STEPSSTEPSSevere Thunderstorm and Severe Thunderstorm and

Precipitation StudiesPrecipitation StudiesMay-July 2000May-July 2000

STEPS ObjectivesSTEPS ObjectivesTo gain a better understanding of interactions between kinematics,To gain a better understanding of interactions between kinematics,precipitation production and electrification in severe thunderstormsprecipitation production and electrification in severe thunderstormsover the High Plains.over the High Plains.

What are the conditions that differentiate supercell storms into high precipitation, What are the conditions that differentiate supercell storms into high precipitation, moderate precipitation, and low precipitation events?moderate precipitation, and low precipitation events?

Why do some severe storms produce anonymously large amounts of positiveWhy do some severe storms produce anonymously large amounts of positivecloud-to-ground lightning? (e.g., greater than 50% positive)cloud-to-ground lightning? (e.g., greater than 50% positive)

In what ways may this particular lightning signature be associated physicallyIn what ways may this particular lightning signature be associated physicallywith the occurrence of tornadoes and large hail? Is there nowcasting potential?with the occurrence of tornadoes and large hail? Is there nowcasting potential?

Lightning Statistics from Lightning Statistics from NLDNNLDN

STEPS domain centered on area with high probability of severe weather. Some, but STEPS domain centered on area with high probability of severe weather. Some, but not all severe storms in this area, produce large amounts of positive cloud-to-groundnot all severe storms in this area, produce large amounts of positive cloud-to-groundlightning. lightning.

STEPS highlightsSTEPS highlightsObservations of 8 weak events, 7 moderate storms, and 5 severe storms.Observations of 8 weak events, 7 moderate storms, and 5 severe storms.

Highlights include major downburst events on 31 May and 19 June, a bow-echoHighlights include major downburst events on 31 May and 19 June, a bow-echoMCS on 11 June, LP supercells on 31 May and 5 July, and MP/HP supercells MCS on 11 June, LP supercells on 31 May and 5 July, and MP/HP supercells on 22 June, 24 June and 29 June.on 22 June, 24 June and 29 June.

STEPS information at STEPS information at http://www.mmm.ucar.edu/community/steps.html

Operations journal (with text and radar summaries) at:Operations journal (with text and radar summaries) at:http://www.mmm.ucar.edu/pdas/Ops-journal/ops-summary.html

Support provided by NSF, NCAR, NSSL, NWS-Goodland and Support provided by NSF, NCAR, NSSL, NWS-Goodland and Colorado State University.Colorado State University.

Network DesignNetwork DesignSurface radar network (3 Doppler radars, two having polarimetric capabilities)Surface radar network (3 Doppler radars, two having polarimetric capabilities)

NMIMT GPS-based 3-D lightning mapping systemNMIMT GPS-based 3-D lightning mapping system

NCAR mobile GPS upsonde unitsNCAR mobile GPS upsonde units

NOAA NSSL/OU mobile mesonetNOAA NSSL/OU mobile mesonet

NOAA NSSL mobile balloon facility (thermodynamic and E field measurements) NOAA NSSL mobile balloon facility (thermodynamic and E field measurements)

SDSMT T-28 armored storm intercept aircraftSDSMT T-28 armored storm intercept aircraft

Goodland NWS Office (forecast and logistical support)Goodland NWS Office (forecast and logistical support)

CoCoRAHS volunteer networkCoCoRAHS volunteer network

Radar NetworkRadar Network

NMIMT Lightning NetworkNMIMT Lightning Network

STEPS FacilitiesSTEPS Facilities

CHILL ITR SiteCHILL ITR Site

STEPS Ops CenterSTEPS Ops Center

CSU-CHILL Data AccessCSU-CHILL Data AccessStart HereStart Here

29 June 200029 June 2000

29 June 200029 June 2000

29 June 200029 June 2000

29 June 200029 June 2000

29 June 200029 June 2000

29 June 200029 June 2000

29 June 200029 June 2000

29 June 200029 June 2000

Tornadic StormTornadic Storm

22 June severe storm22 June severe storm

ReflectivityReflectivity

Radial velocity/TVSRadial velocity/TVS