GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed a narrow northwest-to-southeast oriented swath of snow cover across far northwestern Pennsylvania on 04 November 2020. With full sunshine and strong southerly winds helping air temperatures warm into the 60s F, this narrow band of snow cover melted by the end of the day. This lake effect snowfall event occurred late in the day on 01 November; lake surface water temperatures across interior Lake Erie (below) were as warm as the middle 50s F (brighter green color enhancement).

The lake effect snow cover was more apparent in GOES-16 True Color Red-Green-Blue (RGB) images created using Geo2Grid (below) — a 2-day animation covering the daytime hours on 03-04 November showed how quickly much of this snow cover melted on 03 November, with a narrow swath (where 6-12 inches of snowfall occurred) persisting into 04 November. In addition, a thin ribbon of fog in parts of the Allegheny River valley was apparent right after sunrise on 04 November, which quickly dissipated with the onset of daytime heating. The melting remains of the band are also apparent on 4 November in this toggle of VIIRS True Color imagery (from this blog post)

We’re seeing a nice plume of lake-effect snow across Crawford County and into Venago. We’d love to get some snow reports from the Cooperstown/Franklin/Oil City area! pic.twitter.com/tPiR6zYqGP

— NWS Pittsburgh (@NWSPittsburgh) November 2, 2020

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1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Clean” Infrared Window (10.35 µm), GLM Flash Extent Density and “Red” Visible (0.64 µm) images (above) showed Hurricane Eta as it was rapidly intensifying from a Category 2 to a Category 4 storm on 02 November 2020. For a few hours there was notable lightning activity within the inner eyewall of Eta.

GOES-16 Longwave Infrared (11.2 µm) images, with contours of 02 UTC deep-layer wind shear from the CIMSS Tropical Cyclones site (below) showed that the hurricane was moving through an environment of low shear, which favored intensification.

GOES-16 Infrared – Water Vapor Brightness Temperature Difference images (below) indicated that cloud tops within much of the central dense overcast surrounding the eye were likely above the local tropopause.

===== 03 November Update =====

A toggle between NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (above) displayed Eta at 0729 UTC. Illumination from the Moon — in the Waning Gibbous phase, at 93% of Full — provided a distinct visible image at night.

Eta made landfall along the Caribbean coast of Nicaragua as a Category 4 hurricane around 2100 UTC;1-minute GOES-16 Infrared and Visible images during the period 1000-2100 UTC (below) showed that the overall appearance of Eta had deteriorated somewhat compared to the previous day, with warming cloud-top infrared brightness temperatures and a cloud-filled eye. There was no GOES-16 GLM-detected lightning activity during those 11 hours leading up to landfall.

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1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) and Dust Red-Green-Blue (RGB) images (above) showed the signature of a plume of re-suspended volcanic ash — originating from the region of the Novarupta volcano in Alaska — being transported southeastward across the Shelikof Strait toward Kodiak Island on 02 November 2020. The 1912 eruption of Novarupta left a very deep deposit of volcanic ash, which occasionally gets lofted by strong northwesterly terrain-enhanced winds in the Autumn months (before snowfall covers the ash). Another interesting aspect was a mesolow which had formed in the Shelikof Strait — it appeared as if some of the ash plume was becoming entrained into the western edge of the mesolow’s circulation. Note that Buoy 46077 was located near the center of this meslow, which led to frequent changes in the wind direction.

VIIRS True Color RGB images from NOAA-20 and Suomi NPP viewed using RealEarth (below) provided 2 high-resolution snapshots of the ash plume. The tan-colored surface source region of the Novarupta ash was evident in these True Color images.

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Typhoon Goni hit the Phillipines as a major typhoon on 31 October.  Since then, an increase in shear and the topography of Luzon have both weakened the storm significantly.   The mp4 animation above (click here as an mp4) shows 2.5-minute Himawari-8 Target imagery Infrared (10.41 µm, left) and visible (0.64 µm, right) imagery from 0122 through 1352 UTC on 2 November.  Although significant convection continues, especially after dark near the center, suggesting strengthening, strong easterly shear, shown below, from this website, is present.  Convection in the animation above is displaced to the west of the surface circulation, as expected given the shear.  In addition, sea surface temperatures become progressively cooler along the projected track.  Environmental factors do not favor significant strengthening.

A two-day animation of MIMIC Total Precipitable water (imagery from this ftp site) shows the change in circulation as Goni moved over Luzon.

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