Stratus and fog along the US East Coast

March 23rd, 2021 |

GOES-16 Cloud Thickness and

GOES-16 Cloud Thickness and “Red” Visible (0.64 µm) images, with plots of Ceiling and Visibility [click to play animation | MP4]

GOES-16 (GOES-East) nighttime Cloud Thickness and daytime “Red” Visible (0.64 µm) images (above) displayed a narrow band of marine stratus/fog that was moving southward along the East Coast of the US on 23 March 2021. Plots of Ceiling and Visibility showed that some sites along the coasts of New York, New Jersey and Delaware experienced a reduction in visibility to 1/4 mile at times. The Cloud Thickness product (a component of the Fog/Low Stratus suite) indicated that portions of this feature were 350-400 meters (1150-1300 feet) thick.

With ample illumination from the Moon — which was in the Waxing Gibbous phase, at 68% of Full — a NOAA-20 VIIRS Day/Night Band (0.7 µm) image at 0600 UTC or 2:00 am EDT (below) showed the stratus/fog feature as it was beginning to moved southward along the DelMarVa coast.

NOAA-20 VIIRS Day/Night Band (0.7 ) image [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) image [click to enlarge]

Freezing fog in the Carolinas and Virginia

January 13th, 2021 |

GOES-16 Nighttme Microphysics, Night Fog BTD (10.3-3.9 µm) and Cloud Thickness product [click to play animation | MP4]

GOES-16 Nighttime Microphysics RGB, Night Fog BTD (10.3-3.9 µm) and Cloud Thickness product [click to play animation | MP4]

GOES-16 (GOES-East) Nighttime Microphysics RGB, Night Fog BTD (10.3-3.9 µm) and Cloud Thickness product (above) showed an arc of relatively thin fog across northern South Carolina, eastern North Carolina and southeastern Virginia — which was becoming thicker/deeper in time during the hours leading up to sunrise on 13 January 2021. In areas where the Cloud Thickness increased to 400 meters or more (lighter shades of cyan), freezing fog was observed at nearby METAR sites.

GOES-16 Nighttime Microphysics RGB images with plots of surface observations (below) indicated that air temperatures were near or just below freezing at most sites across the region.

GOES-16 Nighttime Microphysics RGB images, with plots of surface observations [click to play animation | MP4]

GOES-16 Nighttime Microphysics RGB images, with plots of surface observations [click to play animation | MP4]

The band of fog over eastern North Carolina and southeastern Virginia was being pushed eastward by a lower-tropospheric trough, as shown by the NAM40 model 925 hPa wind field at 12 UTC (below).

GOES-16 Nighttime Microphysics RGB image, with a plot of NAM40 model 925 hPa winds at 12 UTC [click to enlarge]

GOES-16 Nighttime Microphysics RGB image, with a plot of NAM40 model 925 hPa winds at 12 UTC [click to enlarge]

After sunrise, GOES-16 “Red” Visible (0.64 µm) images (below) showed that most of the fog quickly dissipated across southeastern Virginia and eastern North Carolina, while thicker fog persisted over much of South Carolina.

GOES-16

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

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.

Fog/stratus in the Snake River Basin of Idaho

December 29th, 2020 |

GOES-17 Night Fog BTD and “Red” Visible (0.64 µm) [click to play animation | MP4]

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

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) Night Fog brightness temperature difference (BTD) and “Red” Visible (0.64 µm) images (above) showed the nighttime and daytime signature of a fog/stratus layer that had persisted throughout much of the Snake River Basin in southern Idaho on 29 December 2020. Some sites along the Interstate 84 corridor were reporting freezing fog — and the surface visibility was restricted to less than 1/4 mile at times in Boise (KBOI).

During the preceding nighttime hours, the extent of fog/stratus cloud within the Basin was well-illuminated by a nearly-full Moon (which was in the Waxing Gibbous phase, at 99% of Full) as seen in a Suomi NPP VIIRS image at 0856 UTC (below).

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

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