Himawari-8 11.22 µm infrared channel images (click to play animation)

Himawari-8 infrared imagery (above, at 2.5-minute time steps and available here as an mp4) shows the development of an eye in Typhoon Dolphin shortly after 1400 UTC when the storm was northwest of Guam. With the subsequent arrival of daylight, mesovortices were clearly seen within the eye on 2.5-minute interval rapid scan visible images (animated gif | mp4 movie file).

About 2 hours prior to eye formation, a Metop satellite overpass allowed the ASCAT instrument to provide surface scatterometer winds of Typhoon Dolphin, overlaid on a MIMIC Total Precipitable Water (TPW) image (below; TPW animation). The maximum TPW values were in the 60-65 mm or 2.4-2.6 inch range, and the highest ASCAT wind value was 68 knots in the eastern eyewall region of the storm.

MIMIC TPW product, with an overlay of Metop ASCAT surface scatterometer winds

During the preceding daylight hours as Category 2 intensity Typhoon Dolphin was approaching Guam, rapid-scan (2.5-minute interval) 0.5-km resolution Himawari-8 0.64 µm visible channel images (below; click image to play animation; also available as an mp4 movie file) revealed a number of large convective bursts — but no eye was yet apparent. As the center of Dolphin passed between the islands of Guam and Rota, the peak wind gust was 70 knots at Agana, Guam (PGUM) and 92 knots at Anderson Air Force Base, Guam (PGUA).

Himawari-8 0.64 µm visible channel images (click to play animation)

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Himawari-8 11.22 µm infrared channel images (click to play animation)

The animation above (available here as an mp4, and here on YouTube) shows 11.22 µm infrared imagery at 2.5-minute time steps (bottom) and 10-minute time steps (top) from Himawari-8 on 14 May 2015. Category 2 intensity Typhoon Dolphin is approaching Guam, seen at the left edge of both panels in the frame. The 2.5-minute imagery gives a much better indication of the quick rise and decay of overshooting tops (IR brightness temperatures of the storm tops approach -95º C!). A 10-minute time step cannot fully resolve the evolution of these features. The 2.5-minute time step also better captures the divergent flow (and outward-propagating gravity waves) at the top of the central dense overcast. No eye was yet apparent in the infrared imagery, or on DMSP SSMI 85 GHz microwave imagery.

A similar animation from the previous day, 13 May, is shown here: gif, mp4, YouTube. The better organization of the storm on 14 May is readily apparent.

How high are the clouds in the Central Dense Overcast (CDO)? Cloud Heights are available from CLAVR-x (Clouds from AVHRR Extended). Data from Geostationary Satellites are processed and are available to download here. Values from COMS-1 and from MTSAT-2 (displayed with McIDAS-V) suggest maximum cloud heights near 55,500 feet.

The MIMIC Total Precipitable Water (TPW) product, below, showed that Typhoon Dolphin was able to tap rich moisture from the Intertropical Convergence Zone (ITCZ) during the 13-14 May period; TPW values within the tropical cyclone circulation were often in the 60-65 mm or 2.5-2.6 inch range (darker red color enhancement).

MIMIC Total Preciptable Water product (click to play animation)

Visible Imagery from Himawari-8, just after sunrise on 15 May, show continuous development of short-lived overshooting tops to the east of Guam. More information on the storm is available at the CIMSS Tropical Cyclones site, the JMA Tropical Cyclone site and the Joint Typhoon Warning Center.

Himawari-8 0.6363 µm visible channel images (click to play animation)

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Himawari-8 0.64 µm visible channel images (click to play animation)

Following a period of rapid intensification, Super Typhoon Noul reached Category 5 strength late in the day on 09 May 2015 (ADT plot) as it slowly approached the northern tip of the Philippine island of Luzon. The Japanese Meteorological Agency (JMA) positioned one of the Himawari-8 rapid-scan “target” areas over the tropical cyclone, providing images at 2.5-minute intervals; 0.5-km resolution 0.64 µm visible (Band 4) images (above; click image to play animation; also available as an MP4 movie file and YouTube Video) showed intricate mesovortices within the eye, as well as gravity waves propagating radially outward from the eyewall region.

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GOES-13 0.63 µm Visible images (click to play animation)

Atmospheric Bores form in stable air and create horizontal cloud bands that propagate perpendicular to the along-band direction. The feature seen above in GOES-13 visible imagery formed in stable air south of a High Pressure system that pushed a backdoor cold front into New England (surface analyses). The southern edge of this bore was likely eroding as it became influenced by warmer less-stable air over with the Gulf Stream — the warm waters of the Gulf Stream were apparent in the toggle, below, of POES AVHRR 0.86 µm visible and 12.0 µm infrared imagery at 1055 UTC. The bore was apparently moving over the top of a shallow layer of sea fog that had formed in the colder waters north of the Gulf Stream.

POES AVHRR 0.86 µm Visible image and 12.0 µm Infrared image at 1055 UTC on 8 May 2015 (click to enlarge)

Suomi NPP overflew the area at ~1800 UTC, affording a very high resolution view of the bore structures with the VIIRS 0.65 µm visible channel, below.

Suomi NPP VIIRS Visible (0.65 µm) imagery, 1807 UTC on 8 May 2015 (Click to enlarge)

The daytime propagation of the bore feature could also be followed on POES AVHRR 0.86 µm visible channel images, shown below.

POES AVHRR 0.86 µm visible images (click to enlarge)

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