emo hurricane season briefing 2019 hurricane season briefing... · 2019-08-29 · emo hurricane...
TRANSCRIPT
EMO Hurricane Season Briefing 2019
Presented by Michelle Pitcher, Deputy Director, BWS:1.BWS oversight & coordination2.Tropical Cyclone Development & Characteristics3.NHC Verification Trends4.BWS Role, Actions and Liaisons
Presented by James Dodgson, Director, BWS:1. Review of 2018 Hurricane Season2. 2019 Hurricane Season forecast3. Tropical Cyclone Climatology specific to Bermuda4. BWS communications
Skyport
• Aviation Forecasts, Watches & Warnings
• NOTAMs & Flight Plans• www.weather.bm/aviation
Tropical Updates, Watches, & Warnings
Coordination
Disaster Risk Reduction
& Mitigation Team(BDA Government)
Bermuda Airport Authority(Bermuda Airport Authority Act 2017)
• Public & Marine Forecasts, Watches & Warnings• Yacht Charts & Briefings• www.weather.bm• Media (TV Channels, Radio & Newspaper)• Climatology
• Severe Weather Watches & Warnings
Tropical Cyclone Formation Basins
These are between 5-15 degrees latitude north & south from the equator and generally tend to move
east to west as the hurricanes develop and grow
Source http://www.srh.noaa.gov/jetstream/tropics/tc_basins.htm
Tropical Cyclone Terminology
• *Tropical Depression - A tropical cyclone in which the maximum sustained
surface wind speed (using the U.S. 1-minute average) is 33 knots or less.
• *Tropical Storm - A tropical cyclone in which the maximum sustained surface
wind speed (using the U.S. 1-minute average) ranges from 34 to 63 knots.
• Hurricane - A tropical cyclone in which the maximum sustained surface wind
(using the U.S. 1-minute average) is 64 knots or higher.
• Major Hurricane - A hurricane that is classified as Category 3 or higher, 96 knots
and higher*Also includes Sub-Tropical Storms
+
-65-80 Years 2-7 Years
El Nino suppresses Atlantichurricane development
Images courtesy of NOAA
La Nina enhances Atlantichurricane development
El Nino & La Nina – impact on Tropical Cyclone formation
Tropical Cyclone Formation
• Warm sea surface temperature (at least 26C/80F)
• Moist & Unstable atmosphere •Low wind shear environment
• Pre-existing Disturbance
• e.g. Tropical Wave, old cold front, upper-level low/trough
Main Development Region (MDR)
Tropical Cyclone Formation
Tropical Wave in the Easterlies
Hurricane Development
This feedback mechanism continues as long as the favorable conditions for hurricane growth continue to exist.
Major Hurricane Nicole
SUOM 1 NPP VIRS Day Night Band 13 Oct 2016 06:15Z
Hurricane Winds & Storm Surge
Storm Surge is a dome of water driven by the persistent strong winds
Strongest winds
on the right side
of the storm
Weaker winds
on
the left side
of the storm
National Hurricane Center – Atlantic Basin
NHC Performance Measures and Goals: Track & Intensity
• As of 9 May 2019
NHC Performance Measures and Goals: Track & Intensity
• As of 9 May 2019 Per NHC:• Intensity is usually
estimated and not directly measured
• Winds damages land stations
• NOAA dropsondes sample portions of entire cyclone
• Data is readily available over land, but not over the ocean
• Greater influence from environmental interactions
• Tends to be conservative• “New” GOES16 will
provide new data for intensity models; increasing skill
BWS, in conjunction with NHC, Responsible for Local Threats, Watches, and Warnings
Distance of Centre• Potential Threat: The centre of a tropical cyclone is
forecast to come within 400 nautical miles of Bermuda within 72 hours.
• Threat: The centre of a tropical cyclone forecast to come within 100 nautical miles of Bermuda OR the effects of the tropical cyclone are possible in 72 hours.
Wind Speeds• (*TS) Hurricane Watch: Possible onset of (TS 34-63
knots) Hurricane force (64+ knots) winds within 48 hours or less.
• (*TS) Hurricane Warning: Possible onset of (TS 34-63 knots) Hurricane force (64+ knots) winds within 36 hours.
* Also includes: Sub-Tropical Storms
30N
20N
40N
60W 50W70W
400nm
100nmT+72 hrs
T+0 hrs
No Threat: Hurricane Lee
30N
20N
40N
60W 50W70W
400nm
100nm
The centre of a tropical system is forecast to come within 400
nautical miles of Bermuda within 72 hours.
Potential Threat: Tropical Depression Six
30N
20N
40N
60W 50W70W
400nm
100nm
The centre of a tropical system is forecast to come within 100 nautical miles of
Bermuda within 72 hours.
