Hurricane Bud

June 12th, 2018 |

GOES-16

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

East Pacific Hurricane Bud peaked at Category 4 intensity (ADT | SATCON) around 06 UTC on 12 June 2018 (just 4 days after Hurricane Aletta reached the same intensity) — and a GOES-16 (GOES-East) Mesoscale Sector was positioned over the storm about an hour before that time, providing “Clean” Infrared Window (10.3 µm) images at 1-minute intervals (above).

A post-sunrise comparison of 1-minute GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images is shown below.

GOES-16 "Red" Visible (0.64 µm, left) and "Clean" Infrared Window (10.3 µm, right) images [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.3 µm, right) images [click to play MP4 animation]

Ocean Heat Content and Sea Surface Temperature analyses, with the track of Hurricane Bud ending at 12 UTC on 12 June [click to enlarge]

Ocean Heat Content and Sea Surface Temperature analyses, with the track of Hurricane Bud ending at 12 UTC on 12 June [click to enlarge]

As mentioned in the NHC discussion at 15 UTC, Bud was beginning to move over water having lower values of Ocean Heat Content and Sea Surface Temperature (above), which would lead to rapid weakening — in fact, an erosion of the northern eyewalll was seen in DMSP-16 SSMIS Microwave imagery at 1105 UTC (below).

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

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

Hurricane Aletta

June 7th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.3 µm, right) images [click to play MP4 animation]

Tropical Storm Aletta was upgraded to Hurricane Aletta at 21 UTC on 07 June 2018. As was the case on 06 June, a GOES-16 Mesoscale Domain Sector centered over the tropical cyclone provided 1-minute data — and an eye eventually became apparent on  “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) imagery (above).

DMSP-15, DMSP-17 and GPM GMI Microwave (85 GHz) imagery from the CIMSS Tropical Cyclones site (below) showed an increase in organization of the eye structure as the day progressed.

DMSP-15 SSMI Microwave image [click to enlarge]

DMSP-15 SSMI Microwave image [click to enlarge]

DMSP-17 SSMIS Microwave image [click to enlarge]

DMSP-17 SSMIS Microwave image [click to enlarge]

GPM GMI Microwave image [click to enlarge]

GPM GMI Microwave image [click to enlarge]

===== 08 June Update =====

GOES-16

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

Aletta went through a period of rapid intensification (ADT | SATCON), reaching Category 4 status by 15 UTC on 08 June. 1-minute GOES-16 Infrared (10.3 µm) images (above) showed the eye becoming more well-defined during the pre-dawn hours.

After sunrise, GOES-16 Visible images (below) initially hinted at the presence of mesovortices within the eye of Aletta.

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.3 µm, right) images [click to play MP4 animation]

Aletta had been moving over relatively warm water and within an environment characterized by low values of deep-layer wind shear (below) — both  of which were favorable factors for intensification. An animation of the deep-layer wind shear over the East Pacific Ocean during 06-07 June is available here.

Sea Surface Temperature and Deep-Layer Wind Shear products [click to enlarge]

Sea Surface Temperature and Deep-Layer Wind Shear products [click to enlarge]

Aletta peaked in intensity later in the day on 08 June (ADT | SATCON) — as pointed out by NHC “This is also consistent with GOES-16 measurements of increased inner-core lightning observed to be occurring to the east of the eastern eyewall, which some research suggests corresponds to a halting of the intensification process”. GOES-16 Infrared (10.3 µm) imagery with GLM Group Density counts are shown below.

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) with GLM Group Density counts [click to play MP4 animation]

Cyclone Mekunu in the northwest Indian Ocean

May 23rd, 2018 |
Meteosat-8 Infrared 10.8 µm imagery, 1630 UTC 22 May - 1715 UTC 23 May 2018 (Click to animate)

Meteosat-8 Infrared 10.8 µm imagery, 1630 UTC 22 May – 1715 UTC 23 May 2018 (Click to animate)

Cyclone Mekunu in the northwest Indian Ocean was approaching Oman and Yemen on the Arabian Peninsula on 23 May 2018, as shown in the animation above. Morphed Microwave Imagery, below, (from this site) for the 24 hours ending at 1900 UTC on 23 May 2018, shows the storm at the periphery of deep tropical moisture.  This moisture will likely lead to devastating floods in the desert regions of Oman and Yemen as the storm approaches. (News Link 1, 2 and 3).  Cyclone Chapala that affected the region in 2015 also caused devastating floods.

