Cold start to summer for Sydney!

Sydneysiders should make the most of today and Tuesday as they are likely to be the warmest days in a while!

Today is already shaping up to be a pleasant sunny day with 26-30 degrees with Tuesday forecast to reach 27-31 degrees.

After a warm night on Tuesday, the beginning of Wednesday will be a balmy 28-31 degrees before showers turn up from the late morning or early afternoon. There is also the potential for thunderstorms which may be severe. The wet weather will provide some cooling but a southerly change due on Wednesday night will lead to a significant temperature drop on Thursday.

Consequently, the first day of summer will feel like more like winter for Sydney with showers and just 20-21 degrees! Cooler than average summer temperatures in the low twenties are forecast to linger for at least another week from Thursday.

This cold and wet change for Sydney is part of a larger system that will affect most of NSW on Wednesday/Thursday. Of particular concern is the rain that is expected to fall over flood affected parts of north-west NSW with up to 50mm possible. While this rain event won't be as severe as last week, it is likely to lead to secondary flood peaks on some rivers.

Sydney bakes in hottest day this spring!

It was a scorcher in Sydney today with temperatures as much as 14 above the November average! The city reached a scorching 37.2 degrees today- a massive 13 degrees above the November average maximum and its hottest day so far this spring!

Penrith was the hottest in Sydney's west with 38.7 degrees. Other notable mentions include Sydney Airport (37.9), Bankstown (37.3) and Campbelltown (37.4).

It's not often that Sydney city reaches the mid-30s in spring, but it's even rarer for the city to be as hot as the western suburbs. The main reason why the city and coastal suburbs usually experience cooler conditions than the west on a hot day is the seabreeze. But today hot NW winds were gusting to 50-60kmh which was strong enough to effectively cap the seabreeze for most of the day, allowing the mercury to rise well above the forecast maximum of 32 degrees, and November average maximum of 24 degrees.

Relief!

Fortunately, relief arrived with a southerly change this evening dropping temperatures by around 10 degrees in 20 minutes! Overnight temperatures should dip below 20 degrees, much more comfortable than the 26-27 degree night that sleepless Sydneysiders sweated through last Wednesday.

Rest of the week?

The rest of the working week will be more bearable with a sunny 26-31 degree day on Tuesday. Wednesday is forecast to reach 25-29 degrees with a stronger southerly change and showers and storms during the afternoon. This will lead to a cooler 23-24 degrees on Thursday with one or two showers. Friday will warm back up to 27-31 degrees with a possible morning shower. Hotter weather is expected next weekend though, with temperatures potentially reaching the mid-30s once again.

Temperatures were even hotter in the western NSW today with Bourke sweating through 41.5 degrees.

Showers making way for a warm weekend in Sydney!

After its driest October in 4 years with just 37.4mm, Sydney has kicked off November in typical erratic spring fashion- sunshine, a southerly buster and widespread showers! Yesterday the city and west enjoyed  a sunny day with 24-27 degrees before a southerly change delivered winds up to 40-50kmh. Late afternoon cloud increased across the city with showers developing overnight.

Moist south-easterly winds have delivered the heaviest falls to coastal suburbs, especially the northern beaches, with lighter falls further west. To 9am this morning: Avalon 25mm, Cronulla 17mm, Chatswood 14mm, City 11mm, Homebush 10mm and Penrith 3.6mm. The mercury will also struggle to get to 20 degrees today across most suburbs. But this gloomy weather will be short lived!

Showers are easing and becoming isolated on Thursday afternoon with dry and partly cloudy skies on Friday with 23-35 degrees. The weekend is heating up on both days with a muggy 27-31 degrees on Saturday with a hot 30-34 degrees on Sunday, around 6-7 degrees above average for November.

Early next week it's expected to stay warm although less comfortable with rising humidity and unstable conditions with the chance of showers and storms. A trough is expected to trigger showers and storms through inland parts of NSW on Sunday and there is a chance that some of these showers and storms may drift towards Sydney as early as Sunday afternoon/evening.

Unseasonal rain and storms in WA!

Record breaking rain hits inland WA...
October ended with record breaking rainfall for normally dry central and northern parts WA. In the past week areas of the Interior and Goldfields picked up 50-100mm of rainfall while parts of the Kimberley have seen over 100mm.

Wiluna in the northern Goldfields received 38mm to 9am Tuesday morning, its heaviest November day of rain in over 100 years of records! Nearby Packsaddle Farm saw 64.8mm on the same day, its heaviest November day of rain since records began in 1995. Both Giles and Warburton in the Interior picked up over 70mm for the month, most of it in the last week, which is almost 5 times their monthly October average rainfall!

