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MIRS Rain Rate from Direct Broadcast

CSPP software processes signals at Direct Broadcast antenna sites to create products and imagery with very low latency from Low-Earth Orbit (LEO) satellites. The software includes Microwave Integrated Retrieval System (MIRS) algorithms, including rain rate (available here). How well does that product do in capturing observed precipitation? The toggle above shows... Read More

GOES-16 Band 13 (Clean Window, 10.3) infrared imagery with ATMS Rain Rate overlain, 1750 UTC on 13 February 2023 (Click to enlarge)

CSPP software processes signals at Direct Broadcast antenna sites to create products and imagery with very low latency from Low-Earth Orbit (LEO) satellites. The software includes Microwave Integrated Retrieval System (MIRS) algorithms, including rain rate (available here). How well does that product do in capturing observed precipitation? The toggle above shows GOES-16 Clean Window infrared imagery and derived rain rates (derived from microwave data). The back edge of the precipitation is captured well by the MIRS product, and several heavier bands of precipitation offshore are also suggested. This product is especially useful in the absence of any radar.

How does the rain rate compare to the radar at the same time? The image below (from the College of DuPage website) shows Mosaic Reflectivity at 1750 UTC on 13 February. The back edge of the precipitation in the radar shows agreement with the Rain Rate shown in the toggle above (or here).

Composite Reflectivity from the COD website, 1750 UTC on 13 February 2024 (click to enlarge)

The side-by-side comparison, below, highlights detected features. The precipitation band circled in purple appears in both Rain Rate and Radar imagery. The heavier precipitation regions to the east, highlighted by the blue arrows, does not appear in the radar, and highlights an advantage of MIRS Rain Rate: it provides information where radar data are not available.

MIRS Rain Rate (left) and NEXRAD Radar Mosaic, 1750 UTC on 13 february 2024 (Click to enlarge)

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Wind, Storms, and Gales in Alaska

On February 12, 2024, much of inland Alaska is experiencing warnings for wintery precipitation, while coastal Alaska is under warnings for storms, gales, and heavy freezing spray. Southeastern Alaska is also under a small craft advisory.The low-pressure system associated with this inclement weather is seen easily from the GOES-West imagery.... Read More

On February 12, 2024, much of inland Alaska is experiencing warnings for wintery precipitation, while coastal Alaska is under warnings for storms, gales, and heavy freezing spray. Southeastern Alaska is also under a small craft advisory.

Figure 1: Hazards issued by the National Weather Service for Alaska on 2024-02-12.

The low-pressure system associated with this inclement weather is seen easily from the GOES-West imagery. Viewers can see a large hook-shaped rotational system swooping in from the south and affecting much of the state. Figure 2 shows Band 9, the mid-level water vapor channel, from GOES-West, illustrating the low pressure system nicely. On the GOES-West Advanced Baseline Imager (ABI), Band 9 is centered on 6.9 µm and is great for tracking storm systems.

Figure 2: An animation of GOES-West Band 9 imagery from 2024-02-12 at 1430Z to 2024-02-12 at 2030Z. Viewers can recreate this animation using RealEarth.

Expectedly, the weather is having unfavorable effects on aviation safety. Marginal visual flight rules (MVFR) cite weather conditions that aircraft pilots can experience at land or ocean surface levels. As seen in Figure 3, satellite and model-derived MVFR probabilities are present throughout inland and coastal areas of Alaska.

Figure 3: An animation of GOES-West MVFR probability from 2024-02-12 at 1430Z to 2024-02-12 at 2030Z. Viewers can recreate this animation using RealEarth.

The animations in this post are replicable for anyone with web access, using RealEarth. RealEarth is a free weather visualization application. To recreate the animations you see in this post, click the links in the animation captions.

