Super Typhoon Hagupit

December 4th, 2014
Advanced Dvorak Technique (ADT) intensity estimation plot

Advanced Dvorak Technique (ADT) intensity estimation plot

As seen on a plot of the Advanced Dvorak Technique (ADT) intensity estimation (above), Typhoon Hagupit underwent a period of rapid intensification in the West Pacific Ocean late in the day on 03 December 2014, reaching Super Typhoon (Category 5) intensity on 04 December. During this period of rapid intensification, COMS-1 10.8 µm IR channel images (below; click to play animation; also available as an MP4 movie file) showed the development of a well-defined eye, with very cold cloud-top IR brightness temperatures (in the -80 to -90º C range, shades of violet) in the surrounding eyewall region.

COMS-1 10.8 µm IR channel images (click to play animation)

COMS-1 10.8 µm IR channel images (click to play animation)

A nighttime comparison of Suomi NPP VIIRS 0.7 µm Day/Night Band and 11.45 µm IR channel images at 15:50 UTC on 03 December (below; images courtesy of William Straka, SSEC) showed great detail in the cloud top IR brightness temperature patterns, as well as demonstrated the “visible image at night” capability of the Day/Night Band (which benefited from an abundance of reflected moonlight from a nearly-full Moon).

Suomi NPP VIIRS 0.64 µm and 11.45 µm IR image comparison

Suomi NPP VIIRS 0.64 µm and 11.45 µm IR image comparison

A longer-term sequence (beginning on 30 November) of storm-centered COMS-1 IR images is shown below (click image to play animation).

COMS-1 10.8 µm storm-centered IR images (click to play animation)

COMS-1 10.8 µm storm-centered IR images (click to play animation)

COMS-1 0.675 µm visible channel images from the CIMSS Tropical Cyclones site (below; click image to play animation) revealed the presence of mesovortices within the eye of Hagupit, with intricatecloud-top banding structures seen surrounding the eye.

COMS-1 0.675 µm visible channel images (click to play animation)

COMS-1 0.675 µm visible channel images (click to play animation)

A DMSP SSMIS 85 GHz microwave image at 22:43 UTC on 04 December (below) also showed the well-defined eyewall structure of the storm.

DMSP SSMIS 85 GHz microwave image

DMSP SSMIS 85 GHz microwave image

For additional images and information on Super Typhoon Hagupit, see the VISIT Meteorological Interpretation blog.

===== 06 December Update =====

A comparison of MTSAT 10.8 µm IR and TRMM TMI 85 GHz microwave images just after 16:30 UTC on 06 December (below) showed the center of Hagupit making landfall on the island of Samar in the Philippines as a Category 3 typhoon. The slow-moving tropical cyclone dropped as much as 300-400 mm (12-16 inches) of rainfall.

MTSAT 10.8 µm IR and TRMM TMI 85 GHz microwave images

MTSAT 10.8 µm IR and TRMM TMI 85 GHz microwave images

Nuri transforms into a strong extratropical storm

November 9th, 2014
MTSAT-2 6.75 µm IR water vapor channel images (click to play animation)

MTSAT-2 6.75 µm IR water vapor channel images (click to play animation)

Super Typhoon Nuri has completed its transition to one of the strongest extratropical cyclones ever on record in the Bering Sea (Link; Shemya Island had a gust to 96 miles per hour!). The animation above (click here for an mp4, or view it on YouTube) covers the entire lifecycle, from birth out of the ITCZ over the western Pacific to occlusion 7500 km north in the Bering Sea. (A faster animation is available as a animated gif or mp4).

Total Precipitable Water, 0000 6 November 2014 through 0600 9 November 2014 (click to enlarge)

Total Precipitable Water, 0000 6 November 2014 through 0600 9 November 2014 (click to enlarge)

Animations of Total Precipitable Water (from MIMIC) from 6-9 November, above, show that deep tropical moisture associated with Nuri did not make it up into the Bering Sea, but instead was shunted off to the east. Earlier, moisture from Nuri was entrained into the development of a storm in the Bering Sea on 4-5 November. A streamer of high-level moisture in the outflow from Nuri moves northeastward and eastward. That storm subsequently slipped southeastward and made landfall over the Pacific Northwest on 8 November.

Suomi NPP Day Night Band Visible Imagery (0.70 µm) over the Bering Sea, 7-10 November 2014 (click to enlarge)

Suomi NPP Day Night Band Visibe Imagery (0.70 µm) over the Bering Sea, 7-10 November 2014 (click to enlarge)

Suomi NPP overflew the developing storm in the Bering Sea about every twelve hours, and the imagery above, from the GINA Direct Broadcast Antenna at the University of Alaska-Fairbanks, shows the rapid development of a tight swirl of clouds by early on 8 November. Subsequently, the weakening storm drifted northward through the Bering Sea.

GOES-15 also viewed the strong development, both in the window channel (YouTube video) and in the water vapor channel (YouTube video (Color Enhanced)). The visible animation, below, shows a strong cyclone by 0300 UTC on 8 November; at the subsequent sunrise, 2000 UTC, the system had occluded.

