Hurricane Danielle undergoes an Eyewall Replacement Cycle

August 28th, 2010 |
Morphed Integrated Microwave Imagery at CIMSS (MIMIC) product

Morphed Integrated Microwave Imagery at CIMSS (MIMIC) product

An animation of the Morphed Integrated Microwave Imagery at CIMSS (MIMIC) product (above) revealed that Hurricane Danielle (which had intensified into a Category 4 storm) was undergoing an Eyewall Replacement Cycle (ERC) during the 27 August – 28 August 2010 period. Note how the smaller inner eyewall deteriorated and became replaced by a much larger outer eyewall during the ERC process.

Following the ERC, GOES-13 10.7 µm IR images from the CIMSS Tropical Cyclones site (below) showed Danielle beginning the recurvature process after weakening to a Category 2 storm.

GOES-13 10.7 µm IR images

GOES-13 10.7 µm IR images

Even though Hurricane Danielle was quite far from the US East Coast (below), long period ocean swells and increasing onshore winds were creating dangerous rip currents along much of the nearshore waters and beaches from Florida to the Mid-Atlantic states.

GOES-13 10.7 µm IR image

GOES-13 10.7 µm IR image

Be sure to check out the PREDICT Field Experiment Blog for additional insights on other tropical cyclone activity in the Atlantic basin.

Unusual Double Eyewall structure in Himawari-8 Infrared Imagery of Typhoon Nangka

July 13th, 2015 |
Himawari-8 10.35 µm infrared imagery, 0540-1540 UTC on 13 July 2015 (Click to animate)

Himawari-8 10.35 µm infrared imagery, 0540-1540 UTC on 13 July 2015 (click to animate)

Himawari-8 10.35 µm infrared imagery showed an unusual (for infrared imagery) double-eyewall structure in Typhoon Nangka over the western Pacific Ocean on 13 July 2015. For such a feature to appear in infrared imagery, the secondary circulations of both the inner and outer eyewall need to be intense enough to support the downdraft/cloud-clearing necessary to create the “moats” between them. Microwave imagery of the storm, below, viewed via MIMIC (from this site), also showed the double eyewall structure quite well. This double-eyewall signature typically indicates that a tropical cyclone is experiencing an eyewall replacement cycle (ERC), which signals that a (temporary) decrease in intensity is soon to follow.

MIMIC imagery of Typhoon Nangka, 0000 - 1200 UTC on 13 July 2015 (Click to enlarge)

MIMIC imagery of Typhoon Nangka, 0000 – 1200 UTC on 13 July 2015 (click to enlarge)

Several hours later, a DMSP SSMIS 85 GHz microwave image at 1756 UTC, below, indicated that the ERC was essentially complete. Subsequently, the Joint Typhoon Warning Center slightly downgraded the intensity of Typhoon Nangka for their 21 UTC advisory. While not as well-defined as in the Himawari-8 imagery, the double-eyewall signature was still evident in the lower-resolution (4-km, vs  2-km) MTSAT-2 IR imagery (animation).

DMSP SSMIS 85 GHz microwave image and MTSAT-2 10.8 µm Infrared image (click to enlarge)

DMSP SSMIS 85 GHz microwave image and MTSAT-2 10.8 µm Infrared image (click to enlarge)

The Himawari-8 Target Sector was centered over Typhoon Nangka during this time; an IR image animation with a 2.5-minute timestep, below (courtesy of William Straka, SSEC), showed the evolution of the double eyewall signature, along with 2 pulses of storm-top gravity waves which propagated radially outward away from the center in the northern semicircle of the typhoon.

Himawari-8 10.4 µm IR channel images (click to animate large 115-Megabyte file)

Himawari-8 10.4 µm IR channel images (click to animate large 115-Megabyte file)

Super Typhoon Hagibis in the West Pacific Ocean

October 7th, 2019 |

Himawari-i8

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

JMA Himawari-8 “Clean” Infrared Window (10.4 µm) images (above) showed the pinhole eye of Super Typhoon Hagibis as it rapidly intensified to a Category 5 storm (ADT | SATCON) by 12 UTC on 07 October 2019. Hagibis exhibited some trochoidal motion and variations in forward speed as it approached the Northern Mariana Islands, eventually moving just south of the small uninhabited island of Anatahan (north of Saipan, station identifier PGSN) around 15 UTC.

