A Rare Severe Weather and Tornado Event in Central New York and Northeast Pennsylvania: July 8, 2014 Presented by Mike Evans 1

A Rare Severe Weather and Tornado Event in Central New York and Northeast Pennsylvania: July 8, Tornadoes and numerous severe reports. 6 Tornadoes and numerous severe reports. First tornado fatalities in our county warning area since First tornado fatalities in our county warning area since A mix of tornadic and non-tornadic supercells. A mix of tornadic and non-tornadic supercells. Fatalities occurred with a relatively subtle Bookend Vortex Signature. Fatalities occurred with a relatively subtle Bookend Vortex Signature. 2 Damage near Smithfield, NY

Forecasting and warning factors New tools helped forecasters to anticipate the evolution and magnitude of the event. New tools helped forecasters to anticipate the evolution and magnitude of the event. Dual polarization data may have been helpful to discriminate between tornadic vs. non-tornadic storms. Dual polarization data may have been helpful to discriminate between tornadic vs. non-tornadic storms. 3 Damage near Smithfield, NY

Synoptic Setup Trough and cold front approach from the west. Trough and cold front approach from the west. Large low-level wind anomalies. Large low-level wind anomalies. Degree of instability was in question. Degree of instability was in question h RAP sounding valid 21z at ITH SREF 500 mb hts (top), 850 v wind (left) and 850 moisture flux (right) and anomalies valid 21z (courtesy WFO CTP  )

Instability forecast trends Potential limit to instability: dense cloud cover ahead of the cold front. Potential limit to instability: dense cloud cover ahead of the cold front. Mean 03Z SREF MLCAPE at BGM ~1200 J/kg with lots of spread. Mean 03Z SREF MLCAPE at BGM ~1200 J/kg with lots of spread. Mean 15Z SREF MLCAPE at BGM increased to over 1500 J/kg with less spread. Mean 15Z SREF MLCAPE at BGM increased to over 1500 J/kg with less spread. 5 SREF MLCAPE plume at BGM (03Z run left, 15Z run right) Visible satellite and surface plot at 18Z

WFO Binghamton Severe Weather Analog System 6

Use MLCAPE = 1300 J/kg 7

Use MLCAPE = 1700 J/kg 8

Comparison 9

SPC Storm-scale ensemble of opportunity NSSL WRF-ARW – 4 km NSSL WRF-ARW – 4 km EMC HRW WRF-ARW – 5.15 km EMC HRW WRF-ARW – 5.15 km EMC HRW WRF-ARW – 5.15 km (time lagged 12 h) EMC HRW WRF-ARW – 5.15 km (time lagged 12 h) EMC WRF-NMM – 4 km EMC WRF-NMM – 4 km EMC HRW NMMB – 4 km EMC HRW NMMB – 4 km EMC HRW NMMB – 4 km (time lagged 12 h) EMC HRW NMMB – 4 km (time lagged 12 h) NAM CONUS Nest – 4 km NAM CONUS Nest – 4 km 10

SPC Storm-scale ensemble 11

SPC Storm-scale ensemble 12

Tornado Tracks Six Tornadoes occurred in BGM CWA. Six Tornadoes occurred in BGM CWA. Two tornadoes were rated EF2. Two tornadoes were rated EF2. The tornado with 5 fatalities occurred in Madison county. The tornado with 5 fatalities occurred in Madison county. 13 Tornado tracks and EF ratings from July 8, 2014

Tornadic vs. non-tornadic supercells A small supercell produced an EF2 tornado in northeast Pennsylvania. (top) A small supercell produced an EF2 tornado in northeast Pennsylvania. (top) Another impressive supercell near Syracuse produced no tornadoes. (bottom) Another impressive supercell near Syracuse produced no tornadoes. (bottom) degree reflectivity (left) and SRM (right) for a tornadic storm in Pennsylvania (top) and non-tornadic storm in New York (bottom). The tornado path is annotated by the black line in upper figures.

SPC Mesoanalysis SPC Mesoanalysis showed a favorable environment for tornadoes across CWA. SPC Mesoanalysis showed a favorable environment for tornadoes across CWA. Strong low-level shear and low LCL heights. Strong low-level shear and low LCL heights. Can dual pol data be used to provide an improved assessment of tornado potential? Can dual pol data be used to provide an improved assessment of tornado potential? 15 SPC Mesoanalysis of 0-1 km shear (top) and LCL height (bottom) valid at 21z

Recent Studies - Conceptual Model ZDR arc around the edge of the inflow ZDR arc around the edge of the inflow Small drops / low ZDR in the hook echo region of the storm. Small drops / low ZDR in the hook echo region of the storm. 16 Conceptual model of ZDR patterns in a tornadic supercell. (from Kumjian et. al. 2011).

Tornadic Storm ZDR arc developed north of the tornado. ZDR arc developed north of the tornado. Low ZDR in the tornadic hook echo. Low ZDR in the tornadic hook echo. 17 Reflectivity and ZDR for a tornadic supercell over northeast Pennsylvania at 2213z. Tornado path is annotated.

Non-Tornadic Storm ZDR pattern was more disorganized. ZDR pattern was more disorganized. No clearly defined ZDR arc. No clearly defined ZDR arc. Areas of large ZDR values also found in the hook near the location of the potential tornado. Areas of large ZDR values also found in the hook near the location of the potential tornado. 18 Reflectivity and ZDR in a non-tornadic supercell over central New York at 2152z

EF-2 with 5 fatalities A subtle radar signature associated with a bookend vortex. A subtle radar signature associated with a bookend vortex. The storm was associated with a strong, highly curved rear inflow jet. The storm was associated with a strong, highly curved rear inflow jet. Forecasters more focused on supercells. Forecasters more focused on supercells degree Reflectivity (top) and SRM (bottom) for a tornadic storm at 23z. Tornado path is annotated.

EF-2 with 5 fatalities The velocity signature developed very suddenly. The velocity signature developed very suddenly. A severe thunderstorm warning was in effect for Madison county (no tornado warning). A severe thunderstorm warning was in effect for Madison county (no tornado warning) degree Reflectivity (top) and SRM (bottom) for a tornadic storm at 23z. Tornado path is annotated.

EF-2 with 5 fatalities ZDR enhanced on the leading edge of the convective system. ZDR enhanced on the leading edge of the convective system. Lower ZDR in the tornadic area of the storm. Lower ZDR in the tornadic area of the storm ° Reflectivity (top) and ZDR (bottom) for the tornadic storm in New York at 23Z.

EF-2 with 5 fatalities TDS developed between 23z and 2306z – just after tornado touchdown. TDS developed between 23z and 2306z – just after tornado touchdown. TDS extended up through 0.9 degrees (~ 7000 feet). TDS extended up through 0.9 degrees (~ 7000 feet). 22 Correlation coefficient for a tornadic storm from 2300 – 2306Z. Tornado path annotated.

Summary A rare severe weather and tornado event in central New York and northeast Pennsylvania occurred on July 8, A rare severe weather and tornado event in central New York and northeast Pennsylvania occurred on July 8, New tools showed promise helping forecasters to anticipate the occurrence and magnitude of the event. New tools showed promise helping forecasters to anticipate the occurrence and magnitude of the event. Dual polarization radar products have potential to help discriminate between tornadic and non- tornadic storms. Dual polarization radar products have potential to help discriminate between tornadic and non- tornadic storms. 23

A rare severe weather and tornado event in central New York and northeast Pennsylvania: July 8, 2014 Contact: Mike Evans 24