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Landphoon NW Australia


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Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

    A low has developed along the monsoon trough in Joseph Bonaparte Gulf off the west coast of the Top End, central pressure 1001 hPa. It's currently moving over land near Wyndham, WA. Over the weekend it's likely to develop further and move into the Indian Ocean next week where it's expected to develop into a tropical cyclone. VWS in the area is low to moderate and SST >30C.
     

    Edited by tropicbreeze
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    Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

    GFS has given up on this system. Although earlier they had it moving off the coast just north of Pardoo, now they have it staying inland and heading south east. BOM is still having an each way bet and give it a moderate chance of being a tropical cyclone Tuesday and Wednesday. Central pressure 1001 hPa.
     

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    Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

    Doesn't seen like anyone is giving this low much of a chance of moving significantly off the coast. So instead of a tropical cyclone maybe a landphoon?

     

    From the Levi Cowen website.

    post-22057-0-58808700-1420510631_thumb.j

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    Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

    The low is still currently centred near Derby, central pressure 995 hPA.

    The ACCESS model for Friday has the low centred pretty much over Broome with a central pressure of 985 hPa and winds in the north western sector to 100 kph.

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    Posted
  • Location: inter drumlin South Tyrone Blackwater river valley surrounded by the last last ice age...
  • Weather Preferences: jack frost
  • Location: inter drumlin South Tyrone Blackwater river valley surrounded by the last last ice age...

    Hi down under :) I've been watching this beauty from afar for a while ..  certainly watering the deserts !

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    Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

    G'day Be cause, it is an interesting system, although not destined for tropical cyclone status by all appearances.  Not so much in the desert areas at this stage, but looks like it'll soon be heading across the Great Sandy and Gibson Deserts. I'd say they'll appreciate the rain there once it all settles down.

    IDW28001
    Severe Weather Warning
    for heavy rainfall
    for people in the Kimberley and North Interior forecast districts

    Issued at 3:57 pm WST on Wednesday 7 January 2015.

    For people in parts of WA northeast of a line from Bidyadanga to Giles. This includes people in, near or between the following towns: Broome, Derby and Kuri Bay.
    Weather Situation

    A slow moving tropical low lies between Derby and Fitzroy Crossing and is continuing to produce showers and thunderstorms over the Kimberley and northeast parts of the North Interior. This system is expected to remain over land over the western Kimberley then move eastwards on the weekend. There is only a small chance that the system moves over water and develops during Thursday and Friday.

    Showers and gusty thunderstorms may produce HEAVY RAINFALL that could cause FLASH FLOODING in parts of the warning area. The areas of greatest risk include Derby, Curtin, the Dampier Peninsula and coastal parts to Kuri Bay, then extending towards Broome during Thursday. Flood Advices have also been issued, please refer to http://www.bom.gov.au/wa/warnings/ for full details.

    As the low deepens during Thursday, strong and squally winds are likely in coastal parts from Broome to the WA/NT border from Thursday afternoon and also in the vicinity of the low.

    Between 9:00 am and 3:00 pm Wednesday, the following rainfall totals have been recorded: Derby Airport 83 millimetres, Curtin RAAF 72.4 millimetres and Lombadina Airstrip 44.8 millimetres.

    The overall weather pattern is not unusual for this time of year, but heavy rainfall may occur in some parts of the warning area and cause damage to property and make road conditions hazardous.

    The Department of Fire and Emergency Services advises that people should:

        If outside find safe shelter away from trees, power lines, storm water drains and streams.
        Close your curtains and blinds, and stay inside away from windows.
        Unplug electrical appliances and do not use land line telephones if there is lightning.
        If there is flooding, create your own sandbags by using pillow cases filled with sand and place them around doorways to protect your home.
        Do not drive into water of unknown depth and current.
        Slow down and turn your headlights on.
        Be alert and watch for hazards on the road such as fallen power lines and loose debris.
        If it is raining heavily and you can not see, pull over and park with your hazard lights on until the rain clears.

    If your home or property has significant damage, like a badly damaged roof or flooding, call the SES on 132 500.

    The next warning will be issued by 11:00 pm WST Wednesday.

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    Posted
  • Location: Camborne
  • Location: Camborne

    Combined w/strong cut-off low over Australia, temps well below normal as monsoon trough cuts across continent. pic.twitter.com/2BHyrRU38t

     

    Very wet over Australia as a land-cane deepens over the Outback & slowly moves east ... 989 mb pic.twitter.com/27NKwiqKao

    Edited by knocker
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    Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

    The MJO is expected to move into the Pacific next week so a lessening of the monsoonal activity is likely. The low near Broome, currently 992hPa, is still stationary. Looks like by Saturday it should start heading south east as a landphoon all the way past Adelaide. Give them a taste of the tropics.

