In support of the RELAMPAGO-CACTI field experiment, GOES-16 (GOES-East) had a Mesoscale Domain Sector centered over northeastern Argentina on 13 November 2018 — and 1-minute “Clean” Infrared Window (10.3 µm) images with plots of GLM Groups (above) showed a large and long-lived Mesoscale Convective System moving eastward across far northeastern Argentina and expanding into southern Paraguay and southeastern Brazil. Note the large amount of lightning in the anvil region far southeast of the core of the convection.

GLM groups are great, but full flash footprints are fantastic. Here’s a movie of 13 Nov 2018 @NOAASatellitePA @goesglm data for @RELAMPAGO2018 – https://t.co/MriT3tv9kF

— Eric Bruning (@deeplycloudy) November 14, 2018

The corresponding GOES-16 Infrared animation without lightning data is shown below. Minimum cloud-top infrared brightness temperatures often reached -90ºC and colder (yellow pixels embedded within darker violet regions).

A comparison of NOAA-20 VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images using RealEarth (below) provided a very detailed view of the MCS at 1703 UTC. On the Infrared image, storm-top signatures often associated with severe thunderstorms included a well-defined enhanced-V (with a pronounced cold/warm couplet) situated over the Paraguay/Argentina border, and a “warm trench” surrounding the cold overshooting top at the vertex of the enhanced-V over extreme southern Paraguay.

The warm trench signature was also evident on 2-km resolution GOES-16 Infrared imagery at that same time (below), just west of Posadas, Argentina SARP. However, the warm trench surrounding the small overshooting top was only apparent from 1700 to 1705 UTC — so it was remarkable timing to have an overpass of the NOAA-20 satellite capture the brief signature in greater detail (at 375-meter resolution). A similar short-lived small overshooting top was seen at the vertex of the enhanced-V signature for the 6-minute period centered at 1652 UTC.

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The NESDIS Blended Total Precipitable Water (TPW) product (above) showed an atmospheric river that was transporting moisture northward from the tropics to south-central Alaska during 11 November – 12 November 2018. TPW values were in excess of 2.0 inches near the leading edge of the moisture plume early in the period.

The corresponding Percent of Normal Blended Total Precipitable Water product (below) indicated that these values of TPW were at or above 200 percent of normal (yellow).

Using the MIMIC Multi-layer TPW site, you can see how TPW is partitioned within various layers of the atmosphere (below). This TPW product uses microwave data from POES, Metop NOAA-20 and Suomi NPP satellites (description). It’s important to keep in mind that the location and continuity of a plume of TPW (such as an atmospheric river) might not always exactly agree what is seen on geostationary satellite Water Vapor imagery, since water vapor spectral bands usually sense radiation being emitted from levels above where the bulk of TPW is normally found (as discussed here).

Anchorage, Alaska rawinsonde data (below) showed that TPW values reached a maximum of 0.73 inch at 00 UTC on 12 September.

The arrival of this moisture produced heavy rainfall and mixed winter precipitation across the region — Portage Glacier (about 50 miles southeast of Anchorage) received 9.99 inches of rainfall in 48 hours, and Anchorage set a new daily precipitation record on 11 November with 0.89″ (which included 1.0 inch of new snow). A summary of temperature and precipitation reports can be seen here.

A comparison of Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 2157 UTC on 12 November (below) revealed widespread layered clouds across most of south-central Alaska.

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1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) showed the thick smoke and hot thermal signature of the Woolsey Fire in southern California on 09 November 2018. On this day it exhibited extreme fire behavior, with the large thermal anomaly or fire “hot spot” (red enhancement) moving rapidly southwestward and reaching the coast (Wildfire Today). The fires were driven by hot, dry Santa Ana winds, which arrived at Camarillo KCMA around 19 UTC (11 AM local time) and reached the coast at Point Mugu Naval Air Station KNTD around 22 UTC (2 PM local time).

