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Eastern US winter storm

By Scott Bachmeier •

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and Near-Infrared “Snow/Ice” (1.61 µm, right) images, with plots of hourly surface reports [click to play MP4 animation]

The initial impacts of a large Eastern US winter storm were seen in a comparison of GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (above) on 03 January 2018 — areas of southeastern Georgia received freezing rain and/or 1-6 inches of snowfall. As clouds began to dissipate, the resulting snow cover appeared bright on the Visible images (since fresh snow is highly reflective at the 0.64 µm wavelength), and darker shades of gray on the Near-Infrared images (since snow and ice are strong absorbers of radiation at the 1.61 µm wavelength). Note the brief appearance of a cloud plume streaming southward from the Hatch Nuclear Power Plant.

Earlier that morning, the Florida Panhandle also received snowfall (text | map), but the lighter accumulations there were insufficient to exhibit a good satellite signature.

In a toggle between Suomi NPP VIIRS true-color and false-color Red-Green-Blue (RGB) images from RealEarth (below), the deeper snow cover in Georgia appears as darker shades of cyan.

Suomi NPP VIIRS true-color and false-color images [click to enlarge]

Suomi NPP VIIRS true-color and false-color images [click to enlarge]

===== 04 January Update =====

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

A toggle between Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 0620 UTC (1:20 AM Eastern time) on 04 January (above; courtesy of William Straka, CIMSS) showed a nighttime view of the rapidly-intensifying storm when it had an estimated minimum central pressure of 972 hPa or 28.70″. Note the signature of snow cover — extending from southeastern Georgia across eastern portions of South Carolina and North Carolina — which is evident on the “visible image at night” Day/Night Band (made possible by ample illumination from the Moon, which was in the Waning Gibbous phase at 92% of Full). A full-resolution version of the Day/Night Band image is available here.

During the following daytime hours, 30-second interval Mesoscale Sector GOES-16 “Red” Visible (0.64 µm) images (below) showed the evolution of the low pressure center of circulation as it continued to rapidly intensify (surface analyses) off the US East Coast.

30-second GOES-16

30-second GOES-16 “Red” Visible (0.64 µm) images [click to play MP4 animation]

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with hourly surface weather type plotted in yellow [click to play MP4 animation]

A larger-scale view (using 5-minute CONUS sector data) of GOES-16 “Red” Visible (0.64 µm) images with hourly plots of surface weather (above) depicted the widespread precipitation associated with the storm. Similarly, plots of hourly wind gusts (below) portrayed the large wind field of the system. Some of the highest snowfall/ice accumulations and peak wind gusts are listed here and here.

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with hourly surface wind gusts plotted in yellow [click to play MP4 animation]

In the wake of the departing storm, the tropospheric column over Florida and the southeastern US was dry enough (3.7 mm or 0.15″ at Tallahassee FL and 4.0 mm or 0.16 ” at Charleston SC) to allow the GOES-16 Lower-level (7.3 µm) Water Vapor imagery (below) to detect the thermal contrast of surface land/water boundaries — portions of the coastline and a few of the larger inland lakes were evident.

"GOES-16

(7.3 µm, left), Mid-level (6.9 µm, center) and Upper-level (6.2 µm, right) images [click to play animation]” class=”size-medium” /> GOES-16 Lower-level (7.3 µm, left), Mid-level (6.9 µm, center) and Upper-level (6.2 µm, right) images [click to play animation]

A full-resolution Suomi NPP VIIRS true-color RGB image at 1738 UTC (below) revealed interesting storm features such its very large cloud shield and convection near the circulation center, as well as the swath of snow cover across parts of Georgia, South Carolina and North Carolina.

Suomi NPP VIIRS true-color RGB image [click to enlarge]

Suomi NPP VIIRS true-color RGB image [click to enlarge]

A toggle between the corresponding Suomi NPP VIIRS Visible (0.64 µm) and Snow/Ice RGB images (below) helped to highlight locations which received a significant accrual of ice from freezing rain– these areas show up as a darker shade of red on the Snow/Ice RGB image (along the southeastern edge of the swath of snow cover, which is a lighter shade of red). Notable ice accumulations included 0.50″ at Brunswick and Folkston GA, 0.25″ at Georgetown and Myrtle Beach SC, and 0.25″ at Kure Beach NC.

Suomi NPP VIIRS Visible (0.64 µm) and Snow/Ice RGB images, with surface station identifiers plotted in white [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Snow/Ice RGB images, with surface station identifiers plotted in white [click to enlarge]

Finally, a 30-meter resolution Landsat-8 false-color RGB image viewed using RealEarth (below) showed the snow-covered Charleston, South Carolina area — areas with less dense trees and vegetation showed a more pronounced snow cover signature (shades of cyan). The Charleston International Airport remained closed, due to snow and ice-covered runways.

Landsat-8 false-color RGB image [click to enlarge]

Landsat-8 false-color RGB image [click to enlarge]

Additional imagery of this explosive cyclogenesis event can be found at this blog post.

Categories: GOES-16, RealEarth, Red-Green-Blue (RGB) images, Suomi NPP, VIIRS, Winter weather