GOES-13 10.7 µm IR images (click to play animation)

4-km resolution GOES-13 (GOES-East) 10.7 µm IR channel images (above; click image to play animation) showed the development and northward propagation of clusters of thunderstorms across Arizona on 04 May 2015. The coldest cloud-top IR brightness temperature was -49º C (darker red color enhancement). As the storms later organized into a mesoscale convective system, cloud-to-ground lightning strikes were seen to exceed 100 per 15-minute period.

A higher resolution view could be seen in a comparison of Suomi NPP VIIRS 0.7 µm Day/Night Band (DNB) and 11.45 µm IR channel images at 0940 UTC or 2:40 AM local time (below). Since the Moon was in the Waning Gibbous phase at 99% of full, this served as a good example of the “visible image at night” capability of the VIIRS Day/Night Band.

Suomi NPP VIIRS 0.7 µm Day/Night Band and 11.45 µm IR images, with METAR surface reports and 1-hour cloud-to-ground lightning strikes

One ingredient that aided in the thunderstorm development was rich moisture, as was noted in this excerpt from a NWS Phoenix forecast discussion:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
840 AM MST MON MAY 4 2015

HOWEVER WHAT WAS NOT SO OBVIOUS…AND A MODEL FAILURE…WAS THE AMOUNT OF BOUNDARY LAYER MOISTURE ADVECTED INTO SOUTHERN AZ FROM MEXICO LATE YESTERDAY AFTERNOON AND NIGHT. JUST LOOK AT THIS MORNINGS TUCSON BALLOON SOUNDING. IT SHOWED AN 800 MB DEWPOINT OF 9 DEG C WHICH LOOKS MONSOONISH. IN OTHER WORDS THE BOUNDARY LAYER MOISTURE THROUGH 700 MB WAS IMPRESSIVE.

This northward transport of moisture could be seen on GOES-15 sounder Total Precipitatble Water (TPW) derived product images (below; click image to play animation); TPW values even exceeded 30 mm or 1.18 inches (yellow color enhancement) as early as 02 UTC on 04 May, reaching a peak of 33.4 mm or 1.3 inches at 04 UTC. A comparison of the Tucson rawinsonde data profiles from 12 UTC on 03 May and 00/12 UTC on 04 May can be seen here — TPW values at that location increased from 13.5 mm (0.53 inch) to 22.3 mm (0.88 inch) during that 24-hour period.

GOES-15 sounder Total Precipitable Water derived product images (click to play animation)

Later in the day on 04 May, as thunderstorms moved northward across the Interstate 40 corridor in northeastern Arizona, swaths of rain-cooled wet ground appeared as lighter-gray areas on the Aqua MODIS 11.0 µm IR image at 2008 UTC (below). These swaths of wet soil exhibited IR brightness temperatures that were as much as 10º C cooler than the adjacent dry soil surfaces which were heating up quickly during the early afternoon hours.

Terra (1828 UTC) and Aqua (2008 UTC) MODIS 11.0 µm IR images

The corresponding 2008 UTC Aqua MODIS Land Surface Temperature (LST) product (below) made it easier to discriminate between the cooler swaths of wet ground (LST values between 70 and 85º F, shades of green) and the adjacent areas of dry soil (LST values as warm as 100-116º F, darker shades of orange).

Aqua MODIS Land Surface Temperature product

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Himawari-8 11.22 µm infrared imagery, 0000 – 1830 UTC on 28 April 2015 (click to play animation)

The 10-minute full-disk imagery that is available from Himawari-8 captures the evolution of Tropical Depression 24S northwest of Australia. Convection is evolving on time-scales of 10 minutes or less, so the high temporal resolution is vital to describing the storm evolution. Of particular note are the development (and decay) of central dense overcast features near the storm center, which have a timescale of less than 30 minutes. Note also the well-developed outflow channel curving anticyclonically to the south and east of the storm.

Sea surface temperature fields (from this site) show very warm ocean waters (SSTs exceed 30º C). Wind shear over the system is small; strengthening is expected.

29 April Update: As anticipated, Tropical Depression 24S continued to intensify, becoming Tropical Storm Quang. A comparison of an MTSAT-2 visible image at 0132 UTC with an overlay of 0135 UTC ASCAT scatterometer winds, below, shows surface winds in the 40.0-45.9 knot range (yellow) in both the western and eastern hemispheres of the storm. A large convective burst (with overshooting tops) was apparent on the visible image, just south of the center of Quang.

MTSAT-2 visible image with ASCAT surface scatterometer winds

Himawari-8 Infrared imagery on 29 April show eye development between 1600 and 1800 UTC. Quang was upgraded to a Cyclone at 1800 UTC. (Link)

Himawari-8 11.22 µm infrared imagery, 0000 – 1830 UTC on 29 April 2015 (click to play animation)

The scanning strategy of the current operational MTSAT satellites is such that the Southern Hemisphere only receives 1 image per hour. The Himawari-8 satellite performs a Full Disk scan every 10 minutes — and as an MTSAT-2 10.8 µm IR vs Himawari-8 10.4 µm IR image comparison demonstrates (below; click image to play animation; also available as an MP4 movie file), the improved Himawari-8 spatial resolution (2 km vs 4 km) and more frequent scans allowed the formation of the eye of Quang to be more accurately followed as it rapidly intensified from a Tropical Storm to a Category 4 Severe Cyclone. A nighttime comparison of Suomi NPP VIIRS Day/Night Band and Infrared images on 29 April/1820 UTC (30 April/02:20 AM local time) can be seen here.

