Weather forecast data allows vegetable growers to consider, sooner, what needs to be planned and prepared to reduce their exposure to flooding or wet weather event impacts. While timing of the event and likely duration is important, the accuracy of predictions for the days leading up to and after are highly critical. The tendency is to turn to rainfall considerations, but wind is also a major factor throughout the period.

The AUSVEG-led Building Biosecurity Capacity and Resilience within the NSW Vegetable Industry project partnered with growers in different NSW growing regions to track their experiences in using weather forecasting platforms to better understand predictions for their farm location in the next 7-10 days, and their crop management response to this information. The investigation was conducted during the summer storm event period, from November to February, experienced in NSW over recent years.

Sam and Claire Micallef manage one of the family farms of their Allandale Produce business at Agnes Banks, only six kilometres from the Bureau of Meteorology’s (BOM) Richmond RAAF Base all weather station (AWS), NSW.

They primarily grow lettuce varieties, cauliflower, cabbage and sweet corn with a strong emphasis on using cover crops and permanent beds to maintain good soil health. Using integrated pest and disease management strategies is also important. Weather events can significantly interrupt the entire system, and managing these has become a necessary part of their farm planning and operations.

“We have experienced severe rain and wind events in the past that resulted in significant direct crop damage and indirectly by flooding from runoff sources outside the farm gate,” says Sam.

Traditionally, Sam has referred to the BOM AWS for his forecasts. While considering himself fortunate to have this ‘local’ resource, he has often questioned its accuracy in relation to the micro-climate of his farm.

Figure 1. An example of the information available to Sam Micallef on 8 January. Moderate wind gusts of 35km/h (blue) and unsuitable (red) spraying conditions were reported, with little rainfall predicted throughout the day. Other data sources forecasted 10.5mm of rainfall and average wind gusts of only 14km/h.

Having confidence in precise rain and wind forecasts has become essential to managing not only weather risks, but also irrigation throughout seasons.

“We can also have extreme heat events here. At those times we need to rely upon the forecasts – temperature, evapotranspiration and wind – to determine how bad these will be and prepare the crops with changes to the irrigation program.”

In either wet-humid or hot-dry scenarios, knowing when and to what extent weather conditions will present themselves, and when they change to aid recovery is critical.

“Weather forecasts help us stay on top of upcoming weather conditions so we can plan critical farm operations like spraying and fertilising in advance, and when we are likely to have the right conditions afterwards to get back onto blocks and continue operations,” explains Sam.

Sam and Claire were supported to trial Jane’s Weather 10-day forecasting platform during the summer of 2024-2025. Over the same period, daily records from the Richmond BOM AWS and weather alerts from Swan System’s Weatherwise seven-day forecast updates, were monitored for comparison. Jane’s Weather is based upon a 9x9km grid surrounding the centre of Agnes Banks, NSW and it uses global weather models as well as local weather stations, then applies AI machine learning to analyse and predict the site-specific conditions for up to 10 days. Weatherwise is based upon a smaller grid system of 6x6km and receives its data from a more limited number of models used by the BOM.

On 8 January, major rainfall was predicted for the Hunter Coast to Illawarra regions, encompassing greater Sydney, for the following four days. Sam provides an insight into how the conditions prevailed for him versus the data on-hand.

“We had a big event forecasted last week (9-12 January) and Jane’s Weather forecast was much closer to what happened. Others predicted much heavier rainfall (up to 60mm), but Jane’s Weather accurately predicted less rain (34mm) which I planned around, and it was pretty much spot-on (27.5mm observed at the Richmond BOM AWS).”

Sam believes that more accurate forecasts help him manage his risks by not under or overreacting to exaggerated or inaccurate forecasts. He is more assured in his decision- -making when armed with a tool he has confidence in.

“I receive a ‘Super Alert Forecast Report’ that I look at each night from Jane’s Weather,” he says.

“It comes in an email format providing information set-up as relevant to my farm and helps me prepare for what needs to be done for the day ahead, including activities to prepare for upcoming events. The rain, wind and frost alerts are what I look at mostly for short-term, but other data such as growing degree days are useful for forecasting when the crop might be ready to harvest

“I can then decide on whether to harvest early ahead of an event to ensure there is no damage to the crop. The price for a quality crop rather than a slightly higher yielding crop is more profitable to most growers.”

While Sam and Claire look to minimise the need to spray, wind forecasts certainly assist them to make applications with greater precision to avoid drift.

“I have noticed that the predicted wind speeds for this location compared to the RAAF base are usually lower,” says Sam.

“This can be the difference between whether I can spray or not. Having the right data by the hour on my phone with Jane’s Weather has opened more windows for spraying. The benefits include more flexibility in allocating labour resources and increased effectiveness as other factors such as pest activity, rainfall and humidity can be accommodated.”

Forecasts relating to periods after events are critical to growers. Many NSW growing regions are more frequently affected by increased humidity and temperatures after rainfall during summer, creating ideal conditions for the establishment and spread of plant diseases.

“Getting a reminder that these will be the conditions prompts me to monitor the crops more closely after rain events,” says Sam.

“Surface run-off onto the farm can bring with it water-loving pathogens and debris such as plant material and seeds and water birds that can spread weeds. If I notice anything, I can respond as soon as the conditions are right.”

Growers have access to a broad range of forecasting websites and smartphone apps today. Many have both free and subscription access options. It is important to investigate the options that provide the most accurate information on the factors that are most relevant to your farm location and growing system. Taking time to compare is important, but making the decision to adopt a tool, and the best way to use it in decision-making, should not be avoided so that the unpredictability of severe or erratic weather events can be better managed.

FOR MORE INFORMATION
Contact Rosalie Daniel – Biosecurity AUSVEG at Rosalie.daniel@ausveg.com.au or 03 9882 0277