Hurricane Florence

September 9th, 2018 |

GOES-16

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

After previously weakening from a Category 4 hurricane (on 04 September) to a tropical storm on 07 September (track/intensity), Florence re-intensified to become a Category 1 hurricane at 15 UTC on 09 September 2018. 1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.63 µm) are shown above, with the corresponding “Clean” Infrared Window (10.3 µm) images shown below. An eye structure appeared for brief intervals during the day, but was often masked by cloud debris from a series of convective bursts within the surrounding eyewall.

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images [click to play MP4 animation]

GPM GMI Microwave (85 GHz) image at 1811 UTC [click to enlarge]

GPM GMI Microwave (85 GHz) image at 1811 UTC [click to enlarge]

GPM GMI (above) and DMSP-16 SSMIS (below) Microwave (85 GHz) images from the CIMSS Tropical Cyclones site revealed that the eye was still partially open at 1811 UTC and 1945 UTC.

DMSP-16 SSMIS Microwave (85 GHz) image at 1845 UTC [click to enlarge]

DMSP-16 SSMIS Microwave (85 GHz) image at 1845 UTC [click to enlarge]

===== 10 September Update =====

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with GLM Group lightning [click to enlarge]

GOES-16 GLM lightning Groups (aggregates of GLM lightning Events) are plotted on “Red” Visible (0.64 µm) images (above) and “Clean” Infrared Window (10.3 µm) images (below), courtesy of Dave Santek, SSEC.

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images, with GLM Group lightning [click to enlarge]

Overlapping GOES-16 and GOES-17 Mesoscale Domain Sectors were positioned over Hurricane Florence beginning at 1200 UTC (providing imagery at 30-second intervals) — Visible animations are shown below.

* GOES-17 images shown here are preliminary and non-operational *

GOES-16

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

GOES-17

GOES-17 “Red” Visible (0.64 µm) images [click to play MP4 animation]

Longer animations of 30-second GOES-16 Visible and Infrared images viewed using AWIPS (below) provided a better view of  the mesovortices within the eye. Florence rapidly intensified (ADT | SATCON) to a Category 4 hurricane during this period.

GOES-16

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

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images [click to play MP4 animation]

One particularly large mesovortex rotated around the eastern edge of the eye after 2100 UTC, significantly eroding the eyewall (below).

GOES-16

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

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images [click to play MP4 animation]

Later in the early evening hours, GOES-16 Infrared imagery (below) showed an area of pronounced cloud-top warming and a thinning of cloud material just south of the eyewall, as Florence began to undergo an eyewall replacement cycle.

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images [click to play MP4 animation]

Super Typhoon Jebi

August 31st, 2018 |

Himawari-8

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

West Pacific Typhoon Jebi underwent a period of very rapid intensification on 30 August 2018 (ADT | SATCON), reaching Category 5 Super Typhoon intensity. Himawari-8 rapid-scan (2.5 minute interval) “Clean” Infrared Window (10.4 µm) images (above) showed that Jebi began to exhibit an annular appearance with a nearly symmetric eyewall as it moved through the Northern Mariana Islands (north of Guam). The eye passed just south of the uninhabited volcanic island of Pagan around 16 UTC on 30 August.

Himawari-8 “Red” Visible images (below) revealed mesovortices within the eye of Jebi.

Himawari-8

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

Toggles between VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP (below) showed more detailed views of (1) the well defined eye, (2) surface mesovortices within the eye, and (3) storm-top gravity waves that were propagating away from the eyewall region. With the Moon in the Waning Gibbous phase (at 77% of Full), ample illumination was available to provide detailed “visible images at night” using the VIIRS DNB.

NOAA-20 Day/Night Band (0.7 µm) and infrared Window (11.45 µm) images at 1602 UTC [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and infrared Window (11.45 µm) images at 1602 UTC [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and infrared Window (11.45 µm) images at 1652 UTC [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and infrared Window (11.45 µm) images at 1652 UTC [click to enlarge]

Convective Rain Rate and Surface Rain Rate products derived from GCOM-W1 AMSR2 data (below) showed the heavy rainfall occurring within the eyewall region and a primary feeder band to the west. VIIRS and AMSR2 images courtesy of William Straka, CIMSS.

GCOM-W2 AMSR2 Convective Rain Rate and Surface Rain Rate products [click to enlarge]

GCOM-W2 AMSR2 Convective Rain Rate and Surface Rain Rate products [click to enlarge]

As Jebi tracked west-northwestward across the West Pacific, products from the CIMSS Tropical Cyclones site showed that it had been moving over waters having high values of Sea Surface Temperature and Ocean Heat Content (below).

Track of Jebi, with Sea Surface Temperature and Ocean Heat Content [click to enlarge]

Track of Jebi, with Sea Surface Temperature and Ocean Heat Content [click to enlarge]

A 48-hour animation of the MIMIC-TC product (below) showed the evolution of the Jebi from 29-31 August. The storm was completing an eyewall replacement cycle near the end of the animation, with the eye becoming distinctly larger.

MIMIC-TC product, 29-31 August

In a comparison of DMSP-16 SSMIS Microwave (85 GHz) and Himawari-8 Infrared Window (10.4 µm) images at 1900 UTC (below), the Microwave data helped to better visualize the structure of the large eyewall in addition to a long, narrow feeder band wrapping inward toward the eye.

