Landphoon, also known as tornadocane, Most commonly called Agukabam or Non-Baroclinical Rejuvenation of Tropical Cyclones when referring to ones that form out of previous tropical Systems from in the Meteorology Field. is a term applied to certain Mesoscale Convective Systems that develop a weather radar signature in the shape of a hurricane in low levels. These storms have a central eye free of precipitation with a minimum central pressure and surrounding arms of strong echoes but are really associated with a supercell thunderstorm or mesoscale convective vortex developing multiple squall lines. These storms are have a warm core, like other mesoscale convective systems. The only use of the term tornadocane occurred on April 15, 1999 over Duplin County, North Carolina, and the term does not exist in any standard dictionary or glossary.
These unusual thunderstorms complexes begin as the rear flank downdraft of a supercell thunderstorm and generate a vigorous gust front at the base of the hook echo region. If the instability and humidity of the air ahead of the front are conducive, a squall line develops from the supercell toward the southwest (northern hemisphere) closing the gap of the bounded weak echo region (BWER) and curving into spiral bands seemingly rotating around the BWER. The supercell itself is often associated with tornadoes while the squall line produces microbursts.
The term landphoon has been used in Australia since at least 2000. While it is not a term officially used in warnings issued by any known country's national meteorological center, the term has been used after the fact with cyclones in Australia, including a former tropical depression. Despite its informal status, the term has been used in the university setting at the University of Munich.
North Carolina case
This tornadocane began as an HP (Heavy Precipitation) supercell on April 15, 1999, and moved across North Carolina while assuming a hurricane shape. It exited the State as a Bow Echo as the parent supercell decayed and the squall line took over. One tornado spawned from this supercell was .8-1.6 km (.5-1 mi) wide, caused major damage and injured 11 people along a 48 km (30 mi) long damage track.
One death and a 265 km/h (165 mph) wind gust were also reported with this storm. This wind gust is thought to have come from a direct hit to an anemometer by a tornado, which is in the F3 windspeed range. However, since only damage can be used to rating of a tornado, that recorded wind speed is ineligible for determining the F scale rating of this tornado.
Filtered image of the Tornadocane with all dBZ Reflectivities less than 35 taken out.
In Popular Culture
A certain Saturday Night Live sketch played up the concept of a "Tornadocane" as being such a powerful event that they had "gained sentience and begun to commit identity theft" and that the end of days was upon us.
Another case of tornadocane happened across the Midwest on July 21, 2003. An area of convection developed across eastern Iowa near a weak stationary/warm front at 0302 UTC and moved to the east along it. By 1203 UTC, the convective system had matured, taking on the shape of a wavy squall line across western Ohio and southern Indiana. The system re-intensified after leaving the Ohio Valley, starting to form a large hook, with occasional hook echoes appearing along its eastern side. A surface low pressure became defined and became more impressive later in the day. By 2244 UTC, a squall line took shape along its band to the south. This began to starve the inner convection and by 0126 UTC, daytime heating had ceased. The squall line ran out ahead of the low, causing the entire convective structure to weaken.
Heavy rainfall and straight wind damages were the main effect of this system. It left a maximum of 102 mm (4 inches) of rain along the path of the system and numerous reports of violent winds. A few weak tornadoes have been reported too.
Another especially significant landphoon type event took place over southern Illinois on May 8, 2009. A wind gust to 106 mph (171 km/h) occurred in Carbondale, Illinois in association with the storm. In Saffir-Simpson scale terms, these winds round to the high end of the category 2 range (though not the extreme high end. The extreme high end would require the winds to be at least 108 MPH but no greater than 112 MPH, rounding to 110 MPH).
- Emanuel, Kerry ; Callaghan, Jeff; and Otto, Peter (2008). A Hypothesis for the Redevelopment of Warm-Core Cyclones over Northern Australia. Massachusetts Institute of Technology, Cambridge, Massachusetts; Bureau of Meteorology, Brisbane, Queensland, Australia.
- Storm Prediction Center. North Carolina "Tornadocane" from 1999. Retrieved on 2008-01-08.
- Gary Padgett. Monthly Global Tropical Cyclone Summary: January 2000. Retrieved on 2007-08-31.
- Bureau of Meteorology. Monsoon Depression or "Landphoon" over northern central Australia. Retrieved on 2007-08-31.
- Robert Goler. Diplomarbeiten. Retrieved on 2007-08-31.
- David M. Roth. MCS with Eye - July 21, 2003. Retrieved on 2008-01-08.
- "Updated: What was it that caused the May 8 windstorm?". National Weather Service Paducah, KY. May 19, 2009. Retrieved June 29, 2009.
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