Mesoscale Convective System in Argentina

November 13th, 2018 |

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images, with GLM Groups plotted in cyan/green [click to play MP4 animation]

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.


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).

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]

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.

NOAA-20 VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images at 1703 UTC [click to enlarge]

NOAA-20 VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images at 1703 UTC [click to enlarge]

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.

GOES-16 "Clean" Infrared Window (10.3 µm) image at 1703 UTC, with and without GLM Groups plotted in cyan/green [click to enlarge]

GOES-16 “Clean” Infrared Window (10.3 µm) image at 1703 UTC, with and without GLM Groups plotted in cyan/green [click to enlarge]

Severe thunderstorms in Pennsylvania

October 2nd, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with SPC storm reports plotted in red [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed severe thunderstorms that moved across Pennsylvania on 02 October 2018, producing large hail, damaging winds and a few tornadoes (SPC storm reports). A parallax-corrected version of the animation — which shifts the location of SPC storm reports northwestward, to be more closely aligned with the storm-top features (assumed to be at a mean altitude of 12 km, based on 00 UTC Pittsburgh rawinsonde data) seen on satellite imagery — is available here.

The corresponding GOES-16 “Clean” Infrared Window (10.3 µm) images (below) indicated that the coldest cloud-top infrared brightness temperatures were in the -60 to -70ºC range (red to black enhancement).

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images, with SPC storm reports plotted in purple [click to play MP4 animation]



Severe thunderstorms in Iowa and Minnesota

September 20th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with SPC storm reports plotted in red [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed thunderstorms that developed in the vicinity of a surface low and associated cold front (surface analyses) that was moving northeastward across the Upper Midwest during the afternoon and evening hours of 20 September 2018. These storms produced damaging winds and several tornadoes across northern Iowa and southern Minnesota (SPC storm reports | NWS FSD summary | NWS MPX summary). An animation of Visible images with hourly plots of surface reports is available here.

GOES-16 “Clean” Infrared Window (10.3 µm) images (below) showed cloud-top infrared brightness temperatures as cold as -70 to -75ºC (black to light gray enhancement) with the more vigorous overshooting tops. These thunderstorms continued moving eastward as a squall line, causing additional damaging winds across northern Wisconsin.

GOES-16

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

Florence produces record rainfall in North Carolina and South Carolina

September 17th, 2018 |

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images, with hourly precipitation type symbols plotted in yellow and SPC storm reports plotted in cyan, 13-17 September [click to play MP4 animation]

After Hurricane Florence made landfall in North Carolina during the morning hours on 14 September, it moved very slowly (at times only 2-3 mph) southwestward into South Carolina during 15-16 September (surface analyses). Prolonged heavy rainfall resulted (WPC summary), with new state records (see below) for precipitation from a tropical cyclone being set in North Carolina (35.93 inches) and South Carolina (23.63 inches). GOES-16 (GOES-East) “Clean” Infrared Window (10.3 µm) images every 5 minutes during the 4-day period of 13-16 September (above) showed the evolution of banding and the development of new convection that produced the heavy rainfall — widespread flooding along with strong winds caused power outages across portions of the 2 states (NC | SC), and closed sections of Interstates 95 and 40. Note that the power outages caused extended dropouts of the plotted surface reports — especially in eastern North Carolina; reports were missing when the gray 4-letter station identifiers disappeared — even though many of those sites were likely experiencing heavy rainfall during those dropout times.

Florence also spawned a few tornadoes on 14, 15 and 16 September — SPC storm reports are plotted in cyan on the GOES-16 Infrared images.

Hourly images of the MIMIC Total Precipitable Water product (below) showed tropical moisture associated with Florence as it moved inland during the 13-17 September period.

MIMIC Total Precipitable Water product [click to play animation | MP4]

MIMIC Total Precipitable Water product, 13-17 September [click to play animation | MP4]

Animations of plots of rawinsonde data from the coastal sites of Newport/Morehead City, North Carolina and Charleston, South Carolina (below) revealed the increase in deep tropical moisture from 13-16 September — Total Precipitable Water values were as high as 68.6 mm (2.70 inches) at Newport and 67.8 mm (2.67 inches) at Charleston.

Daily plots of rawinsonde data from Newport/Morehead City, North Carolina [click to enlarge]

Daily plots of rawinsonde data from Newport/Morehead City, North Carolina [click to enlarge]

Daily plots of rawinsonde data from Charleston, South Carolina [click to enlarge]

Daily plots of rawinsonde data from Charleston, South Carolina [click to enlarge]

As the remnants of Florence moved from Kentucky to West Virginia during the daylight hours of 17 September, numerous tornadoes occurred in central Virginia (SPC storm reports | NWS Wakefield summary). 1-minute GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (below) showed the development of thunderstorms which produced these tornadoes.

GOES-16 "Red" Visible (0.64 µm, left) and "Clean" Infrared Window (10.3 µm, right) images, with plots of SPC storm reports [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.3 µm, right) images, with plots of SPC storm reports [click to play MP4 animation]

 

===== 18 September Update =====

Before/after (26 August/18 September) Terra MODIS False Color RGB images [click to enlarge]

Terra MODIS False Color RGB images, 26 August vs. 18 September [click to enlarge]

A comparison of before/after (26 August/18 September) Terra MODIS False Color Red-Green-Blue (RGB) images from the MODIS Today site (above) showed areas of inland flooding (increasing water coverage appears as darker shades of blue) in the wake of Florence across far southeastern North Carolina and far northeastern South Carolina.

Looking slightly to the south, a similar before/after comparison of Terra MODIS True Color RGB images (below) revealed areas of sediment runoff into the Atlantic Ocean.

Terra MODIS True Color RGB images, 26 August vs. 18 September [click to enlarge]

Terra MODIS True Color RGB images, 26 August vs. 18 September [click to enlarge]