GOES Super Rapid Scan 1-Minute Data Used to Monitor an MCV that Initiated a Severe Thunderstorm across Central North Carolina

GOES-14 was operating in Super Rapid Scan Operations (SRSO) on May 23, 2014, which allowed forecasters to view satellite imagery with 1 minute frequency. On this day, forecasters used the rapid scan imagery during severe weather operations to monitor a MCV that initiated a severe thunderstorm over Moore County North Carolina (NC).  SRSO provided forecasters with visible satellite images every minute compared to the 15 minute intervals between images in normal GOES-13 operations. Dan Lindsey from NOAA/RAMMB/CIRA provided the animation below which provides a comparison of GOES-14 SRSO 1-minute visible imagery (left) with traditional GOES-13 15-minute imagery (right).

Comparison of GOES-14 SRSO 1-minute visible satellite imagery (left) with traditional GOES-East  15-minute imagery (right). Imagery courtesy of Dan Lindsey NOAA/RAMMB/CIRA. Click here to animate.

Comparison of GOES-14 SRSO 1-minute visible satellite imagery (left) with traditional GOES-East 15-minute imagery (right). Imagery courtesy of Dan Lindsey NOAA/RAMMB/CIRA. Click here to animate.

A cluster of thunderstorms developed across southern Missouri on the evening of Thursday, May 22, 2014. The thunderstorms became more numerous and developed into a Mesoscale Convective System (MCS). The MCS initiated a Mesoscale Convective Vortex (MCV) which is an area of low pressure that produces a small and shallow vortex that can sustain or initiate convection, even after its parent MCS has dissipated. The convection associated with the weakening MCS and the associated MCV moved into western NC and downed numerous trees across Madison, Yancey, and Buncombe Counties between 800 and 900 AM EDT on May 23. The MCS weakened as it moved into the southern Foothills of NC while the associated MCV subsequently moved into the Sandhills region during the late morning hours.

The air mass across central NC at 1100 AM EDT (1500 UTC) was somewhat dry with surface dew points in the lower 60s and a well-mixed sub-cloud layer. MLCAPE values ranged between 500- 1000 J/Kg with some convective inhibition resulting from a cap at around 800 hPa. While 0-6 km bulk shear values were impressive at 45-50 kts. A weak cold front stretched from west to east across southern NC. The MCV likely provided a localized region of enhanced flow, increased shear aloft, and some low level warm advection that could support convection.

Plot of 1500 UTC MLCAPE in the upper left, 1500 UTC 0-6km bulk shear in kts in the upper right, 1430 UTC regional radar reflectivity in the lower left and the 1500 UTC WPC subjective surface analysis.

Plot of 1500 UTC MLCAPE in the upper left, 1500 UTC 0-6km bulk shear in kts in the upper right, 1430 UTC regional radar reflectivity in the lower left and the 1500 UTC WPC subjective surface analysis.

Forecasters at the NWS Raleigh office were monitoring the potential for convection to redevelop in the vicinity of the MCV using tools such as radar and satellite data. At around 1100 AM EDT (1500 UTC) a shower associated with the MCV developed and then quickly intensified as it moved into Moore County.  At 1511 UTC the storm contained a 40 dBz core that extended up to about 16,500 feet, 11 minutes later at 1522 UTC, the 41 dBz core extended above 32,000 feet with a 51 dBz core to over 25,000 feet. The storm continued to intensify and a severe thunderstorm warning was issued at 1529 UTC. A report of 1 inch hail was received from near Carthage at 1535 UTC as the storm became supercellular.

While the warning decision was almost exclusively made using KRAX radar data, the SRSO was utilized around the time of the severe thunderstorm warning and especially during the next couple of hours as the MCV moved across central and southeastern NC. The SRSO data was initially used to identify and track the MCV more easily and confidently than with the 15-minute GOES-13 data. SRSO imagery was primarily used to identify locations with incipient or developing cumulus clouds that could signal additional convective growth. Based on the high resolution satellite trends, forecasters were confident that imminent deep convection associated with the MCV was unlikely across central NC and forecast operations were adjusted accordingly. During the next few hours, the MCV failed to initiate any convection, most likely because of its weakening and the decreasing amounts of instability in eastern NC.

Tim Schmit from NOAA/CIMSS provided this impressive loop of 1-minute GOES-14 SRSO visible satellite imagery that shows the MCS moving into western NC with the MCV becoming visible and then moving east across southern NC, initiating the short lived supercell across Moore County NC and then moving east toward the southern portions of Pamlico Sound.

Loop of 1-minute GOES-14 SRSO visible satellite imagery of an MCV initiating a severe thunderstorm across central NC. Imagery courtesy of Tim Schmit NOAA/CIMSS. Click here to animate.

Loop of 1-minute GOES-14 SRSO visible satellite imagery of an MCV initiating a severe thunderstorm across central NC. Imagery courtesy of Tim Schmit NOAA/CIMSS. Click here to animate.

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