A toggle between VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP (below) showed the eye just west of Anatahan.

VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP (credit: William Straka, CIMSS) [click to enlarge]

VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP (credit: William Straka, CIMSS) [click to enlarge]

During the period 06 October/2014 UTC to 07 October/0714 UTC, Himawari-8 “Red” Visible (0.64 µm) images (below) showed the initial period of rapid intensification, during which Hagibis developed a well-defined pinhole eye.

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]

Hagibis was moving over warm West Pacific water with high values of Sea Surface Temperature and Ocean Heat Content — the storm was also moving through an environment characterized by low deep-layer wind shear.

===== 08 October Update =====

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

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

2.5-minute rapid scan Himawari-8 Infrared images (above) showed Hagibis during an eyewall replacement cycle (erosion of the small inner eye, with the subsequent formation of a larger-diameter eye). The small inner eyewall could be seen rotating within the larger eye as this transition was taking place. Once the eyewall replacement cycle was completed, Hagibis re-intensified to a Category 5 storm at 18 UTC.

VIIRS Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 (below) displayed the eye and eyewall region of the Category 4 storm.

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

VIIRS Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 (courtesy of William Straka, CIMSS) [click to enlarge]

A toggle between VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1556 UTC (below) provided a nighttime view of Hagibis.

VIIRS Day/Night Band (0.7 µm ) and Infrared Window (11.45 µm) images at 1556 UTC [click to enlarge]

VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1556 UTC (courtesy of William Straka, CIMSS) [click to enlarge]

Cyclone Fani makes landfall in India

May 3rd, 2019 |

EUMETSAT-8 Meteosat-8 Infrared Window (10.8 µm) umages [click to play animation | MP4]

EUMETSAT Meteosat-8 Infrared Window (10.8 µm) images [click to play animation | MP4]

EUMETSAT Meteosat-8 Infrared Window (10.8 µm) images (above) showed the intensification of Cyclone Fani to a high-end Category 4 storm on 02 May 2019 (ADT | SATCON | PGTW advisory), before eventually making landfall in northeastern India at 0230 UTC on 03 May. During its life cycle, Fani moved over warm sea surface temperature values of 29-30ºC — and deep-layer wind shear of only 5-10 knots on 02 May provided an environment favorable for rapid intensification.

Once inland, Fani was in the process of rapidly weakening to a Category 1 storm as it passed over Bhabaneswar (VEBS), and surface wind gusts to 75 knots were reported at that site (below).

Time series plot of surface observations from Bhabaneswar, India [click to enlarge]

Time series plot of surface observations from Bhabaneswar, India [click to enlarge]

A sequence of VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP as viewed using RealEarth (below) showed snapshots of Fani from 19 UTC on 01 May (over the Bay of Bengal) to 07 UTC on 03 May (after landfall).

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

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

A comparison of VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP on 02 May (below) showed Fani shortly after it had reached Category 4 intensity.

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

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

DMSP-17 SSMIS Microwave (85 GHz) image at 1230 UTC + Meteosat-8 Infrared Window (10.8 µm) image at 1300 UTC [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image at 1230 UTC + Meteosat-8 Infrared Window (10.8 µm) image at 1300 UTC [click to enlarge]

A toggle between a DMSP-17 SSMIS Microwave image at 1230 UTC and a Meteosat-8 Infrared Window image at 1300 UTC  from the CIMSS Tropical Cyclones site (above) showed the eye and totally closed eyewall of Fani when it was at its peak intensity on 02 May. However, the MIMIC TC product (below) indicated that the eastern portion of the eyewall started to erode as Fani approached the coast and began to undergo an eyewall replacement cycle.

MIMIC TC morphed microwave product, 01-02 May [click to enlarge]

MIMIC TC morphed microwave product, 01-02 May [click to enlarge]

On 30 April, VIIRS DayNight Band (0.7 µm) images (below, courtesy of William Straka, CIMSS) revealed widespread mesospheric airglow waves (reference) within the western semicircle of the storm, along with numerous bright lightning streaks associated with convection south of the storm center.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1939 UTC on 30 April [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1939 UTC on 30 April [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 2029 UTC on 30 April [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 2029 UTC on 30 April [click to enlarge]