GOES-15 Rapid Scan Operations (RSO) sector for American Samoa

December 15th, 2015 |

GOES-15 Visible (0.63 µm) images [click to play animation]

GOES-15 Visible (0.63 µm) images [click to play animation]

On 15 December 2015 NOAA/NESDIS conducted a test of the new GOES-15 (GOES-West) Rapid Scan Operations (RSO) sector for coverage of the American Samoa region (SSD message). GOES-15 Visible (0.63 µm, 1-km resolution) images during the test period between 1711 and 1957 UTC are shown above, with plots of surface observations for Pago Pago (station identifier NSTU) and Faleolo (station identifier NSFA). Note that visible images from the Full Disk scan at 1800 UTC and Southern Hemisphere sectors at :22 past each hour are also included in the animation; during routine operations, there are periods when only 1 image per hour is available (from the Southern Hemisphere sector) which covers American Samoa.

The full size of the American Samoa RSO sector is shown below.

GOES-15 Visible (0.63 µm) image showing the size of the American Samoa RSO sector [click to enlarge]

GOES-15 Visible (0.63 µm) image showing the size of the American Samoa RSO sector [click to enlarge]

Displayed below is the American Samoa RSO sector is relation to the typical GOES-West Full Disk scan coverage.

GOES-15 Visible (0.63 µm) image showing the location of the American Samoa RSO sector in relation to the GOES-15 Full Disk scan coverage [click to enlarge]

GOES-15 Visible (0.63 µm) image showing the location of the American Samoa RSO sector in relation to the GOES-15 Full Disk scan coverage [click to enlarge]

The American Samoa RSO sector images were also successfully broadcast over the Satellite Broadcast Network (SBN) for display in AWIPS II; a sample GOES-15 Infrared (10.7 µm, 4-km resolution) image is shown below.

GOES-15 Infrared (10.7 µm) image, displayed using AWIPS II [click to enlarge]

GOES-15 Infrared (10.7 µm) image, displayed using AWIPS II [click to enlarge]

As a preview to the upcoming GOES-R series of satellites, we can examine JMA Himawari-8 Visible (0.64 µm, 0.5 km resolution) images for the same 3-hour time period, as seen below (sun glint over the open water is high during this time of day, due to the sun-satellite geometry of Himiwari-8 positioned at 140º East longitude). The images are available from the AHI instrument every 10 minutes, and show the development of organized clusters of convection just north and south of the larger islands of Samoa and Apia. Remote locations such as American Samoa will receive similar images every 5 minutes from the ABI instrument on GOES-R/S/T.

Himawari-8 Visible (0.64 µm) images [click to play animation]

Himawari-8 Visible (0.64 µm) images [click to play animation]

Bore-like Gravity Wave Signatures over Texas

December 15th, 2015 |

GOES-13 Visible (0.63 µm) images [click to play animation]

GOES-13 Visible (0.63 µm) images [click to play animation]

GOES-13 (above) and GOES-15 (below) both captured the propagation of gravity waves that displayed Bore-like attributes along an inversion with a cold front over central Texas. (Click here for an animation of GOES-13 and GOES-15 side-by-side that includes observed surface winds).

GOES-15 Visible (0.63 µm) images [click to play animation]

GOES-15 Visible (0.63 µm) images [click to play animation]

There was a temperature drop across the front, and modest wind gusts occurred just after the lowest pressure associated with the feature passed, but those gusts occurred only in a narrow corridor in central Texas: KSNK (Snyder) reported gusts of 14 knots (0925 UTC); KSWW (Sweetwater) reported gusts of 15 knots (1035 UTC); KABI (Abilene) reported gusts to 17 knots (1152 UTC); KBWD (Brownwood) reported gusts to 24 knots at 1335 UTC; KMKN (Comanche) reported gusts of 22 knots at 1355 UTC (See also the image below). The narrowness of this corridor is likely related to the strength of the inversion along which the bore is propagating (The 1200 UTC Soundings from Fort Worth and from Del Rio both show a very strong inversion; perhaps there was a weakness in the inversion over central Texas that allowed for more vertical mixing).

GOES-13 Visible (0.63 µm) imagery at 1400 UTC; Station Locations are indicated, including the 5 stations with identifiable Wind Gusts associated with the Bore Feature [click to enlarge]

GOES-13 Visible (0.63 µm) imagery at 1400 UTC; Station Locations are indicated, including the 5 stations with identifiable Wind Gusts associated with the Bore Feature (Gust Strength in knots and time of Gust indicated) [click to enlarge]

During the preceding nighttime hours, the early stage of the undular bore feature was detected on an Aqua MODIS Water Vapor (6.7 µm) image, below, along the leading edge of the colder air and colder surface brightness temperatures (light to medium blue colors) seen on the corresponding MODIS Infrared (11.0 µm) image at 0807 UTC or 2:07 am local time.

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

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

(Hat tip to Mike Johnson, NWS in San Angelo for tweeting about this feature!)