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Satellite signatures of a SpaceX Falcon 9 rocket launch from California

1-minute Mesoscale Domain Sector GOES-18 (GOES-West) images from all 16 of the ABI spectral bands in addition to a Rocket Plume RGB (above) displayed signatures of a SpaceX Starlink Mission Falcon 9 rocket that was launched from Vandenberg Space Force Base, California at 0034 UTC on 10 February or 4:34 PM Pacific Time on 09 February 2024. A warm thermal signature of... Read More

1-minute GOES-18 images of ABI spectral bands 01-16 and a Rocket Plume RGB, from 0033-0048 UTC on 10 February [click to play animated GIF | MP4]

1-minute Mesoscale Domain Sector GOES-18 (GOES-West) images from all 16 of the ABI spectral bands in addition to a Rocket Plume RGB (above) displayed signatures of a SpaceX Starlink Mission Falcon 9 rocket that was launched from Vandenberg Space Force Base, California at 0034 UTC on 10 February or 4:34 PM Pacific Time on 09 February 2024. A warm thermal signature of the Stage 1 rocket booster was evident in images from most of the Near-Infrared and Infrared spectral bands (Bands 04-16) and the RGB imagery as it quickly moved east-southeastward from the launch site — and either a somewhat bright reflectance signature or a relatively cool thermal signature of the Stage 1 rocket booster condensation cloud was seen in most of the spectral bands as it drifted slowly southward.

In a toggle between Upper-level Water Vapor (6.2 µm) images from GOES-16 (GOES-East) and GOES-18 (GOES-West) at 0036 UTC, both remapped to a common projection (below) note the large offset in apparent location of the Falcon 9 vapor trail — this is due parallax, which was significant due to (1) the altitude of the rocket’s vapor plume at that time, which was around 45 km and (2) the difference between satellite viewing angle magnitude (62.34 degrees for GOES-16 vs. 43.82 degrees for GOES-18) and direction.

Upper-level Water Vapor (6.2 µm) images from GOES-16 and GOES-18, at 0036 UTC on 10 February [click to enlarge]

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Turbulence near the axis of a strong subtropical jet stream

GOES-16 (GOES-East) Upper-level Water Vapor (6.2 µm) images that included plots of Derived Motion Winds along with Pilot Reports (PIREPs) of turbulence (above) showed that there was widespread turbulence in the general vicinity of the axis of an anomalously-strong subtropical jet stream moving across the US on 09 February 2024. Wind speeds along the axis... Read More

GOES-16 Upper-level Water Vapor (6.2 µm) images with plots of Derived Motion Winds (red), Pilot Reports of Light to Moderate turbulence (blue) and Severe turbulence (bold red), from 0801-2201 UTC on 09 February [click to play animated GIF | MP4]

GOES-16 (GOES-East) Upper-level Water Vapor (6.2 µm) images that included plots of Derived Motion Winds along with Pilot Reports (PIREPs) of turbulence (above) showed that there was widespread turbulence in the general vicinity of the axis of an anomalously-strong subtropical jet stream moving across the US on 09 February 2024. Wind speeds along the axis of the subtropical jet were 180-190 knots, with embedded jet streak maxima around 200 knots (RAP40 model MaxWind isotachs at 1500 UTC). A Derived Motion Wind speed of 202 knots was sampled over SW Missouri at 1031 UTC.

There were 4 pilot reports of Severe turbulence during the 14-hour period shown above: over Kentucky around 1026 UTC, over Virginia around 1500 UTC, over Oklahoma around 1700 UTC and over Illinois at 2144 UTC. According to GOES-16 Derived Motion Winds, speed shear was notable in the vicinity of those cases of Severe turbulence: 1501 UTC | 1701 UTC | 2146 UTC.

GOES-16 Upper-level Water Vapor images with contours of Moderate or Greater (MOG) Turbulence Probability within the 38-41 kft layer (below) depicted intermittent pockets of 33% (green) to 50% (yellow) probability along or near the axis of the subtropical jet — and the 2 high-altitude (41-43 kft) Severe turbulence PIREPs occurred in the general proximity of MOG Probability contours in the 33-50% range (1701 UTC | 2146 UTC).

GOES-16 Upper-level Water Vapor (6.2 µm) images with contours of Turbulence Probability within the 38-41 kft layer, from 0801-2201 UTC on 09 February [click to play animated GIF | MP4]

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