Threat: Hurricane Nicole
Implementation
T + 72 hours BWS monitoring NHC & other agencies for information Liaison with DRRMT, BAA, Skyport on tropical cyclones moving towards BDA as necessary
T = 72 hours Cyclone deemed (Pot.)Threat, Email to: DRRMT, BAA, Skyport, MAROPS, Briefings in person and via video begin
T = 48 hours TS/HURCN Watch issued, email updates and briefings continue, EMO Meeting
T = 36 hours TS/HURCN Warning issued, email updates and briefings continue
T - 36 → 0 hours Continued updates, forecast wind onset and cessation time tables created exclusively for the marine area, the Island, and the Airport
Implementation
CPA Potential for the strongest winds, highest swells/surge, passage of the eye
Winds < 64 knots HURCN Warning downgraded to TS
Winds < 34 knots TS Warning downgraded to Small Craft Warning
All Clear Final communications to EMO, BAA, Skyport, & MAROPS
NB: BWS staff stay at the office for the duration of the event; maintaining continuity of our 24 hour operations
James Dodgson [email protected]
Director, Bermuda Weather Service (BWS), aSection of the Aviation Services Delivery Unit, Bermuda Airport Authority
EMO Hurricane Season Briefing
1. Review of 2018 hurricane season2. 2019 hurricane season
• Predictions (including season so far)• Atlantic & Bermuda tropical climatology • BWS communications
Review of 2018 Hurricane Season
BDA
Very active in the central Atlanticand along parts of the US Gulf coast (e.g. Major Hurricane Michael) as well as the US eastern Seaboard (Major Hurricane Florence)
Image courtesy of NOAA/NHC
Despite some agencies forecastingan average or below average season,there were no less than 15 named storms, compared to an average of 12
However, for Bermuda, it was another welcome quiet season, with NO Tropical watches/warnings issued
Review of 2018 Hurricane Season
September 12th -
HURCN Florence Cat 3
HURCN Helene Cat 1
TS Isaac
STS Joyce
Florence
Isaac
Helene
JoyceBDA
Hurricane Florence – forecast challenges
ATLANTIC SEASONAL HURRICANE FORECAST FOR 2015
WHY increased activity? Despite forecasting agency projections suggesting near or just below average, last year was above average, largely due to poorly forecasted warming SSTs in August, as well as a slower than expected El Nino development. 2017 was very active due to a developing La Nina.
Atlantic Hurricane Season Summary 2018(& 2017)
ForecastParameter
Climatology(average 1981-2010)
Last year’s tally, 2018
Previous year, 2017
Named Storms 12 15 17
Hurricanes 6 8 10
Major Hurricanes 3 2 6
Despite these two active years, Bermuda was not directly impacted by any tropical cyclones, with no watches/warnings issued for first time since 2007!
2019 Hurricane Season
1. 2019 Seasonal Forecast - season so far & latest August update
3. BWS communications with EMO before, during and after a tropical system affecting BDA
2. Atlantic & Bermuda Tropical Climatology
2019 Hurricane Season – current stats
ACE is the measureof all the energyassociated with aTropical cyclone.It stands for:AccumulatedCycloneEnergy
Current ACE is 5 compared with seasonal average of 20
Image courtesy of Colorado State
2019 Hurricane Season – current stats
STS Andrea caught BWS’sattention ahead of official start of season – no impact
Hurricane Barry causedextensive damage to Lafayette, Lake Charles, and Baton Rouge
All systems rather short-lived, not generating muchACE
Image courtesy of Wikipedia
ATLANTIC SEASONAL HURRICANE FORECAST FOR 2015
REMEMBER, what ever the projections are, it only takes one storm to make it
an active season for us! E.g. Hurricane Nicole
The very fact that NO tropical watches/warnings were issued by BWS in the
last two seasons makes it increasingly likely BWS will issue some this season!
Why are forecast numbers slightly above average for this season?
Recent El Nino event has now ended. El Nino typically suppresses Atlantic
hurricane activity but now that’s gone, we are likely to see a slightly above
average season ahead. This is coupled with the current on-going era of more
conducive conditions (positive phase of the AMO – warmer SSTs) since 1995.
