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.

Hurricane Dorian

August 28th, 2019 |

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

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

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (above) showed cold overshooting tops (darker black infrared enhancement) over the Leeward Islands as well as subtle mesospheric airglow waves propagating southward away from the center of Tropical Storm Dorian at 0606 UTC on 28 August 2019.

In a toggle between GOES-16 (GOES-East) “Clean” Infrared Window (10.35 µm) and DMSP-18 SSMIS Microwave (85 GHz) images from the CIMSS Tropical Cyclones site (below), the Microwave image revealed a convective band that was wrapping around the northern portion of the center of Dorian at 0930 UTC.

GOES-16 "Clean" Infrared Window <em>(10.35 µm)</em> and DMSP-18 SSMIS Microwave <em>(85 GHz)</em> images [click to enlarge]

GOES-16 “Clean” Infrared Window (10.35 µm) and DMSP-18 SSMIS Microwave (85 GHz) images [click to enlarge]

1-minute Mesoscale Domain Sector GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (below) also showed a convective burst wrapping around the eastern and northern edges of the center of Dorian after 15 UTC. The coldest cloud-top infrared brightness temperature associated with that early convective burst was -83ºC.

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]

Dorian was upgraded to a Category 1 Hurricane at 18 UTC. Prior to that time, the tropical cyclone had been moving through an environment of low deep-layer wind shear (below), one factor that is favorable for intensification. Dorian was also passing over water possessing warm sea surface temperatures and modest ocean heat content.

http://cimss.ssec.wisc.edu/goes/blog/wp-content/uploads/2019/08/.gifGOES-16 Infrared Window (10.35 µm) images, with contours of deep-layer wind shear at 19 UTC [click to enlarge]

GOES-16 Infrared Window (10.35 µm) images, with contours of deep-layer wind shear at 19 UTC [click to enlarge]

VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP as viewed using RealEarth are shown below, from around the time when Dorian was upgraded from a Tropical Storm to a Hurricane.

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

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

A comparison of GOES-16 Infrared (at 2330 UTC) and GMI Microwave (at 2341 UTC) images (below) revealed Dorian’s small eye.

GOES-16 Infrared (10.35 µm) and GMI Microwave (85 GHz) images [click to enlarge]

GOES-16 Infrared (10.35 µm) and GMI Microwave (85 GHz) images [click to enlarge]

===== 29 August Update =====

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]

On 29 August, 1-minute GOES-16 Visible and Infrared images (above) showed that periodic convective bursts persisted around the center of Category 1 Hurricane Dorian.

During one of those convective bursts from 1800-1900 UTC, an increase in GOES-16 GLM Flash Extent Density was evident (below).

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

GOES-16 Visible and Infrared images at 1852 UTC with and without an overlay of GLM Flash Extent Density are shown below. At that particular time, the overshooting top infrared brightness temperature reached a minimum value of -82.5C.

GOES-16 “Red” Visible (0.64 µm) image at 1853 UTC, with and without an overlay of GLM Flash Extent Density [click to enlarge]

GOES-16 “Red” Visible (0.64 µm) image at 1852 UTC, with and without an overlay of GLM Flash Extent Density [click to enlarge]

GOES-16 “Clean” Infrared Window (10.35 µm) image at 1853 UTC, with and without an overlay of GLM Flash Extent Density [click to enlarge]

GOES-16 “Clean” Infrared Window (10.35 µm) image at 1852 UTC, with and without an overlay of GLM Flash Extent Density [click to enlarge]

===== 30 August Update =====

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]

The eye of Dorian became more well-defined in 1-minute GOES-16 Visible and Infrared images (above) during the morning hours on 30 August.

A DMSP-17 Microwave (85 GHz) Microwave image at 1141 UTC (below) did not yet show a completely closed eyewall structure at that earlier time.

DMSP-17 SSMIS Microwave (85 GHz) Microwave image [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) Microwave image [click to enlarge]

Dorian was upgraded to a Category 3 hurricane at 18 UTC — the storm was moving into a narrow corridor of weaker deep-layer wind shear around that time. During the 3 hours leading up to 18 UTC, animations of 1-minute GOES-16 Visible and Infrared imagery — with and without an overlay of GLM Flash Extent Density — are shown below.

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]

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

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

===== 31 August Update =====

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

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

Overlapping 1-minute GOES-16 Mesoscale Domain Sectors provided imagery at 30-second intervals — Visible and Infrared animations of the Category 4 hurricane from 1430-1900 UTC are shown above and below, respectively. A longer Visible animation from 1100-2259 UTC is available here (courtesy of Pete Pokrandt, AOS).

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

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

Hurricane Barbara in the East Pacific

July 2nd, 2019 |

GOES-17

GOES-17 “Red” Visible (0.64 µm, top) and “Clean” Infrared Window (10.3 µm, bottom) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed the eye of Category 4 Hurricane Barbara on 02 July 2019. Mesovortices were briefly seen within the eye in the Visible imagery. Barbara was moving through an environment of low deep-layer wind shear and over warm water, factors favorable for rapid intensification (ADT | SATCON).

DMSP-17 SSMIS Microwave (85 GHz) imagery from the CIMSS Tropical Cyclones site (below) showed a closed eyewall at 1448 UTC.

DMSP-17 SSMIS Microwave (85 GHz) image [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image [click to enlarge]

A 1700 UTC  GOES-17 “Red” Visible image with an overlay of Metop-A ASCAT winds (below) revealed surface scatterometer wind speeds as high as 76 knots just north of the eye.

GOES-17

GOES-17 “Red” Visible (0.64 µm) and Metop-A ASCAT winds [click to enlarge]

===== 03 July Update =====

GOES-17 "Red" Visible (0.64 µm, top) and "Clean" Infrared Window (10.3 µm, bottom) images [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm, top) and “Clean” Infrared Window (10.3 µm, bottom) images [click to play animation | MP4]

Barbara maintained Category 4 intensity on 03 July — and 1-minute GOES-17 Visible and Infrared GOES-17 images (above) provided a better view of mesovortices within the eye.