Tropical Storm Ela east of Hawai’i

July 9th, 2015 |
Suomi NPP VIIRS visible (0.64 µm) and Infrared (11.45 µm) images of Tropical Depression 4E at 2224 UTC on 08 July

Suomi NPP VIIRS visible (0.64 µm) and Infrared (11.45 µm) images of Tropical Depression 4E at 2224 UTC on 08 July

Tropical Storm Ela began as Tropical Depression 4E about 900 miles east of Hilo, Hawai’i around 03 UTC on 08 July 2015. A comparison of daytime images of Suomi NPP VIIRS 0.64 µm Visible channel and 11.45 µm Infrared channel images (above) showed the somewhat disorganized appearance of TD 4E at 2224 UTC on 08 July — the low-level circulation center (LLCC) was located to the southwest of the clusters of deep convection associated with the system.

About 12 hours later, a nighttime comparison of VIIRS 0.7 µm Day/Night Band (DNB) and 11.45 µm Infrared channel images at 1052 UTC on 09 July (below) continued to show a similar disconnect between the LLCC and clusters of deep convection in the eastern semicircle of recently-upgraded Tropical Storm Ela. The coldest cloud-top IR brightness temperature in the convection closest to the storm center was -78º C. Even though the Moon was in the Waning Crescent phase (at 43% of Full), it still provided enough illumination to aid in the location of the LLCC, as noted in a discussion issued by the CPHC:

TROPICAL STORM ELA DISCUSSION NUMBER   7
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP042015
500 AM HST THU JUL 09 2015

A 1052Z VIIRS DAY/NIGHT BAND IMAGE WAS INSTRUMENTAL IN HELPING TO LOCATE THE PARTIALLY EXPOSED CENTER OF ELA THIS MORNING.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared (11.45 µm) images of Tropical Storm Ela at 1052 UTC on 09 July

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared (11.45 µm) images of Tropical Storm Ela at 1052 UTC on 09 July

According to satellite-derived winds products from the CIMSS Tropical Cyclones site, there was strong divergence and a well-defined outflow channel in the northern quadrant of Ela (below), whose center was located at 19.3º N 145.1º W at 09 UTC on 09 July.

GOES-15 water vapor (6.5 µm) images with satellite wind derived upper tropospheric divergence and winds

GOES-15 water vapor (6.5 µm) images with satellite wind derived upper tropospheric divergence and winds

The reason that the LLCC remained exposed from the elements of deep convection was the fact that Ela was encountering increasing amounts of southwesterly deep-layer wind shear as it tracked northwestward  (below).

GOES-15 Infrared (10.7 µm) images, with an overlay of deep-layer wind shear at 18 UTC on 09 July

GOES-15 Infrared (10.7 µm) images, with an overlay of deep-layer wind shear at 18 UTC on 09 July

========================= Added July 10 2015 ============================

The southwesterly shear over the storm decoupled the surface circulation from the overlying convection, and Ela was downgraded to a depression early on 10 July 2015. The 0700 UTC 10 July 2015 image below shows ASCAT Scatterometer winds depicting a low-level swirl well east of Hawai’i; deep convection with the system is hundreds of kilometers to the northeast.

ASCAT Scatterometer winds and GOES-15 infrared (10.7 µm) imagery, 0700 UTC 10 July 2015

ASCAT Scatterometer winds and GOES-15 infrared (10.7 µm) imagery, 0700 UTC 10 July 2015 (Click to enlarge)

Tornado-producing severe thunderstorm in northern Italy

July 8th, 2015 |
Metoesat-10 High Resolution Visible (0.8 µm) images (click to play animation)

Metoesat-10 High Resolution Visible (0.8 µm) images (click to play animation)

EUMETSAT Meteosat-10 SEVIRI High Resolution Visible (0.8 µm) images (above; click to play animation) showed the development of an isolated supercell thunderstorm that produced large hail and a violent tornado (1 fatality; estimated EF3 damage) near Venice, Italy (station identifier LIPZ) around 1530 UTC on 08 July 2015. Additional information and imagery is available from meteonetwork.

The corresponding Meteosat-10 Infrared (10.8 µm) images (below; click to play animation) revealed the development of a very cold overshooting top prior to the development of the tornado (1430-1500 UTC) — the minimum cloud-top IR brightness temperature was -70º C (darker black enhancement) on the 1445 UTC image. The overshooting top then rapidly collapsed, as seen by the warming cloud-top IR brightness temperatures on the 1515 and 1530 UTC images. Such an overshooting top collapse sometimes occurs prior to tornado formation in a supercell thunderstorm.

Meteosat-10 Infrared (10.8 µm) images (click to play animation)

Meteosat-10 Infrared (10.8 µm) images (click to play animation)

A close-up view of the 1500 UTC Metosat-10 Infrared (10.8 µm) image is shown below, as displayed using SSEC RealEarth.

