the 11 june 2008 severe pulse storm over newberry sc

The 11 June 2008 Severe Pulse Storm over Newberry SC

Michael W. Cammarata (NWS CAE)

Jamie Christopher (former Student Volunteer, NWS CAE)

Overview

• During the late afernoon of 11 June 2008 a severe pulse thunderstorm produced 0.88 inch hail over Newberry SC

NAM 16h forecast sounding valid at 2200 GMT shows moderate to strong instability, weak shear, and wet bulb zero temperatures favorable for large hail…also note dry layer 12-22k ft…evaporative cooling can lower freezing level increasing large hail potential

2123Z

*Note - Small reflectivity core

develops above -20C (red line).

Max 44dbz

2127Z

*Note – Reflectivity core

strengthens above -20C line.

Max 54dbz

*Note – Reflectivity core

increases in coverage.

Max 64dbz

2131Z

*Note – Reflectivity core lowers in height

and higher reflectivity is seen.

Max 69dbz

Good indication that hail has increased in

size.

2135Z

*Note – Reflectivity core lowers below the 0C level (yellow line).

Max 66dbz

Updraft is weakening

and hail size is decreasing

as melting occurs.

2140Z

*Note – Core continues to lower

as storm continues to

collapse.

2144Z

Sfc temp = 92F

Significant melting of

hailstones is occurring as sfc

temp is very warm.

*Note – Main core continues to

weaken.

Heavy rain is more of a

possibility at this point.

2148Z

*Note – Storm has almost fully collapsed.

Heavy rain is still a

possibility.

2152Z

Conclusion

• 3-D analysis of radar data makes it easy to visualize the delopment of high reflectivity cores aloft early in the storm life cycle.

• Can lead to increased lead times in pulse events