Hurricane Douglas moves just north of Hawai’i

July 26th, 2020 |

GOES-17 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed  Category 1 Hurricane Douglas as it moved just north of Hawai’i during the day on 26 July 2020 (the boundary of the Mesoscale Sector was abruptly shifted westward at 1658 UTC). The coldest cloud-top infrared brightness temperatures were around -80ºC.

GOES-17 “Clean” Infrared Window (10.35 µm) images, with analysis of deep layer wind shear at 20 UTC [click to enlarge]

GOES-17 “Clean” Infrared Window (10.35 µm) images, with analysis of deep-layer wind shear at 20 UTC [click to enlarge]

The apparent storm center as seen in satellite imagery was shifted north of the actual surface center location, due to the presence of southerly/southwesterly deep-layer wind shear as shown by a 20 UTC analysis from the CIMSS Tropical Cyclones site (above). This offset was also evident in a comparison of a DMSP-17 SSMIS Microwave (85 GHz) image at 1711 UTC with the analyzed surface position of Douglas at 1800 UTC (below).

DMSP-17 SSMIS Microwave (85 GHz) image at 1711 UTC, with the analyzed surface position of Douglas at 1800 UTC [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image at 1711 UTC, with the analyzed surface position of Douglas at 1800 UTC [click to enlarge]

===== 27 July Update =====

GOES-17 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-17 Visible and Infrared images (above) showed that the low-level circulation became exposed from the deep convection of Douglas a few hours after sunrise on 27 July, as it moved southwestward near the island of Nihoe. An analysis of deep-layer wind shear at 22 UTC (below) indicated the presence of 25-30 knots of southwesterly shear over that area — an unfavorable environment for tropical cyclone intensification/maintenance, in spite of the fact that the storm was moving over favorably-warm water.

GOES-17 “Red” Visible (0.64 µm) images, with analysis of deep layer wind shear at 22 UTC [click to enlarge]

GOES-17 “Red” Visible (0.64 µm) images, with analysis of deep-layer wind shear at 22 UTC [click to enlarge]

Tropical Cyclone Harold makes landfall on Vanuatu

April 5th, 2020 |

Himawari-8 Infrared Window (10.4 µm) images [click to play animation | MP4]

Himawari-8 Infrared Window (10.4 µm) images [click to play animation | MP4]

Tropical Cyclone Harold made landfall on Vanuatu’s largest island of Espiritu Santo as a Category 4 storm (ADT | SATCON) on 05 April 2020. JMA Himawari-8 Infrared Window (10.4 µm) images (above) showed the emergence of a well defined eye — which exhibited some trochoidal motion. Cloud-top infrared brightness temperatures were -90ºC and colder (yellow pixels embedded within dark purple) before the eye became evident. The structure of the eye was seen to deteriorate somewhat after Harold made landfall.

Himawari-8 “Red” Visible (0.64 µm) images (below) revealed a similar deterioration of the eye after landfall.

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]

VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP as viewed using RealEarth (below) provided more detailed view of Harold several hours before landfall.

VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

A toggle between NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1359 UTC (below) helped to highlight the cloud-top gravity waves between the eye of Harold and the west coast of Espiritu Santo.

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (credit: William Straka, CIMSS) [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (credit: William Straka, CIMSS) [click to enlarge]

A DMSP-18 SSMIS Microwave (85 GHz) image from the CIMSS Tropical Cyclones site (below) showed Harold at 1719 UTC.

DMSP-18 SSMIS Microwave (85 GHz) image [click to enlarge]

DMSP-18 SSMIS Microwave (85 GHz) image [click to enlarge]

===== 06 April Update =====

Himawari-8 "Clean" Infrared (10.4 µm) images [click to play animation | MP4]

Himawari-8 “Clean” Infrared (10.4 µm) images [click to play animation | MP4]

Himawari-8 Infrared images (above) showed Harold as it intensified to a Category 5 storm while moving across the islands of Vanuatu on 06 April.

 

Hurricane Lorenzo in the Atlantic Ocean

September 26th, 2019 |

 

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

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

GOES-16 (GOES-East) “Clean” Infrared Window (10.35 µm) images (above) showed Hurricane Lorenzo as it rapidly intensified from a Category 2 storm at 00 UTC to a Category 4 storm by 15 UTC (ADT | SATCON) on 26 September 2019.

A toggle between VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 as viewed using RealEarth (below) provided a detailed view of the eye and eyewall region of Lorenzo at 1542 UTC and 1632 UTC. On the Suomi NPP Infrared image, note the transverse banding northwest of the eye, and a small packet of gravity waves southwest of the eye.

