alberta broadcasters public alerting recognition symposium meteorological decision making image...
TRANSCRIPT
Alberta Broadcasters Public Alerting Recognition Symposium
Meteorological Decision Making
Image Courtesy Steve Ricketts
Outline• Alberta Summer Weather
• Weather Centre Operations
• Severe Weather Meteorologist
• Convective warnings
• Decision Making Process
Photo Courtesy Justin Hobson
Elie Manitoba June 22, 2007
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April May June July August Sept
Month
AB
SK
MB
Alberta Convective Climate
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06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 01 02 03 04 05
Time (UTC)
# o
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nts
AB
SK
MB
Annual Alberta Svr Weather EventsYear Hail Wind Tornado Rain Total
2000 56 9 15 1 81
2001 44 7 6 3 60
2002 12 4 3 1 20
2003 70 19 14 1 104
2004 52 17 15 6 90
2005 68 6 9 4 87
2006 83 14 5 4 106
2007 89 37 12 8 146Average 48 12 11 8 79
Weather Centre OperationsPASPC
• Responsible for Public and Marine Forecasts & Warnings
• Edmonton & Winnipeg split the Responsibility
• Each office 2.4 people shifts, 24hrs per day, 365 days per year
• Automation leveraged• Co located with Aviation
forecast centre – CMAC in Edmonton
PSPCOSPC
PASPCPASPC ASPC
SPC Areas of Responsibility
Graphic Courtesy McCarthy 2007
Equivalent Areas of ResponsibilityS ize of the PA SP C ’s area of respons ibility
if it w ere in Europe
L a superfi c ie de la region de responsabilite du CP T PA vis -a-vis l’Europe
S ize of the PA SP C’s area of respons ibilityif it w ere in the U nited S tates
(equal to approx . 65-70 U .S . Weather offi c es)
L a superfic ie de la region de responsabilite du CP T PA vis -a-vis les E tats -U nis
(l’equivalent d’environ 65-70 bureaux meteorologiques americ ains)
Graphics Courtesy McCarthy
Means for Dissemination
• Weatheroffice web site. Most popular Web site in gc.ca domain…
• Specialized media site• WeatherRadio• ATADs• Media Partners• EPWS• Warning Lead time for
supercells/tornados is critical
Weather Radio Network in Alberta
Severe Weather Meteorologist• Supervisor on shift • Analysis/Diagnosis/
Prognosis• Highly trained• Convective weather • Radar interpretation• Decision making
Phases of shift• Workup-anticipation• Weather watch• Heat of battle
Bulletins• Thunderstorm
Watches/warnings• Tornado
Watches/warnings
Radar
• Critical and sophisticated tool• Spirit River, Jimmy Lake
Carvel, Strathmore, Schuler• Measures hydrometeor
intensity and radial motions• Detects rotating storms
(Supercells) but not tornadoes
• Ground reports critical for tornadoes
• Doppler coverage of southern and central Alberta is not continuous
Decision MakingInformation• Analysis of temp, wind
and moisture• NWP guidance• Radar and satellite
– Monitor boundaries• Lightning detection• Soundings including
aircraft• Weather watchers
Thunderstorm Options
• Watches - When to issue? Where? Type to issue?
• Thunderstorm Warnings – When? Where?
• Difference between a Watch and a Warning?
• Tornado warnings• On busy days numerous
bulletins can be in effect
Photo copyright Neil Taylor
Decision Making EPWS
• Always Issue for Dangerous Supercells
• Tornado warnings require SPC to trigger EPWS
• Most effective way to deliver message
• Nerve racking task• Practice is key
Info includes storm/tornado location and motion
Preset Forms• Unusually strong
Supercell• Possible tornado
(rotation detected within doppler range)
• Tornado on ground
Conclusion
• Weather Radio fills an important gap in our dissemination process because said radios can sleep until a programmed watch or warning id is received
• EPWS decisions add to the work load of the forecast team
• However, within Environment Canada’s dissemination network there is no better means to quickly disseminate life threatening severe weather situations than the EPWS
Copyrighted and courtesy of Brad McLeod
Why do we activate EPWS?