DMSP-16 SSMIS Microwave (85 GHz) and Himawari-8 Infrared Window (10.4 µm) images [click to enlarge]

DMSP-16 SSMIS Microwave (85 GHz) and Himawari-8 Infrared Window (10.4 µm) images [click to enlarge]

Typhoon Soulik in the northwest Pacific Ocean

August 20th, 2018 |

Himawari-8 AHI Band 13 Clean Window (10.4 µm) imagery, 0900-1400 UTC on 18 August 2018 (Click to animate)

Typhoon Soulik, south of Japan and moving westward, has acquired a very large eye — almost 100 miles across! Himawari-8 imagery, above (courtesy JMA), shows the evolution and enlargement of the eye between 0900 and 1400 UTC on 20 August 2018.

GCOM, Suomi NPP and NOAA-20 all passed over Soulik between 1600 and 1715 UTC on 18 August. The Infrared Toggle, below, from NOAA-20 (1608 UTC) and Suomi NPP (1658 UTC) also shows a large eye.

NOAA-20 (1608 UTC) and Suomi NPP (1658 UTC) 11.45 µm Infrared Imagery of Soulik on 18 August 2018 (Click to enlarge)

Day Night Band Imagery from Suomi NPP, below, also shows a large eye. There was little lunar illumination occurring at the time because the moon was below the horizon.

Suomi NPP Day Night Band Visible (0.70 µm) Imagery over Soulik, 1658 UTC on 18 August 2018 (Click to enlarge)

GCOM overflew Soulik at 1702 UTC, and the AMSR-2 instrument on board gave estimates of rain rate, both convective and a the surface. Those are toggled below.

GCOM AMSR-2 Microwave estimates of Precipitation over Soulik, 1702 UTC on 18 August 2018 (Click to enlarge)

(Suomi NPP, NOAA-20 and GCOM imagery courtesy William Straka, CIMSS)

Soulik’s eye was wide enough that a NUCAPS soundings retrieval (Click here for more information on NUCAPS soundings) could be made from data collected during a Suomi-NPP overpass at 0350 UTC on 21 August 2018.  Note the green sounding location within Soulik’s eye — Green dots denote regions where the infrared retrieval was successful.  The sounding at that point is shown below. (NUCAPS imagery courtesy Landon Aydlett, WFO Guam).

Suomi NPP NUCAPS sounding locations at 0350 UTC on 21 August 2018 on top of AHI 10.4 µm Clean Window imagery (Click to enlarge)

Suomi NPP NUCAPS Sounding within the eye of Soulik at 0350 UTC on 21 August 2018 (Click to enlarge)

You can use NUCAPS Soundings to diagnose the difference between the environment in the storm eye, and in the surrounding environment. The animation below shows locations of 5 soundings, one in the Eye, and one north, east, south and west of the CDO.  The five selected soundings are shown at the bottom, with insets showing which sounding is which.  The sounding in the eye shows remarkable warmth, as expected:  at 555 hPa, for example, eye temperatures are around 8º C;  values at the 4 outside points range from 0.4º to 2.9º C.  Sounding parameters as viewed in AWIPS can be seen here.

Suomi NPP NUCAPS Sounding Points overlain on a Day Night Band Image, ~0350 UTC on 21 August 2018 (Click to enlarge). Sounding locations are indicated.

NUCAPS Soundings in and around Typhoon Soulik at the locations indicated, ~0350 UTC on 21 August 2018 (Click to enlarge)

Soulik’s path is projected to remain south of Japan and approach the Korean Peninsula by mid-week. For more information on Soulik, consult the CIMSS/SSEC Tropical Weather Website, or the Joint Typhoon Warning Center.

Hurricane Lane in the eastern Pacific Ocean

August 17th, 2018 |

NOAA-20 VIIRS Imagery at 1023 UTC on 17 August 2018. Day Night Band Visible (0.7 µm) and I05 Infrared (11.45 µm) imagery are shown (Click to enlarge)

The active eastern Pacific Hurricane season continues, as Lane has formed. Suomi NPP and NOAA-20 overflew the system early on 17 August 2018. The toggle above, from NOAA-20’s VIIRS Instrument, shows both the Day Night Band 0.70 µm visible Image and the 11.45 µm infrared channels. Lack of lunar illumination means that only Earthglow is making clouds visible; a distinct eye is not present. The step animation below between the NOAA-20 11.45 µm infrared and, 50 minutes later, Suomi NPP’s 11.45 µm Infrared, right at the limb of the scan, also show no distinct eye.

VIIRS I05 11.45 µm Infrared Imagery from NOAA-20 (1023 UTC) and Suomi NPP (1113 UTC) on 17 August 2018 (Click to enlarge)

In fact, however, an eye was likely present at this time. As noted in the National Hurricane Center’s 0900 UTC Discussion (Link), “Recent microwave images show a well-defined low-level eye, but this feature is not yet apparent in geostationary satellite images.”  AMSR-2 (Advanced Microwave Scanning Radiometer 2) estimates of Convective Precipitation and Surface Rainfall in the toggle below (data from 1003 UTC) show a distinct eye.  AMSR-2 is a microwave instrument that flies on JAXA’s GCOM satellite;  microwave views of tropical cyclones are able to penetrate the cirrus shield that is commonly present, revealing important information about the low-level structure of a developing system.

GCOM AMSR-2 estimates of convective precipitation and surface rainfall rates at 1003 UTC on 17 August 2018 (Click to enlarge)

Polar Orbit tracks are available here. For the latest information on Hurricane Lane, refer to the National Hurricane Center or to the CIMSS/SSEC Tropical Weather Website. Imagery from Polar Orbiters are available at this site that shows data from an antenna in Honolulu.

Thank you to William Straka, CIMSS, for the imagery.