MTSAT-2 10.8 µm (top) and Himawari-8 10.4 µm (bottom) IR images [click to play animation]

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Himawari-8 3.9 µm shortwave IR images (click to play animation)

The Kilauwea Volcano on the Big Island of Hawai’i began erupting in March 2008 (blog post | USGS reference), and has been in a nearly continuous phase of activity since then. During the pre-dawn hours of 28 April 2015, thermal signatures of the Kilauwea summit lava lake and nearby lava flows could be seen on McIDAS-V images of 10-minute interval Himawari-8 3.9 µm shortwave IR images (above; click image to play animation). The dark black pixels represent the hottest IR brightness temperatures.

On the corresponding Himawari-8 2.3 µm near-IR channel images (below; click image to play animation), the clusters of bright white pixels represent the glow of the hot lava features.

Himawari-8 2.3 µm near-IR channel images (click to play animation)

A different view is provided by the polar-orbiting Suomi NPP satellite — a comparison of AWIPS II images of VIIRS 0.7 µm Day/Night Band and 3.74 µm shortwave IR data (below) revealed the locations of the hottest lava features (black to yellow to red color enhancement) at 11:40 UTC (1:40 am local time).

Suomi NPP VIIRS 0.7 µm Day/Night Band and 3.74 µm shortwave IR images

A longer animation using GOES-15 (GOES-West) 3.9 µm shortwave IR images (below; click image to play animation) showed considerable temporal fluctuation in the location and intensity of the hot lava pixels (black to yellow to red color enhancement). For the latest information on the Kilauea eruption, visit the Hawaiian Volcano Observatory.

GOES-15 3.9 µm shortwave IR images (click to play animation)

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NOAA/CIMSS ProbSevere Output from AWIPS on 24 April, 1902, 1908, 1912, 1930, 1938, 1944, 1948, 1950, 1954 and 1958 UTC (click to play animation)

Severe thunderstorms moved across central Texas on April 24th (Link). The NOAA/CIMSS ProbSevere product can be used with storms like this to alert a forecaster to when severe weather will develop. ProbSevere output tells you the probability that a given storm cell will first produce severe weather in the next 60 minutes. (The type of severe weather — hail, high winds or tornado) are not specified by the product. In the animation, a strong thunderstorm is just entering Coke county from Sterling county to the north of Tom Green county. The list below shows ProbSevere values with the three storms shown in the animation above.

1. 1902 UTC  (Northern Cell)  ProbSevere 46%
2. 1908 UTC (Northern Cell) ProbSevere 50%
3. 1912 UTC (Northern Cell) ProbSevere 85%
4. 1930 UTC (Northern Cell) ProbSevere 95%
5. 1932 UTC (Northern Cell) ProbSevere 95% (Severe Thunderstorm Warning active)
6. 1948 UTC (Southern Cell) ProbSevere 23%
7. 1950 UTC (Southern Cell) ProbSevere 50%
8. 1954 UTC (Middle Cell) ProbSevere 57%
9. 1956 UTC (Middle Cell) ProbSevere 70%

So, the northern cell crossed the 50% ProbSevere threshold at 1908 UTC, the southern cell crossed the 50% ProbSevere threshold at 1950 UTC, and the small middle cell had a >50% ProbSevere from the start, at 1954 UTC.

Severe hail (1.25″ in diameter) was reported at 1928 UTC (20 minutes after ProbSevere crossed the 50% threshold) 8 miles west (31.89 N, 100.62 W)of Robert Lee, TX (the county seat of Coke County). At 1957 UTC, 1.75″ Hail was reported four miles north (31.94 N, 100.30 W) of Bronte, TX (also in Coke County).

The middle cell in the animation above eventually merged with the southern cell, and intensified. The animation from 1958 through 2014 UTC is below. ProbSevere with the middle storm (that merges with the southern cell) is 70%, rising to 98% at 2014 UTC.

NOAA/CIMSS ProbSevere Output from AWIPS on 24 April, 1958, 2000, 2008, 2010, 2012, 2014 UTC (click to play animation)

At 2015 UTC, the National Weather Service issued a Severe Thunderstorm Warning. At this time, 2.75″ Hail was falling five miles northwest of Tennyson in Coke County. (31.79N, 100.35W). The 2016 UTC ProbSevere output is here.

The ProbSevere product is something that distills many bytes of information: model output that describes the environmental conditions, satellite data that describes the initial growth of convection, and MRMS radar data that captures the present state of a storm. The distilled data can be used to increase the confidence that a severe event will occur within the next 60 minutes.

An animation of the 10.7 µm imagery from 1800 through 2015 UTC is shown below. The locations of the severe hail reports noted above are included on the relevant images.

GOES-13 10.7 Brightness Temperature 1800-2015 UTC on 24 April 2015; Coke County is highlighted (click to play animation)

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