NWS Squall

Offshore Weather Services has been providing a squall monitoring and squall forecasting service in support of Woodside Energy Limited operations over the NW Shelf, Western Australia for the past 5 months.

Squall events over the NW Shelf and along the Pilbara coast are not frequent but when they do occur they are likely to be of a severe variety with winds speeds in excess of 35kt. Squalls are characterized by a very rapid onset of winds well above those prevailing at the time. These elevated winds strengths last for several minutes before gradually decreasing. Squalls pose a very real risk to the safety of operations, have been known to cause significant damage to assets in the region and are an unwelcome disruption to operations.

OWS utilise the high resolution Weather Research and Forecasting (WRF) atmospheric model programmed by OWS’s modelling specialist Dr Simon Caine to assist forecasters in evaluating the potential risk of squalls developing, their expected movement and intensity. Specialised tracking software is then used to track individual cells or squall lines giving more accurate predictions as to the timing and likely impact at the client’s locations. Surface and upper air observations, radar and satellite data are additional tools to assist with squall monitoring and development.

A squall event occurred on 10 February 2014 producing sustained winds to 35kt (as recorded at Lagendre Island) and with gusts to over 50kt.  The WRF model captured the event very well as shown by the simulated radar images for 1200-1400UTC, and is an invaluable and proven aid in the forecasting of squall events.

OWS has been providing similar squall warnings to clients throughout Southeast Asia for many years utilising the same technology as introduced to the NW Shelf.