(NB: THIS FORECAST WILL BE PERIODICALLY UPDATED.)

CLOSING REMARKS: What a race! The early rain certainly made all the difference - plus some fantastic track action all-round. Well done Jenson; let's see what Malaysia brings - early indications offer a threat of wet weather emerging again as a factor...

NOWCAST UPDATE, SUN. 07:10HRS BST: I expect it to turn dry for a while now... tricky stuff!!

NOWCAST UPDATE, SUN. 06:15HRS BST: Further showery outbreaks of rain likely across the circuit in the next 45mins.

NOWCAST UPDATE: SUN. 05:30HRS BST: The Met Office's model got it spot-on in terms of timing: some rain has already fallen across Albert Park ahead of the race starting, but it'll now prove quite knife-edge in terms of how much affects the race itself. Patchy outbreaks of drizzle and light rain are quite extensive to the NW, feeding towards Melbourne, albeit as expected the heavier pulses are crossing away to the southwest. Intermittently damp weather looks decidely likely for Albert Park, but any such conditions (assuming rain doesn't become persistent) should quite readily dry off the circuit given the breeze and temperature. Wind currently northerly, about 13mph, gusting to 25mph.

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This is a 'new style' approach to the weather forecasts I've previously provided on the BBC's 606 Forum, alongside our live online, radio and TV coverage of all the action during each Formula One race weekend.

The 2nd race of the 2010 season - the Australian Grand Prix - takes place at Albert Park, Melbourne, this coming weekend and I'll keep you updated here on the developing weather prospects.

Dry running is pictured here at Melbourne, but will this year's event escape the rain entirely? (Photo: William West/Getty Images)

Unlike the dry, almost cloudless conditions experienced a fortnight ago in Bahrain, there's a chance of some rain falling periodically in Melbourne to add additional on-track uncertainty through the coming weekend. And don't underestimate the wind: this could prove quite an issue later on Sunday!!

Since I first opened this blog entry, it's been noteworthy how the essential forecast theme has changed very little - irrespective of whatever meteorological model is followed. This continuity provides high confidence in the broad thrust of the Melbourne forecast, albeit the local detail will inevitably now prove more of a 'nowcast' issue.

And with this in mind, you can keep an eye on the local rainfall radar (as the teams surely will!) through this link.

So, here's the current forecast thinking:

The UK Met Office's Global Model, above, hints at the expected proximity & generally light intensity of rain during the Australian Grand Prix (which starts at 5pm local time). Other forecast models offer a broadly similar solution.



SUNDAY FORECAST:

Summary & model assessment: Light to moderate rain highly likely during the race. Turning quite windy. Overcast but very warm.

Unsettled conditions are spreading eastwards as an area of low pressure (circa 1000 mB) moves across the Great Australian Bight towards Tasmania, swinging a trough and a band of rain, some heavy, into coastal districts of South Australia and then across parts of SW Victoria.

The various forecast models we employ (UK Met Office's Global Model; USA's GFS; plus the Australian Bureau of Meteorology's own prediction) all offer agreement on the evolution and provide improving continuity regarding the timing of rainfall progression into Melbourne.

Precipitation & cloud cover: Some showery outbreaks of light rain have crossed Melbourne overnight and it's likely the circuit will prove rather 'green' again by dawn.

It'll be an overcast race with cloud cover becoming quite extensive well before the race start at 5pm local time. The probability of light to moderate rain affecting the event, more especially post-6pm local time, is now considered high.

The Met Office's Global Model suggests the rain could arrive patchily (as drizzle or generally light intensity) even by the start of the race. This could increase a little in intensity later, albeit peak rainfall rates are unlikely to ever exceed 3-5mm per hour.

The US-GFS model, running at similar resolution, has flip-flopped repeatedly in recent runs between offering light rain above Melbourne by the race start, or holding it out west until later. The latest (1200 GMT) output reverts back to the slightly slower solution, with light rain arriving towards the end of the event.

The Australian Bureau of Meteorology's prediction, combining the output of 9 national and international models, further supports the notion of any rainfall being light in nature.

So broadly, the UKMO, GFS and other models offer comparable forecasts in terms of both the high likelihood of some damp weather arriving into Melbourne districts at some stage during the race (if not actually by 5pm local) and the generally light to moderate intensity of any precipitation once in-situ. So it's now a nowcast issue....

Temperature: With the prevailing flow off the hot continental interior, it will become very warm at around 29-31C mid-afternoon. Ambient temperature during the race likely to be 28-29C.

