assessing the utility of normalized rotation in detecting ...assessing the utility of normalized...
TRANSCRIPT
![Page 1: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/1.jpg)
Assessing the utility of normalized rotation in detecting tornado development in the
Allegheny Front
Dylan T. Cooper – NOAA/NWS, WFO Charleston, WV
Alex J. Vorst – Ohio University, Athens, OH1
1Present affiliation: Mechanicsburg High School, Mechanicsburg, OH
Northeast Regional Operational Workshop XVII 3 November 2016
![Page 2: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/2.jpg)
Outline
• Motivation/methodology • Definition • Individual cases
– Discrete supercell – QLCS – Single cell
• Overall results • Conclusions • Final thoughts
Two tornadoes near Dodge City, KS – 25 May 2016
2/21
![Page 3: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/3.jpg)
Motivation
Problem: numerous operational challenges
– Many non-supercell and supercell variant modes
– Atypical Z/V radar patterns
– Complex terrain
Bottom line: improve tornado detection by using
NROT with radar & environmental analysis
Washington County, OH tornadic storm – 20 June 2015
3/21
![Page 4: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/4.jpg)
Methodology
Domain: JKL, RLX, PBZ CWAs/WSR-88Ds – Used SPC’s SVRGIS page for events
– Events occurring 2006-2015 within 80 nm of radar site
Sampling strategy: – Five consecutive volume scans [t-4
to t=0 (closest to t-genesis)]
– Three lowest slices per scan
– 0.5° SAILS scans not used
GR2Analyst: – Calculated max NROT values per scan
– All radar data from NCEI (NCDC) archive
Data analysis: – Stratified events by storm mode
– Basic statistical analysis
Domain with all historical tornado tracks. From SPC SVRGIS
(loose, 3-tier classification scheme)
Total cases used: 37
4/21
![Page 5: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/5.jpg)
Definition
Very similar to NSSL Rotation tracks in
AWIPSII
Sources: GR2AE NROT product description, Mike Ekster (WFO GYX) 5/21
![Page 6: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/6.jpg)
Case 1: Supercell 27 July 2015 - Leslie Co., KY
36.6 nm from KJKL (touchdown)
Motion: 315° 30 kts
Magnitude: EF-1
Length: 2 miles
Width: 900 yards
2025 UTC 0.5° BV/SRM
Storm must possess deep, persistent mesocyclone
6/21
![Page 7: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/7.jpg)
Case 1: Supercell
t=0 (2025 UTC)
0.5°
0.9°
1.4°
7/21
![Page 8: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/8.jpg)
Case 1: Supercell
t-4 t-3 t-2 t-1 t=0
0.5°
0.9°
1.4°
(1.05) (1.13) (1.28) (1.84) (1.84)
(0.97) (0.69) (1.21) (1.56) (2.04)
(0.85) (0.69) (1.09) (1.28) (1.80)
~22 min
Max NROT value noted in parentheses
8/21
![Page 9: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/9.jpg)
Case 1: Supercell
0
10
20
30
40
50
60
70
t-4 t-3 t-2 t-1 t=0
Max Vr (kts)
0.5°
0.9°
1.4°
0
0.5
1
1.5
2
2.5
t-4 t-3 t-2 t-1 t=0
Max NROT
0.5°
0.9°
1.4°
Max Vr calculated as (max outbound SRM + max inbound SRM)/2 9/21
![Page 10: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/10.jpg)
Case 2: QLCS 1 December 2006 - Westmoreland
Co., PA
33.8 nm from KPBZ (touchdown)
Motion: 237° 60 kts
Magnitude: F-1
Length: 8.87 miles
Width: 50 yards
1638 UTC 0.5° BV/SRM
Linear convective bands with no deep, persistent mesocyclone
10/21
![Page 11: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/11.jpg)
Case 2: QLCS
t=0 (1638 UTC)
0.5°
0.9°
1.4°
11/21
![Page 12: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/12.jpg)
Case 2: QLCS
t-4 t-3 t-2 t-1 t=0
0.5°
0.9°
1.4°
(1.13) (1.01) (1.05) (0.73) (0.61)
(1.13) (1.13) (1.21) (0.77) (0.77)
(1.21) (1.28) (1.40) (0.97) (1.01)
~17 min
Max NROT value noted in parentheses
12/21
![Page 13: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/13.jpg)
Case 2: QLCS
Max Vr calculated as (max outbound SRM + max inbound SRM)/2
0
10
20
30
40
50
60
70
t-4 t-3 t-2 t-1 t=0
Max Vr (kts)
0.5°
0.9°
1.4°
0
0.5
1
1.5
2
2.5
t-4 t-3 t-2 t-1 t=0
Max NROT
0.5°
0.9°
1.4°
13/21
![Page 14: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/14.jpg)
Case 3: Single Cell 8 July 2014 - Mercer Co., PA
40.8 nm from KPBZ (touchdown)
Motion: 244° 34 kts
Magnitude: EF-1
Length: 2.46 miles
Width: 150 yards
1848 UTC 0.5° BV/SRM
Classified as other if no mesocyclone present, no significant linear features
14/21
![Page 15: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/15.jpg)
Case 3: Single Cell
t=0 (1848 UTC)
0.5°
0.9°
1.4°
15/21
![Page 16: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/16.jpg)
Case 3: Single Cell
t-4 t-3 t-2 t-1 t=0
0.5°
0.9°
1.4°
~21 min
Max NROT value noted in parentheses
(0.57) (0.53) (0.73) (0.89) (0.53)
(0.65) (0.61) (0.81) (1.28) (0.85)
(0.69) (0.69) (0.77) (1.36) (1.32)
16/21
![Page 17: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/17.jpg)
Case 3: Single Cell
Max Vr calculated as (max outbound SRM + max inbound SRM)/2
0
10
20
30
40
50
60
70
t-4 t-3 t-2 t-1 t=0
Max Vr (kts)
0.5°
0.9°
1.4°
0
0.5
1
1.5
2
2.5
t-4 t-3 t-2 t-1 t=0
Max NROT
0.5°
0.9°
1.4°
17/21
![Page 18: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/18.jpg)
Overall Results (all modes)
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
1.80
2.00
2.20
2.40
t-4 t-3 t-2 t-1 t=0
NROT vs. Time (all modes)
Supercell QLCS Other
n=8 n=15 n=14
18/21
![Page 19: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/19.jpg)
Conclusions
PRELIMINARY!
• Better correlation with positive NROT values
• Look at upper/lower bounds and TRENDS
• Better skill for supercells?
• Null cases?
• Good first step, more in depth study needed
• Other studies significance of values ≥ 0.8
19/21
![Page 20: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/20.jpg)
Final Thoughts
Is there utility in using NROT for tornado prediction? Yes. Need to assess how much and best applications
Refine current data, add new data (statistical significance) Build conceptual understanding of NROT and its application Re-work with MRMS low-level rotation tracks
Only one of many tools. Still must use radar, env. data for decision-making!
Finally: • Develop training and guides to help forecasters • Hands on familiarization via W2B/GR2AE simulations • Full introduction to ops
20/21
![Page 21: Assessing the utility of normalized rotation in detecting ...Assessing the utility of normalized rotation in detecting tornado development in the Allegheny Front Dylan T. Cooper –](https://reader035.vdocuments.us/reader035/viewer/2022071216/6046b0b84160eb0de450be18/html5/thumbnails/21.jpg)
Questions
21/21