GOES-14 0.63 µm visible channel images (click to play animation)

The GOES-14 satellite was in Super Rapid Scan Operations for GOES-R (SRSOR) mode providing 1-minute imagery over the eastern US on 18 August 2014. From the late morning into the afternoon hours, 0.63 µm visible channel images (above; click image to play animation; also available as an MP4 movie file or a YouTube video) revealed a large and well-defined mesoscale convective vortex (MCV) propagating eastward across northern Mississippi. This MCV was spawned from a thunderstorm which rapidly developed over far southwestern Arkansas during the preceding nighttime hours (beginning around 06:15 UTC: GOES-13 IR images).

A comparison of Suomi NPP VIIRS 11.45 µm IR channel images (below) showed the rapid growth of the parent thunderstorm from 07:18 UTC to 08:59 UTC. The coldest cloud-top IR brightness temperatures were -80º C.

Suomi NPP VIIRS 11.45 µm IR channel images

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GOES-14 0.63 µm visible channel images (click to play animation)

GOES-14 is in special SRSO-R operations that provides 1-minute imagery, allowing a compelling look at the dissipation of valley fog over Pennsylvania this morning. This animation is also available as a YouTube video, or as an mp4.

A description of the detection of the fog development overnight can be found on the CIMSS Fog Blog.

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GOES-14 0.63 µm visible channel images (click to play animation)

The GOES-14 satellite was placed into Super Rapid Scan Operations for GOES-R (SRSOR) mode on 14 August 2014, providing imagery at 1-minute intervals with the goal of monitoring the western US for convection and/or wildfire activity. McIDAS images of 0.63 µm visible channel data (above; click image to play animation; also available as an MP4 movie file) showed the development of clusters of slow-moving thunderstorms in the Las Vegas, Nevada region. These storms produced strong winds (gusts estimated at 60 mph) and heavy rainfall which caused flash flooding: Boulder City in far southern Nevada (located just east of Henderson, station identifier KHND) received 0.75 inch of rain in only 30 minutes. In addition to the state boundaries and yellow station identifiers, Interstate highways are drawn in red and State highways are cyan.

Another item of interest to note on the GOES-14 visible images: Lake Mead located to the east of Las Vegas was at an all-time record low level (1080.19 feet on 12 August) since it was filled back in the 1930s. The dark blue map outline represents the boundary of the lake as recently as the mid-1990s; the current area occupied by the darker water in Lake Mead’s Overton Arm (which extends northward) is drastically smaller in size, a result of the long-term severe to extreme drought.

AWIPS-2 images of the GOES-15 sounder Total Precipitable Water (TPW) derived product (below; click image to play animation) showed that these thunderstorms developed along a very sharp moisture boundary that was oriented roughly southwest to northeast across the area — TPW values of 30-40 mm (1.2-1.6 inches, yellow to red color enhancement) were seen east of the boundary, with TPW values of 10-20 mm (0.4-0.8 inch, shades of blue) west of the boundary.

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

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GOES-13 10.7 µm infrared imagery on 13 August 2014; The Islip airport (KISP) is at the violet square (click to animate)

The system that caused flooding in Detroit, MI on 11 August and in Baltimore/Washington on 12 August has moved eastward: Islip, NY, on central Long Island, had historically heavy rainfall early in the morning on 13 August as more than 13″ of rain fell (9.71″ in two hours, and 5.34″ in one hour!!), smashing the New York state record for 24-hour rainfall (Record Event Report).

The GOES-13 animation above shows the satellite presentation of the storms that produced the heavy rainfall (the heaviest rain fell between 0900 and 1100 UTC). It is immediately apparent that the deepest convective clouds were not responsible for the heavy rains: cloud-top IR brightness temperatures over Islip were only near -30º C (per the 1200 UTC OKX sounding, that was around 300 hPa; the tropopause was closer to 150 hPa) and cloud-to-ground lightning was not detected. Winds at the Islip airport shifted from easterly/northeasterly to southeasterly as the heavy rains ended (time series plot of surface weather): an approaching frontal boundary may have helped force the heavy rains.

The animation shows continual cold cloud redevelopment at/near Islip, suggesting that training shower development was an important factor in the flooding.

Although the region was generally cloudy, holes in the cloud cover revealed GOES-13 sounder Total Precipitable Water values (below; click image to play animation) of 45-50 mm or 1.8-2.0 inches over Long Island just ahead of the advancing frontal boundary. The Blended Total Precipitable Water product showed a sudden jump to over 50 mm or 2.0 inches around 10 UTC over Long Island, and these TPW values were around 150% of normal for that location and time of the year.

GOES-13 sounder Total Precipitable Water derived product images (click to play animation)

The MIMIC Total Precipitable Water product (below) showed a northward surge of tropical moisture into the region on 13 August.

MIMIC Total Precipitable Water (11-13 August)

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