With fire season well under way, there are currently 32 fires ablaze in the NT, 15 in Qld and 11 in the north and interior of WA. Some of the most significant of these fires can be seen by satellite imagery as shown in the image below (Fig.1). 

Fig. 1: Northern & eastern Australia satellite imagery highlighting the main areas of burning fires, as at 17:25 AEDT on Saturday October 14th using Himawari satellite imagery.

Some of the most significant fires have been burning for at least the last 24 hours in the central-west district of Tanami in the Northern Territory. 

The main culprits for these fire outbreaks are exactly what you'd expect: hot temperatures, gusty winds and low humidity. 

A broad low-pressure trough spanning the north of the country is now acting as a 'moisture barrier'. In other words, the position of the trough is such that only hot, dry winds can blow into the region whilst trapping any moisture to the north of the trough. Take a look at the figure below and the arrows showing the movement of warm-to-hot air over the northern interior. 

Fig. 2: Synoptic chart for Monday Oct 16 at 10:00PM AEDT, showing the hot temperatures being 'trapped' by the trough (Weatherzone, 2023).

It comes as no surprise that Catastrophic Fire Danger Ratings were declared for Barkly in the NT's east on both Monday and Tuesday. Gregory South East, just north of where the Tanami fires are, is expecting Extreme Fire Danger Ratings for both days too.  

The trough looks to linger until at least Wednesday, when moisture looks to push into eastern Queensland, but the hot, dry air could continue funnelling into interior NT for at least the next 6 days. 

Fig. 3: Catastrophic fire danger rating (red) for Barkly in the NT's east for both Monday 16th and Tuesday 17th October (Bureau of Meteorology, 2023).

Zooming into Tanami shows just how intense these fires are getting with little to no relief. The plumes can be seen directing to the top of the image (north), indicating the persistence of the dry southerly winds.  

Fig. 4: Fires burning over the Tanami Fire Weather District in western NT at 3:40pm local time on Saturday, 14th October, using Himawari Satellite Imagery.

Fig. 5: A broader view of the central NT bushfires using Himawari satellite imagery, encompassing the Barkly South region to the right of the image.

The heat trough is not only bringing catastrophic fire danger to interior NT. The area around Darwin is expecting severe heatwave conditions until Monday October 16th. 

We wrote yesterday about this broad trough stretching down into western WA. The trough has brought some severe heatwave conditions to western WA, with Geraldton experiencing its hottest 3-day October spell in 44 years. This is the hottest temperature this early in the season in at least 80 years, with maximum temperatures across the 3 days averaging 38.2ºC.  

Fig. 6: Heatwave forecast map from Saturday 14th Oct to Monday 16th Oct. (Bureau of Meteorology, 2023).

To top it all off, Total Fire Bans have been declared across Greater Sydney, Greater Hunter and a number of districts in northeastern NSW for Monday. Extreme fire danger ratings are in place for a large portion of these districts. 

Strong westerly winds are expected across the state ahead of a front, increasing into the afternoon ahead of a southerly change expected to provide some cool relief on Tuesday.  

Fig. 7: Total Fire Bans & Fire Danger Ratings across NSW on Monday, October 16th (Bureau of Meteorology, 2023).

As always, we remind you to please be safe during this fire season. No matter where you are in the country, it's always a good idea to check warnings, prepare a bushfire survival plan, and be alert.