Overview of storm event 1300 26 July 2008

The current weather warning was issued by the MetService at 0814 on 26/7/2008 as follows:

 

A very deep low is approaching northern New Zealand this morning from the north Tasman Sea. This unusually intense low is forecast to move over Cape Reinga towards evening and then track southeastwards past Coromandel Peninsula around midnight, and lie near East Cape by midday Sunday. East to southeast gales are expected to buffet the North Island, with potentially damaging wind gusts of around 130 km/h possible in many exposed parts of the North Island, excluding Wairarapa and Hawkes Bay. MetService advises the public that winds of this strength have the potential to damage trees, powerlines and insecure structures and make driving hazardous, especially combined with heavy rain and possible slips. Boaties are advised to avoid going out and should have made moorings secure as high winds and very large waves are likely about northern and eastern coasts of the North Island.

 

A front ahead of the low is expected to bring widespread rain to the North Island by the end of Saturday. The heaviest rain should be in Northland,northern Auckland, Coromandel Peninsula, Gisborne and the Hawkes Bay. In these areas streams and rivers could rise quickly, with surface flooding and slips likely.

 

THIS IS A POTENTIALLY DESTRUCTIVE AND DANGEROUS STORM AND PEOPLE IN THE NORTH ISLAND, ESPECIALLY FROM WAIKATO NORTHWARDS, WOULD BE WELL ADVISED TO AVOID UNNECESSARY TRAVEL.

 

For the Coromandel Peninsula, in the 24 hours from 9am Saturday to 9am Sunday, 150 to 200mm of rain is likely about the ranges. In lower lying eastern areas 60 to 90mm is possible, with 50 to 70mm just west of the ranges. Heaviest falls are expected late afternoon and evening, when intensities could reach 20 to 30mm per hour about the ranges.

 

For the Coromandel Peninsula and Waikato, easterly winds rising to gale this morning, and to severe gale in exposed places between 11am Saturday and 2am Sunday, with 130 km/h gusts or possibly more. The winds are expected to turn to the southwest early Sunday morning, with further severe gale gusts of 120 km/h possible through to Sunday afternoon.

 

Observed rainfall

 

Rainfall is beginning to reach the upper Waikato Region, however is yet to register significant quantities on Environment Waikato’s telemetry system.

 

Observed wind speeds

 

The wind speed in the Firth of Thames has been steadily increasing from 2100 last night and is currently around 20 km/h (gusting to around 40 km/h).

 

Observed coastal conditions

 

No coastal issues have been reported.

 

The last high tide occurred as follows:

 

- Firth of Thames: 1.48 m at midnight on 26/7/2008

 

- Mercury Bay: 0.75 m at midnight on 26/7/2008

 

Response of river systems

Coromandel Peninsula

 

Environment Waikato is not aware of any Coromandel Peninsula river systems that have responded to this rainfall event.

 

Ohinemuri

 

The Ohinemuri River has not responded to this rainfall event.

 

Waihou River and tributaries

 

The Waihou River has not responded to this event and continues to recede following earlier rainfall.

 

Piako River and tributaries (including Waitoa River)

 

The Piako River has not responded to this event and continues to recede following earlier rainfall.

 

Environment Waikato response

Emergency Management

 

Environment Waikato duty EMO1 and EMO2 are on heightened alert and are monitoring rainfall and river levels across the Waikato Region.

 

All Emergency Management issues should be forwarded to the duty Emergency Management Officer (Greg Ryan) on (027) 499 2120.

 

Operations

 

Environment Waikato operations staff in the Waihou Piako zone are on stand-by to respond as necessary. Staff from the Lower Waikato zone are also on stand-by to provide support as necessary.

 

All operational issues should be forwarded to the RCS Operations Manager (Guy Russell).

 

Technical

 

Environment Waikato technical staff are on stand-by to respond as necessary to provide assistance with flood forecasting and emergency response.

 

All technical issues should be forwarded to the RCS Technical Manager (Ghassan Basheer).

 

Telemetry

 

The Environment Waikato telemetry system is functioning normally. Support staff are on stand-by to respond as necessary (including IQuest and EW IT support).

 

All telemetry issues should be forwarded to IQuest support (Michael Cook).

 

Communications

 

Environment Waikato communications staff are on stand-by to respond to media enquiries and to produce media releases. The Environment Waikato website has been amended to include direct links to relevant information (situation report, rainfall and river levels, road conditions and weather conditions).

 

All communications issues (including media enquiries) should be forwarded to the duty officer (Stephen Ward).