hurricane preparedness week 2020 · 2020. 6. 1. · • an active 2020 atlantic hurricane season is...

Hurricane Preparedness Week 20201-5 June 2020

In collaboration with the Government of Bermuda Disaster Risk Reduction Mitigation Team

Hurricane Season 2020

Agenda

27/05/2020 2:34 PM Bermuda Airport Authority 2

Take-home points

Hurricane Basics

Science and Predictions

• 2019 Season - Review

• 2020 season - Precursor conditions and seasonal predictions

Operations:

• BWS and NHC Products

• Communications with local stakeholders


Take Home PointsSeasonal Outlook

• An active 2020 Atlantic Hurricane Season is expected.

• While the most active part of the season is usually August through October, a tropical storm or hurricane is possible at any time - June-November is officially Hurricane Season, but Arthur proves tropical systems can occur beyond these times.

• It only takes one storm to make it an ‘active season’ for Bermuda

COVID-19 Impacts and Response

• Operations at the Bermuda Weather Service have remained 24/7 through the shelter-in-place period, and are expected to continue on that basis.

• Predictability may be decreased due to reduced aircraft data availability.Source: Cooperative Institute for Meteorological Satellite

Studies / University of Wisconsin-Madison

http://cimss.ssec.wisc.edu/

http://www.wisc.edu/


Take Home Points

• Tropical Update Bulletins (TUBs) are issued on active systems every 6 hours - Intermediate TUBs possible for imminent systems

• Potential Threat – storm centre to track within 400 nm in next 72 hours

• Threat – storm centre to track within 100 nm in next 72 hours

• TS/Hurr Watch – TS/Hurricane conditions possible within 48 hours

• TS/Hurr Warning – TS/Hurricane conditions expected within 36 hours

BWS Operational Products

Tropical Cyclone Terminology

• Tropical Depression* - A tropical cyclone in which the maximum sustained surface wind speed is <34 knots.

• Tropical Storm*- A tropical cyclone in which the maximum sustained surface wind speed ranges from 34 to 63 knots.

• Hurricane - A tropical cyclone in which the maximum sustained surface wind is 64 knots or higher.

• Major Hurricane - A hurricane that is classified as Category 3 or higher, 96 knots and higher

*Also includes Subtropical Cyclones

Tropical Depression Arthur

NASA

Hurricane Igor

NASA

BWS

Areas of Responsibility

NHC: analysis and forecasting of tropical cyclones in the North Atlantic, Caribbean Sea and Gulf of Mexico

BWS: Observations, forecasts, analyses, watches & warnings for Bermuda and Marine Area out to 25nm


Climatology of Atlantic Tropical Cyclones - Early

MAY

Arthur


Climatology of Atlantic Tropical Cyclones - Peak

18 September 2019 Major Hurricane Humberto

12-13 October 2016Major Hurricane Nicole

17 October 2014Major Hurricane Gonzalo

5 September 2003Major Hurricane Fabian


Climatology of Atlantic Tropical Cyclones - Late

Preferred storm track pathways

Source: FSU and BIOS

Historical Tropical Cyclone Record For Bermuda

Storms within 100nm (i.e. meeting BWS Threat criterion)Sources: NOAA, BWS, BIOS, University of Reading


Hiroyuki Murakami et al. PNAS doi:10.1073/pnas.1922500117

©2020 by National Academy of Sciences


2019 Atlantic Hurricane Season Review

• 18 Named Storms

• 6 Hurricanes

• 3 Major Hurricanes

• 3 named storms that achieved threat criteria.

• 1 Major hurricane impact

Summary


Hurricane Humberto – September 2019

Track and Wind Swath Satellite Imagery & Rainfall



Wind field expansion Doppler Radar Imagery



Highest recorded wind speeds & gusts Resulting Damage



Storm surge

Maximum surge at NOAA’s Esso Pier Tide Gauge:18/09/2019 20:54 (local time) 3.143 feet above the predicted tide

Resulting Damage


2020 Atlantic Hurricane Season

Source: Cooperative Institute for Meteorological Satellite Studies / University of Wisconsin-Madison

http://cimss.ssec.wisc.edu/

http://www.wisc.edu/


• Ocean Temperatures – influence over seasonal hurricane activity

• Warm Atlantic Main Development Region

• Cool Equatorial Pacific

Ocean Surface Temperature Anomalies

Source: tropicaltidbits.com

Source: NOAA

Source: tropicaltidbits.com

More locally:

• Currently cooler than average

• Warming to the south

Bermuda Airport Authority 19

Decreased aircraft and surface observations could degrade weather forecast model reliability.

