RAINFALL
I'll try to keep this updated as the Wet season progresses for anyone curious about rainfall on the Mitchell Plateau. The first proper storms in Broome usually appear early/mid December so the rain gauge up here should get a little more action then hopefully, with most rain falling Jan - Mar. The average Wet season rainfall (Oct - Apr) is1,468mm. - the highest rainfall in north-western Australia.
Oct 23: 49mm
Nov 16: 3mm
Nov 19: 1mm
Nov 25: 6.5mm
Nov 26: 12mm
Nov 27: 1.5mm
Total for Nov: 24mm
You can see in the chart below, pulled from an old Department of Conservation document, November is well below the recorded average of 127mm, according to an old weather station that operated at the nearby airstrip until 1986. Plenty of time hopefully to make up the shortfall.
Dec 1: 6mm
Dec 2: 48mm
Dec 8: 15mm
Dec 11: 17mm
Dec 12: 7mm
Dec 13: 15mm
Dec 14: 24mm
Dec 17: 18mm
Dec 18: 2mm
Dec 22: 37mm
Dec 23: 2mm
Dec 31: 21mm
Total for Dec: 212mm
Despite the last week of December being very dry, New Year's Eve brought a welcome 21mm, which puts our December monthly rainfall 30mm over the monthly average of 182mm. January is supposed to be closer to 400mm. Let's hope it delivers.
Jan 2: 6mm
Jan 4: 3mm
Jan 5: 44mm
Jan 6: 179mm
Jan 7: 107mm
Jan 8: 40mm
Jan 10: 40mm
Jan 11: 13mm
Jan 12: 5mm
Jan 13: 2mm
Jan 15: 10mm
Jan 17: 3mm
Jan 19: 22mm
Jan 20: 54mm
Jan 25: 52mm
Jan 26: 1mm
Total for Jan: 581mm
It was quite a dry end to the month but thanks to ex tropical Cyclone Blake the monthly total is 202mm above the average. Average rainfall for Oct-Jan is usually 740mm and we are now sitting on 817mm. However, with Feb & Mar being high rainfall months the Wet season total could still go either way. We're now over half way towards the goal of 1,468mm.
Feb 4: 55mm
Feb 5: 25mm
Feb 7: 8mm
Feb 11: 1mm
Feb 17: 11mm
Feb 19: 15mm
Feb 21: 31mm
Feb 27: 11mm
Feb 28: 59mm
Feb 29: 112mm
Total for Feb: 327mm
Ex tropical cyclone Esther delivered some good rains and a lot of the Kimberley got the soaking that we desperately needed. Technically February ended up being 40mm below the recorded average, but with January being 203mm over we're still hitting our Wet season targets for overall average rainfall. The average for Oct - Feb is 1,107mm. We are now sitting comfortably on 1,144mm. By all normal measures the Wet season seems to be delivering the goods this year.
Mar 1: 62mm
Mar 2: 14mm
Mar 3: 10mm
Mar 14: 7mm
Mar 25: 15mm
Total for Mar: 108mm
In terms of rainfall March turned out to be a major disappointment. Except for the tail-end of ex tropical cyclone Esther, which delivered 86mm in the first 3 days of the month, we had a total of 22mm in the remaining 28 days of March. Overall that's 212mm short of what we needed to hit the monthly average. As things stand we are 126mm short of where we need to be in an average Wet season on the Mitchell Plateau. Considering the 2018-2019 Wet season was so far below average we really needed LOTS more. April is typically a dry month in the Kimberley but with the Wet season starting late this year there's a possibility we could get lucky and get something in the next few weeks. Fingers crossed.
Apr 4: 1mm
Apr 6: 12mm
Apr 8: 10mm
Apr 9: 31mm
Apr 10: 4mm
Apr 11: 7mm
Total for April: 65mm
Wet Season Total: Oct - Apr: 1,366mm
1,366mm puts us about 100mm below the Mitchell Plateau average (Nov-Apr) of 1,468mm. With last year being so dry we could certainly have used a lot more but, all things considered, it was essentially a standard Wet season here in the north-west.
It's worth noting that the average is based on weather observations from 1970 - 1986, which are the only accurate rainfall records for the area. I'd be curious to know, with a warming climate and changing weather patterns, if 1,468mm is still an accurate average for the previous 10 years. Despite being slightly below average this year it is still the highest rainfall in north-western Australia.
What has really struck me about the Wet season is just how dependent this rainfall is on large, slow-moving tropical lows, as opposed to isolated local storms. For example, ex tropical cyclone Blake brought 423mm of rain in 6 days. And ex tropical cyclone Esther brought 268 in 6 days. That's almost half of our Wet season rainfall in 2 storms - or 12 days - and almost as much rain as Melbourne gets in 12 months. It starts to explain why our Wet seasons can be very hit or miss, depending on those tropical lows and how they track across the Kimberley.
Oct: 49mm. Average: 52mm
Nov: 24mm. Average: 127mm
Dec: 212mm. Average: 182mm
Jan: 581mm. Average: 379mm
Feb: 327mm. Average 367mm
Mar: 108mm. Average 320mm
Apr: 65mm. Average 41mm.
Total: 1,366mm. Average (Oct - Apr): 1,468mm.