A longer animation of GOES-16 Shortwave Infrared imagery (below) begins at 2115 UTC (1:15 PM local time) on 08 November — when a Mesoscale Sector was first positioned over California — and ends 52.5 hours later at 0149 UTC on 11 November (5:49 PM local time on 10 November). The first Ventura County fire to show a pronounced thermal signature was the Hill Fire; the earliest appearance of Woolsey Fire pixels that were hot enough to be color-enhanced (yellow) was at 2254 UTC (30 minutes after the reported start time of 2224 UTC). The area of hottest (red) pixels then began to increase in coverage and spread toward the southwest after about 06 UTC on 09 November (10 PM local time on 08 November), when Santa Ana winds began to increase at higher elevations several miles inland. As was seen in the Visible / Shortwave Infrared animation above, the morning period from 15-19 UTC (7-11 AM local time) on 09 November was when the fire moved very quickly toward the California coast and the beaches of Malibu. After sunset on 09 November, the area and intensity of hot red/yellow pixels began to decrease, and after 10 UTC (2 AM local time) on 10 November only darker black fire pixels persisted. During the day on 10 November, color-enhanced hot fire pixels were again evident from 1726-2353 UTC (9:26 AM to 3:53 PM local time). Note that at 19 UTC the marine layer began to move inland, with the dewpoint jumping to 46ºF at KNTO and to 33ºF at KCMA an hour later — the fire responded to this influx of moist air by beginning to die down.

A nighttime comparison of Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images at 0923 UTC (1:23 AM local time) on 10 November (below) showed a marked reduction in coverage and intensity of hot pixels compared to 15 hours earlier.

The smoke was very dense as it moved out over the adjacent offshore waters of the Pacific Ocean on 09 November, as seen in a sequence of MODIS and VIIRS Visible images (below).

VIIRS True Color Red-Green-Blue (RGB) images from Suomi NPP at 2104 UTC and NOAA-20 at 2154 UTC on 09 November (below) also depicted the optically-thick nature of the smoke.

The smoke was so thick that Suomi NPP VIIRS Aerosol Optical Depth values exceeded 1.0 (below) —  this is likely due to the VIIRS Cloud Mask product (a component of the AOD algorithm)  falsely flagging the thick center portion of the smoke as “cloud”.

===== 11 November Update =====

Santa Ana winds began to increase again on 11 November — 1-minute GOES-16 Visible and Shortwave Infrared images (above) showed the development of new smoke plumes and hot thermal signatures around the periphery of the ongoing Woolsey Fire. As of 1812 UTC (10:12 AM local time), the fire had burned 83,275 acres and was listed as 10% contained.

The new smoke plumes (as well as residual smoke from previous days of burning) could be seen on VIIRS True Color RGB imagery from Suomi NPP at 2029 UTC and NOAA-20 at 2114 UTC (below). The entire image swaths as captured and processed by the Direct Broadcast ground station at CIMSS/SSEC can be seen here and here.

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NWS Duluth requested a GOES-16 (GOES-East) Mesoscale Domain Sector to monitor the potential for lake-enhanced snowfall along the south shore of Lake Superior on 09 November 2018 — and 1-minute “Red” Visible (0.64 µm) images (above) showed the cyclonic flow around abroad area of low pressure over the Great Lakes (surface analyses), along with the formation of convective elements within the northeasterly flow over western Lake Superior.

A closer look at GOES-16 Visible imagery (below) showed that as the convection moved inland over north-central Wisconsin and far western Upper Michigan, moderate snow developed at Ashland WI and heavy snow was reported at Ironwood MI beginning around 2030 UTC. GOES-16 GLM Flash data did not indicate any lightning associated with the lake-enhanced convection. Hourly surface wind barbs are also plotted; 10-minute wind data for Buoys ROAM4 and DISW3 are available here and here — northerly wind gusts at Buoy ROAM4 reached 25.2 m/s (49 knots) at 2257 UTC and 21.1 m/s (41 knots) at Buoy DISW3 at 2048 and 2202 UTC.

A sequence of Suomi NPP and NOAA-20 VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images (below) showed a more detailed view of the convection that developed over western Lake Superior (in response to instability from cold air moving over relatively warm water — the temperature difference between cold air aloft at 850 hPa and the lake surface was on the order of 15-20º C).  Snowfall rates were also locally enhanced by lifting when northerly/northwesterly surface winds off the lake interacted with the topography of the Gogebic Range in Wisconsin and Michigan (where elevations rise to 1800 feet).

A comparison of Snow Depth at 12 UTC on 09 and 10 November, plus 24-hour Total Snowfall ending at 12 UTC on 10 November from NOHRSC (below) showed accumulations of 14 inches at two sites in north-central Wisconsin; other snowfall amounts included 8.6 inches at Bayfield WI and 14.6 inches at Ironwood MI.

Animations of radar reflectivity over the Upper Midwest and Wisconsin are available here and here (courtesy of Pete Pokrandt, UW-AOS).

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