1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Clean” Infrared Window (10.35 µm) and “Red” Visible (0.64 µm) images (above) showed Tropical Storm Eta as it began to move across the Florida Straits after 15 UTC on 08 November 2020. Deep convection began to develop across far southern Florida around 02 UTC on 09 November, just north of Eta’s broad circulation center — and the tropical storm made landfall in the Florida Keys at 0400 UTC. The strongest wind gusts were found to the north/northeast of the storm.

Maps of Sea Surface Temperature and Ocean Heat Content from the CIMSS Tropical Cyclones site (above) indicated that Eta was moving over warm water (SST around 28ºC, and a pocket of modest OHC) north of Cuba. GOES-16 Longwave Infrared (11.2 µm) images, with contours of 02 UTC deep-layer wind shear (below) showed that the hurricane was moving through an environment of moderate southwesterly shear, which limited intensification.

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The CIMSS Direct Broadcast site is now routinely creating True-Color imagery over 6 different domains: The Great Lakes, and each of the 5 individual lakes: Superior, Huron, Michigan, Erie, Ontario (Click on each image to see the domain). File name examples are shown here. Suomi NPP and NOAA-20 are in similar orbits, about 50 minutes apart, so it’s common to be able to create an animation, as shown below with Lake Erie. Note that the colors in the toggle below, and in the Basin-wide toggle above, can show differences because of view angles. In particular, the slanted view angle over Lakes Michigan and Superior in the 1729 UTC Suomi-NPP image in the toggle above allows for the true-color imagery to show a thin layer of smoke over portions the those lakes.

If NOAA-20 or Suomi-NPP only samples part of the lake, then a partial image is created, as shown below from NOAA-20 pass viewing Lake Ontario at 1639 UTC on 4 November. (NOAA-20 viewed the entirety of Lake Ontario at 1818 UTC).

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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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