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Formula One Weather Forecast: Korean Grand Prix 2010

Ian Fergusson | 14:25 UK time, Tuesday, 19 October 2010

Yeongam, 22 - 24 October 2010 (Round 17)

(This forecast will be regularly updated. This entry: Friday 22 October, 18:40hrs BST)

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 Forecast Summary:

(PPN = Precipitation)

Emphasis: High confidence for dry Friday; Saturday's FP3/Quali sessions also expected to remain dry. Improving inter-model continuity suggests a threat of rain arriving into Sunday, with increasing potential to affect the race.

Friday: CONFIDENCE HIGH: Sunny spells and dry. Chance of PPN 5%. Max 22C.  Breezy at times. Wind ENE.

Saturday: CONFIDENCE HIGH: Turning cloudier during the day. Rather breezy again. Expected to remain dry throughout FP3/Quali.  Chance of PPN 30% until end of quali, but rain arriving late evening / towards midnight. Max 21C. Wind ENE.

Sunday: CONFIDENCE MODERATE (improving): Mostly cloudy. Rain expected to have arrived overnight, albeit heaviest PPN expected further to the south. Possible that wet weather will have departed before race start, but this remains open to a high degree of uncertainty. Chance of PPN 70%.  Max 19C. Breezy.  Wind ENE. 


Synopsis & Forecast Evolution:

Update to original entry (below):

Friday Update, based on 12z Model runs:

There's closer agreement generally now between the main operational centres, with a high chance of rain falling across the circuit at some stage later Saturday and into Sunday. This has been strongly signalled for some time in the ECMWF-ENS output for Mokpo; ditto (with good continuity) by Canada's GM, the UKMO-GM, Japan's GM and (on and off) by NOGAPS. Korea's own KMA modelling and meteogram spread offers a similar idea.

The US-GFS has tended to play catch-up of late, now bringing rain overnight Saturday and into Sunday morning, but clears it well ahead of race start. This solution has about 50% support and we'll see if the 00z GFS (and other op centres) build on the theme of dry weather and / or only light showery outbreaks of rain prevailing by the time the lights go out. Certainly not impossible, in my view.  The Canadian model falls into a roughly similar camp, with fairly heavy overnight and morning rain trending much lighter ahead of race start.

Meanwhile, the Japanese, EC and UKMO modelling still threaten outbreaks of rain (some heavy) continuing into the race window. The Canadian output had also doggedly stuck to this idea virtually all week, with UKMO not far behind in terms of continuity and remaining so in the latest run. ECMWF's output is best summarised in a remark from the Met Office's Deputy Chief Forecaster made to me earlier today, who - after analysing the Mokpo EP meteogram - concluded: "....(there's) clearly a high chance for some heavy rain, either before the race, if not actually during it."

So it's a very finely balanced situation; further runs are needed to gauge continuity on the areal spread of heaviest rainfall and the timing of any clearance off eastwards. Broadly speaking, a middle ground approach is to anticipate rain arriving overnight and into the morning (= green track), mostly clearing away to the east before midday but with potential for some lighter showery outbreaks continuing for a while into the afternoon.

Thursday Update, based on 12z Model runs:

Today's ensembles maintain a trend - already offered with high forecast confidence some days ago - for dry running to prevail throughout Friday's sessions and a strong prospect of the same outcome on Saturday. The focus of forecast attention remains very much fixed on Sunday, with a growing prospect of rain arriving during the day, courtesy of the ex-Megi remnants described in the original entry (below). As also highlighted below, this threat of wet weather has been consistently offered by some models as a minority to 50% solution, while the US-GFS - suffering some earlier upstream divergence in handling Megi's track - has continued to oscillate in solutions for Sunday.

Crucially however, it has tended to erratically edge the prospect of rain northwards in successive recent runs. It's 12z output now comes into broader, if not exact, agreement with most other operational centres (ECMWF, UKMO, JMA, CMC, NOGAPS etc.) by bringing a prospect of rain across the extreme SW and S districts of South Korea throughout Sunday. Other models are more bullish, with a more northerly, extensive threat of rain and in the case of CMC (exhibiting strong continuity), offering showers potentially slightly earlier from overnight Sat-Sun. The timing of this - plus precise degree of northerly extent of any precipitation - will be the critical factors during race day. 