Wind: Could be key factor, in my opinion. It will turn noticeably breezy during the afternoon, with the north to northeasterly wind gusting 25+mph at times and possibly over 30mph periodically by the start of (and during) the race. The Met Office modelling suggests a prevailing NNE wind averaging from 10-15mph.

It will offer a headwind component on the pit straight; a tricky, gusty crosswind in some of the other sections not well sheltered by the trees and perhaps critically, a noticeable tailwind element through the back of the circuit from turns 10-13. Local funnelling effects of the wind through the adjacent urban areas and down the walled sections of the circuit such as from turns 10 to 11 could be quite an issue, affecting braking stability into the (ever-tricky) high speed left-right switch at 11-12; ditto into the quite fast right-hander at turn 13.

All the latest forecast model runs continue to hold any threat of heavy rain W/SW of Melbourne until later into the evening. However, even intermittent light rain will add a real lottery to proceedings, as emphasised by Hirohide Hamashima, Bridgestone's director of motorsport tyre development:

"If there is rain before tomorrow's race we will face quite a difficult track, and those starting on the soft tyre will have the concern of graining on the left tyres, either front, rear, or both depending on the car and set-up. If a driver can protect their tyres then a one stop strategy should be possible...The soft tyre is around 0.5 seconds faster for its fastest lap than the harder tyre, but we really don't have sufficient data to know how long it will last here. This, and the variable of the Melbourne weather, will be the biggest unknowns for tomorrow's race."

I do urge keeping a close eye on the rainfall radar (here's an alternative version, if you so prefer) - this will offer a real-time answer as to whether it'll rain by race start (and save me trying to type innumerable updates; I'll find it tricky due to mounting excitement / stress level as the race unfolds!)

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(Previous forecasts:)

SATURDAY:

NOWCAST UPDATE, 05:20HRS GMT: Some moderate intensification of the showery rain to the west of Melbourne, but current trajectories suggest these are likely to run south of the city.

NOWCAST UPDATE, 04:10HRS GMT: Despite a scattering of light showers in parts of Victoria, it's highly likely qualifying should remain dry.

FORECAST: High pressure (1024 mB) sits over Tasmania and the remnants of Friday's front continues to decay over Victoria.

Largely cloudy conditions will once again prevail and a good deal of dry weather will dominate during the day. There's a small chance of isolated light to moderate showers developing above Melbourne through the morning and into early afternoon. Some could appear during 3rd practice and indeed there's a risk of some further showers during qualifying (starting at 5pm local time), but on balance it's very likely both sessions will run in the dry..

Temperatures will be somewhat less than Friday's values, peaking around 24C into the afternoon. Winds will be predominantly light/moderate SE to then SW for much of the morning and early afternoon, averaging 8-10mph.

FRIDAY:

NOWCAST UPDATE, FRIDAY 0606GMT: The current shower will soon fade - some running likely again soon thereafter, assuming the track dries speedily. But more showers still likely in the next 30mins.

NOWCAST UPDATE, FRIDAY, 0555GMT: The first shower duly arrived and more look likely before the end of this session. Signs of moderate intensification of these shower cells on rainfall radar... doubtless the teams well aware that they need to take full advantage of the current dry window.

NOWCAST UPDATE, FRIDAY, 0500GMT: Light to moderate showers crossing eastwards, as now seen on rainfall radar, look likely to affect the Melbourne district towards 2nd Practice. Currently the heavier (and in places thundery) showers are remaining well south of the city.

FORECAST: An area of high pressure slowly eases eastwards from southeastern Australia, with another established out west across the Great Australian Bight. An ever-weakening cold front will sit between the two anticyclones during Friday, arcing northwards above Tasmania but quickly losing intensity in-situ.

Dry weather should thus dominate during both practice sessions, with a small chance of isolated showers appearing as the day develops. Most of these should be light in nature, but there's sufficient instability aloft to offer a scattered sharper (possibly even thundery) shower. It'll prove a hit-and-miss situation, more especially into 2nd practice. So worth watching the rainfall radar link I provided earlier in this blog...

Increasingly cloudy skies will be above Albert Park during the afternoon as temperatures reach about 25-27C. Winds will shift from N/NW around to SW by midday; a tad breezy, averaging approx. 10-15mph but closer to 15-20mph by midday.

The combination of ambient / track temperature plus a moderate breeze will readily clear any dampness that might arise from light showers, so on current forecast expectations I expect nothing other than slick tyres being employed during both sessions unless the circuit catches an isolated heavier downpour. Unlikely, but possible!