Marco becomes a hurricane in the Gulf of Mexico

August 23rd, 2020 |

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (with and without an overlay of GLM Flash Extent Density) [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (with and without an overlay of GLM Flash Extent Density) [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 — with and without an overlay of GLM Flash Extent Density (above) showed Marco as it intensified from a Tropical Storm to a Category 1 hurricane at 1630 UTC on 23 August 2020. A pronounced semi-circular convective burst was seen to develop near the storm center shortly before 19 UTC.

A toggle between time-matched Infrared images from Suomi NPP and GOES-16 (below) indicated that the coldest cloud-top infrared brightness temperature on the Suomi NP VIIRS image was -86.8ºC, compared to -81.5ºC from the GOES-16 ABI instrument (the same color enhancement has been applied to both images). The northward parallax displacement associated with GOES-16 imagery over the southern Gulf of Mexico was also apparent.

Infrared images from Suomi NPP and GOES-16 [click to enlarge]

Infrared images from Suomi NPP (11.45 µm) and GOES-16 (10.35 µm) [click to enlarge]

Isaias re-intensifies to a Hurricane

August 3rd, 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 the 10-hour period leading up to the time when Tropical Storm Isaias re-intensified to Category 1 hurricane intensity on 03 August 2020. The center of Isaias passed near Buoy 41004 (below) — ahead of the storm, there was a wind gust to 62 knots (71 mph) at 21 UTC, and after the storm  center had passed there was a wind gust to 68 knots (78 mph).

Plot of wind speed (blue), wind gust (red) and air pressure (green) at Buoy 41004 [click to enlarge]

Plot of wind speed (blue), wind gust (red) and air pressure (green) at Buoy 41004

GOES-16 Infrared images with and without an overlay of GLM Flash Extent Density (below) showed that there was some lightning activity associated with areas of deep convection around the center of Isaias.

GOES-16 “Clean” Infrared Window (10.35 µm) images, with and without an overlay of GLM Flash Extent Density [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with and without an overlay of GLM Flash Extent Density [click to play animation | MP4]

Hurricane Isaias made landfall  in North Carolina at 0315 UTC on 04 August (11:15 PM EDT); a few hours later, VIIRS Day/Night Band (0.7 µm) images from the VIIRS Today site (below) showed the hurricane as it was moving further inland.

VIIRS Day/Night Band (0.7 µm) images from Suomi NPP and NOAA-20 [click to enlarge]

VIIRS Day/Night Band (0.7 µm) images from Suomi NPP and NOAA-20 [click to enlarge]

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]

Hurricane Hanna makes landfall in Texas

July 25th, 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 Category 1 Hurricane Hanna making landfall along the South Coast of Texas at 2200 UTC on 25 July 2020. The coldest cloud-top infrared brightness temperature was -88.6ºC at 1633 UTC. Winds gusted to 76 mph at Buoy 42020, and at 18 UTC a ship about 30 miles off the Texas coast reported blowing spray.

GOES-16 GLM Flash Extent Density (below) showed little to no lightning activity within the immediate eyewall region of Hurricane Hanna during the 9 hours leading up to landfall; however, lighting did increase somewhat after the 22 UTC landfall.

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]

A comparison of time-matched Infrared images from Suomi NPP and GOES-16 ABI (below) showed the effect of parallax displacement, even at the relatively low latitudes of South Texas. The coldest cloud-top infrared brightness temperature on the VIIRS image was -86ºC, compared to -81ºC on the ABI image (the same color enhancement is applied to both images).

Infrared images from Suomi NPP and GOES-16 ABI [click to enlarge]

Infrared images from Suomi NPP and GOES-16 ABI [click to enlarge]