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NOAA-20 detection of flooding over California

The Community Software Processing Package (CSPP) includes Flood Detection algorithms that can be applied to VIIRS data at Direct Broadcast sites (such as at CIMSS). The daytime NOAA-20 orbit over California on 22 January 2023 overflew mostly clear skies, resulting in the True Color and False Color imagery shown above, and the diagnosed regions of floods, mainly in the Sacramento and San Joaquin... Read More

NOAA-20 VIIRS True Color, False Color, and Flood Detection, 2031 UTC on 22 January 2023 (Click to enlarge)

The Community Software Processing Package (CSPP) includes Flood Detection algorithms that can be applied to VIIRS data at Direct Broadcast sites (such as at CIMSS). The daytime NOAA-20 orbit over California on 22 January 2023 overflew mostly clear skies, resulting in the True Color and False Color imagery shown above, and the diagnosed regions of floods, mainly in the Sacramento and San Joaquin River basins. Note that flooding in these two river basins can also be a result of agricultural diversions to support rice farming. So a good question is: Was the water put there intentionally — or did it flood? The modest flood signal in the Salinas River basin (south and east of Salinas) is more likely actual flooding.

These images were created using geotiff images from CSPP that were inserted into Google Earth and are courtesy Kathy Strabala, SSEC/CIMSS. VIIRS flood imagery (including imagery displayed in concert with ABI and AHI data) are also available here.

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Industrial plumes producing light snow in Wisconsin

GOES-16 (GOES-East) Near-Infrared “Snow/Ice” (1.61 µm) images (above) displayed industrial plumes (from sources such as power plants) that produced brief periods of light snow as they drifted over a few sites in northern Wisconsin on 22 January 2023. Particles emitted from industrial stacks acted as cloud condensation nuclei, “seeding” the surrounding supercooled water cloud... Read More

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm) images, with and without plots of hourly surface reports [click to play animated GIF | MP4]

GOES-16 (GOES-East) Near-Infrared “Snow/Ice” (1.61 µm) images (above) displayed industrial plumes (from sources such as power plants) that produced brief periods of light snow as they drifted over a few sites in northern Wisconsin on 22 January 2023. Particles emitted from industrial stacks acted as cloud condensation nuclei, “seeding” the surrounding supercooled water cloud droplets which then created a higher concentration of smaller cloud droplets — and these smaller cloud droplets were more efficient reflectors of incoming solar radiation, making the plumes appear slightly brighter than the surrounding clouds.

GOES-16 Day Snow-Fog RGB images (below) provided a bit more cloud-top contrast, helping to slightly enhance the appearance of the industrial plumes.

GOES-16 Day Snow-Fog RGB images, with and without plots of hourly surface reports [click to play animated GIF | MP4]

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30-second imagery of mountain waves over the Mid-Atlantic states

Overlapping 1-minute Mesoscale Domain Sectors provided GOES-16 (GOES-East) imagery at 30-second intervals over the Mid-Atlantic states on 20 January 2023 — and Mid-level Water Vapor (6.9 µm) images (above) revealed widespread mountain waves east of the Appalachians (produced by strong westerly flow interacting with the terrain). There were numerous pilot reports of light to moderate... Read More

GOES-16 Mid-level Water Vapor (6.9 µm) images, with pilot report (PIREP) plots of turbulence [click to play MP4 | animated GIF]

Overlapping 1-minute Mesoscale Domain Sectors provided GOES-16 (GOES-East) imagery at 30-second intervals over the Mid-Atlantic states on 20 January 2023 — and Mid-level Water Vapor (6.9 µm) images (above) revealed widespread mountain waves east of the Appalachians (produced by strong westerly flow interacting with the terrain). There were numerous pilot reports of light to moderate turbulence associated with these mountain waves.

The 1200 UTC Water Vapor image with plots of rawinsonde sites (below) indicated that Sterling, Virginia KLWX (which replaced the Washington-Dulles site KIAD) was located within the region of drier air where mountain waves were prevalent at that time.

GOES-16 Mid-level Water Vapor (6.9 µm) image at 1200 UTC, showing the locations of rawinsonde sites [click to enlarge]

Plots of GOES-16 Water Vapor spectral band (08, 09 and 10) weighting functions calculated using 1200 UTC rawinsonde data from Washington-Dulles, Virginia (KIAD) are shown below — due to the presence of dry air throughout the middle and upper troposphere over that location (Skew-T plot), the water vapor weighting functions were shifted to lower altitudes; the peak of the 6.9 µm (Band 09) weighting function was at the 617.5 hPa pressure level, with significant upwelling radiation contributions originating from as low as the 700 hPa level.

Plots of GOES-16 Water Vapor spectral band (08, 09 and 10) weighting functions, calculated using 1200 UTC rawinsonde data from Sterling, Virginia (KIAD) [click to enlarge]

30-second GOES-16 “Red” Visible (0.64 µm) images are shown below.

GOES-16 “Red” Visible (0.64 µm) images, with pilot report (PIREP) plots of turbulence [click to play MP4 | animated GIF]

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Disturbed weather in the tropics near American Samoa

GOES-18 Clean window infrared imagery (10.3 µm, displayed at full resolution in a special sector over American Samoa, in the latest AWIPS build) shows an area of convection, within a region of abundant moisture (GOES-18 Total Precipitable water values are close to 2.5″), approaching the Samoan islands (that are located... Read More

GOES-18 Clean Window infrared (10.3 µm) imagery along with clear-sky estimates of Total Precipitable Water, 0920-1550 UTC on 20 January 2023 (click to enlarge)

GOES-18 Clean window infrared imagery (10.3 µm, displayed at full resolution in a special sector over American Samoa, in the latest AWIPS build) shows an area of convection, within a region of abundant moisture (GOES-18 Total Precipitable water values are close to 2.5″), approaching the Samoan islands (that are located in the center of this domain). The Pago Pago sounding from 1200 UTC on 20 January is shown below, (from this site), and it also shows moisture (2.15″) over the island. Moisture behind the remains of tropical cyclone Irene are affecting Fiji in this image (Heavy Rains/flooding warnings are occurring), and at the far western edge of the domain, high clouds associated with Invest 92P are apparent.

1200 UTC Skew-T/log p sounding at Pago Pago, 20 January 2023 (Click to enlarge)

GOES-18 Level 2 Total Precipitable Water is computed only where clear skies are present. Total Precipitable Water can also be estimated using microwave data; microwave-derived MIMIC total precipitable water fields are shown below. The cyclonic circulations of Irene (passing between New Caledonia and Fiji on 18-19 January) and the developing 92P (near New Caledonia at the end of the animation) are apparent.

MIMIC Total Precipitable Water fields, 0000 UTC on 16 January through 1200 UTC 20 January 2023 (Click to enlarge)

How likely is the tropical development of the disturbed weather over Samoa into a tropical cyclone? Wind shear values from the SSEC/CIMSS Tropical site, shown below, show a region of small shear over the Samoan islands, moving west with time. However, development is not anticipated; the chief threat for this region is likely persistent rains.

Wind shear (850 – 200 mb) over the south Pacific, 1500 UTC on 20 January 2023 (click to enlarge)

The area of disturbed weather (Invest 92P) between Australia and New Caledonia has a moderate to strong possibility of strengthening into a tropical storm, per the RSMC in Fiji, shown below (from this link).

Tropical Disturbance Advisory for 06F (Invest 92P) from Fiji RSMC, 1315 UTC on 20 January 2023 (Click to enlarge)

GOES-18 imagery in this blog post was created using a cloud instance of AWIPS from TOWR-S. Thank you!

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