GOES-West Operational Interleave Round 2 began today, 10/13, at 1600 UTC, and is expected to continue through 11/16. See this blog post from Interleave Round 1 for more details and examples. To summarize what this means for NWS users: to mitigate impacts of the GOES-17 (currently operational GOES-West satellite) ABI cooling system issues during the Oct-Nov warm period, GOES-West ABI Imagery (single-band imagery, band differences, RGBs) is now from GOES-18. Other GOES-West products, such as from GLM, and ABI derived products (cloud products, TPW, DMWs, etc) remain from GOES-17.
Figures 1 and 2 capture the two hours prior to and two hours after the start of Interleave for Ch08 WV and Airmass RGB, respectively. The improvement of the imagery from GOES-17 to GOES-18, for these products, is obvious.
Winds gusting over 40 mph across southern Saskatchewan during the afternoon on 11 October 2022 resulted in lofted aerosols from localized regions becoming long and narrow plumes carried downstream into northeast Montana and northwest North Dakota. GOES-East 5-min Geocolor imagery captured these light gray colored plumes quite well as they were fairly opaque and their appearance contrasted nicely with otherwise brown/green surface (Fig 1). From the Geocolor alone, one could deduce these plumes were likely emanating from or near a lakebed. A quick look at the source lat/lons on google maps also reveals lakebeds.
Viewing these sources in recent high resolution Sentinel-2 True Color Imagery, we see from the high reflectance signature that these are indeed mostly to fully dry lakebeds, confirming the source of the lofted aerosols to be dry lakebed sediments (Fig 2 and 3).
Due to drought conditions across the region over the past few years, there has been a drying of saline lakes in the area resulting in these types of blowing salt-dust events. As a result, there have been numerous highway accidents due to reduced visibility, and cattle are getting sick and dying due to contamination of drinking water. This article from a month ago discusses an event that caused a multi-vehicle pile-up.
Strong winds continued across the region the next day (Oct 12), and resulting blowing dust salt was captured in GOES-East Meso-2 1-min sector (Fig 4).
Viewing a zoomed out, full disk version of GOES-East Geocolor, we notice smoke wrapping around a low as it advances east across Canada (Fig 5). Where did this smoke come from?
Investigation of Day and Night VIIRS Geocolor Imagery (with semi-transparent Fire Temperature RGB overlay) from the past few days captures the burst of a large wildfire complex in Northwest Territories, Canada (Fig 6). VIIRS Geocolor includes the real-time DNB light information as well, which provides detailed info about the active fire areas during the evening that wasn’t quite captured in the thermal bands. The image combination depicts both the actively burning wildfire as well as the smoke plume in great detail. This complex and other nearby fires were the source for the broad smoke plume observed wrapping around the Canada low on the 11th. This image combination can be viewed on the Polar SLIDER here.
Viewing the nighttime DNB NCC product alone during the past few nights, we see the light associated with the fire increase dramatically during the night of the 9th-10th (Fig 7).
Bill Line, NESDIS/STAR
Kyle Ziolkowski (ECCC/MSC/Storm Prediction Centre – Winnipeg)
On Saturday October 1st the remnants of Hurricane Ian were moving northward through the Mid-Atlantic region, after making a second U.S. landfall the previous day in South Carolina. Overnight, the SPC was monitoring the final stages of Ian’s extra-tropical transition with a marginal threat for severe weather in the coastal North Carolina/Virginia region.
One forecaster on shift that night was monitoring the remnants from the perspective of GOES-16, and noted how various ABI products could be used to examine cloud layers and types in this dynamic environment.
CH7 shortwave and CH13/15 longwave IR shows mainly the cooler cloud tops associated with high-level clouds. Low-level clouds can be inferred by the warmer temps (CH7) or weaker grey features in CH13/15. However, the NtM [Nighttime Microphysics] RGB composite satellite data neatly contrasts colder, high-level clouds (western PA westward and in a warm conveyer belt over the Atlantic) from the lower but cool clouds (North Carolina into Virginia) and the very low, warm clouds (southeast Pennsylvania into New Jersey and Delaware). Though buoyancy is scant and severe is not expected in this area, the NtM RGB composite’s ability to contrast cloud types in this event demonstrates potential to identify important cloud features related to severe weather.
SPC Forecaster Comment
When overlaid with the RAP mesoanalysis field at 500 mb, the Channel-13 (Clean Longwave IR) and Channel-7 (Shortwave IR) bands from the ABI reveal the higher, cooler cloud tops north of the low into Pennsylvania. The warm conveyor belt over the Atlantic coast can be seen in the 500 mb RAP mesoanalysis with enhanced southerly winds east of low, and from the ABI infrared imagery with a lack of high clouds due to upper level subsidence.
While these bands individually can be used to point out these features, the forecaster notes that the Nighttime Microphysics RGB allows them to more readily identify and monitor these cloud features from the tropical cyclone remnants at night. This is driven by the RGB’s ability to combine information from multiple ABI bands (7, 13, and 15) to provide qualitative information for forecasters regarding cloud types and heights.