25th Anniversary of the Oakfield, Wisconsin F5 tornado

July 18th, 2021 |

An F5 tornado struck the village of Oakfield, Wisconsin late in the day on 18 July 1996 (NWS Milwaukee story). An animation of GOES-8 (GOES-East) Visible images (below) showed the development of supercell thunderstorms as they moved east-southeastward across the area. Oakfield is located just southwest of Fond du Lac (KFLD), and is denoted by the yellow ‘+’ symbol on the images. Overshooting tops were evident on these thunderstorms.

GOES-8 Visible images [click to play animation | MP4]

GOES-8 Visible images [click to play animation | MP4]

The corresponding GOES-8 Infrared Window images (below) revealed cloud-top infrared brightness temperatures as cold as -63.6ºC (darker shades of red) at 2345 UTC, which was approximately 30 minutes prior to the tornado moving through Oakfield (the GOES-8 imager instrument was actually scanning the Oakfield area at 2348 UTC).

GOES-8 Infrared images [click to play animation | MP4]

GOES-8 Infrared images [click to play animation | MP4]

On a larger-scale view of GOES-8 Water Vapor images (below), a sharp gradient of warm-to-cool brightness temperature — orange/yellow to blue enhancement, portraying the gradient of dry air to moist air — highlighted the presence of a middle-tropospheric jet streak that was moving southeastward across the state.

GOES-8 Water Vapor images [click to play animation | MP4]

GOES-8 Water Vapor images [click to play animation | MP4]

Examples of Derived Product Images from the GOES-8 Sounder can be seen here.

GOES-15 temporarily brought out of storage

February 10th, 2021 |

Water Vapor images from GOES-17 (6.9 µm, left) and GOES-15 (6.5 µm, right) [click to play animation | MP4]

Water Vapor images from GOES-17 (6.9 µm, left) and GOES-15 (6.5 µm, right) [click to play animation | MP4]

Beginning on 06 February 2021, the GOES-15 satellite was brought out of storage for a 14-day period of imaging (as part of its annual checkout activities). On 10 February, a comparison of Water Vapor images from GOES-17 (6.9 µm) and GOES-15 (6.5 µm) showed mountain waves over southeastern Wyoming and central Colorado (above). This comparison helped to highlight some of the improvements in the GOES-R Series, such as

  •  improved spatial resolution with ABI Water Vapor (and other infrared) spectral bands — 2 km at sub-satellite point for GOES-17, vs 4 km at sub-satellite point for GOES-15
  •  improved temporal resolution — 5-minute image interval for GOES-17, vs 15-minute image interval for GOES-15 (except for 30-minute gaps every 3 hours, during Full Disk scans)
  • more stable image navigation

Multi-panel animations of GOES-15 images from the Imager and Sounder instruments are shown below (credit: Tim Schmit, NOAA/ASPB). In addition, there are animations of GOES-15 Visible and Infrared Window images.

GOES-15 Imager spectral bands [click to play animation | MP4]

GOES-15 Imager spectral bands [click to play animation | MP4]

GOES-15 Sounder spectral bands [click to play animation | MP4]

GOES-15 Sounder spectral bands [click to play animation | MP4]

GOES-15 data were downloaded, processed and archived by SSEC Satellite Data Services. Real-time GOES-15 imagery is temporarily available here: Imager | Sounder.

GOES-14 is brought out of storage

July 31st, 2019 |

GOES-14 Visible (0.63 µm) images [click to enlarge]

GOES-14 Visible (0.63 µm) images [click to enlarge]

GOES-14 was brought out of storage on 31 July 2019, for its annual week of Image Navigation and Registration (INR) testing and a North/South station-keeping maneuver — the first few hours of Full Disk Visible (0.63 µm) images are shown above. The SSEC Satellite Data Services group was able to position a spare rooftop antenna to receive the GOES-14 data during this test.

A closer look at the southwestern portion of Hudson Bay (below) revealed a large and anomalously-late area of First-year ice off the coast of Ontario.

GOES-14 Visible (0.63 µm) images [click to enlarge]

GOES-14 Visible (0.63 µm) images [click to enlarge]

In addition to the Imager, the GOES-14 Sounder is also operating. Recall that the sounder provides 18 infrared spectral bands and one visible band (below). A combined image showing both the Sounder and Imager bands has been generated.

Sample GOES-14 multi-spectral image

GOES-14 Sounder mult-spectral animation from August 1, 2019 [click to play animation]

GOES-14 Sounder imagery are being posted in near real-time during this annual test.

===== 01 August Update =====

GOES-14 Shortwave Infrared (3.9 µm) images [click to enlarge]

GOES-14 Shortwave Infrared (3.9 µm) images [click to enlarge]

GOES-14 Shortwave Infrared (3.9 µm) images (above) revealed the warm thermal anomaly or “hot spot” (darker red to black pixels) resulting from a natural gas explosion and fire in central Kentucky on 01 August (blog post).

Middle/upper-level deformation zone over the East Pacific Ocean?

May 23rd, 2017 |

GOES-15 Water Vapor (6.5 µm) images, with pilot reports of turbulence [click to play animation]

GOES-15 Water Vapor (6.5 µm) images, with pilot reports of turbulence [click to play animation]

An interesting linear feature appeared over the East Pacific Ocean on GOES-15 (GOES-West) Water Vapor (6.5 µm) images (above) on 23 May 2017, which at first glance immediately nominated it for the “What the heck is this?” blog category. A contrail was ruled out, since it was not oriented along a common or busy flight route — so potential large-scale dynamic processes were briefly investigated. Since the linear feature was perpendicular to the busy California/Hawaii flight route, pilot reports of turbulence are plotted on the water vapor images; two reports of light turbulence at altitudes of 33,000-34,000 feet (at 0918 and 1109 UTC) appeared to be close enough to have possibly been related to the linear feature.

GOES-15 Water Vapor (6.5 µm) images, with contours of satellite wind derived upper-level divergence [click to enlarge]

GOES-15 Water Vapor (6.5 µm) images, with contours of satellite wind derived Upper-Level Divergence [click to enlarge]

Satellite atmospheric motion vector (AMV) derived products such as Upper-Level Divergence (above) calculated at 3-hour intervals (source) revealed an area of divergence focused near the area of the linear satellite image feature — around 30º N, 140º W, at the center of the images — which reached its peak intensity at 12 UTC; this suggested that the feature may have formed along the axis of the sharp deformation zone between two upper-level lows over the East Pacific Ocean (mid/upper level winds | 200 hPa Vorticity product).

GOES-15 sounder Water Vapor (6.5 µm, top; 7.0 µm, middle; 7.5 µm, bottom) images [click to enlarge]

GOES-15 sounder Water Vapor (6.5 µm, top; 7.0 µm, middle; 7.5 µm, bottom) images [click to enlarge]

Unfortunately, this region was not within the view of Himawari-8 or GOES-16 (each of which provide 2-km resolution water vapor imagery at 3 atmospheric levels). However, the GOES-15 sounder instrument has 3 similar water vapor bands (above) — albeit at a more coarse 10-km spatial resolution at satellite sub-point — which showed the linear “deformation axis cloud signature” at all 3 levels of the atmosphere. The GOES-15 sounder water vapor weighting functions for a “typical” US Standard Atmosphere are shown below.

GOES-15 sounder Water Vapor band weighting functions [click to enlarge]

GOES-15 sounder Water Vapor band weighting functions [click to enlarge]