* GOES-17 images shown here are preliminary and non-operational *

Beginning at 1530 UTC on 28 August 2018, GOES-17 data and imagery became available via the GOES Rebroadcast (GRB) distribution mechanism — and beginning at 1700 UTC via the Satellite Broadcast Network (SBN) that provides data to AWIPS (above). While images are available from all 16 of the ABI spectral bands, it is important to note that ABI cooling system issues will affect the image quality from certain bands during certain times.

GOES-17 Mid-level Water Vapor (6.9 µm) imagery is shown below.

A closer look using1-minute Mesoscale Domain Sector GOES-17 “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (below) showed ship tracks in the Pacific Ocean off the coast of Washington, Oregon and northern California. The ship tracks appear warmer in the 3.9 µm imagery because aerosols from the exhaust of ships cause a “cloud seeding effect”, which results in a higher concentration of smaller cloud droplets compared to the surrounding unperturbed marine boundary layer clouds. These smaller cloud droplets are more effective reflectors of sunlight, resulting in a warmer appearance (darker orange to red enhancement) on Shortwave Infrared images.

GOES-17 is currently positioned over the Equator at 89.5º West longitude during its checkout phase, but will eventually be moved to 137º West and become the operational GOES-West satellite later in 2018. The current coverage as viewed in the operational GOES-West perspective is shown below — Hawai’i and far southeastern Alaska appear in the limb of the satellite view.

However, Full Disk images in AWIPS are not available at full resolution; to get the best view of Alaska, for example, one must use imagery processed by software such as McIDAS. On this particular day, the peaks of Denali and the Alaska Range extended above the low-level clouds, and could be seen on the extreme limb of GOES-17 “Red” Visible (0.64 µm) imagery (below).

GOES-16 (GOES-East) is positioned at 75.2º West longitude — the western extent of its coverage is shown below. Hawai’i and Alaska (with the exception of the Alaska Panhandle) are not scanned by GOES-16.

View only this post Read Less

GOES-17 images shown here are preliminary and non-operational

The GOES Rebroadcast (GRB) is now transmitting GOES-17 data that remain Preliminary and non-operational.  The first data sent were at 1530 UTC on 28 August. The toggle above shows Bands 3 (“Veggie Band”, 0.86 µm) and Band 7 (“Shortwave Infrared”, 3.9 µm) from the Meso-1 sector that was positioned over the West Coast at 1607 UTC on 28 August 2018.  Band 13 (“Clean Window”, 10.3 µm), below, from the Meso-2 sector is over the High Plains.

Visible (Band 2, 0.64 µm) Imagery from 1531 UTC, below, was produced using CSPP Geo, a software package that reads the GRB signal and produces imagery. (Image courtesy Graeme Martin, CIMSS)

The Geo2Grid Software Package can be used with GRB output to produce True-Color imagery, as shown below. The full-disk image was created in about 8 minutes using a centOS server, and it is corrected for atmospheric and solar zenith angle effects. Green Band information is simulated from other ABI channels.

Full Disk examples of imagery from all 16 ABI bands (in addition to a Natural Color RGB image) are shown below (courtesy Mat Gunshor, CIMSS).

View only this post Read Less

 * GOES-17 images shown here are preliminary and non-operational *

A comparison of Visible images from GOES-15 (GOES-West), GOES-17 and GOES-16 (GOES-East) (above) showed a severe thunderstorm that developed ahead of an advancing cold front (surface analyses) in central South Dakota late in the day on 26 August 2018. This storm produced hail as large as 4.0 inches in diameter (SPC storm reports), and also exhibited an above anvil cirrus plume (AACP) which is a signature often associated with severe thunderstorms.

The images are displayed in the native projection of each satellite, with no re-mapping. Note the important differences due to satellite scan strategy — the GOES-15 imager was initially performing a Full Disk scan, so imagery was only available every 30 minutes; the GOES-17 ABI was scanning at the standard “CONUS Sector” 5 minute interval; a GOES-16 ABI Mesoscale Domain Sector was providing images every 1 minute.

View only this post Read Less

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (above; courtesy of William Straka, CIMSS) showed the eye of Hurricane Lane in the central Pacific Ocean at 1208 UTC on 22 August 2018, a few hours after it reached Category 5 intensity (SATCON). Surface mesovortices were evident within the eye, and storm-top gravity waves were seen propagating west-southwestward away from the eyewall.

