Cold air advection in the Bering Sea

January 5th, 2021 |

GOES-17

GOES-17 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-17 (GOES-West) “Red” Visible (0.64 µm) images (above) displayed cloud streets across the Bering Sea — cloud features that frequently occur in areas with a strong flow of cold air over warmer water. This northerly flow of cold air across the Bering Sea was due to a strong pressure gradient between high pressure over Siberia and broad low pressure centered over the Gulf of Alaska (surface analyses).

In a GOES-17 Visible image with plots of ASCAT scatterometer surface winds from Metop-A (below), ASCAT sampled winds with speeds as high as 33 knots (although the instrument did not adequately sample the western portion of the Bering Sea, where the strongest winds likely existed).

GOES-17 "Red" Visible (0.64 µm) image, with plots of Metop-A ASCAT winds [click to enlarge]

GOES-17 “Red” Visible (0.64 µm) image, with plots of ASCAT winds from Metop-A [click to enlarge]

A sequence of Suomi NPP VIIRS Day/Night Band (0.7 µm) images (below) provided higher-resolution views of the cold air advection cloud streets.

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

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

A toggle between Suomi NPP VIIRS Day/Night Band (DNB) and GOES-17 Visible images around 2320 UTC (below) highlighted the advantage of  VIIRS DNB imagery at high latitudes, particularly during low-light periods of the winter season.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and GOES-17

Suomi NPP VIIRS Day/Night Band (0.7 µm) and GOES-17 “Red” Visible (0.64 µm) images [click to enlarge]

GOES-R Fog/Low Stratus products are in RealEarth

January 5th, 2021 |

RealEarth instance of 1401 UTC GOES-16 IFR Probability fields, 5 January 2021, over the Mississippi River Valley (click to enlarge)

GOES-16 versions of the GOES-R Fog/Low Stratus products, such as IFR/Low IFR/Marginal VFR Probability fields, and GOES-R Cloud Thickness, are now available in RealEarth. These products are still available at the CIMSS GEOCAT site as well (link, for an image like this), but RealEarth offers pan, zoom and overlay capabilities. The RealEarth image from 1401 UTC on 5 January is shown above; the same time image from AWIPS is shown below. This link shows a more recent image in RealEarth.

AWIPS Screen Capture of IFR Probability and surface observations of ceilings and observations, 1401 UTC on 5 January 2020 (Click to enlarge)

GOES-17 IFR Probability will become available once that product is deemed Operational. Additional information on IFR Probability products is available at the Fog Blog.