GOES-16 has periodically been scanning 1-min mesoscale sectors in South America for the RELAMPAGO Research Mission since this past October. Strong thunderstorms in Argentina were captured in the mesoscale sector on 11 December 2018.
Focusing in on one of the storms for a 1.5 hour period (FIg 1-3), a persistent and large overshooting top is clear, along with a downstream above anvil cirrus plume, both indicating a particularly strong updraft and possible severe weather at the surface. Shown are VIS, IR, and a VIS/IR sandwich combo.
Also shown are 15-min loops and wider views of the storm cluster moving across Argentina.
A GOES-16 1-min sector captured strong thunderstorms developing within a corridor of relatively high atmospheric moisture on Dec 14. The GOES-16 Total Precipitable Water product showed values up to 2.5″ within a large corridor of 2″+.
The field study continued into 2019. Widespread thunderstorm activity was captured by the GOES-16 1-min sector over Argentina during the morning of 6 Jan. Figures 6 and 7 show ongoing convection after sunrise, including several storms exhibiting overshooting tops and above anvil cirrus plumes, which are indicative of particularly strong and potentially severe updrafts. Figure 8 shows the rapid development of a thunderstorm over a 95 minute period.
On 15 Jan 2019, 1-min visible imagery over Argentina provided an intriguing visualization of atmospheric shear. Loading Derived Motion Winds (DMWs) as well (updating every 5-min in mesoscale sectors), the shear can be better quantified. Sampling some winds in the area, we see 10-15 knot winds from 160 degrees at around 950 mb and 30 knot winds from 310 degrees at 550 mb yields a deep layer shear magnitude of around 40 knots.
Both the GOES-16 (GOES-East) and GOES-17 (future GOES-West) ABI’s operated in Mode 4 today (Dec 4, 2018) for close to four hours in order to “test storage updates” (according to NESDIS). Recall Mode 4, also known as Continuous Full Disk Mode, scans a full disk (entire hemisphere) image every five minutes, and that is all. The default Mode 3 “Flex Mode” only scans a full disk image every 15-minutes, but also scans a CONUS image every 5-minutes, and two mesoscale sectors every 1-minute. See Table 1 for a comparison between scan modes. Mode 6 is under evaluation.
Figure 1 shows a world perspective of the two ABI’s operating in Mode 4 (1825 UTC to 2200 UTC) and then switching back to Mode 3 (2215 UTC to 0200 UTC). Notice the imagery appears to “speed up” when switching from 5-min to 15-min resolution. Note the 2015 UTC GOES-17 and 2020 UTC GOES-16 images are incomplete.
On a related note, there is not yet a nicely stitched East/West image composite available in AWIPS. Users can easily load both the East and West imagery together (as is done in this post), but there will be a large region of poor quality imagery overlapping better quality imagery along the edge of the top image. This is due to degraded spatial resolution far from the satellite sub-point. Further, the limb cooling effect will lead to differences in brightness temperature for IR channels (especially water vapor) along the transition.
Bill Line, NWS
GOES-17 data are preliminary and non-operational at the time of this post.