A Rare Severe Weather and Tornado
Event in Central New York and Northeast
Pennsylvania: July 8, 2014
Presented by
Mike Evans
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A Rare Severe Weather and Tornado Event in Central
New York and Northeast Pennsylvania: July 8, 2014
• 6 Tornadoes and
numerous severe
reports.
• First tornado fatalities
in our county warning
area since 1998.
• A mix of tornadic and
non-tornadic supercells.
• Fatalities occurred with
a relatively subtle
Bookend Vortex
Signature.
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Damage near Smithfield, NY
Forecasting and warning factors
• 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.
Damage near Smithfield, NY
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Synoptic Setup
• Trough and cold front
approach from the west.
• Large low-level wind
anomalies.
• Degree of instability was in
question.
00-h RAP sounding valid 21z at ITH
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SREF 500 mb hts (top), 850 v wind (left) and 850 moisture flux
(right) and anomalies valid 21z
(courtesy WFO CTP http://cms.met.psu.edu/sref/ensembles/)
Instability forecast trends
• Potential limit to
instability: dense cloud
cover ahead of the cold
front.
Visible satellite and
surface plot at 18Z
• 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.
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SREF MLCAPE plume at BGM (03Z run left, 15Z run right)
WFO Binghamton Severe Weather Analog
System
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Use MLCAPE = 1300 J/kg
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Use MLCAPE = 1700 J/kg
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Comparison
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SPC Storm-scale ensemble of opportunity
http://www.spc.noaa.gov/exper/sseo/
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NSSL WRF-ARW – 4 km
EMC HRW WRF-ARW – 5.15 km
EMC HRW WRF-ARW – 5.15 km (time lagged 12 h)
EMC WRF-NMM – 4 km
EMC HRW NMMB – 4 km
EMC HRW NMMB – 4 km (time lagged 12 h)
NAM CONUS Nest – 4 km
SPC Storm-scale ensemble
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SPC Storm-scale ensemble
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Tornado Tracks
• Six Tornadoes
occurred in BGM
CWA.
• Two tornadoes
were rated EF2.
• The tornado with
5 fatalities
occurred in
Madison county.
Tornado tracks and EF ratings from July 8, 2014
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Tornadic vs. non-tornadic supercells
• A small supercell
produced an EF2
tornado in
northeast
Pennsylvania. (top)
• Another impressive
supercell near
Syracuse produced
no tornadoes.
(bottom)
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0.5 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.
• Strong low-level shear and
low LCL heights.
• Can dual pol data be used
to provide an improved
assessment of tornado
potential?
SPC Mesoanalysis of 0-1 km shear (top)
and LCL height (bottom) valid at 21z
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Recent Studies - Conceptual Model
• ZDR arc around the
edge of the inflow
• Small drops / low
ZDR in the hook
echo region of the
storm.
Conceptual model of ZDR patterns in a tornadic supercell. (from
Kumjian et. al. 2011).
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Tornadic Storm
• ZDR arc developed
north of the
tornado.
• Low ZDR in the
tornadic hook echo.
Reflectivity and ZDR for a tornadic supercell over northeast
Pennsylvania at 2213z. Tornado path is annotated.
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Non-Tornadic Storm
• ZDR pattern was
more disorganized.
• No clearly defined
ZDR arc.
• Areas of large ZDR
values also found in
the hook near the
location of the
potential tornado.
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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.
• The storm was
associated with a strong,
highly curved rear inflow
jet.
• Forecasters more
focused on supercells.
0.5 degree Reflectivity (top) and SRM
(bottom) for a tornadic storm at 23z.
Tornado path is annotated.
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EF-2 with 5 fatalities
• The velocity signature
developed very
suddenly.
• A severe thunderstorm
warning was in effect for
Madison county (no
tornado warning).
0.5 degree Reflectivity (top) and SRM
(bottom) for a tornadic storm at 23z.
Tornado path is annotated.
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EF-2 with 5 fatalities
• ZDR enhanced on
the leading edge of
the convective
system.
• Lower ZDR in the
tornadic area of the
storm.
0.5° Reflectivity (top) and ZDR (bottom)
for the tornadic storm in New York at 23Z.
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EF-2 with 5 fatalities
• TDS developed
between 23z and
2306z – just after
tornado touchdown.
• TDS extended up
through 0.9 degrees
(~ 7000 feet).
Correlation coefficient for a tornadic storm from 2300 – 2306Z.
Tornado path annotated.
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Summary
• A rare severe weather and tornado event in
central New York and northeast Pennsylvania
occurred on July 8, 2014.
• 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 nontornadic storms.
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A rare severe weather and tornado event in central New
York and northeast Pennsylvania: July 8, 2014
Contact: Mike Evans
michael.evans@noaa.gov
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