Rapidly intensifying mid-latitude cyclone off the US East Coast

March 5th, 2016 |

GOES-13 Water Vapor (6.5 µm) images [click to play MP4 animation]

GOES-13 Water Vapor (6.5 µm) images [click to play MP4 animation]

An area of low pressure rapidly intensified off the US East Coast during the 04 March05 March 2016 period (surface analyses). GOES-13 (GOES-East) Water Vapor (6.5 µm) images (above; also available as a large 57 Mbyte animated gif) showed classic signatures of the various stages of strong mid-latitude cyclone development — most notably the formation of a well-defined comma head and dry slot. Even though the storm was well offshore, impacts near and along the coast included snowfall amounts as high as 6.7 inches at Princess Anne, Maryland, 5.0 inches at Montross, Virginia, and 2.6 inches at Topsfield, Massachusetts; winds gusted to 55 mph at Jennettes Pier, North Carolina and 53 mph at Nantucket, Massachusetts. In Newfoundland, Gander received 17.3 inches of snow, and winds gusted to 77 mph at Cape Pine.

Aqua MODIS Water Vapor (6.7 µm), Infrared (11.0 µm), and Visible (0.65 µm) images [click to enlarge]

Aqua MODIS Water Vapor (6.7 µm), Infrared (11.0 µm), and Visible (0.65 um) images [click to enlarge]

Aqua MODIS Water Vapor (6.7 µm), Infrared Window (11.0 µm), and Visible (0.65 µm) images at 1737 UTC (above) and Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images at 1722 UTC (below) showed the storm around the time the Ocean Prediction Center indicated that it began producing hurricane force winds (18 UTC analysis).

Suomi NPP VIIRS Visible (0.64 µm) and Infrared (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Infrared (11.45 µm) images [click to enlarge]

A sequence of POES AVHRR Infrared (12.0 µm) images at 1852, 2205, and 0100 UTC along with Metop ASCAT surface scatterometer winds (below) showed the storm as it continued to intensify. Even though AWIPS labeled the ASCAT winds with a time stamp of 0228 UTC, cursor sampling found winds as strong as 57 knots south of the storm center and 59 knots north of the storm center at 0155-0156 UTC.

POES AVHRR Infrared (12.0 µm) images at 1852, 2205, and 0100 UTC, with Metop ASCAT winds at 0155 UTC [click to enlarge]

POES AVHRR Infrared (12.0 µm) images at 1852, 2205, and 0100 UTC, with Metop ASCAT winds at 0155 UTC [click to enlarge]

The Ocean Prediction Center posted an animation of Geocolor images of the storm on Twitter:


Aircraft “hole punch” and “dissipation trails” over the eastern Great Lakes

March 3rd, 2016 |

GOES-13 (GOES-East ) Visible (0.63 µm) images centered over Lake Erie, Lake Ontario, and central New York state (below) showed a variety of aircraft “hole punch” and “dissipation trails” over the eastern Great Lakes on 03 March 2016.

GOES-13 Visible (0.63 µm) images, centered over Lake Erie [click to enlarge]

GOES-13 Visible (0.63 µm) images, centered over Lake Erie [click to play animation]

GOES-13 Visible (0.63 µm) images, centered over Lake Ontario [click to play animation]

GOES-13 Visible (0.63 µm) images, centered over Lake Ontario [click to play animation]

GOES-13 Visible (0.63 µm) images, centered over New York state [click to play animation]

GOES-13 Visible (0.63 µm) images, centered over New York state [click to play animation]

These cloud features were caused by aircraft that were either ascending or descending through layers of cloud composed of supercooled water droplets, which covered much of the region as shown by the POES AVHRR Cloud Type product at 1545 UTC (below). Cooling from wake turbulence (reference) and/or the particles from the jet engine exhaust acting as ice condensation nuclei cause the small water droplets to turn into larger ice crystals (which then often fall from the cloud layer, creating “fall streak holes“). Similar features have been discussed in previous blog posts.

POES AVHRR Cloud Type product at 1545 UTC [click to enlarge]

POES AVHRR Cloud Type product at 1545 UTC [click to enlarge]

There were numerous pilot reports of light to moderate icing between FL120 and FL160 (flight level 12,000-16,000 feet) when passing through the supercooled water droplet cloud layers (below). The pilot report altitudes agree well with the POES AVHRR Cloud Top Height product values of 4-5 km over Lake Erie at 1545 UTC.

GOES-13 Visible (0.63 µm) images with pilot reports of icing [click to play animation]

GOES-13 Visible (0.63 µm) images with pilot reports of icing [click to play animation]

A comparison of 250-meter resolution Terra MODIS true-color and false-color Red/Green/Blue (RGB) images at 1649 UTC as visualized using RealEarth (below) indicated that the cloud material in the center of the aircraft dissipation trail over the north shore of Lake Erie had glaciated (snow, ice, and ice crystal clouds exhibit a darker cyan appearance on the false-color image).

Terra MODIS true-color and false-color images over Lake Erie [click to enlarge]

Terra MODIS true-color and false-color images over Lake Erie [click to enlarge]

A panorama photo from the ground was taken in Binghamton, New York (station identifier KBGM, located near the center of the New York GOES-13 images):