Clearly, tomorrow's runs will be important in terms of continuity (or lack thereof); CMC, UKMO and some others having already 'led the way' in threatening a wet or potentially wet race, with GFS tending to play catch-up in the last 24hrs. I'll update you all again tomorrow, by which time we'll have seen just how the teams fare on the new circuit in dry, fine conditions during FP1 and 2!


(Original Entry follows)

While the Suzuka forecast was a (rare) example of great inter-model continuity and bullish forecast confidence - even quite a few days ahead of the event - assessing weather prospects at this inaugural Korean event have been proving quite the opposite!

Forecast confidence is now starting to improve and consolidate. Currently, only the weather for Friday's practice sessions can be foretold with a very high degree of certainty: it's looking dry, fine and rather breezy for those. The various models are starting to show increasing agreement for the rest of the track action to stay dry, too.

Now, I hope you can keep up with this next bit - but it's pretty critical in determining just how dry (or not) the new and doubtless rather slick asphalt will remain by the end of the race weekend!

The complications emerge especially during Sunday, much of them courtesy of how extra-tropical remnants from Typhoon 15W, named 'Megi', track and evolve through the mid to latter parts of next week.

Right now, Megi - located SE of Hong Kong - is tracking very much as anticipated, steered around the southern boundary of a deep-layered mid-level subtropical ridge. With time, the western portion of that ridge of high pressure will subside due to mid-latitude influences coming east out of China, while the typhoon itself is expected to continue it's more poleward track.

Megi is currently expected to make landfall into S.E. China / Hong Kong, according to the official model output from the Joint Typhoon Warning Center.  Therafter however, the complex evolution of the dissipating core - and extent and distribution of it's northward rainfall outflow - are all influenced by various factors, including a trough emerging south-eastward through mid-central China. However, it will certainly dissipate and weaken as the poleward journey continues during the week, through the increasing influence of land and decreasing potency of vertical wind shear. But the northerly-orientated outflow of rainfall and associated 'lobes' of low pressure will remain pretty noteworthy features on weather charts for a few days still, some of this possibly crossing - or at least grazing -South Korea later during the race weekend. However, this is most likely to occur post-race and  overnight int Monday.

The main 'free' forecast model output available on the web, feeding many automated popular forecast websites, is the US-GFS model. Importantly, it has persisted in offering a divergent track in certain respects compared to the collective (and very similar) output of other dynamic models (e.g., ECMWF, UKMO, NOGAPS, GFDN). On the basis of consensual expert analysis, the GFS track you might see on some weather websites is still presently considered the 'outlier' solution by the Joint Typhoon Warning Center and is, in their words, "....deemed as unlikely, considering the strength and position of the steering subtropical ridge positioned to the north." 

Consequently, the GFS forecast further 'downstream' into later stages of next week may prove somewhat unreliable for south Korea (at least at this range), albeit continuity in the broader weekend prospects for Mokpo is now improving.

The UK Met Office and Canadian CMC models were both quite progressive in taking a threat of rain - some heavy - northward towards Korea into the weekend. Previous runs of UKMO suggested overnight wet weather Sat-Sun but unlikely to directly impact track sessions; CMC, meanwhile, offered a decidedly wet race. UKMO has now reverted to a dry solution for Saturday and Sunday, bringing the threat of rain only later during Sunday and into Monday. CMC, however, sticks to the notion of a very wet spell into and throughout the race window. It remains effectively alone in this very pessimistic solution (but that doesn't mean it's to be discounted!).

GFS has exhibited some pretty typical oscillations at this sort of forecast range and especially in a complex set-up.  It sticks to the idea of dry weather all weekend, steering any rainfall southwards across Japan. ECMWF, meanwhile, is essentially the closest to the Megi 'official' track published by the Joint Typhoon Warning Center and also looks to keep the race weekend dry or largely so.

A reasoned summary, for now at least, suggests:

- dry, sunny & breezy weather all of Friday;

- very probably dry (and again breezy, plus eventually somewhat cloudier) conditions for Saturday's sessions, and

- a dry, breezy and fairly warm race the more likely outcome, but with an uncertain, low % threat of rain appearing during the event.

