a convective wind event over southeastern alberta on 15 july 2008
DESCRIPTION
A Convective Wind Event over Southeastern Alberta on 15 July 2008. Stephen Knott and Chris Wielki Prairie and Arctic Storm Prediction Centre - Edmonton. Outline. Synoptic Setup Radar Evolution Mesoscale Convective Vortex? Post Storm Investigation Summary. 00z 16 July 2008. 250 MB. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/1.jpg)
A Convective Wind Event over Southeastern Alberta
on 15 July 2008
Stephen Knott and Chris WielkiPrairie and Arctic Storm Prediction Centre - Edmonton
![Page 2: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/2.jpg)
Outline• Synoptic Setup
• Radar Evolution
• Mesoscale Convective Vortex?
• Post Storm Investigation
• Summary
![Page 3: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/3.jpg)
00z 16 July 2008250 MB 500 MB
700 MB 850 MB
![Page 4: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/4.jpg)
Surface Conditions
![Page 5: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/5.jpg)
Adjusted 12z Olds SoundingUNSTABLE 2008 (25/12 0C)
![Page 6: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/6.jpg)
Radar Evolution (1 Hr)
![Page 7: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/7.jpg)
SUDDS 21:00z
![Page 8: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/8.jpg)
SUDDS 22:00z
![Page 9: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/9.jpg)
SUDDS 23:00z
![Page 10: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/10.jpg)
SUDDS 00:00z
![Page 11: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/11.jpg)
SUDDS 01:00z
![Page 12: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/12.jpg)
SUDDS 02:00z
![Page 13: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/13.jpg)
SUDDS 03:00z
![Page 14: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/14.jpg)
SUDDS 04:00z
![Page 15: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/15.jpg)
Vulcan Storm2240z 15 July 0820 minutes prior to report of tornado
![Page 16: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/16.jpg)
Vulcan TornadoRated F1 (Sills)
• Path Length 100m; Path Width 30m, motion 330• Lat/Long50.4303/ -113.189• Two empty grain silos (approx. weight 5000lbs) were torn from their
foundations (bolted about 8 cm into cement pads) and thrown through the air approx. 70m. No sign of being rolled or dragged. Adjacent silos had some damage but did not leave their foundation (even ones with wood foundations). A few trees in the path were damaged or destroyed. Straw bales (approx. weight 1000lbs) were tossed around. Evidence of convergence in the flattened grass along the path.
![Page 17: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/17.jpg)
Mesoscale Convective Vortex
• At 0120z strong persistent rotation found at all three levels.
• Vortex persists 90 minutes, diameter of 15-20 km, tracks 80km from 260 and moves north of Cypress Hills.
• Radar echoes initially show hook but disintegrate into no definable pattern and yet wind damage to homes reported at Irvine.
![Page 18: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/18.jpg)
Meso-Vortex
![Page 19: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/19.jpg)
Meso-Vortex
![Page 20: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/20.jpg)
Meso-Vortex
![Page 21: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/21.jpg)
Meso-Vortex
![Page 22: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/22.jpg)
Meso-Vortex
![Page 23: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/23.jpg)
Meso-Vortex
![Page 24: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/24.jpg)
Meso-Vortex
![Page 25: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/25.jpg)
7:31 pm
![Page 26: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/26.jpg)
7:32 pm
RFD Dry Slot?
Flanking Line associated with RFD gust front
![Page 27: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/27.jpg)
7:33pm
![Page 28: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/28.jpg)
7:48pm
![Page 29: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/29.jpg)
Medicine Hat
Funnel cloud picture is from Seven Persons looking towards 290 degrees ~ 0120 UTC
0120 UTC 3.5 km CAPPI
0120 UTC
0120 UTC
Damage Survey Route
![Page 30: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/30.jpg)
Main damage swath was from anarea just south of Seven PersonsEastwards.
0120 UTC 0130 UTC 0140 UTC 0150 UTC
215 kmh-1 measured 80 m above ground
![Page 31: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/31.jpg)
Peak Winds and damage swath
Estimated damage path (F1 or greater) was approx 250 km long and up to 31 km wide
2100 UTC
0200 UTC
Speeds in kmh-1
![Page 32: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/32.jpg)
Summary• During the event operations believed the mesoscale vortex had a
high likelihood of generating a tornado• EPWS triggered 3 times during storm lifetime, first as a dangerous
supercell then along with a tornado warning• Damage survey results suggest this large-scale persistent rotation
may not have equated to a tornado– apparent predominant straight line wind damage on the order of F1 and
low F2 categories in the RFD region of the supercell• More work required with respect to origin of large-scale meso-vortex
but authors speculate a low-level jet from near Alberta US border interacted with storm enhancing the RFD and spinning up vortex.
• Was some speculation from damage path that the event may reach derecho criteria though this not the case
• Weakening radar echoes did not correlate with diminishing of severe winds
![Page 33: A Convective Wind Event over Southeastern Alberta on 15 July 2008](https://reader036.vdocuments.mx/reader036/viewer/2022062520/56815853550346895dc5ad1c/html5/thumbnails/33.jpg)
Thank You