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The page is updated every 30 minutes at about 20 and 50 minutes past the hour.
For weather news as it breaks that is tagged and organised, use the links on the Weather and Climate Media Reports page.
Australian weather briefs
- The BoM has produced a detailed but concise summary of TC Debbie's activities in QLD from 27 to 30 March 2017.
- The village of Rockley, 30km S of Bathurst NSW, had a massive but very isolated thunderstorm on Thursday 6 April between about 15.30 and 16.30. Unfortunately, the BoM Hydro raingauge there was not working, but the hotel's publican measured 84mm in 45 minutes and this was verified by the Bureau's official 24-hour reading at the nearby Post Office at 09.00 next morning of 85mm. Substantial small hail fell with the storm. Other gauges in the area recorded little or nothing though radar showed it was a very small and intense slow-moving storm.
- There's been no problem organising a picnic in Broken Hill NSW for a few months with no rain falling over the past 84 days. The long run of fine days may be ended on Thursday when a northwest rain band is forecast to arrive in the area.
Cyclone Cook explained ... and forecast criticised
As anticipated in yesterday's AWN News, criticism has emerged of MetService's somewhat off-the-mark forecast for Cyclone Cook late last week. This, from Radio New Zealand, is an example. MetService, in its blog, has produced a detailed, and very interesting, response showing how the event unfolded and where the error occurred. If nothing else, it is a timely reminder that our knowledge of the weather is still not perfect and therefore our forecasts can't be, either.
Recent weather briefs - NORTH AMERICA
- The United States has set a new and unenviable record with more than 100 tornadoes reported in each of the first four months of 2017, according to WeatherNation. 536 twisters have touched down so far this year, though there are two caveats to the claimed record. Firstly, with more storm chasers hunting down tornadoes equipped with better technology, radar, and satellite imagery than ever before, the chances of them being seen and documented are better than any time in history. Secondly, the early months of the year, especially January and February, are usually quiet for tornadoes which start to ramp up during April. Over half of them occur in May and June, so if those months are quiet this year, the early record could quickly evaporate. Accuweather has some thoughts on why it's been such an active season so far.
- While on tornadoes, a supercell thunderstorm last Friday 14 April lasted for nine hours as it pushed through the Texas panhandle, spawning hail larger than baseball size then tornadoes according to Weather Underground. The largest of these, near Dimmitt TX, was on the ground for over 20 minutes with a path over 7km in length and a maximum width of 1.8km. Radar imagery of the storm is here. While there were few buildings in the rural area to help classify the strength of the tornado, it was given an EF3 (Enhanced Fujitsa Scale) rating, based on the fact it destroyed and moved a metal building over 100m, giving a wind speed as high as 225km/h. While the tornado missed Dim mitt (pop. 4,000), it damaged several houses and cars, and completely destroyed one home while the family sheltered in the basement.
- While floods swept through southern and central Texas [Floodlist], Florida declared a state of emergency as over 100 bushfires burned the state, the worst situation in six years and focused on the south. 42% of the state is in moderate drought and 13% in a severe drought, a bad situation as it moves into the hotter, drier months of summer [WeatherNation].
- Much of California's five-year drought is at an end following a summer/autumn of repeated flooding rain and deep mountain snow. The northern Sierra has had its snowiest/wettest July to June period on record - with over two months still left to go [Bob Henson, Category 6]. As of yesterday, 17 April, the Northern Sierra Index, an average of eight measurements of snowpack depth along the range converted to water content, sat at 2,309mm, the highest on record since the index began in the 1923-24 water year (July to June), and 208% of the average as at 17 April. The heavy snows have produced some spectacular figures for skiers at resorts, with many reporting accumulated snow depths over 700 inches (17.78m) and Sugar Bowl Resort measuring 777 inches (19.736m) [Weather Underground]. Some wind gust figures have been eye-popping, too, as the jet streams as least partly responsible for the prolific snow have descended to mountain peak weather stations: Ward Mountain recorded 320km/h on 20 February 2017 [Bob Henson and Jeff Masters, Weather Underground].