Tuesday, 1 June 2010 - Monthly Climate Summary for Tasmania - Product code IDCKGC27R0

Tasmania in May 2010: Cool weather arrives, rain in the northeast

• First significant snow of the year on the 11th
  
• Some very cold mornings
  
• Localised flooding rain in the northeast on the 28th and 29th
  

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Mild weather replaced by cool

May started mild, with some days reaching into the low 20s and continuing a pattern seen in recent months. This changed when a cold front crossed early on the 11th, bringing with it a blast of chilly air that saw snow settling on the highlands — the first significant snowfall of the year, but one that mostly melted away quickly. Although daytime temperatures recovered a little in the following week, more cool weather followed from about the 20th, especially in the east and south. The final few days were again mild. Taken across the month, daytime maximum temperatures were a fraction above the long-term average in most areas, although a little below average in parts of the inland north.

The warmest day was at Swansea Post Office with 23.4 °C on the 4th, and the warmest days on average were at Bicheno (Council Depot) with 17.2 °C. At the other extreme, the coolest days on average were on the summit of Mount Wellington with 5.4 °C, which also had the coldest day with -0.4 °C on the 21st.

Cold nights

There were several cold nights through the month, with the first taste on the morning of the 3rd when a few spots dipped below zero. The cold change of the 11th heralded a run of cooler nights, with morning fogs and frosts reported. Winds slackened and skies cleared as a high moved over the state late on the 21st, allowing temperatures to plummet on the morning of 22nd. Liaweneedipped to -10.2 °C, the second-coldest May temperature ever recorded in Tasmania (the coldest was -10.5 °C at the same place on 30 May 2006). The 23rd was another cold and frosty morning, and although no significant records were broken several sites had their coldest May temperature for several years.

Taken across the month, overnight minimum temperatures were below average in most areas, typically by half a degree but by almost two degrees in the Upper Derwent Valley and the southern Midlands. Dover had its lowest May mean daily minimum temperature on record, although the record there is only 20 years long so of more significance are Bushy Park and Swansea which had their lowest May mean daily minimum temperature since 1979.

Heavy rain in the northeast

On the 28th the combination of a high to the southeast and a low to the northeast directed very moist and unstable air onto Tasmania's northeast highlands; a "classic" situation for heavy rainfall in that area. Thunderstorms, lightning and hail were reported, and by 9 am on the 29th Gray (Dalmayne Rd) had recorded 191.6 mm, St Marys (Clive Street)  158.4 mm and St Marys (Cullenswood) 143.8 mm, whilst Swansea had its highest May daily rainfall on record with 131.6 mm. Flooding of both streams and rivers was reported, along with damage to roads and other structures. More rain was reported in the area the following day, and ensured that some sites in the area had their highest total May rainfall since at least 1988. The heaviest of the rain was localised, with the southeast, Midlands, Central Plateau and west having just a few millimetres.

Relatively dry overall

Cold fronts and westerly winds brought rain to the west and south for the first two weeks, but the second half of the month had few fronts and mostly only light falls in the west. The southeast also missed out on the bulk of the rain events for the month. Overall, May rainfall totals were below average in most areas. Despite the dry end to the month in the west, the wettest overall was Mount Read with 287.8 mm, but it was closely followed by Gray (Dalmayne Rd) with 263.6 mm, almost all from the heavy rain in the final few days.

Details Extremes Maps Records Summaries Important notes the top

Maps
	Observed	Anomaly	Decile rank
Total rainfall
Mean daily maximum temperatures
Mean daily minimum temperatures

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Details Extremes Maps Records Summaries Important notes the top

Details Extremes Maps Records Summaries Important notes the top