Nice example of a pretty cold inversion being broken apart by warmer upper winds when the temp at Perisher rose from -5.5 to +0.4 at 3.30 this morning.

Laurier, the variation between Perisher and Top station Thredbo has been baffling me in recent times. Either Perisher is very poorly exposed or Thredbo is being affected by some ice or a combination of the two.

PD, Perisher and Charlotte Pass are both at the bottom of valleys, while Thredbo Top Stn is on a ridge which would account for some differences. When Perisher's temp rose 6C this morning, it was accompanied by a change from a long period of calm to WNW winds around 10-15km/h, so I'm pretty sure it was an inversion blow-out. Coonabarabran was at it again a few days ago, with -4 at the station in town in the valley but +4 at the airport on the ridge south of town.

Laurier, what you say now about Perisher is right of course, I know the difference in height and all the factors. But the problem is still now for example at 11am its -3.1/96%rh on Top station, while Perisher is +3.5/31% rh. This has nothing to do with inversions atm because inversions never linger up there unless they are strata cu inversions, clearly this is not that either at 11am.

The difference in RH is not possible because there are no clouds there atm to do this, neither is the difference in temps of 6.7deg in only 221m.

I think its a combination of 2 things, Top station has not been maintained and filled with snow/ice on the sensors causing a wet bulb reading. Perisher could also be slightly over exposed to warmth on sunny days in that sheltered spot where it is.

The annoying thing about this is that we now do not have reliable high country records to know if the winter is warm or cold. This problem seems to have been a lot worse since last year.

http://www.weatherzone.com.au/news/canberras-coldest-mornings-in-36-years/22038

Wheres Canberra weather guy these days? The one who always use to complain about the hot weather in Canberra

Looks very spring-like out there today, puffy cu all over the place. Temps will easily exceed 20C on several days this week in Sydney.

Yes, PD, I agree that the difference is hard to account for by adiabatic warming, and there is a good W to WNW airstream being reported at both stations. Current vis satpic shows a bank-up of stratocu on the western side of the main range, which I'd imagine would be affecting Thredbo but not Perisher, but even assuming some Fohn effect the large differences in dry bulb and dew point are hard to account for. I also agree that our record of reliable, long-term high country records is abysmal. Try getting any information outside the Alps on snow depths for instance, and even the Alpine snow-depth record is reliant on non-Bureau sources such as the Hydro and the RTA equivalent in Victoria.

Do not know, but I will have a go at replacing him by complaining anyway. I find this record very hollow, because the lowest temp in the period is only -6.1, long way off potential -9 to -10 at near mid winter. Also this result is only because of too much high pressure caused by contracted polar vortex.

Laurier, where are you seeing the Sc cloud. I cannot pick it on the vis satpic. I can see the Snowy range bright white from snow but no Sc cloud. Even the web cams show its quite clear to the west.

Laurier, look at the 3pm readings at Top station and some other spots,
-5.0 top station, perisher +4.5, Ginini 4, Cabrummara 5.7.
That station is cactus

that's just crazy PD, the screen must be full of snow/ice! I remember Mt Hotham had a whole month without a +temp a few years ago, which i believe was due to the screen not being cleared of snow/ice. Thredbo must be loving it, all those people out there thinking how good the snow must be with such cold temps.

The other 3pm observation of interest is Thredbo Village which is a manual station at 1380m. It is reading +4.0 with a dew point of -6.8 compared to Thredbo Top Station at 1957m on -5.0/-6.8 and Perisher at 1738m on 4.8/-9.7. Thredbo Village is reporting 3 octas of high cloud. A screen filled with snow should give a dry bulb reading close to zero, so I'm wondering if the dry bulb sensor is in fact wet, which would bring Top Station a few degrees below the wet bulb reading you'd expect based on the other two - reasonable given its higher altitude but, of course, still wrong. It's also curious that Thredbo Village, which is 358m below Perisher, is reporting a temperature almost a degree lower. The winds at Perisher and the Village are both very light (2 and 4km/h respectively) so there may be some local effects going on.

In other news, I was at Ebor Falls overnight, about half way (as the budgie flies) between Bellingen and Guyra. As it turns out, the Ebor Falls Motel is in a great little frost hollow, possibly even better than the Glen Innes Airport. I had ice forming on the car from 7.30pm last night, and it was super thick by this morning with a temp of -5.4C.



I took this pic from the lookout deck above upper Ebor Falls - plenty of ice there.



Only a min of -1.6C at the Glen Innes airport this morning. Though I must say, this morning was probably an unfair comparison, as cloud moved over that part of the Northern Tablelands during the early hours. (I suspect so anyway... I reached Guyra at 9am under thick stratus with a base of about 1500m)

A few more photos here.

Brizwx, The waterfall was not frozen then like in 2007?. Anyway I believe that Ebor actually does record the lowest temps on the NT's in the right conditions.

Unfortunately not PD... not even one bit of ice in the falls. The min temps in the NTs this Winter are the lowest since 2007, but overall 2007 was a fair bit colder, and helped by some snowfalls and more numerous single days IMO.

The bloke at the motel claimed "it's about -10 this morning". And when I asked about 2007 "it got down to -20" lol. Obviously that wasn't the case, but I think he was trying to say it was very cold (-15C I think is possible there)

Its interesting because I have never seen a waterfall frozen in other parts of the world the way it was in 2007 unless its been -20. But I also cannot see how that could happen, so -15 seems a good guess at least. Not sure how much difference there can be at Ebor just between that town and lower parts of the river near the falls. I think the lowest temps may actually be in between the 2 waterfalls in that slightly deeper valley after the first drop off, maybe in there is was close to -20.

This is largely anecdotal but I reckon you'd struggle to see too many near-record overnight temperatures coming off the back of two consecutive La Niña events. I think it's the case that most long term overnight records [in places subject to radiative cooling] are set during dry periods when surface moisture (which inhibits radiation somewhat) is low.

In wonder what the comparison between the old and new Canberra Ap sites would have been over the last week. Presumably of negligible difference.

9.50 A.M. Saturday 14/7/12 "REDFERN Sydney"
Beautiful blue sky and the "promise" of 4 days of it........... I sure needed this with this "flu" around.

That is what I would have said too, Andrew, but my observations do not support it. Only the first of the last two La Ninas had Dew Points indicating high surface moisture.

My record for the last 3 years is in graphs here.
The middle left graph shows smoothed monthly anomalies of early morning Dew Point. While Dew Points were high in the La Nina of late 2010 and in the winter before it, they have been low (or very low) ever since.
At my station, the La Nina of late 2011 did not take Dew Points up to as high as normal. Earlier and later values were lower still. The raw value for mean early morning Dew Point in May 2012 was extraordinarily low: 0.8 degrees, which is 4.4 degrees below the normal May value of 5.2 degrees.

My record of frosts in recent years is plotted here.

While winter 2010 (leading to the first La Nina) was non-frosty, winter 2011 (between La Ninas) was normally frosty, and this winter seems likely to be somewhat frostier.

http://www.weatherzone.com.au/news/sydneys-warmest-mid-winter-in-years/22098

Whilst this warm spell is noteworthy, the heatwave in early August last year was probably more significant and across a wider area. I have only recorded one day above 20C this July (last Friday).

Temps should be closer to normal from Thursday onwards, but I suspect warmth will be the norm as we head into spring.

Felt like spring today, no wind, just perfect really, would love to see a week of it, like todays weather.

Bom have chance of thunderstorms for tomorrows forecast in the upper Hunter, would love to see that come through!!
Even the marine forecast for Hunter's waters has chance of T'storms in the evening, prehaps a lightshow is on the cards!!