Welcome to our twelfth wet season wrap up for Northern Australia where we take a look at Northern Australian towns/cities and go through their previous wet season. In October, we continue our features by speculating at what the early modelling might be showing for the upcoming wet season for these locations so become a subscriber, show your support and get access to this exclusive information. Today we head to NE NT and specifically the town of Nhulunbuy (pop approx 3250).
Bauxite mining keeps this town alive with port facilities offering easy exporting of those materials to SE Asia. Nhulunbuy lies on the NE section of the Top End in the Arnhem Land and along the Gove Peninsula. The town has a monsoonal climate with a warm dry season and a hot wet season, however the heat is moderated by moderate to fresh sea breezes. The lack of significant mountain ranges around the town means that while rainfall is quite good during the wet season during monsoonal active periods, there is no added uplift to enhance it. The town relies on monsoonal north-west to north-east convergence zones to form for the bulk of its rainfall. Despite the abundant thunderstorm activity in the Arnhem District, Nhulunbuy sees very few of these inland storms due to the unfavourable generally east to west thunderstorm steering that is present during the storm season. The town recieves about 1300mm of rain over about 95 days and unlike the locations in WA we have recently covered, the wet season occurs in a more traditional period between December and April.
WET SEASON 2018/19 RAINFALL It was a dreadfully slow start to the 2018/19 wet season with the build up almost non-existent in the Gove Peninsula (in fact the 'build up' was quite poor right across the Top End). No rainfall was recorded in November and almost no significant rainfall until Christmas week. The Monsoon arrived but not in its typical form, it arrived only over Queensland and the Coral Sea so Nhulunbuy remained on the western edge of the first monsoonal pulse. Nevertheless they got some reasonable rain out of it with that final week in December yielding about 90mm, certainly below what we have come to expect from the first m,onsoon burst of the season, but at that point with so little rainfall any rain was a bonus.
Once the initial burst of the monsoon passed through, the town was fine for about a fortnight before we got to see some mid morning shower activity impact the place mid month. Then daily mid afternoon storms began hitting the town around Australia Day (between Jan 23 - Jan 27) resulting in about 120mm of rain over those 4 days. February was uneventful except for an early morning storm on the 8th pouring 50mm quickly on the town, but that didn't save the month from being well below average rain wise.
March was highlighted by TC Trevor whose outer bands casued a strong convergence line to push through the town resulting in 129mm of rain overnight on the 22nd. Once the cyclone hit the NT coast on the 23rd/24th a humid northerly airstream established itself and this humid airstream resulted in a fortnight of unsettled weather over the town. Thjis culminated in the 2nd biggest rain day of the season on April 7 into the morning of April 8 where 120mm of rain fell. This was due to a combination of a weak monsoon trough and a small disturbance that formed right along the NT Top End coast. Nhulunbuy was located on that favourable eastern side of that system resulting in the squeezing of NW and NE winds. Interestingly between the 22nd March and the 7th April (16 day period) about 600mm of rain fell - which was about half of the wet season's total rainfall. The back end of April saw the monsoon retreat and a humid east to south-east air flow establish itself allowing for a scattering of showers to hit Nhulunbuy to end the wet season.
Overall, I was surprised to see that the season in Nhulunbuy was actually almost bang on average. That mostly came down to those 16 days in late March and early April. I think most local residents if asked, would feel it was a poor wet season, but the data suggests otherwise.
TROPICAL CYCLONE IMPACTS
While TC Owen, Penny and Trevor all operated in the Gulf in 2018/19, they did not directly impact Nhulunbuy.
Some convergence banding wrapping in towards Trevor did create a significant rain day on the 23rd March that saw 129mm fall, 85mm of which fell in an hour overnight between 12:20AM and 1:20AM. That same band of convergence saw winds gust up to 61km/hr.
Check out the outer bands of Trevor as he buffeted the town overnight on March 23
In general with the monsoon unable to cool the place down due to its relative inactivity. Nhulunbuy suffered through a much warmer than normal Wet Season in 2018/19. The town broke numerous 39 year old records this past season.
Below are some of the highlights temperature wise.
1 - 25th to 30th November - 5 day period with minimum temps well above average including a record breaking warm minimum temps on November 27th of 28.6 degrees.
2 - December 4th and 6th broke the maxium daily December high temp records with 38.7 and 38.4 degrees respectively.
3 - The overall December minimum temperatures broke a record for being the warmest December nights on average in 37 years.
4 - February 20-22 saw the February daily maximum record broken on three consecutive days with Fri 22nd topping the charts with 36.7 degrees
5 - February nights on average were the warmest ever recorded with an average minimum temperature of 25.8 degrees.
Monday we go back to Queensland.
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