    ACCESS forecast for 05:00 AEDT on Monday 12 January 2015
    post-22057-0-51273800-1420664850_thumb.p

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    Posted
  • Location: The Netherlands
  • Location: The Netherlands

    The MJO is expected to move into the Pacific next week so a lessening of the monsoonal activity is likely. The low near Broome, currently 992hPa, is still stationary. Looks like by Saturday it should start heading south east as a landphoon all the way past Adelaide. Give them a taste of the tropics.

     

    Interesting to note how such a tropical low has been able to intensify over land. It is most likely not strengthened by baroclinic processes (as tends to happen with extratropical cyclones). Does anybody have an explanation for how this cyclone has been able to strengthen this much? Was it probably aided by the moonsoon?

     

    Nevertheless, the GFS seems to be willing to drag the system across Australia southward toward sea, so prospects of tropical cyclone development seem to have gotten to a close.

     

    17.track.png

    GFS 12Z 07-01-2014 forecast of the tropical low.

     

    Source:

    http://moe.met.fsu.edu/cyclonephase/gfs/fcst/archive/15010712/17.html

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    Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

    I first heard of this maybe 8 - 10 years ago, where tropical lows or remnant tropical cyclones ramped up over land. The term applied to it then was "landphoon". Basically low latitude desert soils (mainly sands) absorb a lot of heat. As outer rain bands of the systems drop water down onto the soil the heat transfers into the water which evaporates and passes rapidly to the surface. This then creates similar convection to what happens over warm sea waters. There have been studies done on this phenomenon. It doesn't necessarily have to be desert, just sufficiently high temperatures for heat to seep into the ground and then sufficient water to create the convection.

    In that area around the Kimberley during the months of October, November, December were getting air temperature highs of 40+, ground temperatures were a lot higher. That's a lot of heat transfered into the soil, and that makes for a lot of warm water when the rains come. That's why I suggested a couple of days ago that since this system wasn't going to head out to sea it could become a landphoon.

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    Posted
  • Location: The Netherlands
  • Location: The Netherlands

    I first heard of this maybe 8 - 10 years ago, where tropical lows or remnant tropical cyclones ramped up over land. The term applied to it then was "landphoon". Basically low latitude desert soils (mainly sands) absorb a lot of heat. As outer rain bands of the systems drop water down onto the soil the heat transfers into the water which evaporates and passes rapidly to the surface. This then creates similar convection to what happens over warm sea waters. There have been studies done on this phenomenon. It doesn't necessarily have to be desert, just sufficiently high temperatures for heat to seep into the ground and then sufficient water to create the convection.

    In that area around the Kimberley during the months of October, November, December were getting air temperature highs of 40+, ground temperatures were a lot higher. That's a lot of heat transfered into the soil, and that makes for a lot of warm water when the rains come. That's why I suggested a couple of days ago that since this system wasn't going to head out to sea it could become a landphoon.

     

    Thanks for the explanation! It is much appreciated.

     

    So if I am correct the system actually 'feeds' itself by latent heat that falls out of self-generated areas. Does that also mean that such lows can only sustain themselves well near the coast?

     

    The system itself does look like quite a healthy one, with plenty of banding to its north and also convection persisting over land as well.

     

    post-20885-0-92044200-1420752490_thumb.g

    Visible satellite loop of the Australian low. The loop can be activated by clicking on it.

     

    The low seems to be able to cause quite a severe precipitation event over Central Australia. . Below is a news article about the low:

     

    http://www.9news.com.au/national/2015/01/08/15/40/heaviest-rain-in-decades-expected-for-south-australia

     

    Quite interesting to see the amounts of convection that are caused by the low over the Australian desert.

     

    Sources:

    http://www.9news.com.au/national/2015/01/08/15/40/heaviest-rain-in-decades-expected-for-south-australia

    http://www.ssd.noaa.gov/PS/TROP/floaters/99S/99S_floater.html

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    Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

    I'm still really only a rank amateur but have picked up lots of bits and pieces over time. One of the early ones I saw was centred about Tennant Creek. There was not a lot of rain from it at the time. But central pressure was right down and the winds were strong. Thought then that if it had have been over the sea it'd probably have been a category 1. Will be interesting to see how this one goes when it's completely inland. It seems to have started out on its cross country trek now. The weather here looks to be changing as a result. I should probably change the title of the thread to something that more appropriately reflects the current situation.
    post-22057-0-09128600-1420767831_thumb.p

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    Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

    The low has made a significant move into the interior and is currently 990 hPa. Alice Springs has had about 48mm over the past 24 hours, and Wulungurru (WA/NT border) 74.4mm.
    post-22057-0-09388100-1420840159_thumb.p

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    Posted
  • Location: Noonamah, Top End NT
  • Location: Noonamah, Top End NT

    Looks like it's pretty much over. A lot of people will be thankful for it having come through, from the dry inland to the areas that were being ravaged by bushfires.

    The last 3 charts at 12 hour intervals.

     

    post-22057-0-46827200-1420939741_thumb.p post-22057-0-60257600-1420939757_thumb.p post-22057-0-67983400-1420939791_thumb.p

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