Microwave-based Total Precipitable Water for 24 hours ending 1900 UTC on 23 May 2018 (Click to enlarge)

Microwave imagery, below, (from this site) shows how the organization of the storm changed in the 24 hours ending around 1600 UTC on 23 May 2018.   AMSU microwave imagery for this storm can be found here (off of this website).

Morphed Microwave Imagery over Mekunu for the 24 hours ending at 1600 UTC (Click to enlarge)

Satellite intensity estimates for the storm are shown below (taken from this website). The Meteosat-8 infrared animation, above, shows a periodic increase and decay in the strong convection near the center. Satellite estimates of strength (below) show a consistent lowering of the central pressure of the storm, however; winds have consistently increased.

Satellite-based estimates of Mekunu’s central pressure (Click to enlarge)

Mekunu is traversing a region with very high Sea Surface Temperatures and modest shear. Significant weakening is not forecast.

Sea Surface Temperatures and Shear over the northwest Indian Ocean (Click to enlarge)

More information on this unusual tropical cyclone can be found at the CIMSS Tropical Weather Website (link) and the CIRA Tropical Weather Website (link).

=============== Added, 24 May 2018 ==============

Suomi-NPP overflew Mekunu at 2133 UTC on 23 May 2018, and the toggle below (between the Day Night Band and the 11.45 µm infrared;  Click here for a zoomed-in toggle between the Day Night Band and the 11.35 µm infrared image) shows the storm well-illuminated by a waxing gibbous Moon.  Strong convection with lightning is apparent north of the island of Socotra.  (VIIRS imagery courtesy Will Straka, CIMSS)

Suomi NPP VIIRS Infrared (11.45 µm) and Day Night Band Visible (0.70 µm) imagery over Mekunu, 2133 UTC on 23 May 2018 (Click to enlarge)

=============== Added, 25 May 2018 ==============

Mekunu is approaching the coast of Oman on 25 May 2018 from the southeast.  The animation below of visible (0.6 µm, left) and Infrared (10.8 µm ,right) imagery shows a compact storm with deep convection around an eye.  Microwave Imagery for the 24 hours ending at 1300 UTC on 25 May (here, from this site) suggest Mekunu is strengthening as it nears the coast. (Satellite-estimated winds and pressure also suggest strengthening near landfall).

Meteosat-8 Visible (0.6 µm, left) and Infrared (10.8 µm, right) imagery over Mekunu, 1145 UTC on 24 May to 1215 UTC on 25 May 2018 (Click to animate)

Visible Imagery from 1045 to 1430 UTC, below, suggests landfall will occur shortly after sunset east of the Oman/Yemen border.  Infrared Imagery (at bottom) shows a landfall near 1800 UTC.

Meteosat-8 Visible (0.6 µm, left) imagery over Mekunu, 1045 UTC to 1430 UTC on 25 May 2018 (Click to animate)

Meteosat-8 Infrared (10.8 µm, left) imagery over Mekunu, 1415 UTC to 1830 UTC on 25 May 2018 (Click to animate)

Surface observations from Salalah, in southern Oman (click here), show sustained tropical-storm force winds, with gusts to 60 knots, from the east for several hours today. Normal annual precipitation for the region is about 5″.

Super Typhoon Jelawat

March 30th, 2018 |

Himawari-8 “Red” Visible (0.64 µm) Imagery, hourly from 2200 UTC 29 March through 0800 UTC 30 March (Click to animate)

Super Typhoon Jelawat has developed in the central Pacific Ocean, to the west of Guam and the Marianas Islands. The hourly imagery, above, from Himawari-8, from 2200 UTC on 29 March through 0800 UTC on 30 March show a rapid eye development. Satellite presentation seems best at around 0500 UTC, with a well-defined eye. Subsequently, high clouds covered the eye as it became less symmetric.

Himarwari-8 AHI Band 13 (“Clean Window”, 10.41 µm) Infrared Imagery, 2300 UTC on 29 March 2018 through 0140 UTC on 30 March 2018 (Click to enlarge)

Infrared Imagery (10.41 µm) imagery, above, shows a well-defined eye shortly after 0000 UTC. Following a data outage, imagery from 1400 UTC to 1600 UTC, below, shows a central region of cold convective clouds, but no obvious eye.

