MTSAT-2 6.7 µm water vapor channel images (click image to play animation)

Tornadoes are relatively rare in Japan, and the majority of them occur in association with tropical cyclones — but a tornado struck the city of Tsukuba, Japan on 06 May 2012, and was responsible for one fatality, over 40 injuries, and damage (rated F2 to F3) to nearly 500 homes and buildings. MTSAT-2 6.7 µm water vapor channel images (above; click image to play animation) showed that strong convection developed over Japan along the eastern periphery of a large upper-level low. The location of Tokyo Narita International Airport (station identifier RJAA) is overlaid on the images — Tsukuba is about 30 miles northwest of RJAA.

Also important to note on the water vapor imagery (prior to 05 UTC) was the appearance of a small area of lee waves immediately downwind of the Mt. Fuji area (just to the west of RJAA), suggesting the presence of a strong jet streak moving northeastward over the Japanese island of Honshu. A longer animation showed the development of a number of distinct cyclonic vortices, many marked by a pronounced warm/dry signature on the water vapor imagery. These vortices corresponded to individual Potential Vorticity (PV) anomalies; one of the stronger PV anomalies moved just south of RJAA and helped to initiate a new cluster of convection offshore toward the end of the long animation.

A closer view using MTSAT-2 10.8 µm IR channel images (below; click image to play animation) showed that cloud top IR brightness temperatures associated with the tornadic supercell quickly cooled to the -55 to -60º C range (darker red color enhancement), and exhibited subtle cold/warm thermal couplets and brief enhanced-V signature at 04:01 UTC.

MTSAT-2 10.8 µm IR channel images (click image to play animation)

MTSAT-2 0.7 µm visible channel images (below; click image to play animation) revealed subtle indications of overshooting tops, as well as a brief anvil plume (at 06:32 UTC). The hazy signature of a blowing dust plume was also evident just to the south and east of Japan.

MTSAT-2 0.7 µm visible channel images (click image to play animation)

The tornado was reported to have occurred at Tsukuba around 1 pm local time (05:00 UTC), with hail at Mito around 1:20 pm local time (05:20 UTC). The location of the tornado (T) and hail (H) are overlayed on a close-up view of the 05:01 UTC MTSAT-2 0.7 µm visible channel image (below), which showed a well-defined flanking line boundary of convection feeding northwestward into the parent thunderstorm.

MTSAT-2 0.7 µm visible image + Surface reports + Tornado and Hail report locations

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

AWIPS images of 4-km resolution GOES-13 10.7 µm IR channel data (above; click image to play animation) showed the development of large thunderstorms over the far eastern Gulf of Mexico during the pre-dawn hours on 03 May 2012.

Better detail of the cold convective cloud tops could be seen in a series of 1-km resolution POES AVHRR 10.8 µm IR and MODIS 11.0 µm IR channel images (below).

POES AVHRR 10.8 µm IR and MODIS 11.0 µm IR images

McIDAS images of 1-km resolution GOES-13 0.63 µm visible channel data (below; click image to play animation) revealed the formation of a mesoscale convective vortex (MCV) after the night-time convection dissipated.

GOES-13 0.63 µm visible channel images (click image to play animation)

A GOES-13 10.7 µm IR image at 16:10 UTC with an overlay of ASCAT scatterometer surface winds at 16:05 UTC (below) suggested that the MCV was causing a perturbation in the general southeasterly flow as it was beginning to organize.

GOES-13 10.7 µm IR image + ASCAT scatterometer surface winds

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GOES-13 10.7 µm IR channel + 0.63 µm visible channel images (click image to play animation)

Surface outflow from dissipating convection over southern Manitoba, Canada during the pre-dawn hours on 02 May 2012 created an undular bore, which then propagated southeastward across northeastern North Dakota and northwestern Minnesota. AWIPS images of 4-km resolution GOES-13 10.7 µm IR channel data followed by 1-km resolution GOES-13 0.63 µm visible channel data after sunrise (above) showed the undular bore wave clouds. Surface winds associated with this convective outflow gusted to 30 knots in southern Manitoba at 12 UTC and 27 knots in northwestern Minnesota at 13 UTC.

POES AVHRR 12.0 µm IR image

An AWIPS image of 1-km resolution POES AVHRR 12.0 µm data (above) indicated that the wave cloud top IR brightness temperature was in the +2 to +3 C range. According to the 12 UTC rawinsonde data from International Falls, Minnesota (below), a temperature inversion located between 683 hPa and 693 hPa was likely acting to duct the undular bore as it moved southeastward.

International Falls, Minnesota rawinsonde data (12 UTC)

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Suomi NPP VIIRS 0.64 µm visible channel images

AWIPS images of Suomi NPP VIIRS 0.64 µm visible channel data (above) and 11.45 µm IR channel data (below) showed cloud and ice features over the Arctic Ocean on 28 April 2012. For geographic reference, station identifier CWMD is Mould Bay, located on Prince Patrick Island in the far northwestern portion of the Canadian Arctic Archipelago.

The meteorological cloud features at this time were fairly benign, with some low stratus seen over the northern portion of the satellite scene, and multi-level clouds associated with a cyclone developing to the south. Of particular interest was the amount of sea ice motion during this relatively short 8-hour period — several ice leads opened up and became very prominent features on both the visible and the IR imagery.

Suomi NPP VIIRS 11.45 µm IR channel images

Suomi NPP VIIRS 1.61 µm near-IR images (below) revealed a number of narrow “streaks” of supercooled water droplet clouds (which appear as brighter white features) moving away from the islands, suggesting that there were strong winds across the region helping to move the sea ice. Water (and cloud shadows) appear black on the near-IR images, while ice and snow cover appear as darker shades of gray.

Suomi NPP VIIRS 1.61 µm near-IR images

Surface analyses at 12 UTC and 18 UTC (below) indicated that there was a strong pressure gradient over the region, between the High over the Arctic Ocean and a deepening Low over far northern Canada. The effect of this tightening pressure gradient was strong offshore (easterly) winds — the closest available observation site was Sachs Harbour on Banks Island, where they had easterly winds of 25 knots with gusts to 30 knots, and zero visibility with heavy snow and heavy blowing snow at 22 UTC.

12 UTC and 18 UTC surface analyses (NOAA/NCEP/OPC)

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