Meteosat-10 Infrared (10.8 µm) image, displayed using RealEarth

Meteosat-10 Infrared (10.8 µm) image, displayed using RealEarth

Typhoons Chan-Hom and Nangka in the same Suomi NPP VIIRS Overpass

July 8th, 2015 |
Suomi NPP Day/Night Band (0.70 µm) and Infrared Window Channel (11.45 µm) images at 1616 UTC 8 July 2015 (Click to animate)

Suomi NPP Day/Night Band (0.70 µm) and Infrared Window Channel (11.45 µm) images at 1616 UTC on 8 July 2015 (click to enlarge)

The toggle above shows Suomi NPP VIIRS 0.7 µm Day/Night Band and the 11.45 µm Infrared images (courtesy of William Straka, SSEC). It is unusual because two strong tropical cyclones (Category 2 Typhoon Chan-Hom on the left, and Category 4 Typhoon Nangka on the right) are captured in one satellite overpass.

The Day/Night Band (DNB) image shows little evidence of lightning (bright white streaks) with either storm; due to ample illumination from a Third Quarter Moon (at 54% of Full),  the DNB was able to provide a “visible image at night”. Both images show Nangka to be the stronger storm: the eye is more pronounced, and is more symmetric. More information on these storms is available here.

Himawari-8 is now operational over the western Pacific

July 7th, 2015 |
Himawari-8 10.35 µm infrared imagery, 1447-2002 UTC on 6 July 2015 (Click to animate)

Himawari-8 6.2 µm (top), 6.9 µm (middle) and 7.3 µm (bottom) water vapor infrared imagery, 0000 UTC 5 July 2015 – 1200 UTC 7 July 2015 (click to animate)

The Japanese Meteorological Agency is using Himawari-8 as its operational satellite, effective 0200 UTC on 7 July 2015. The animation above shows two days of water vapor imagery from Himawari-8 (6.2 µm, top, 6.9 µm, middle and 7.3 µm, bottom) over the tropical Pacific, revealing the train of three tropical cyclones moving westward towards Asia (testimony to why satellite data are important!). Typhoon Nangka, on the right, has developed an eye. Himawari-8 samples a full-disk image every 10 minutes, with nominal 2-km resolution in the infrared channels. Moveable sectors are also available at 2.5-minute intervals, such as shown in this animation from here.

Himawari-8 has 0.5-km resolution in the 0.64 µm visible channel. A 3-hour animation over Typhoon Nangka, at routine 10-minute time-steps, is shown below.

Himawari-8 0.64 µm visible imagery, 0400 UTC 5 July 2015 - 0700 UTC 7 July 2015, showing Typhoon Nangka (Click to animate)

Himawari-8 0.64 µm visible imagery, 0400 UTC 5 July 2015 – 0700 UTC 7 July 2015, showing Typhoon Nangka (click to animate)

The sixteen channels on the AHI instrument onboard Himawari-8 are similar to those that will be found on the ABI instrument onboard GOES-R, which is scheduled for launch in March of 2016. The animation below shows all 16 channels of the Himawari-8 AHI.

Himawari-8 data, all AHI channels, over Typhoon Nangka, 0400 UTC 5 July 2015 - 0810 UTC 7 July 2015, (Click to animate)

Himawari-8 data, all AHI channels, over Typhoon Nangka, 0400 UTC 5 July 2015 – 0810 UTC 7 July 2015 (click to animate)

A very large (74 MegaByte) Himawari-8 true-color Red/Green/Blue (RGB) full-disk image at 0340 UTC is shown below (courtesy of Jerrold Robaidek, SSEC).

Himawari-8 true-color image

Himawari-8 true-color image

A few interesting features to point out on the full-disk image are shown below (from north to south):

Wildfire smoke and thunderstorms in Siberia

Wildfire smoke and thunderstorms in Siberia

Smoke from fires in Alaska and Canada

Smoke from fires in Alaska and Canada

Blowing dust/sand in the Gobi Desert, and air pollution in northeastern China

Blowing dust/sand in the Gobi Desert, and air pollution in northeastern China

Mountain waves downwind of Japan, and developing storms in the North Pacific Ocean

Mountain waves downwind of Japan, and developing storms in the North Pacific Ocean

Tropical Storm Linfa off the coast of China

Tropical Storm Linfa off the coast of China

Typhoons Chan-Hom and Nangka in the West Pacific Ocean

Typhoons Chan-Hom and Nangka in the West Pacific Ocean

Thunderstorms over the Indian Ocean

Thunderstorms over the Indian Ocean

Banded thunderstorms over northern New Zealand, and snow cover in the mountains of southern New Zealand

Banded thunderstorms over northern New Zealand, and snow cover in the mountains of southern New Zealand

Winter storm along the coast of Antarctica

Winter storm along the coast of Antarctica