GOES-15 0.62 µm IR Visible Imagery on 7, 8 and 9 November 2014 (click to play animation)

GOES-15 0.62 µm IR Visible Imagery on 7, 8 and 9 November 2014 (click to play animation)

An extratropical storm containing the remnants of Ana makes landfall in North America

October 27th, 2014
GOES-15 6.5 µm water vapor channel images (click to play animation)

GOES-15 6.5 µm water vapor channel images (click to play animation)

A strong storm that contains the remnants of former central Pacific Hurricane Ana began to make landfall along the West Coast of North America on 27 October 2014 (12 UTC surface analysis). The 17-day animation of GOES-15 6.5 µm Water Vapor channel imagery, above, shows Ana emerging out of the Intertropical Convergence Zone, skirting south of Hawai’i, weakening and meandering in the central Pacific (showing the effects of strong vertical wind shear), briefly reaching Hurricane intensity again on 25 October, and eventually moving eastward after having been picked up and absorbed by a strong system in the Westerlies. Recurving tropical systems can sometimes be prolific rain producers in the mid-latitudes; however, the animation of MIMIC Total Precipitable Water, below, suggests that most of the tropical moisture that was associated with Ana was no longer present.

MIMIC Total Precipitable Water for 72 hours ending 1200 UTC 27 October 2014 (click to enlarge)

MIMIC Total Precipitable Water for 72 hours ending 1200 UTC 27 October 2014 (click to enlarge)

The annotated animation below shows 1200 UTC imagery from 11-27 October. The red arrow points to Ana, either as a developing tropical cyclone, Hurricane, or post-tropical system. An animation without the red arrow is here.

GOES-15 6.5 µm water vapor channel images (click to play animation)

GOES-15 6.5 µm water vapor channel images (click to play animation)

Hurricane Ana south of Hawai’i

October 21st, 2014
Advanced Dvorak Technique (ADT) intensity estimate plot for Ana

Advanced Dvorak Technique (ADT) intensity estimate plot for Ana

A plot of the Advanced Dvorak Technique (ADT) intensity estimate for Ana (above) shows that the strength of the tropical cyclone fluctuated during its multi-day lifetime (storm track), initially becoming a strong Tropical Storm on 15 October, weakening on 16 October, and then slowly intensifying into a Category 1 Hurricane. A sequence of Suomi NPP VIIRS 11.45 µm IR channel images (below; click image to play animation) shows Ana at various stages during the 15-21 October period; the coldest cloud-top IR brightness temperature seen was -95º C at 00:40 UTC on 19 October.

Suomi NPP VIIRS 11.45 µm IR channel images (click to play animation)

Suomi NPP VIIRS 11.45 µm IR channel images (click to play animation)

After prior testing of additional Rapid Scan Operations (RSO) capabilities, the GOES-15 satellite was placed into RSO mode over the Hawai’i region to monitor Ana. During the 17-19 October period that Ana was classified as a Hurricane, GOES-15 10.7 µm IR channel images (below; click image to play a 75 MB animated GIF; also available as an MP4 movie file) revealed a number of robust convective bursts, with some exhibiting cloud-top IR brightness temperatures in the -80 to -85º C range (violet color enhancement). This was the first operational implementation of GOES-West RSO imagery over the Hawai’i region since the early 1990s, and the higher frequency of images — 8 images per hour, instead of the routine 4 images per hour — proved to be helpful for monitoring Ana (CPHC forecast discussion).

Longer-term animations of GOES-15 RSO imagery covering the lifetime of Ana are available in YouTube format (IR | visible). Much of the Hawaiian Islands received heavy rain, with amounts in excess of 11 inches reported on Hawai’i and Oahu.

GOES-15 10.7 µm IR channel images (click to play animated GIF)

GOES-15 10.7 µm IR channel images (click to play animated GIF)

Even after Ana was downgraded to a Tropical Storm early on 20 October, a Suomi NPP VIIRS 11.45 µm IR image showed that cloud-top IR brightness temperatures were still as cold as -90º C (yellow pixels within the violet-enhanced cloud tops). Also note the presence of cloud-top gravity waves propagating outward away from the storm center.

Suomi NPP VIIRS 11.45 µm IR channel image, with overlays of surface analysis and surface observations

Suomi NPP VIIRS 11.45 µm IR channel image, with overlays of surface analysis and surface observations

Late in the day on 20 October, GOES-15 0.63 µm visible channel images (below; click to play animation; also available as an MP4 movie file) revealed that the Low-Level Circulation Center (LLCC) of Ana became exposed as it moved to the southwest from beneath the canopy of deep convective cloud tops. This was a result of moderate southwesterly deep-layer wind shear across the region.

GOES-15 0.63 µm visible channel images (click to play animation)

GOES-15 0.63 µm visible channel images (click to play animation)

During the following night, the exposed LLCC was still very apparent on a Suomi NPP VIIRS 0.7 µm Day/Night Band image at 12:30 UTC or 2:30 am local time (below).

Suomi NPP VIIRS 0.7 µm Day/Night Band image