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

McIDAS images of 1-km resolution GOES-15 0.63 µm visible channel data (above; click image to play animation) showed that Hurricane Emilia was beginning to exhibit as well-defined eye as it rapidly intensified over the East Pacific Ocean on 09 July 2012.

During the subsequent night-time hours, an eye signature was still evident on 4-km resolution GOES-15 1-.7 µm IR channel images (below; click image to play animation). Cloud top IR brightness temperatures were as cold as -82 C (violet color enhancement) at 06:00 UTC.

GOES-15 10.7 µm IR channel images (click image to play animation)

Emilia was in an environment of low deep-layer (850-200 hPa) wind shear (below), which was one factor that favored intensification.

GOES-15 10.7 µm IR images + Deep layer wind shear

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Suomi NPP VIIRS 11.45 µm IR + 0.7 µm Day/Night Band images

A comparison of AWIPS images of 375-meter resolution (projected onto a 1-km AWIPS grid) Suomi NPP VIIRS 11.45 µm IR channel data with the corresponding 0.7 µm VIIRS Day/Night Band (above) showed a large Mesocale Convective System (MCS) with an expansive cold cloud shield (exihibiting IR brightness temperatures as cold as -84 C) over parts of North Dakota and South Dakota at 08:43 UTC (3:43 AM local time) on 06 July 2012. A number of well-defined cloud-top gravity waves could also be seen propagating northward and northeastward outward away from the core of the storm. There was a damaging wind report at 09:03 UTC in south-central North Dakota:  SW WIND GUST OF 68 MPH AT 403 AM CDT...AND N WIND GUST OF 68 MPH AT 408 AM CDT. Illumination from a full moon made convective overshooting tops and some of these cloud-top gravity waves easy to see on the Day/Night Band image.

About 2 hours later, these cloud-top gravity waves wee more difficult to identify on a 1-km resolution POES AVHRR 10.8 µm IR image (below) at 10.32 UTC (5:32 AM local time), although a few could still be seen in eastern North Dakota, western Minnesota and southern Manitoba. There was a wind gust to 51 knots (59 mph) reported at 10:40 UTC in southeastern North Dakota.

POES AVHRR 10.8 µm IR channel image + METAR surface reports and severe wind reports

As the MCS began to dissipate around sunrise, a vivid display of transverse banding cirrus filaments could be seen on 1-km resolution GOES-13 0.63 µm visible channel images (below; click image to play animation) forming along the southern periphery of the storm over eastern South Dakota, southern Minnesota, and far northern Iowa. This transverse banding is a satellite signature of potential high-altitude turbulence — and there was one pilot report of moderate turbulence at 38,00 feet in eastern South Dakota.

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

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Suomi NPP VIIRS 0.7 µm Day/Night Band image + 3.74 µm shortwave IR image

A comparison of AWIPS images of the Suomi NPP VIIRS 0.7 µm Day/Night Band (DNB) with the corresponding 3.74 µm shortwave IR data (above) showed a large arc-shaped layer of dense smoke aloft over much of central South Dakota at 09:21 UTC (4:21 AM local time) on 04 July 2012, along with a number of shortwave IR “hot spots” (black to yellow to red color enhancement) and brightly-glowing DNB signatures from active wildfires that were burning in southeastern Montana and eastern Wyoming. Since the Moon was in the full phase, it provided good illumination of the various cloud features across the region.

The following afternoon, the dense smoke feature was still very evident over eastern South Dakota into western Minnesota on Terra and Aqua MODIS true-color Red/Green/Blue (RGB) images from the SSEC MODIS Direct Broadcast site (below). Other areas of smoke were seen in the vicinity of the fires in Montana and Wyoming. High aerosol concentrations were also indicated by the Suomi NPP Ozone Mapper Profiler Suite.

MODIS true-color Red/Green/Blue (RGB) images

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Suomi NPP 11.45 µm IR, 0.7 µm Day/Night Band, and 3.74 µm shortwave IR images

A comparison of AWIPS images of Suomi NPP VIIRS 11.45 µm IR, 0.7 µm Day/Night Band, and 3.74 µm shortwave IR data (above) showed (1) a pair of strong thunderstorms over the Montana/North Dakota/South Dakota border region, with cold cloud top IR brightness temperatures and excellent illumination of the overshooting tops and other cloud features due to the full phase of the moon, and (2) a few wildfires that were burning, with the largest ones being located in southeastern Montana and northeastern Wyoming. The wildfires exhibited “hot spots” (black to yellow to red color enhancement) on the shortwave IR image, and also appeared very bright on the Day/Night Band image due to the large areas of flames.

METAR surface reports plotted on the VIIRS IR image (below) revealed that Buffalo, South Dakota (station identifier K2WX) had a wind gust of 48 knots (55 mph). Hail of 2.0 inches in diameter was reported from this storm 25 minutes earlier at 09:15 UTC.

Suomi NPP VIIRS 11.45 µm IR image + METAR surface reports

A comparison of the 275-meter resolution (projected onto a 1-km AWIPS grid) Suomi NPP VIIRS 11.45 µm IR image with the corresponding 4-km resolution GOES-13 10.7 µm IR image (below) demonstrates (1) the obvious advantage of higher spatial resolution, with better details seen in the storm top structure; the coldest cloud top IR brightness temperature on the VIIRS image was -77 C, compared to -63 C on the GOES image, and (2) the significant geo-location displacement of the GOES-13 image features, due to the problem of parallax with such a large satellite viewing angle (which is about 60 degrees for this region from the GOES-13 satellite).

Suomi NPP VIIRS 11.45 µm IR image + GOES-13 10.7 µm IR image

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