Many inland parts of WA would typically receive no more than 20mm on average for the month of October so this heavy rain is unusual for this time of year.

WA Rainfall totals (mm) Week ending 1st November 2011. Source: Bureau of Meteorology

Perth and southern WA next...
While the heavy rain and storms have been concentrated in central and northern parts of the state over the last few days, it will start to ease from tomorrow with the focus shifting further south. Widespread rain and potentially severe storms are expected for southern parts of the state on Thursday.

Perth is a chance to see a storm on Wednesday afternoon but the greatest risk is on Thursday with severe storms possible in Perth with the potential of flash flooding.

On Friday the rain and storms will shift eastwards across the state providing a break for Perth, but lighter showers are still expected in the city for the rest of the week from frontal activity.

Early wet season smashes rain records in North QLD!

The wet season has kicked in across northern QLD smashing rainfall records!

Cairns has just experienced its wettest October day in 67 years of records with 213.4mm falling in just 24 hours to 9am Wednesday. This completely overshadows the previous October daily rainfall record of 86.8mm set in 1964. It is now also the wettest October on record in Cairns.

Even though October marks the beginning of the wet season, such heavy falls are usually only experienced during the cyclone season- infact, the last time Cairns picked up this much rain was during Cyclone Yasi in February 2011.

But Cairns isn't the only one to get an early wet season soaking. Widespread falls of 100-200mm have also been recorded from Tully to Mossman in just 24 hours! This is on top of widespread 50-100mm falls the day before. In 48 hours, both Menavale and Goldsborough Valley have seen over 400mm of rain!

Wet season kicks in to QLD's tropics!

Last week it was SE QLD, but now QLD's North Tropical Coast is copping a soaking! Strong onshore winds are loading the coast with moisture while a low pressure trough sparks showers and storms.

Together, the two weather features have delivered massive rain totals to the region in 24 hours to 9am this morning: Menavale 199mm, Bolinda 113mm, Corsis 113mm, Goldsborough Valley 105mm, Gordonvale 98mm, Tully 74mm, Topaz 74mm.

Over the next 4 days, over 50mm is expected north of Townsville with over 100mm between Cairns and Cardwell. The rain is expected to ease from Thursday onwards.

So what can northern QLD expect this wet season? Last year, QLD experienced its wettest year on record largely due to one of the strongest La Nina's on record. It looks like La Nina is back for another so northern and eastern Australia can expect above average rainfall. But it is important to note that this La Nina is much weaker than last year so a repeat of last year's record-breaking rainfall is unlikely.

What about cyclones? The long-term average for eastern Australia over the November- April period is 3-4 cyclones. The latest seasonal outlook from the Bureau of Meteorology suggests a 65% chance of exceeding this average in eastern Australia, with an 80% chance of above average tropical cyclone activity across the Australian region this season.

Wild storms threaten QLD and NE NSW this week!

8 Day Rainfall 11/10/2001- 18/10/2011. Source: Bureau of Meteorology

In my most recent weather updates on Ten's Weekend News, I gave a heads up on some major rain and thunderstorm activity that's on the way to parts of QLD and northeast NSW this week. I thought I'd give you some more detail.

Last weekend, southeast QLD experienced fierce thunderstorms with wind gusts reaching as high as 139kmh in Oakey (that's as strong as a cat 2 tropical cyclone), widespread falls of 20-70mm (most that occurring over 1-2 hours) and almost 30,000 lightning strikes!

This week, we have the ideal atmospheric set-up for the most intense and widespread thunderstorm activity so far this season. Onshore winds are carrying humid, moist maritime air from the Coral Sea right over inland parts of QLD and northeast NSW. But it's not enough just to have a saturated atmosphere- you need a trigger. This "trigger" will arrive in the form of a low pressure trough. This trough will rapidly lift this warm, moist air high up into atmosphere where it will condense and form into cumulonimbus thunderstorm clouds.

On Tuesday and Wednesday, isolated showers and storms are likely on the QLD coast mainly in southern parts of the Central Coast and Capricornia districts, roughly from about Townsville/Bowen to Gladstone. Some falls may spread inland to affect the Central Highlands and Coalfields. But the main rain and thunderstorm activity will be from Thursday onwards with most of eastern, southern and central QLD and northeast NSW affected. These thunderstorms have the potential to be severe with flash flooding from heavy rain (there is so much available moisture!), damaging winds and large hailstones. By the end of the week, widespread falls of 50-100mm are likely, but some places may see this amount in the space of a few hours underneath isolated intense thunderstorms. Some river flooding may also develop.