GOES-14 has been out of storage mode and operating in Super Rapid Scan Operations for GOES-R (SRSOR) mode since August 10, providing 1-min imagery. As with past SRSOR data collection periods, the 1-min imagery is available for display in the SPC operational NAWIPS data visualization system. SPC forecasters have been utilizing the imagery in operations when available over relevant areas.
Today (8/18/15) the imagery was especially valuable as GOES-15 (West) underwent a scheduled maneuver, causing a data outage between 1630 and 1759 UTC. More significant to SPC was that GOES-East, to cover for the West outage, operated in Full Disk mode, collecting images only every half hour from 1615 and 1815. This was at a time when convection began to fire ahead and along a cold front passing through an SPC slight risk area across the central US.
The 1-min satellite imagery aided in 2 watch decisions during the early afternoon hours: a severe thunderstorm watch issued at 1815Z over parts of MO/IL, and a tornado watch issued at 1830Z over parts of WI/IA/IL. Cu developing in the clear sky ahead of the front in east-central MO clearly became agitated as a gravity wave feature traversed eastward through 1715Z. Over the next hour, cu quickly evolved into towering cu before eventual initiation took place. Additional development was analyzed further to the north under high clouds near the IA/IL border. Even further north in NE Iowa, strengthening of convection could be seen as bubbling/texture came through a more opaque/smooth cloud shield. Forecasters have commented that the very high temporal restitution satellite imagery allows for easier/more accurate tracking of individual cloud features/structure, especially when partially obscured by upper-level clouds. Evolution of individual features becomes disconnected with longer time between scans, making it difficult to interpret important trend information.
The first animation below shows the 1-min imagery in the time period leading up to and just after initiation during which GOES-East was in Full Disk operations. The second animation shows GOES-East imagery during the same period. SPC watches appear on both. Click animations to enlarge.
Bill Line, SPC/HWT Satellite Liaison
Fig 1: GOES-14 1-min visible satellite imagery for 1645-1859Z on 8/18/2015.
Fig 2: GOES-East visible satellite imagery for 1645-1900Z on 8/18/2015.
The UW-CIMSS Cloud Top Cooling (CTC) product was utilized at the SPC mesoscale desk on 9/17/14 during a marginal severe weather event over South Carolina. The CTC product not only highlights where initial rapid convective development is occurring, but it also quantifies the vigor of said growth. See past blog posts (eg. http://atomic-temporary-39547612.wpcomstaging.com/2014/04/02/cloud-top-cooling-product-with-kansas-severe-weather/) for background information on the CTC product and its use in SPC operations.
The CTC product first signaled cooling of around -10 K/15 min in the IR at 1830 UTC in South Carolina near the Georgia border (Fig. 1), indicating convection was at least trying to develop. Over the next few scans, the product signaled multiple areas of significant growth with increasing intensity over much of the southern half of South Carolina. At 1915 UTC, cooling of over -40 K/15 min was measured with a storm that would be warned on 19 minutes later. Several of the storms would go on to produce severe wind and hail, with the first severe report coming in at 2035 UTC.
Figure 1: September 17, 2014 1815-2030 UTC GOES-East visible satellite imagery, Cloud Top Cooling product, NWS severe warnings, SPC storm reports.
The SPC forecaster on the mesoscale desk was monitoring the CTC product over the region, and referenced it in a related Mesoscale Discussion: “THE MODERATE INSTABILITY AND -10 C 500 MB TEMPERATURES ARE PROVING SUFFICIENT FOR RAPID CLOUD TOP COOLING WITH MOST OF THE STORM CELLS IN THIS REGION PER GOES-R CLOUD TOP COOLING PRODUCT” (Fig. 2). The forecaster mentioned that seeing many areas of significant cooling gave him confidence that the environment would be conducive to the development of severe weather. This is a good example of a forecaster using the CTC product output to enhance his understanding of the environment.
Bill Line, SPC/HWT Satellite Liaison
GOES-14 has come out of storage and will be providing Super Rapid Scan Operations for GOES-R (SRSOR) 1-min data for the next 2 weeks. Forecasters at SPC have found operational value in this imagery in the past (see previous blog posts), and are once again taking advantage of its availability. Feedback from SPC forecasters is been helpful in assessing the operational utility of 1-min satellite imagery, a capability of the GOES-R Advanced Baseline Imager (ABI) that will be routinely available. For more information, including links to the real-time 1-min imagery and past examples, please visit: http://cimss.ssec.wisc.edu/goes/srsor2014/GOES-14_SRSOR.html.
– Bill Line, SPC/HWT Satellite Liaison
Fig 1: August 14, 2014 1439 to 1511 UTC GOES-14 SRSOR 1-min visible imagery.
The GOES-R Overshooting Top (OT) Detection algorithm (applied to current GOES) was utilized during the very early morning hours of June 23 across the Texas panhandle and western Oklahoma. This algorithm, which automatically detects the location of OT’s using the GOES IR window channel, has proven to be especially valuable in monitoring the evolution of mature convection, especially overnight in the absence of the higher resolution visible imagery. As has been mentioned in previous posts, OT’s indicate the presence of strong updrafts within a convective system, and likely areas of hazardous weather. The algorithm provides forecasters with a tool to quickly spot, in the imagery, where OT’s are present as well as trends in the feature.
By 0400Z on the 23rd, an MCS was propagating across the Texas panhandle/western Oklahoma, producing heavy rainfall and severe winds across the region. An SPC forecaster on shift viewing the OT product utilized it to help monitor trends in the strongest updrafts and areas most likely to be experiencing hazardous weather. The forecaster mentions in a 0723Z SPC Watch Update Mesoscale Discussion (MD,Fig. 1): “TRENDS IN 7 KM AND 9 KM CAPPI AND GOES-R OVERSHOOTING TOP PRODUCT INDICATED THE MORE PERSISTENT UPDRAFTS SINCE AT LEAST 0530z HAVE BEEN FROM THE SRN TX PANHANDLE INTO WRN OK…WITH FORWARD MOVEMENT OF THIS ACTIVITY AT 35-40 KT TOWARD THE SSE.”
Figure 2 is an animation of GOES-East IR imagery with overshooting tops and SPC storm reports overlayed during the time of and in the vicinity of the MD. Notice the cluster of persistent Overshooting Tops within the large cloud shield across the Texas panhandle between 0415 and 0530Z. This is where the highest concentration of severe weather (and heavy rainfall) was reported. Between 0530 and 0730 UTC, the MCS continued to propagate to the SSE as the overshooting tops became more spread out along the leading edge of the system from the southern Texas panhandle into western Oklahoma, as was mentioned in the MD. A few wind reports and heavy rainfall were reported in the vicinity of the persistent OT’s. After 1000Z, the OT’s dropped off completely as the MCS began to weaken.
Fig. 2: June 23, 2014 0415-1345 UTC GOES-East IR imagery, Overshooting Top Magnitude, SPC storm reports.
-Bill Line, SPC/HWT Satellite Liaison