27/05/2020 2:34 PM

• Aircraft produce over 700 000 high-quality daily observations of air temperature, winds, humidity and turbulence. (Source: World Meteorological Organization).

• “Recent figures show a decrease of 80% of such observations in Europe and 60% globally.” (Source: European Centre for Medium-range Weather Forecasts).

March 2020 European AMDAR observations. Source: DWD (German Met. Service).

Degradation of Surface Observations

There is a decrease in the number of surface andaircraft meteorological measurements due toCOVID-19. These issues highlight the importanceof ongoing surface & upper-air observationsthrough weather balloon launches.


BWS’ team of Meteorological Technicianshave continued a 24/7 service of makingweather observations and maintainingBermuda’s climate record through theshelter-in-place period.

5/27/2020 2:34 PM BERMUDA AIRPORT AUTHORITY 21

Spring Seasonal Hurricane Predictions

https://seasonalhurricanepredictions.bsc.es/

High activity

To Date:

0

Average Prediction:

8

Note: Hurricane predictions only (does not include tropical / subtropical storms)

https://seasonalhurricanepredictions.bsc.es/


Review of Operational Products

NOAA

Also reflected in BWS products

60-h Forecast Information on Cone Graphic

Forecast Products at the US National Hurricane Center


The ‘Cone of Uncertainty’

Track forecast accuracy improvements lead to smaller cone of uncertainty.



Forecast Products at the Bermuda Weather Service

• Based on NHC Advisory # and time

• Current position relative to Bermuda and intensity details

• Timing and location of forecast closest point of approach (‘CPA’), within the next 72 hours

• Any additional detail (e.g. Watch/Warning valid)

• Whether the system is a ‘Threat’ or ‘Potential Threat’ (see next slide)

Tropical Update Bulletin

30N

20N

40N

60W 50W70W

400nm

100nmT+72 hrs

T+0 hrs

Threat Criteria, Watches and Warnings

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.


30N

20N

40N

60W 50W70W

400nm

100nm

Threat:

The centre is forecast to come within 100 nautical miles of Bermuda OR the effects of the tropical system (including tropical storm force winds) are possible within 72 hours.



• Tropical Storm Watch: 48 hours or less prior to possible onset of tropical storm force winds (34-63kt). Includes similar conditions in subtropical storms and outer fringes of hurricanes.

• Tropical Storm Warning: tropical storm force winds expected within 36 hours.

• Hurricane Watch: 48 hours or less prior to possible onset of hurricane force winds (64 knots or more) or other damaging hurricane conditions.

• Hurricane Warning: Hurricane force winds &/or damaging hurricane conditions expected within 36 hours.

Timeline for Threats, Watches and Warnings

T-72hrs T-48hrs T-36hrs T-0hrs CPA>T-72hrs

Creation of TUBs

Issuance of POTENTIAL THREAT (400nm) orTHREAT (100nm)

Issuance of TS/HURCN WATCH

Issuance of TS/HURCN WARNING

Onset of TS/Hurcn force winds

Potential for strongest winds/swells/ surge and eye passage

Cessation of hurcn force winds. HURCN WARNING downgraded to TS WARNING

Cessation of TS force winds. TS WARNING downgraded to Small Craft warning

<64kt <34kt

Time=>

Reminder of BWS/NHC Policy Changes

• BWS, in consultation with NHC, is able to issue watches & warnings on tropical disturbances that are not yet a tropical cyclone, but which pose the threat of bringing TS or Hurricane conditions to the Island within 48hrs.

• These will be labelled ‘Potential Tropical Cyclones’

• An example of when this might have been useful was Hurricane Karen in 2001 which formed on Bermuda’s doorstep – BWS was able to issue gale and storm warnings but not ‘more impactful’ tropical warnings

BWS Communications

www.weather.bm

Automated BTC 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

Full redundancy for BWS equipment, electricity & comms

http://www.weather.bm/

http://www.facebook.com/BermudaWeatherService

Messages for the Public

◦ 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

◦ EMO website for preparation information

◦ Emergency Broadcast Facility (100.1FM) during event

◦ Bermuda Tree Frog app

◦ Press release to be issued; various links/videos on www.weather.bm

◦ Please do not become complacent.

◦ Review/create a Hurricane Preparedness Plan for your family and business incorporating lessons from previous years.



Hurricane Preparedness Week 20201-5 June 2020

In collaboration with the Government of Bermuda Disaster Risk Reduction Mitigation Team

hurricane preparedness week 2020 · 2020. 6. 1. · • an active 2020 atlantic hurricane season is...

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