Satellite signatures of the Mars 2020 Perseverance Rover launch

July 30th, 2020 |

GOES-16 images from all 16 ABI spectral bands [click to play animation | MP4]

GOES-16 images from all 16 ABI spectral bands [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) images from all 16 of the ABI spectral bands (above) revealed a variety of signatures of the Mars 2020 Perseverance Rover launch from Kennedy Space Center in Florida on the morning of 30 July 2020. Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images provided the best thermal signature the trail of hot combustion byproducts (water vapor and carbon dioxide) in the wake of the ULA Atlas V rocket booster engines. Closer to the launch site, thermal and reflective signatures of the lower-altitude rocket condensation cloud were seen drifting slowly westward in imagery from all 16 spectral  bands.

Potential Tropical Cyclone 9 intensifies to become Tropical Storm Isaias

July 29th, 2020 |

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed Potential Tropical Cyclone Nine as it moved northwestward across the Caribbean Sea on 29 July 2020. In Puerto Rico, Luis Muñoz Marin Airport in San Juan (TJSJ) had a wind gust to 44 knots (51 mph) around 19 UTC. Numerous pulsing overshooting tops were seen, with some exhibiting cloud-top infrared brightness temperatures as cold as -89ºC — according to plots of rawinsonde data from San Juan, Puerto Rico (below), such temperatures were about 10ºC colder than that of the tropopause. Note the significant increase in moisture from the 12 UTC to the 00 UTC soundings, as PTC9 moved closer to Puerto Rico.

Plots of rawinsonde data from San Juan, Puerto Rico [click to enlarge]

Plots of rawinsonde data from San Juan, Puerto Rico [click to enlarge]

GOES-16 Infrared images with an overlay of GLM Flash Extent Density (below) revealed a modest amount of lightning activity associated with some of the larger clusters of convection.

GOES-16 “Clean” Infrared Window (10.35 µm) images, with an overlay of GLM Flash Extent Density [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with an overlay of GLM Flash Extent Density [click to play animation | MP4]

===== 30 July Update =====

GOES-16 “Clean” Infrared Window (10.35 µm) images, with an overlay of GLM Flash Extent Density [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with an overlay of GLM Flash Extent Density [click to play animation | MP4]

PTC9 continued to organize and intensify, becoming classified as Tropical Storm Isaias at 0300 UTC on 30 July — GOES-16 Infrared images with an overlay of GLM Flash Extent Density (above) displayed persistent overshooting tops (with brightness temperatures in the -85 to -90ºC range) along with intermittent lightning activity. Several large clusters of thunderstorms produced flash flooding across pars of Puerto Rico.

GOES-16 Visible images (below) showed Isaias just after sunrise.

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

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

Dry Air in the southwest Atlantic Ocean

July 29th, 2020 |

Saharan Air Layer (SAL) analysis at 1500 UTC on 29 July 2020 (Click to enlarge)

An analysis of the Saharan Air Layer, above (from this website), shows dry conditions stretching from Africa to the southwestern Atlantic, wrapping around the clouds associated with a strong tropical disturbance that is forecast to move northwestward over the Lesser and Greater Antilles in the next couple days.  (Both the dry air and the presence of high terrain in the Antilles will likely affect the development and structure of this storm).

The Saharan Air Layer is accompanied by an Elevated Mixed Layer (EML) that was apparent in the 0000 UTC Upper-Air sounding from San Juan (TJSJ), as shown below (from this site).  (At 0000 UTC, Puerto Rico was entrenched within the SAL air as shown in this analysis).  Note the steep lapse rate from 800 to 550 mb and the strong east winds in the layer.  By 1200 UTC, moist air moving in from the east had altered the EML.

Skew-T of temperature and pressure, 0000 UTC on 29 July 2020, at station 78526 (TJSJ, San Juan, Puerto Rico) (Click to enlarge)

NOAA-20 overflew this region just after 0600 UTC (orbits, from this website), and its thermodynamic profiles also gave evidence of the EML.  NUCAPS profiles in the region were produced by infrared/microwave retrievals that converged to a solution, as shown in the map below.  (The region of the tropical disturbance, over the Leeward Islands, shows red sounding dots where rain is likely falling).

NOAA-20 NUCAPS sounding locations in/around Puerto Rico at ~0550 UTC on 29 July 2020 (Click to enlarge)

Two soundings from this overpass are shown below, along 65º W at ~21º N and ~20º N, also show evidence of an Elevated Mixed Layer in the same region of the atmosphere.  (It is more apparent at 21.15º N/64.73º W)

NUCAPS Profiles from ~0600 UTC 29 July 2020 at 21.15 N, 65 W (left) and at 19.75 N, 65 W (right) (click to enlarge)

Gridded NUCAPS fields are available in AWIPS, but they are also available outside of AWIPS at this site from NASA SPoRT.  850-500 mb and 700-500 mb Lapse rates, shown below, show a region of steep lapse rates as you might expect from an EML to the north of Puerto Rico (yellow in the color enhancement applied).

850-500 mb Lapse Rates (left) and 700-500 mb Lapse Rates (right) from the ~0600 UTC NOAA-20 overpass (Click to enlarge)

Gridded NUCAPS fields also confirm the dry air associated with the SAL air that contains the EML.  Total Precipitable water is around 30 mm, and 850-mb relative humidity is under 40% in the region where the EML is indicated by lapse rates.

Total Precipitable Water (left) and 850-mb Relative Humidity (right) derived from the NOAA-20 NUCAPS data from the ~0600 UTC overpass on 29 July 2020 (click to enlarge)

For the latest information on Potential Tropical Cyclone #9 (should this system be named, the next name in the Atlantic alphabet is Isaías), refer to the National Hurricane Center website.

Vortices downwind of the Kuril Islands

July 28th, 2020 |

Himawari-8 “Red” Visible (0.64 µm) images [click to play animation | MP4]

Himawari-8 “Red” Visible (0.64 µm) images [click to play animation | MP4]

JMA Himawari-8 “Red” Visible (0.64 µm) images (above) showed trains of vortices extending downwind (southeast) of the Kuril Islands on 28-29 July 2020 (surface analyses). One unusual aspect of these features was the development of small cloud elements within the cloud-free “hole” portion of some of the vortices.

H/T to Santiago Gassó for alerting us to this interesting case.