 

A rare and sobering sight tonight in the Central Pacific, as Hurricane #Lane becomes only the 6th recorded Category 5 hurricane in this part of the Pacific, and the nearest to #Hawaii a Cat 5 hurricane has ever been observed. #hiwx pic.twitter.com/d8zLbVKjad

— Michael Lowry (@MichaelRLowry) August 22, 2018

GOES-15 (GOES-West) Infrared Window (10.7 µm) images (below) revealed a significant amount of trochoidal motion as Lane moved northwestward during the 21 August – 22 August period. The storm weakened somewhat to Category 4 intensity as of 15 UTC on 22 August.

Hurricane Lane was near the limb of the Full Disk view of both Himawari-8 and GOES-17, as seen in a comparison of “Red” Visible (0.64 µm) images from the two satellittes (below).

* GOES-17 images shown here are preliminary and non-operational *

DMSP-16/17 SSMIS Microwave (85 GHz) images from the CIMSS Tropical Cyclones site are shown  below.

Since forming as Tropical Depression 14E on 14 August. Lane had been moving westward over water having only modest Ocean Heat Content but Sea Surface Temperature values of 27-28ºC (below).

===== 23 August Update =====

Hurricane Lane remained at Category 4 intensity during the early hours of 23 August — however, the satellite presentation began to deteriorate as the eye became cloud-filled as seen in toggles between VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from NOAA-20 at 1150 UTC (above) and Suomi NPP at 1240 UTC (below). An interesting narrow “warm trench” signature became very pronounced within the northwestern quadrant of Lane on the later Suomi NPP Infrared image.

GOES-15 Visible (0.63 µm) and Infrared Window (10.7 µm) images after sunrise (above) showed that the eye of Lane moved over Buoy 51002 — located about 200 miles southwest of the Big Island of Hawai’i — just after 19 UTC (below). The peak wind gust measured by the buoy was 93 knots or 107 mph ay 1830 UTC; the lowest wind and air pressure values were recorded while in the eye from 1930-2110 UTC.

At 1703 UTC Buoy 51002 was located just west of the eye, beneath strong convection of the eyewall as seen on a DMSP-17 SSMIS Microwave (85 GHz) image (below).

A Suomi NPP VIIRS Day/Night Band (0.7 µm) image at 2334 UTC or 1:34 pm HST on 23 August is shown below.

===== 24 August Update =====

A Suomi NPP VIIRS Day/Night Band (0.7 µm) image (above) showed Category 3 Hurricane Lane at 1211 UTC or 2:11 am HST on 24 August. Thin tendrils of high-altitude transverse banding can be seen along the western and northern periphery of the storm.

GOES-15 Infrared Window (10.7 µm) images (below) showed the development of the transverse banding as Lane eventually weakened to a Category 1 storm during the course of the day; a rapid warming of the cloud-top infrared brightness temperatures began around 2100 UTC. Even though the Ocean Heat Content and Sea Surface Temperature in the waters immediately west of Hawai’i were still fairly high, the hurricane was moving into an environment of increasingly unfavorable deep-layer wind shear which acted to decouple the low-level and mid-level circulations and hasten the weakening process.

GOES-15 Visible (0.63 µm) images (below) provided a slightly closer look at the storm during the daylight hours.

A dramatic difference was seen between Suomi NPP VIIRS Day/Night Band images at 1211 UTC and 2315 UTC (below), as Lane weakened from a Category 3 to a Category 1 hurricane in this 11-hour period.In spite of the rapid weakening, very heavy rainfall continued across much of the State, with 24-hour amounts exceeding 20 inches at some locations on the Big Island of Hawai’i. Note that the Low-Level Circulation Center (LLCC) of Lane had become exposed on the later 2315 UTC image (in spite of a thin veil of cirrus overhead), and was located to the southwest of the rapidly-dissipating convection that was closer to the islands.

===== 25 August Update =====

On the islands, the highest wind gust associated with Lane was 74 mph — and storm total rainfall amounts greater than 50 inches were recorded, with Hilo setting a record 3-day accumulation of 31.85 inches and a record 4-day accumulation of 36.76 inches. Rainfall rates on the Big Island exceeded 19 inches in 24 hours on 23 July.

Hourly images of the MIMIC Total Precipitable Water (TPW) product during the period 22-25 August (below) showed the circulation of Lane transporting high amounts of moisture across the Hawaiian Islands. TPW values of 60 mm (2.4 inches) or more were also seen in rawinsonde data from Hilo on many of these days.

A toggle between Suomi NPP VIIRS Day/Night Band images from 24 August / 2315 UTC and 25 August / 1152 UTC (below) showed a slow north/northwestward motion of the exposed LLCC of what had further weakened to Tropical Storm Lane.

View only this post Read Less