Atlantic Seasonal Hurricane Forecast 2019ForecastParameter
Climatology(average 1981-2010)
Tropical Storm Risk issued 6 August
Colorado State issued 5 August
NOAA CPCissued 8 August
UK Met Office issued 21 May
NamedStorms
12 13 14 14 13
Hurricanes 6 6 7 7 7
MajorHurricanes
3 2 2 3 3
Tropical Climatology of Atlantic - August
Images courtesy of NOAA
BDA
Tropical Climatology of Atlantic - September
Images courtesy of NOAA
BDA
Tropical Climatology of Atlantic - October
Images courtesy of NOAA
BDA
Tropical Climatology of Atlantic - November
Images courtesy of NOAA
BDA
Historical Record For Atlantic Basin
12-13 October 2016
Major Hurricane Nicole
4-5 October 2015
Hurricane Joaquin
17 October 2014
Major Hurricane
Gonzalo
12 October 2014
Hurricane Fay
Historical Record For Bermuda (Hurricanes)
Historical Record For Bermuda (Tropical Storms & Hurricanes)
44
34
Timeline for Threats, Watches and Warnings
T-72hrs T-48hrs T-36hrs T-0hrs CPA>T-72hrs
Threat considerationEmail to EMO executiveLikely convening of EMO as directed by NDC
Issuance of POTENTIAL THREAT (400nm) orTHREAT (100nm)
Issuance of TS/HURCNWATCH
Issuance of TS/HURCNWARNING
Onset of TS/Hurcnforce winds
Potential for strongest winds/swells/ surge and eye passage
Cessation of hurcn force winds. HURCNWARNING downgraded to TS WARNING
Cessation of TS force winds. TS WARNING downgraded to Small Craft warning
<64kt <34kt
Time=>
All clear
Final communication between BWS & EMO to give all clear – EMO post event meeting as required
Creation of TUBs
BWS Operations
• www.weather.bm
• Automated telephone recordings 977, 9771, 9772, 9773
• Radio interviews (including 100.1FM)
• Marine VHF Channel 2 (Bermuda Radio)
• OneComm Channel 4 & WOW Channel 100 BWS Weather Channels
• Social Media – BWS Facebook page: www.facebook.com/BermudaWeatherService
• News media announcements
• Communications with EMO, Aviation & Marine operations via email, fax, phone, satellite phone BWS # +881 631 452 873
• Full redundancy for BWS equipment, electricity & comms
BWS Operations
Additional information provided to EMO
• BWS director will email the EMO executive email group when a system is expected to affect BDA in any way – Regiment contacts are also included
• Weather briefings provided to the EMO as needed in advance of a warning issuance
• Before, during and after the event, information will be conveyed via email to the EMO executive email group (NDC then re-distributes the information to wider membership)
– Onset/cessation and directions of winds reaching the following thresholds:
• 34 knots (Tropical Storm force)
• 50 knots (potential Causeway &/or Airport closure, depends on multiple variables including wind direction, tide cycle, time of day, forecast etc.)
• 64 knots (Hurricane)
– Maximum wave heights expected & the effects due to storm surge/tidal levels
– Time and distance of the closest point of approach of the centre of the storm
• Online Video briefings - produced by BWS when the EMO cannot convene, e.g. during the event or on weekends/short notice events or during preparation.
Title
24 hours
15 hours
12 hours
Eye approx. 45 min
** 4 hrs Cat3
- Cat2
Onset/cessation Wind Timings (example)
How can we improve for 2019 Season?
• United front of Information- EMO, DC & BWS
• Communication
– BWS – Impact based & colour coded for government department planning. Did this help last few years? Should we
continue? – NHC & WMO pushing impact based forecasting in future –e.g. high rainfall versus flood/surge warning
BLUE – Sea state event: Parks (Lifeguards)
YELLOW – 50 kt threshold: Parks, Education, Transport, Causeway, etc
RED – Damages possible – All departments
HPW19 – Hurricane Preparedness Week 2019
• Ran from June 3rd – 7th 2019
• In collaboration with the Disaster Risk Reduction Mitigation Team
• Press release issued; various links/videos on www.weather.bm/HurPWeek.asp
• Asking the public to: Please do not become complacent– Please review/create a Hurricane Preparedness Plan
• for your family and business incorporating lessons from recent years– Tropical systems do not behave like winter weather – they can change very
rapidly. At the watch stage, please monitor the progress carefully at the warning stage please respond to preparations
• Keep updated on the official sources of information– www.weather.bm maintained by BWS, a 24hr local operation & updated
routinely – every 3 hours in tandem with NHC advisories (in threat)• for Bermuda’s official weather forecast, Watches & Warnings
– www.gov.bm for preparation (also the Tree Frog app)– Emergency Broadcast Facility (100.1FM) during event
Thank-you. Any questions?
Aderonke Bademosi WilsonDirector, Department of
Communications
Government of Bermuda’s Treefrogapp
About the app
• Designed by four students at Bermuda College with support from the Portals Management team, Information and Digital Technologies Department and a US app developer and project managed from the Cabinet Office;
• Launched in April;
• Designed to provide users with press releases, alerts and notifications that are issued by the Department of Communications.
Downloading the App
• It is free, easy and user-friendly• Download from the App store or Google Play• Look for Bermuda Treefrog• You can select which categories you want to
receive information about:– Announcements– Government closures– Health– Service Disruptions– Traffic
During an emergency
• The option you cannot turn off is Public Safety
• Before, during and after a hurricane, Communications Officers will send out notices to the media and the information will be immediately posted to the website and pushed to Treefrog
• Treefrog will give users direct access to information and updates about the hurricane.
• This information will also be posted on social media.
Questions?
BWS Website updates – New Radar and AWOS (Automated Weather Observing System) products