Monday, 23 May 2016

Record-breaking rainfall forecast for Queensland

RECORD BREAKING RAINFALL LIKELY THIS WEEKEND IN PARTS OF NORTHERN QUEENSLAND


21 May, 2016

Continuing our series coverage of the rain event for North-Eastern Australia. This morning we are taking a look at honing in on those areas that may experience substantial and possible record breaking rainfall this weekend from the unseasonal combination of tropical moisture and an upper level trough. The image below from the Bureau Of Meteorology depicts how much rainfall North Queensland is expecting across the next 4 days (Saturday until Tuesday). You can see the clear cutoff for heavy falls is around Ingham to Cooktown on the East coast. However it's the rain across the inland and Western Peninsula that is most surprising.
 
The rarity of an event like this can not be underplayed. We need to understand that we are now getting stuck into the dry season. Ordinarily by this time in May we have seen a drying out process in the lower levels of the atmosphere as strong HIGHS dominate Southern and Central Australia. These HIGHS are interspersed with strong cold fronts that drag dry polar air northwards in their wake. This season we really haven't seen that happen. So far we've had temperatures that have been some of the warmest on record, we have some of the highest dew points on record across many stations in Northern Australia as well. It's almost as if the wet season really hasn't finished. 
To truly understand the intensity and rarity of this event, let's take a look at some rain averages for May and when you look at these averages, bear in mind that a huge proportion of the average May rainfall tends to fall in the first 2 weeks of the month. 
STATION
​​PREVIOUS MONTH RECORD (mm)
PREVIOUS 24HR RECORD (mm)
EXPECTED RAIN IN NEXT 4 DAYS (ROUGH GUIDE in mm)
AVERAGE MONTHLY RAIN (mm)
Kowanyama (West Peninsula)
​​291
​​125
120-200
11
Palmerville (inland Peninsula)
​​171
​​133
70-100
​​16
Karumba (Gulf Country)
13
13
30-50
1
Cairns (North East Coast)
​​322
​​90
100-200
91
Innisfail (North-East Coast)
1063
​​214
150-250
302
Cooktown (East Peninsula)
​​278
108
100-200
60
The issue I have with the event is that its true intensity is likely to go unrecorded. The highlighted area below is where the computer models are predicting falls of 200-300mm (and over 100m/day)  yet the Bureau Of Meteorology unfortunately have no recording stations. So the record-breaking nature of this event in this region is likely to never see a record book and that disappoints me greatly. Nevertheless, despite this lack of record, I hope the figures above show you that it is certainly one of the more significant and widespread events to affect the Far North of Queensland at this time of year. 
 
In our blog update later today, I will go into detail of when and where we will witness these tremendous rainfalls using high resolution deterministic modelling rather than consensus/ensemble modelling. Remember the intensity of this event isn't likely to surface until overnight tonight and into tomorrow. So for today we can expect scattered showers, but tomorrow is when the magic happens.



No comments:

Post a Comment