Thunderstorms over Argentina

November 29th, 2018 |

Suomi NPP VIIRS True Color RGB image at 1753 UTC [click to enlarge]

Suomi NPP VIIRS True Color RGB image at 1753 UTC [click to enlarge]

A Suomi NPP VIIRS True Color Red-Green-Blue (RGB) image viewed using RealEarth (above) showed numerous thunderstorms developing across the foothills of the Andes in western Argentina on 29 September 2018, in advance of a cold front that was moving northward.

Closer views of VIIRS True Color and Infrared Window (11.45 µm) images from Suomi NPP at 1753 UTC and NOAA-20 at 1843 UTC (below) depicted several cold overshooting tops (darker red enhancement) associated with the more vigorous thunderstorm updrafts.

Suomi NPP VIIRS True Color RGB and Infrared Windoe (11.45 µm) images at 1753 UTC [click to enlarge]

Suomi NPP VIIRS True Color RGB and Infrared Windoe (11.45 µm) images at 1753 UTC [click to enlarge]

NOAA-20 VIIRS True Color RGB and Infrared Windoe (11.45 µm) images at 1843 UTC [click to enlarge]

NOAA-20 VIIRS True Color RGB and Infrared Windoe (11.45 µm) images at 1843 UTC [click to enlarge]

In support of the RELAMPAGO-CACTI field experiment, a GOES-16 (GOES-East) Mesoscale Domain Sector had been positioned over the region, providing 1-minute imagery — animations of “Red” Visible (0.64 µm), Near-Infrared “Snow/Ice” (1.61 µm) and “Clean” Infrared Window (10.3 µm) imagery (below) showed the upscale development of the convection from 1300-2330 UTC. The largest storms were in the vicinity of and to the south of Mendoza (SAME) and Rio Cuarto (SAOC).

GOES-16

GOES-16 “Red” Visible (0.64 µm) images [click to play MP4 animation]

GOES-16 Near-Infrared "Snow/Ice" (1.61 µm) images [click to play MP4 animation]

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm) images [click to play MP4 animation]

GOES-16 "Clean" Infrared Window (10.3 µm) images [click to play MP4 animation]

GOES-16 “Clean” Infrared Window (10.3 µm) images [click to play MP4 animation]

Toward the end of the day, a closer look at one storm along the southeastern end of the large convective complex (below) showed that it exhibited awell-defined enhanced-V signature around 20 UTC and shortly thereafter produced a long-lived Above-Anvil Cirrus Plume (AACP). Both are signatures of storms that often produce large hail, damaging winds or tornadoes.

GOES-16 "Red" Visible (0.64 µm, top), Near-Infrared :Snow/Ice" (1.61 µm, center) and "Clean" Infrared Window (10.3 µm, bottom) images [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm, top), Near-Infrared :Snow/Ice” (1.61 µm, center) and “Clean” Infrared Window (10.3 µm, bottom) images [click to play MP4 animation]

The AACP exhibited a colder (around -55ºC, shades of orange) infrared brightness temperature than the anvil beneath it (-40 to -50ºC, green to yellow enhancement), due to the atmospheric temperature profile aloft as seen on 12 UTC rawinsonde data from nearby Santa Rosa (below). The sounding profile suggests that the AACP was at or perhaps above the tropopause.

Plot of 12 UTC Santa Rosa rawinsonde data [click to enlarge]

Plot of 12 UTC Santa Rosa rawinsonde data [click to enlarge]