Himarwari-8 AHI Band 13 (“Clean Window”, 10.41 µm) Infrared Imagery, 1420 UTC on 30 March 2018 through 1600 UTC on 30 March 2018 (Click to enlarge)

Water Vapor Infrared Imagery from Himawari, below, shows that outflow from Jelawat is well-established to the north; outflow appears to be entrained into the mid-latitude westerlies. MIMIC Total Precipitable Water for the 24 hours ending 1600 UTC on 30 March (shown underneath the water vapor infrared imagery below) also shows the entrainment of tropical moisture around Jelawat into mid-latitudes.  The Total Precipitable Water shows a band of rich moisture extending to the east-southeast of Jelawat, portending a wet period for the Marianas Islands.

Himawari-8 AHI Water Vapor Imagery, Bands 8 (6.24 µm) and 10 (7.35 µm) at 1600 UTC on 30 March 2018 (Click to enlarge)

Morphed Microwave Observations of Total Precipitable Water, 1700 UTC on 29 March 2018 to 1600 UTC on 30 March 2018 (Click to enlarge)

Morphed Storm-centered Microwave Imagery for the 24 hours ending at 0900 UTC on 30 March, 2018 (from this site), show the rapid intensification after 0000 UTC on 30 March.  (Update:  a similar animation that ends at 1900 UTC on 30 March 2018 demonstrates a rapid collapse of the eyewall convection!)

Morphed Microwave Imagery for the 24 hours ending at ~0900 UTC on 30 March 2018 (Click to enlarge)

Full-resolution Visible Imagery from AHI (Band 3, 0.64) is shown below. (Faster and slower animations are available). A rapid organization and clearing of the eye is apparent around 0400 UTC with an equally-rapid apparent subsequent obscuration.

Full-Resolution Himawari-8 “Red” Visible (0.64 µm) Imagery, hourly from 0000 UTC 30 March through 0850 UTC 30 March (Click to animate)

GCOM overflew the storm at around 1610 UTC on 30 March, and the toggle below shows the 36.5 and 89.0 Ghz imagery over the storm (the same enhancement is used in each image).  The 36.5 Ghz imagery suggests a very asymmetric storm.  Eyewall convection in the 89 Ghz imagery is not robust. (These data were downloaded at the Direct Broadcast antenna on Guam and are courtesy Kathy Strabala, SSEC/CIMSS)

GCOM AMSR-2 36.5 and 89.0 GHz imagery over Jelawat, 1604 UTC on 30 March 2018 (Click to enlarge)

NOAA-20 and Suomi NPP also both overflew Jelawat around 1600 UTC on 30 March. The toggles below show NOAA-20 and then Suomi NPP Day Night Band visible imagery. and Infrared 11.45 Imagery, at 1549 and 1639 UTC. (Imagery courtesy William Straka, SSEC/CIMSS)  In contrast to the Visible and Infrared imagery from Himawari earlier in the day (at top), an eye is not present.  (Note that NOAA-20 data are provisional, non-operational, and undergoing testing still.)

VIIRS Infrared Imagery (11.45 µm) from NOAA-20 (1549 UTC) and Suomi NPP (1639 UTC) on 30 March 2018 (Click to enlarge)

VIIRS Day Night Band Visible Imagery (0.70 µm) from NOAA-20 (1549 UTC) and Suomi NPP (1639 UTC) on 30 March 2018 (Click to enlarge)

Suomi NPP also overflew the storm on 29 March 2018, at 0421 UTC. This was before Jelawat’s rapid intensification. The toggle below again uses data from the Direct Broadcast antenna on Guam and shows VIIRS visible (0.64 µm) and infrared (11.45 µm) imagery, MIRS products (Total Precipitable Water and Rain Rate) derived from data from the ATMS microwave sounder on Suomi NPP, and individual microwave channels from ATMS: 31, 88, 165 and 183 Ghz.

Suomi NPP VIIRS Visible (0.64 µm) and Infrared (11.45 µm) Imagery, MIRS Total Precipitable Water and Rain Rate, and individual Suomi NPP ATMS Channels: 31, 88, 165 and 183 GHz, all at 0421 UTC on 29 March 2018 (Click to enlarge)

Interests in the Marianas Islands should closely monitor the progress and evolution of this storm. This site and this site both have information on the system.