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

The GOES-14 satellite was placed into Super Rapid Scan Operations for GOES-R (SRSOR) mode to monitor the development of severe weather over a rare SPC High Risk region on 12 June 2013. In SRSOR mode, images were available at 1-minute intervals (compared to the routine 15-minute image interval). The development of numerous large thunderstorms can be seen on GOES-14 SRSOR 0.63 µm visible channel images (above; click image to play animation; also available as a QuickTime movie). These storms produced tornadoes, large hail, and damaging winds across parts of Minnesota, Iowa, Wisconsin, and Illinois (SPC storm reports). One item of interest revealed on the 1-minute imagery was the appearance of “inflow feeder band” clouds that were developing along the western edge of the large thunderstorm located over northeastern Iowa during the 20:15 – 20:58 UTC time period; without the 1-minute temporal resolution, such subtle mesoscale features would be difficult if not impossible to identify on conventional 15-minute imagery. Numerous overshooting tops could also be seen on some of the larger storms.

During the SRSOR period, there were breaks in the 1-minute interval coverage to allow for tasks such as satellite “station-keeping” –  and the longest break occurred between 19:41 UTC and 20:15 UTC (below). You can see that during this particular 34-minute period, considerable convective development occurred in areas such as northwestern Illinois. With current Routine GOES scanning schedules, there is a similar 30-minute gap in coverage over the Continental US (CONUS) which occurs every 3 hours during a full disk scan of the Earth. It is important to note that with the Advanced Baseline Imager (ABI) instrument on the next-generation GOES-R satellite there will be no such long gaps in the imagery — in fact, during high-impact weather events such as this one, images will be available over special mesoscale sectors every 30 seconds.

GOES-14 0.63 µm visible channel images at 19:41 and 20:15 UTC

The GOES-13 sounder Convective Available Potential Energy (CAPE) derived product (below; click image to play animation) showed that there was considerable instability (CAPE values of 4000-5000 J/kg, violet color enhancement) that developed during the afternoon hours across much of southeastern Iowa and northern Illinois, in the warm sector of the area of low pressure that was developing over northeastern Iowa.

GOES-13 sounder Convective Available Potential Energy (CAPE) product (click image to play animation)

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GOES-13 0.63 µm visible channel images

Now that GOES-13 is the operational GOES-East satellite again, we have a view that covers the far eastern Atlantic Ocean into the far northwestern portion of Africa. The hazy signature of an outbreak of Saharan Air Layer (SAL) dust streaming off the African coast is evident of GOES-13 0.63 µm visible channel images (above).

The CIMSS SAL product (below; click image to play animation) also indicated that a strong outbreak of dust was moving westward across the Atlantic Ocean.

Meteosat-9 Saharan Air Layer (SAL) product (click image to play animation)

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19 bands of the GOES-13 Sounder (upper panels) and 5 bands of the GOES-13 Imager (lower panels)

GOES-13 became the operational GOES-East satellite once again at 15:45 UTC on 10 June 2013 (following recovery from an anomaly on 22 May) — the multi-panel image above shows all 19 bands of the GOES-13 Sounder along with all 5 bands of the GOES-13 Imager at that time.

The images below show the GOES Sounder 7.4 µm water vapor channel data using AWIPS, and the footprint change from GOES-14 at 14:46 UTC to GOES-13 at 15:46 UTC is obvious.

GOES-West and GOES-East Sounder 7.4 µm water vapor channel

A comparison of all 19 bands of the Sounder instrument on GOES-14 and GOES-13 (below) shows some improvement in noise in a few of the bands (due to an “outgas” procedure being performed on the GOES-13 Sounder during recovery from the anomaly).

Comparison of the 19 Sounder bands on GOES-14 (14:46 UTC) and GOES-13 (15:46 UTC)

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The transition from GOES-14 to GOES-13, as seen in 0.63 µm visible channel data from the Imager instrument

The transition from GOES-14 to GOES-13 is also shown above, using McIDAS images of 0.63 µm visible channel data from the Imager instrument. Once again, the image perspective is different, due to the fact that GOES-14 is positioned over the Equator at 105 W longitude, and GOES-13 is at 75 West longitude. This difference in satellite viewing perspective is very apparent when comparing the Full Disk views of 0.63 µm visible channel images from GOES-14 at 14:45 UTC and GOES-13 at 17:45 UTC (below).

GOES-14 vs GOES-13 Full Disk 0.63 µm visible channel images

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GOES-15 6.5 µm water vapor channel images (click image to play animation)

AWIPS images of GOES-15 6.5 µm water vapor channel data (above; click image to play animation) showed the formation of an unusually dry signature associated with a cut-off low near the coast of southern California during the 08 June – 09 June 2013 period. Water vapor channel brightness temperatures were as warm as -9.0º C (darker orange color enhancement), which is an abnormally warm/dry value to be seen on water vapor imagery.

This warm/dry signal was also very apparent on imagery from the 3 water vapor channels (6.5 µm, 7.0 µm, and 7.4 µm) that are available from the GOES-15 sounder (below; click image to play animation). These 3 GOES sounder water vapor channels sense the amount of mosture within 3 different vertical layers of the atmosphere, and are used to create the GOES sounder Total Precipitable Water (TPW) derived product — which in this case depicted TPW values as low as 11 mm or 0.43 inch at 18:00 UTC. The Blended Total Precipitable Water Percent of Normal product indicated that the TPW values within the dry cut-off low were generally 40-70% of normal for this time of year over that region.

GOES-15 Sounder and Imager water vapor channel images (click mage to play animation)

The very warm/dry signature seen on the GOES-15 water vapor imagery was well-correlated with elevated values of GOES-15 sounder Total Column Ozone, which suggests an abnormally low tropopause within that feature. This was verified with fields from the CRAS model, which indicated that the height of the dynamic tropopause (taken to be the PV1.5 surface) was as low as the 570 hPa pressure level at 18:00 UTC. GOES sounder Total Column Ozone values were as high as 382 Dobson Units within the dry cut-off low.

GOES-15 imager 6.5 µm water vapor channel image + GOES-15 sounder Total Column Ozone product (with overlays of CRAS model fields)

===== 10 June Update =====

Comparison of GOES-15 Sounder and Imager water vapor channel data

The dry cut-off low began to move inland over southern California on 10 June, and an AWIPS image comparison of GOES-15 Sounder and Imager water vapor channel data (above) showed that it was centered approximately over Vandenberg Air Force Base (KVBG) at around 12 UTC that morning. A comparison of the GOES-15 Sounder and Imager water vapor channel weighting functions (below) indicated that the individual water vapor channels were sensing radiation from layers that were at much lower altitudes in the dry air mass over Vandenberg, California than they were farther to the north over Medford, Oregon (KMFR) where the atmosphere had much more moisture distributed within the middle to upper troposphere.

Comparison og GOES-15 Sounder and Imager water vapor channel weighting function plots

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