WEATHER BRIEF FOR TBEC 12 November 2013, Nukualofa Tonga Met Service Nukualofa Ofa Faanunu Tonga Met...
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Transcript of WEATHER BRIEF FOR TBEC 12 November 2013, Nukualofa Tonga Met Service Nukualofa Ofa Faanunu Tonga Met...
WEATHER BRIEF FOR TBEC
12 November 2013,Nuku’alofa
‘Ofa Fa’anunu
Tonga Met ServiceMINISTRY OF INFRASTRUCTURE
RAINFALL
Mean annual rainfall for Tonga's main islands (1971-2000)
2453
2374
2150
1619
1721
0 500 1000 1500 2000 2500 3000
Niuafo'ou
Keppel
Vava'u
Ha'apai
Tongatapu
Isla
nd g
roup
mm
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC0
50
100
150
200
250
FUA'AMOTU AVERAGE RAINFALL FOR 1971-2000
AVERAGE
MONTH
MM
DRY DRY
Seasonal Cycles
06/02/10 Tonga Meteorological Services 6
Seasonal Cycles
NIUAFOOU NIUATOPUTAPU VAVAU
HAAPAI NUKU’ALOFA
NFO = ABOVE 1001MMNTT = ABOVE 864MMVAV= ABOVE 8I3MMHAP= ABOVE 580MMTBU = ABOVE 565MM
TROPICAL CYCLONES
What is a tropical cyclone?
Tropical Cyclone = wind circulation around a centre > 34kts
Warnings Wind speed
Gale warning = 34-47kt
Storm warning = 48-63kt
Hurricane warning = >64kt
10/18/10 10Tonga Meteorological Services
10/18/10 11Tonga Meteorological Services
A Tropical Cyclone will be categorized as per the Australian and South Pacific
Category System as follows: Category Potential damage
10-Min Mean Wind Maximum 3-Sec Gust
Category 1 (Tropical Cyclone)
(Negligible house damage. Damage to some crops and trees. Boats may drag anchor e. g. TC CILLA)
63 – 87 km/hr (34 – 47 knots)
Less than 125 km/hr (Damaging Winds)
Category 2 (Tropical Cyclone)
(Minor house damage. Significant damage to trees. Heavy damage to crops. Risk of
power failure. Small boats my break anchor e. g. TC HINA)
88 – 117 km/hr (48 – 63 knots)
125-169 km/hr (Destructive Winds)
Category 3 (Severe Tropical Cyclone)
(Some roof and structural damage. Power failure likely e. g. TC KINA)
118 – 157 km/hr (64 – 85 knots)
170-224 km/hr (Very Destructive Winds)
Category 4 (Severe Tropical Cyclone)
(Significant roofing loss and structural
damage, Dangerous airborne debris e. g TC WAKA)
159 – 200 km/hr (86 – 110 knots)
225-279 km/hr (Very Destructive Winds)
Category 5 (Severe Tropical Cyclone)
(Extremely dangerous with widespread destruction. e. g. TC HETA)
Over 200 km/hr) (Over 110 knots)
Over 280 km/hr (Very Destructive Winds)
10/18/10 13Tonga Meteorological Services
06/02/10 Tonga Meteorological Services 14
Impacts and Extremes
Average number of tropical cyclones per season (66 years)
El Nino 1.88 La Niňa 1.63 Neutral 1.64
All seasons
1.74
Tropical Cyclone Outlook for 2013/14
Average to Below average no of TCs expected in the SW Pacific (mod confidence);
TC risk is higher than normal for the countries west of and around the Dateline;
4 to 8 named tropical cyclones expected this season;
Average to above average activity for Tonga
Tropical Cyclone Outlook for 2013/14
Chance of getting a cyclone in Tonga this season is 114% (High). Likely 2
Severe TC Risk for Tonga 171% (Very High);
Cyclone formation and track will most likely be from west to north quadrant
TC Season for 2013/14 similar conditions to
1981/82 - TC Isaac (Severe – C&S Tonga) 1984/85 - TC Lance (Storm), TC Drena
(Storm) both N.Tonga, TC Eric (Severe – C&S Tonga)
1990/91 – TC Sina (Severe – C&S Tonga), TC Val (Severe – Northern Tonga)
1996/97 – TC Hina (Severe Southern Tonga), TC Keli (June) (Severe N.Tonga)
2001/02 – TC Waka (Severe N&C Tonga)
TSUNAMI
2 natural cuts in the reef
PACCSAP Project
Nukualofa
Sea flooding already affectsNuku’alofa from subsidence even before the tsunami arrives
After modeling
• Confirmed extreme tsunami risk for Tongatapu
• There are wave depths of >10m in places and several km inland depending on local topography.
