SPC

1-min Satellite Imagery Utilized by SPC Forecasters – 8/18/15

Posted by Bill Line on 08/18/2015
Posted in: SPC, SRSOR. Tagged: , . Leave a comment

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 1: GOES-14 1-min visible satellite imagery for 1645-1859Z on 8/18/2015.

Fig 1: GOES-East visible satellite imagery for 1645-1900Z on 8/18/2015.

Fig 2: GOES-East visible satellite imagery for 1645-1900Z on 8/18/2015.

Cloud Top Cooling Product use in SPC with NV/ID Severe

Posted by Bill Line on 09/18/2014
Posted in: CTC, SPC. Tagged: , , , , . Leave a comment

The UW-CIMSS Cloud Top Cooling (CTC) product was once again utilized at the SPC mesoscale desk on 9/18/14 during a marginal severe weather event over parts of Nevada and Idaho.  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.

Figure 1: September 18, 2014 1715-2030 UTC GOES-West visible satellite imagery, Cloud Top Cooling product, NWS severe warnings.

Figure 1: September 18, 2014 1715-2030 UTC GOES-West visible satellite imagery, Cloud Top Cooling product, NWS severe warnings.

With relatively weak instability in place, there was some uncertainty as to whether significant convection would develop in the region despite favorable shear and forcing associated with an approaching shortwave. The CTC product first indicated rapid initial convective growth in excess of -16 K/15 min at 1745 UTC in northeast Nevada (Fig. 1). By 1845, notable cooling rates were being measured along an area of confluence north into southeast Idaho. The first warning was issued in Nevada at 1911 UTC, with storms being warned on in Idaho shortly thereafter. The CTC product provided increased confidence that the environment would indeed support strong updrafts, and potentially severe weather. The forecaster referenced the CTC product in a related SPC Mesoscale Discussion: “THE GOES-R CLOUD TOP COOLING PRODUCT VERIFIES THIS TREND PER SEVERAL STORMS FROM NERN NV TO ERN ID HAVING STRONGER/SUSTAINED UPDRAFTS (Fig. 2).”

Bill Line, SPC/HWT Satellite Liaison

Cloud Top Cooling Product used in SPC with South Carolina Severe

Posted by Bill Line on 09/18/2014
Posted in: CTC, SPC. Tagged: , , , , . Leave a comment

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: Septemeber 9, 2014 1815-2030 UTC GOES-East visible satellite imagery, Cloud Top Cooling product, NWS severe warnings, SPC storm reports.

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 SRSOR 1-min Imagery in SPC Aug 14-28

Posted by Bill Line on 08/14/2014
Posted in: SPC, SRSOR. Tagged: , , . Leave a comment

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.

Fig 1: August 14, 2014 1439 to 1511 UTC GOES-14 SRSOR 1-min visible imagery.