Weather Information for FIHTA Members
Issued 8am Saturday 13 March 2010
At 6am this morning TC Tomas was located near 11.2S 178.8W or about 600km NNE of Vanua
Levu. At this time TC Tomas was estimated to have winds close to the centre gusting up to
120kmph making it a weak Category 2 cyclone in the scale of 1 to 5 (see
http://www.bom.gov.au/weather/qld/cyclone/windstr.shtml).
Overnight TC Tomas has moved only very slowly west-southwestwards, however the satellite
imagery shows that the cyclone has intensified. This is evident in both the more organized
structure of the convective bands feeding into the centre of the cyclone at low levels, and the
establishment of outflow at the top of the circulation which can be seen in the thin wispy ice
clouds (cirrus cloud) on the extreme right of the attached satellite image. Strong outflow at the
top of the cyclone acts as an exhaust sucking air faster up the eye wall and hence lowering the air
pressure at the surface.
INTENSITY - Based on the surrounding environmental conditions which are favourable for
continued intensification, we can expect TC Tomas to continue strengthening over the next 4872 hours. The intensification will occur at close to the normal rate, with averaged wind speeds
near the centre of the cyclone increasing by about 10 knots every 6 hours or 40 knots per day.
This would bring the cyclone to Category 4 strength by midday tomorrow which it is expected to
sustain until landfall. Wind speeds during gusts at landfall may well exceed 240kmph.
This infers very destructive winds are likely so you should ensure shutters and other measures to
secure structures are in place today if you are in eastern and central parts of the country. In the
west you can probably wait for a while to see if it is likely to come closer, however the west will
likely experience east to southeast winds well below the destructive force expected further east
YOU SHOULD FOLLOW ALL DISMAC ADVISORIES RELEVANT TO THE REGION OR
LOCATION YOU ARE IN.
MOVEMENT - Later today the path of TC Tomas is expected to turn more southwest then
southward as it interacts with a middle and upper level low pressure wave moving across
latitudes to the south near NZ. Precisely when it starts to turn from its WSW to southerly path
will determine where in Fiji it ultimately makes landfall. Best indications are at this time that
landfall will be somewhere along the Vanua Levu coast between Labasa and Udu Point
sometime after midnight Sunday and before midday Monday (65-75% likelihood).
There is a risk that the cyclone could make landfall further west closer to Viti Levu if the current
slow west-southwestward movement lasts a little longer than expected today (25%). The chances
of TC Tomas either recurving early or continuing westward and this avoiding Fiji altogether is
low (less than 10%).
Forecast for Fiji Today - Freshening SE winds becoming gusty at times this afternoon and
evening. Mostly cloudy with a few showers and a thunderstorm or 2. Expect rain and
thunderstorms to increase in frequency and intensity as the hours pass over the weekend.
STRONG WIND WARNING IS CURRENT FOR ALL FIJI COASTAL WATERS. Mariners
use caution.
TC Ului - A second cyclone is now being warned upon. TC Ului lies to the far WNW over
northern Vanuatu and is moving slowly westward away from Fiji and poses no threat to any land
areas around Fiji at this time.
Next update by midday.