Weather Wize

Second tropical cyclone invades WA last week

By Peter Nelson

Last week a second tropical cyclone of this season hit the north west region of WA. The cyclone named Joyce brought more heavy rainfalls to Broome, Cygnet Bay, Derby and right across to Marble Bar where 115 mms fell to last Saturday morning, 13th January.

At Derby 353 mms has fallen this month so far and on top of 227 mms in December it is already the sixth wettest December to January period on record in 135 years of records. The wetter December to January periods to date were in 1898-99, 1906-07, 1926-27, 1930-31, and 1996-97 at Derby.

Tropical cyclone Joyce like the earlier cyclone Hilda, brought very uncomfortably humid conditions late last week to our regions, but rainfalls were lighter and patchy although Hotham and Falls Creek had heavy rains.

Currently Joyce has weakened and has taken a different path to that of Hilda and is now approaching Perth. It may set up the next spell of hot weather this week in our regions. An active frontal passage with strong southerly winds from as far south as Macquarie Island, terminated the hot spell last weekend in our regions. There were light snowfalls on the Sunday morning at Alpine resorts.

Surprisingly, no snow fell on Tasmanian highest mountains. This may be due to the above normal sea surface temperatures around Tasmania and across the Tasman Sea to New Zealand. Macquarie Island last year had it's warmest year since 1989.

Macquarie Island has a peculiar but vile climate. Last year there were 337 rain days, 313 days when wind gusts exceeded 50 kph, 128 days of no sunshine. The highest temperature last year at Macquarie Island was 11.3.

Actually there were two successive sunny days last year, 14.3 hours on 28th November and 14.7 hours on 29th November. It is not possible to get more than 14.0 hours of sunshine in a single day in the summer months in our regions.

The cool windy conditions of last weekend will soon be replaced by more hot conditions which look like continuing on most days up to about 24th January. There will be sporadic thunderstorms during the next frontal passage due about next weekend.