A Study on Convective Modes Associated with Tornadoes in Central New York and Northeast Pennsylvania Timothy W. Humphrey 1 Michael Evans 2 1 Department of Atmospheric and Environmental Sciences, University at Albany State University of New York, Albany, New York 2 NOAA/NWS, Weather Forecast Office, Binghamton, New York
A Study on Convective Modes Associated with Tornadoes in Central New York and Northeast Pennsylvania. Timothy W. Humphrey 1 Michael Evans 2 1 Department of Atmospheric and Environmental Sciences, University at Albany State University of New York, Albany, New York - PowerPoint PPT Presentation
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A Study on Convective Modes Associated with Tornadoes in Central New York and Northeast Pennsylvania
Timothy W. Humphrey1
Michael Evans2
1Department of Atmospheric and Environmental Sciences, University at Albany
State University of New York, Albany, New York 2NOAA/NWS, Weather Forecast Office, Binghamton, New York
Uniform horizontal shear in lowest elevation angles
Low level rotation:~20 min
Rotation “spins up” from surface
Spikes in horizontal shear in lowest elevation angles
Low level rotation:~12 min
Supercell Rotational Velocity (Vr)
0 50 100 150 200 250 300 350 400 450 5000
10
20
30
40
50
60
VerifiedNull
0 - 1 km SRH (m^2 / s^2)
0.5
nm V
r (kt
s)
QLCS Rotational Velocity (Vr)
100 150 200 250 300 350 400 450 500 550 6000
2
4
6
8
10
12
VerifiedNull
0 - 1 km SRH (m^2 / s^2)
0.5
nm V
r (kt
s)
0 100 200 300 400 500 600 7000
5
10
15
20
25
30
35
40
VerifiedNull
0 - 1 km SRH (m^2 / s^2)
0.5
nm V
r (kt
s)Supercell/QLCS Vr
Conclusions
• Majority of tornadoes associated with supercells
• Supercell tornadoes appeared dependent on low level helicity and bulk shear
• QLCSs had little difference in mesoscale conditions
• Low level helicity a potential discriminator between verified and null events
Acknowledgments:
Hollings Scholarship Program
Michael Evans
NWS Binghamton Staff
Brook Taber, NWS Burlington
References:Thompson, R.L., R Edwards, J.A. Hart, K.L. Elmore, and P.
Markowski, 2003: Close proximity soundings within supercell environments obtained from the Rapid Update Cycle. Wea. Forecasting, 18, 1243-1261.
Trapp, R.J., S. A. Tessendorf, E. S. Godfrey, and H. E. Brooks, 2005: Tornadoes from squall lines and bow echoes. Part I: Climatological distribution. Wea. Forecasting, 20, 23–34.