VIIRS True Color RGB and Infrared Window<em> (11.45 µm)</em> images from Suomi NPP and NOAA-20 [click to enlarge]

VIIRS True Color RGB and Infrared Window (11.45 µm) images from Suomi NPP (at 1542 UTC) and NOAA-20 (at 1632 UTC) [click to enlarge]

A DMSP-18 SSMIS Microwave (85 GHz) image from the CIMSS Tropical Cyclones site (below) revealed a well-defined eyewall wrapping around the southern, eastern and northern periphery of the eye.

DMSP-18 SSMIS Microwave (85 GHz) image at 1941 UTC [click to enlarge]

DMSP-18 SSMIS Microwave (85 GHz) image at 1941 UTC [click to enlarge]

Hurricane Dorian reaches Category 5 intensity

September 1st, 2019 |

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]

Overlapping 1-minute Mesoscale Domain Sectors provided GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images at 30-second intervals (above) as Hurricane Dorian reached Category 5 intensity just east of Great Abaco Island in the Bahamas during the morning hours on 01 September 2019. West of Dorian, station Identifier MYGF is Freeport on Grand Bahama Island (which stopped reporting at 00 UTC on 01 September, due to evacuation).

As noted in the 15 UTC NHC discussion, the eye of Dorian was exhibiting a pronounced “stadium effect”, with a smaller-diameter surface eye sloping outward with increasing altitude (below).

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images at 1200 UTC [click to enlarge]

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images at 1200 UTC [click to enlarge]

GOES-16 Visible images with and without overlays of GLM Flash Extent Density (below) revealed that lightning activity began to ramp up within the eyewall region after 12 UTC.

GOES-16 “Red” Visible (0.64 µm) images, with and without overlays of GLM Flash Extent Density [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images, with and without overlays of GLM Flash Extent Density [click to play animation | MP4]

A Mid-Level Wind Shear product (below) showed that Dorian had been moving through an environment of low shear — generally 10 knots or less — during the 00-15 UTC time period on 01 September.

Mid-layer Wind Shear product, 00-15 UTC [click to enlarge]

Mid-layer Wind Shear product, 00-15 UTC [click to enlarge]


As pointed out by NWS Grand Forks (above), portions of the outer cays just east of Great Abaco Island could be seen in GOES-16 Visible imagery through breaks in the low-level clouds within the eye (below).

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]

VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 as viewed using RealEarth are shown below, as the eye was moving over Great Abaco Island.

VIIRS True Color RGB and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 [click to enlarge]

VIIRS True Color RGB and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 [click to enlarge]


After moving slowly westward across Great Abaco Island, Dorian later became the first Category 5 hurricane on record to make landfall on Grand Bahama Island (below). Station identifier MYGF is Grand Bahama International Airport in Freeport, and MYGW is West End Airport.

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

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

===== 02 September Update =====

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

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

Prior to sunrise on 02 September, 1-minute GOES-16 Infrared images (above) showed Dorian moving very slowly — with a forward speed of only 1 mph — across the eastern end of Grand Bahama Island (as it remained at Category 5 intensity).

After sunrise, 1-minute GOES-16 Visible and Infrared images (below) showed that the eye of Dorian was finally beginning to move very slowly northwestward away from Grand Bahama Island. At the end of the animation (15 UTC), Dorian was downgraded slightly to a high-end Category 4 hurricane.

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]

Suomi NPP VIIRS True Color RGB and Infrared images (below) provided a view of Dorian at 1817 UTC.

Suomi NPP VIIRS True Color RGB and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS True Color RGB and Infrared Window (11.45 µm) images [click to enlarge]

At 21 UTC, a comparison of MIMIC Total Precipitable Water and DMSP-16 SSMIS Microwave images (below) suggested that a tongue of drier air from the northwest and west was wrapping into the southern and southeastern portion of Dorian’s circulation.

MIMIC Total Precipitable Water and DMSP-16 SSMIS Microwave images at 21 UTC [click to enlarge]

MIMIC Total Precipitable Water and DMSP-16 SSMIS Microwave images at 21 UTC [click to enlarge]

A long animation of GOES-16 Infrared images (below) covers the 1.5-day period from 1200 UTC on 01 September to 2359 UTC on 02 September — and initially includes 30-second images from 1200-1515 UTC on 01 September. Dorian was rated at Category 5 intensity from 1200 UTC on 01 September until 1400 UTC on 02 September. Station identifier MYGF is Grand Bahama International Airport in Freeport.

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

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


Additional satellite imagery and products are available from EUMETSAT.