• Nuku’alofa and eastern Tongatapu are most vulnerable.
• Warning times will be very limited (10-25 minutes)
• There are several small pockets of safer (higher) ground
WILL NOT WORK IN A
LOCAL EVENT
Detecting a local tsunami
• Tonga seismic network problematic (5 seismic stations) & no direct access by warning center
• Earthquake data from USGS
• Geological Survey Unit send an automatic message through HYDRA system (often can receive a preliminary center & magnitude quicker than PTWC)
• Warning center looking to using earthquake intensity meters to measure ground shaking as an early warning indicator
• Sea Level monitoring equipment to be improved through SPCR Project
Current warnings
1) Urgent Tsunami Alert
– Ready made and ready to go (TMS)
2) Tsunami Warning
- As received by PTWC
(3) Local Earthquake Bulletin – Anything above 4.5M and below 70km depth
(4) PTWC international SMS direct to mobile
phone
Future warnings (from later 2014)
1) Urgent Tsunami Warning (ready made)
2) Tsunami Warning (when verified)
(3) Local EQ Advisory (4.5 <M<7.5) <50km
(4) Regional EQ Advisory (M>7.5) <50km
(5) Distant EQ Advisory
(6) Tsunami No threat Advisory
(7) Tsunami Marine Warning
Disseminating the warnings
• 24hr SMS mobile alert service via 1 Telecom provider (Digicel) to selected users relevant to the warning system
• Live broadcast on national radio (Radio Tonga) – national coverage (both MET and NEMO)
• Activation of sirens in place
• Met Service Website
• Email distribution
• Telefone/fax
KALAA’U
KALA’AUFAHEFA
THIS ROCK IS THOUGH TO BE BROUGHT BY A TSUNAMI
Things to do in an earthquake or tsunami in Tonga
• When there is an earthquake find something solid and lie down next to it. Do not go underneath table or bed etc
• If the earthquake is strong enough for you to loose balance, move away from the coast immediately a tsunami might be on its way in less than 15mins
Things to do in an earthquake or tsunami in Tonga
• Move inland by 1 mile and wait there. Listen to radio. If no radio then wait there for an hour
• Know where you live. Be aware of high strong buildings. Even tall trees you can climb
• If you are on a small island, move to the centre of the island a find a strong tree to climb
Things to do in an earthquake or tsunami in Tonga
• Be aware of what the wildlife and animals are doing. Often their senses are keener than humans
• If u are at sea and you hear a tsunami warning stay out at sea, you are safe there
• Do not drive when evacuation your home….WALK!!
Things to do in an earthquake or tsunami in Tonga
• Teach your family about tsunami and where to evacuate. You should not pickup your school children from school in an event of a tsunami
• All tsunami are dangerous. Large or Small. Heed warnings at all times
• Tsunami is not just one wave. It is a series of waves and the first is not necessarily the biggest
Things to do in an earthquake or tsunami in Tonga
• If you see the tide receding after a major earthquake..RUN!!
• Do not attempt to go and see a tsunami. On level ground, when you see a tsunami is usually too late to escape
MALO AUPITO