Would you rather it be wet and muggy or hot and dry this summer? Photo: Jen White.
Hot one day, pouring rain the next – that’s next week’s weather forecast, and this scenario is likely to continue over summer.
After five straight years of El Nino or La Nina (ENSO) events (mostly cool, wet La Nina events) it’s easy to think El Nino or La Nina arrives each year, but historically that isn’t the case.
El Nino and La Nina years are interspersed with neutral years, with about three out of every seven years being neutral.
After several years of floods, coming straight off the back of horrific bushfires, it may be a relief to know that this summer is forecast to be the neutral phase of the ENSO cycle.
ENSO isn’t the only system that drives our weather, though.
Bureau of Meteorology senior climatologist Felicity Gamble said several systems were “playing tug-of-war” with weather patterns in our corner of Australia at the moment, with the struggle set to continue over summer.
“There isn’t a strong wet or dry forecast signal across much of NSW,” Felicity said.
“There is an equal chance of above or below average rainfall for the next few months, with wetter than average conditions slightly more likely in coastal areas.
“We saw a weak, short-lived La Nina last year and this year has a very similar pattern in the Pacific, but it’s still borderline.
“People are more familiar with ENSO, but we also have the Indian Ocean Dipole, or IOD, influence our weather patterns and this year we have some influence from southern stratospheric warming.
“We’re in a negative phase of the IOD and that would usually bring wetter than average conditions, but the southern stratospheric warming is bringing warm and dry conditions with westerlies from the interior.
“The Southern Annual Mode also has a drying influence, so it’s a tug-of-war as to what we will see play out over the summer months.”
Based on that information, the decision about whether to host Christmas in the backyard or the dining room might have to be made at the last minute.
The one thing the outlook does strongly indicate is that it’s time to get your bedroom prepared for some hot summer nights.
Felicity said there was a very high chance of warmer than average overnight temperatures over the coming months, with the potential to crack the top 20 per cent historic range of overnight temps.
Daytime temperatures are equally likely to be above or below average.
On top of prepping for Christmas and planning how to keep the house cool enough to get a good night’s sleep, Felicity said the lead-up to summer is a good time to prepare for emergencies.
“A lot of coastal NSW saw a very wet winter and that can lead to more fuel from increased vegetation,” she said.
“Even though it may seem quite green and lush at the moment it only takes a few days of warm windy conditions to dry the landscape out and prime it for fire.
“As we enter our high-risk weather season it’s important to be prepared for events like bushfires, heatwaves and severe storms.
“Don’t be complacent, have your plans ready to go.”
That way, you can relax and enjoy the silly season – whatever the weather.
