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 jdodgson@airportauthority.bm

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