GOES-16 (GOES- East) “Clean” Infrared Window (10.35 µm) images, with and without plots of GLM Groups (above) showed a Mesoscale Convective System (MCS) that was propagating southward across eastern Mexico (in advance of an approaching cold front) from 2001 UTC on 25 April to 1501 UTC on 26 April 2020. The coldest cloud-top infrared brightness temperatures were -90ºC (yellow pixels embedded within dark purple regions). This MCS was prolific lightning-producer — which included numerous anvil streamers that extended well east and northeast of the main convective core (below).

A toggle between NOAA-20 VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images at 0841 UTC (below) also revealed isolated pixels in the overshooting top region with brightness temperatures of -90ºC (yellow enhancement) — along with numerous bright lightning streaks in the Day/Night Band image, located well east of the convective core (consistent with the GOES–16 GLM imagery). At that time, the core of the MCS was located just off the coast of Mexico, between Poza Rica (MMPA) and Veracruz (MMVR).

Plots of rawinsonde data from Veracruz, Mexico (below) showed that the coldest tropopause temperatures were -78.1ºC at a pressure level of 103 hPa — so the coldest GOES-16 and NOAA-20 infrared brightness temperatures of -90ºC indicated overshooting tops extending well about the tropopause.

On 25 April, GOES-16 True Color Red-Green-Blue (RGB) images created using Geo2Grid (below) portrayed a well-defined rope cloud with an undular bore along the cold frontal boundary. Also evident was widespread dense smoke across much of the Gulf of Mexico, a result of prolonged fire activity in the Yucatan Peninsula of Mexico and parts of Central America.

So after breaking the #lightning archive tool a few times (because of searching a time period with too much lightning)…I’ve counted up the dots between 2000 UTC 25 April and 1500 UTC 26 April. 1.1 million! https://t.co/yQrmbONPQ0 pic.twitter.com/K0eedrOAdC

— Ch?is Vagas|?y (@COweatherman) April 26, 2020

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GOES-16 (GOES-East) True Color Red-Green-Blue (RGB) images created using Geo2Grid (above) revealed the large, dark smoke plume resulting from a fire — likely at the Muelle Bachaquero Oil & Natural Gas Company (Google maps) — along the eastern shore of Lake Maracaibo in far northwestern Venezuela on 25 April 2020. Other features apparent in the imagery were persistent pyrocumulus clouds over the fire source, and the bright appearance of solar reflection off surface oil slicks caught within a counterclockwise gyre in the middle of the lake (similar solar reflection was seen off the Deepwater Horizon oil slick, as documented here and here).

VIIRS True Color RGB images from Suomi NPP and NOAA-20 as viewed using RealEarth (below) indicated that the leading edge of the dark smoke plume had drifted westward across the Venezuela/Colombia border after 18 UTC.

GOES-16 Shortwave Infrared (3.9 µm) images (below) showed the thermal anomaly or fire “hot spot” (small cluster of dark black pixels), which first appeared at 1100 UTC.

Black smoke from a refinery fire on Lake Maracaibo.

Seen by GOES-East on Saturday (4-25): https://t.co/QMXKD3VVar. pic.twitter.com/nVcIIHaqCr

— CIRA (@CIRA_CSU) April 29, 2020

Dense and large #smoke cloud from (probably) oil industry related fire, pretty images but none of the operational aerosol retrievals (MODIS,VIIRS, GOES) picked up this event. UV sensors (#OMPS, OMI, #Tropomi) fared better but no aerosol OD retrievals.(h/t @GOESguy) pic.twitter.com/mtqfGVWLM9

— Santiago Gassó (@SanGasso) April 29, 2020

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1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed the circulation of Tropical Invest 90E in the East Pacific Ocean on 24 April 2020. The low-level circulation center appeared to be located about 100 miles southwest of the 18 UTC surface analysis position.

GOES-17 Visible images with a plot of Deep-Layer Wind Shear from the CIMSS Tropical Cyclones site (below) indicated that Invest 90E was embedded within an environment of low shear — the National Hurricane Center gave the feature an 80% chance of further developing into a tropical depression within 48 hours.

VIIRS True Color RGB and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP as viewed using RealEarth (below) revealed tendrils of transverse banding along the western and northern periphery if the disturbance.

===== 25 April Update =====

GOES-17 Infrared images (above) showed the period when the disturbance became classified as Tropical Depression One-E at 15 UTC — making this the earliest tropical cyclone on record in the East Pacific basin during the satellite era.

GOES-17 Infrared images with plots of tropical surface analyses (above) indicated that TD One-E was situated just north of the Intertropical Convergence Zone (ITCZ). The MIMIC-TPW product (below) showed that the tropical depression was tapping moisture from the ITCZ and drawing it northward.

GOES-17 Visible images (below) revealed an exposed low-level circulation that was displaced north-northwest of the primary cluster of deep convection.

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NOAA/NESDIS has modified the GOES-17 Mode 6 scanning schedule during times of increased data-outages related to the faulty Loop Heat Pipe (LHP) mechanism (Blog Post 1, 2, 3 on that subject;  see also here) on GOES-17.  (The OSPO Notification is here).  Between 0600 and 1200 UTC, Full Disk scans are imaged every 15 minutes, rather than every 10;  the two flexible mesoscale sectors (including the one with a default location over Alaska) are scanned every 2 minutes, rather than every minute;  the GOES-17 ‘CONUS’ domain, also known as the PACUS domain, typically scanned every 5 minutes, is not scanned at all.  These modifications will be in place in 2020 from 9 April through 1 May, from 12 August through 1 September and from 14 October through 31 October.  Dates for 2021 (and beyond) have not yet been determined.  The ‘time-time’ chart for this modified scanning is shown below (figure source).

This change in scanning strategy mitigates heating-caused imagery losses because it reduces the amount thermal energy absorbed by the ABI when it is pointed towards a warm source (that is, Earth) instead of cold outer space.  By reducing the scanning periods, OSPO reduced (but did not eliminate) the span of time during which time data from many of the infrared channels of the ABI are unusable because of saturated sensors.

Note in the animation above how the time-step changes at 0600 UTC to every 15 minutes, and then changes back to every 10 minutes at 1200 UTC.  A slower animation from 0530 – 0630 UTC (link) shows that increment change more clearly.  Because the so-called CONUS scan does not happen, GOES-17 CONUS scan imagery is not available during this time window;  of course, data are available in the CONUS region via the every-15-minute Full Disk scans.

The image below, courtesy Mat Gunshor, CIMSS, (derived from this website) shows how this Mode 3 Cooling Operations reduces the window when data are unavailable.  The time span when data are unusable (highlighted by the green double-headed arrows) is shorter in 2020 as a result of this new scanning strategy.  Also, the peak Focal Plane Module (FPM) Temperature is reduced, which may have implications for the long-term health of the satellite.

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