I'll of course keep you updated all the way...


  • Comment number 1.

    Well, I don't envy you when it comes to trying to work all this out Ian, looks very very difficult to predict at this stage.

  • Comment number 2.

    great blog. this one is one to watch...

    btw. the link on the bbc f1 website still links to your suzuka forecast, not this one.

  • Comment number 3.

    I'll gladly settle for dry conditions. The track will likely be slick enough as it is, without rain adding to it.

  • Comment number 4.

    Well, it seems to now possibly, maybe, perhaps switching back to a wet Sunday. This really is absolutely impossible to predict.

  • Comment number 5.

    Thanks for this latest update Ian. Still seems very unpredictable. It sounds like the track will be slippy enough with a dry track tomorrow, so if it's wet on Sunday, well, anything could happen, and it could end up incredibly slippery. Still, let's hope we don't get snakes causing red flags (saw a picture earlier of a snake on the track believe it or not).

  • Comment number 6.

    Yep nice update, the GEFS had hinted at wet conditions for a while, seems like the op has come on board now.

    Ian I hope to see you on Netweather soon lol

  • Comment number 7.

    Hi Speed_Racer, indeed so - the threat of rain had always looked bothersome and far from a clear minority solution; indeed really from the start of the week, it's been evident based on a broader examination of the main operational centres (and for that matter Korea's own Met agency); plus it's been important to take into account some of the earlier GFS difficulties handling Megi upstream. The latest GFS 12z output (obviously with 18z awaited) is in much closer alignment to the more consensual approach already evident from EC, UKMO, JMA, CMC and NOGAPS, which collectively lean towards offering rain (albeit light PPN rates) into Mokpo and environs by race start. Clearly, there's plenty of time to see the emphasis change again back to dry, but it's been noteworthy how the 'damp' trend has increased, rather than decreased, into the race window. We shall see. Interesting stuff. Cheers, Ian

  • Comment number 8.

    Still seems a bit uncertain as to if any rain will hit the track, and if so, when. Even if the track is dry for the race, if it rains beforehand and then dries out for the start, it'll be very interesting to see just what sort of grip there is, given the slippery conditions we had today. Still doesn't seem totally certain anyway, as was likely to be the case given that this rain is due to Typhoon Megi (or what was Typhoon Megi anyway).

  • Comment number 9.

    That latest update shows just how difficult this forecast is. Even though the continuity is improving, it's still very much knife edge. Really appreciate these updates Ian, you do an excellent job for us. This must be 1 of the more difficult forecasts of the year for you (in terms of F1 weather).

  • Comment number 10.

    Interesting this morning.... GFS still going for rain pushing away by 0200 BST, but NOGAPS going for light rain just before race and UKMO heavy rain during the race!

  • Comment number 11.

    Hi Ian,

    Thanks again for these great F1 weather blogs this season. Looking at the radar on the Korea Meteorological Administration's website, it looks pretty wet across the south the country currently and the forecast (I think - my geographic knowledge of Korea is not that hot!) is still quoting a 70% chance of rain for 15:00 local, so your figure of 70% you gave on Friday evening was pretty good.

    At the very least, this rain should make for an very interesting race for a number of reasons -
    * The rain will wash away all the rubber put down over the weekend so far. As this is a brand new surface with no "ground in" rubber, we should have a totality green track with very little difference in grip levels between on and off-line, hopefully helping overtaking. Also those on the wrong side of the grid shouldn't be at so much of a disadvantage. Autosport were reporting that Kubica thought that the differing grip levels between the two sides resulted in a 20 meter difference on track before the rain.
    * Apparently this is the first "proper" rain that has fallen on to the new surface other than 1 light shower. No-one really knows how the asphalt surface is going to react to the rain, oils coming up out of the surface etc that may drastically alter the fundamental grip level of the track.
    * Even if the rain were to stop soon given the high humidity (currently 96%) and the (probable) overcast conditions, we should end up with a damp track at the very least which is always fun with tyre selections etc.

    In short, I'm defiantly setting my alarm for the morning to watch the race live!

  • Comment number 12.

    G'day Ian
    It is now 09.30 on tuesday in Worle were is the heavy rain its as dry as a bone here.
    You have been a lot better than angin dont get as bad as he was


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