexico, while blowing dust plunged southward from Colorado/Kansas (along and behind a cold front) on 29 April 2022. 

Taking a closer look at the New Mexico wildfires using 1-minute Mesoscale Domain Sector GOES-16 “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images along with 5-minute Fire Power and Fire Temperature products (below), the smoke plume point sources and thermal signatures of these 3 fires could be seen in great detail. Downwind of one of the fires, smoke restricted the surface visibility to 1-3/4 mile at Las Vegas (KLVS). 3.9 µm Shortwave Infrared brightness temperatures of the 2 larger fires reached 138.71ºC — which is the saturation temperature of ABI Band 7 detectors. The Fire Temperature and Fire Power derived products are components of the GOES Fire Detection and Characterization Algorithm FDCA.

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Finally, to the east and northeast across the central Plains, severe thunderstorms developed which produced several tornadoes, hail up to 4.00 inches in diameter and wind gusts to 91 mph — 1-minute GOES-16 Visible images (above) and Infrared images (below) include time-matched plots of SPC Storm Reports. One of the tornadoes caused EF-3 damage in Andover, Kansas (further discussed here).

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On 28 April, SPC’s convective outlook showed a small region of SLGT RSK over western Nebraska, with Marginal probabilities over most of Nebraska and Kansas (link to 2000 UTC outlook). The animation above shows hourly CAPE predictions from a 3-km version of the Rapid Refresh that is run hourly and initialized with Polar Hyperspectral Data (infrared and microwave, from Metop and from Suomi-NPP and NOAA-20) fused with GOES-16 ABI data, thereby using the strengths of ABI (fine spatial and temporal resolution) and Polar Hyperspectral Soundings (excellent spectral resolution). The animation above (a mix of initial fields — 1700 – 1900 UTC ; 1 – 4h forecasts from 1900 UTC; and 6-9h forecasts from 1800 UTC) shows CAPE developing over the High Plains and then rotating north into Kansas by 0300 UTC on 29 April 2022. A later forecast of CAPE, below, runs from 2100 UTC 28 April through 0600 UTC 29 April (showing initial fields at 2100/2200 UTC, then forecasts from 2200 UTC at 2300 UTC through 0400 UTC [i.e., 1-6h forecasts], followed by 8h and 9h forecasts from 2100 UTC on 0500 and 0600 UTC). By 0600 UTC, an axis of instability stretches from western Nebraska southeastward into central Kansas. The two forecasts show similar patterns.

The toggle below compares two forecasts for 0300 UTC, a 9-h forecast from 1800 UTC on 28 April, and a 5-h forecast from 2200 UTC on 28 April. The 5-h forecast is a bit less quick in moving the high CAPE values northward.

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So, what happened? The toggle below compares the 6-h forecast from 2200 UTC, valid at 0400 UTC on 29 April, with the initial field for the 0400 UTC model run. As above, it appears that the forecast model from 2200 UTC was a bit too fast in moving the CAPE northward and eastward into Kansas/Nebraska. But overall there is very good agreement between the two fields.

The animation below shows PHSnABI CAPE fields hourly from 0400 – 0700 UTC (initial fields from 0400-0600; 1-h forecast at 0700), side by side with observed GOES-16 ABI Band 13 color-enhanced brightness temperatures. The convection that develops is along the edges of the CAPE; that is, it forms along the CAPE gradient in the model. Click here to view SPC Storm Reports from 28-29 April.

The animation below shows ABI Infrared Imagery overlain on top of the forecast CAPE field. This drives home to point that convection on this day occurred where the gradient of CAPE was outlined/predicted by this forecast model.

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PHSnABI data will be demonstrated at the Hazardous Weather Testbed in late May/Early June. Model output is available outside of AWIPS at this website. To view more blog posts on this project, click the ‘Hyperspectral’ tag below.

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Conventional Meteorological Canon is that the Day Convection RGB, shown above in full-disk imagery from AWIPS (and because it’s Full Disk, the resolution is degraded to 6 km in both latitudinal and longitudinal directions), shows yellow in regions where cloud (ice) particle sizes are very small at the top of strong updrafts, and because they are small, there is much more reflectance of 3.9 µm solar radiation, so that the Day Fog Difference (3.9 µm – 10.3 µm), the green component of the RGB, acquires a very strong positive value. One of the Level 2 products derived from the Advanced Baseline Imager (ABI) is Cloud Particle Size Distribution (PSD). What does the PSD look like over that developing convection. This can be explored using the Satellite Information Familiarization Tool (SIFT).

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The toggle below shows the Day Convection RGB and the GOES-16 Level 2 Cloud Particle Size at 1700 UTC on 27 April 2022, with growing convection over the large island (Marajó) in the Amazon Delta. The Cloud Particle Size individually with a color bar is shown below as well.

Cloud Particle size values over the growing convection do appear to be smaller than in regions surrounding the growing convection. SIFT includes functionality to compare values within regions. The toggle below shows a small polygon — shaded in magenta — over the growing convection. The scatterplot beneath compares the Day Fog Difference and Cloud Particle Size within the polygon. Note that the Cloud Particle Size Distribution product is computed in daytime with ABI Bands 2 (0.64 µm) and 6 (2.25 µm) (ATBD).

The scatterplot above does suggest that Night Fog Brightness Temperature Difference fields — when large (which means where the Convection RGB will acquire a yellowish hue) — are related to Cloud Particle Size over the developing convection: smaller cloud particles are indicated where the Day Convection RGB is most yellow. There are other regions of yellow in the scene — and other regions of small particle size. Consider the region to the east, for example, as shown in the toggle below. Similar to the scene above, where the Brightness Temperature Difference is large, the Cloud Particle Sizes are small. A region-wide comparison (i.e., for the whole scene), is here.

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A 30-meter resolution Landsat-8 False Color image viewed using RealEarth (above) displayed thin filaments of ice (brighter shades of cyan) in far western Lake Superior, just off the northern coast of Wisconsin, on 27 April 2022. Chequamegon Bay in northern Wisconsin also had significant amounts of ice remaining from the winter months. Remnant snow cover (muted shades of cyan) was also apparent across much of northeastern Minnesota and parts of northern Wisconsin.

During the preceding overnight hours, a NOAA-20 VIIRS Advanced Clear-Sky Processing for Ocean (ACSPO) Sea Surface Temperature image around 0831 UTC (below) indicated that SST values were generally around 34^oF (darker blue enhancement) in the portion of the lake north of the ice filaments. Farther to the east, the West Superior Buoy 45006 was reporting a SST value of 33^oF at that time.

GOES-16 (GOES-East) True Color RGB images displayed using CSPP GeoSphere (below) showed that (1) the thin ice filaments just off the coast of Wisconsin were moving southwestward during the day, and (2) within Chequamegon Bay, significant ice fracturing began during the afternoon hours.

This ice filament motion and ice fracturing was the result of persistent northeasterly surface winds during the day, which gusted to 29 knots at Duluth Sky Harbor Airport (below).

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