Oz Cyclone Chasers Cyclone Blog
TC CHANCES UPGRADED TO MODERATE FOR NW TOP END COAST INCLUDING TIWI ISLANDS AND DARWIN
We have been monitoring the Monsoon Trough development in the Arafura Sea for some time now and to be honest have been reluctant to say much given so much model uncertainty. At this stage the Monsoon Trough is becoming very active but it is also a complex setup with a smaller secondary low or eddy possible near Gove. At lunchtime Saturday the main low is roughly 520kms NW of Maningrida and the BOM have mentioned it in their TC Outlook attached further below. They give it a moderate chance of developing early next week and following a similar track to TC Blanche, however conditions look more favourable this time for earlier development.
The general model consensus is the main low will drift SW away from the NT into the Timor Sea, however all is not set in stone and that is possibly due to the secondary low that could develop near Gove. While this second low will further enhance rainfall for the Gove and NE Coast regions it will also throw a spanner in the works when it interacts with the main system north of the Tiwis.
There is every chance this interaction could be the reason some models including the BOMs own ACCESS model shown above, have the low/TC moving very close to the NW Top End Coast as opposed to a more rapid WSW movement as favoured by others. Interaction between low pressure systems, even weak ones can be a real headache for forecasters so it will be interesting to see how it plays out.
I know you are all probably saying what a dud Blanche was and not give this system any credence but because it's later in the season we have good ingredients in play for development. The SE winds affecting the Top End in recent days have been the strongest in months and there is a strong surge of monsoonal North Westerlies to the north so the 'spin' is already there. While wind shear could be an issue initially just like Blanche, there appears to be a much broader favourable environment once this system moves a little further south, moisture does not look like being an issue either.
We will be looking at model ensembles closely over the next day or two as we are sure the BOM are but it might be a good idea to acknowledge we are not out of the TC season yet, particularly if you're in the Tiwi Islands or Darwin region. It's not unusual to see very intense systems develop in April, we only have to look at TC Ingrid in 2005, TC Monica in April 2006 and more recently our midget friend Ernie out in the Indian Ocean going from a tropical low to a Cat 5 in a day. Of course if this next TC which will be called Frances is a midget then it's effects will be very localised but with strong SE winds to the south of the system, there is a good chance winds and gusty storms will increase for the NW Top End early next week.
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