Winter 2010
These reports are done as time permits. Further information will be added to them periodically.
July 15th, 2010:
Light snowfalls again occured across the Oberon Plateau early this morning with a few cm on the ground above about 1250M, even the Oberon township saw snow showers last night but not much settling to my knowledge. Reports from snow chasers at Weatherzone forums indicated a few cms at Shooters Hill by dawn and similar amounts at Mt Trickett and Mt Bindo. Blackheath saw sleet and some wet snow between about 12:45am and 1:45am. Thanks to Mr NASA for his bleary-eyed, local reporting. This system followed the pattern of cold fronts this year with the bulk of the cold air mass staying south of the Oberon Plateau and the Blue Mountains. Just to our south, the Nowra sounding this morning showed -29C at 500hPa, -10C at 700hPa and about -1C at 850hPa. That would have probably given us snow in the upper Blue Mountains, maybe even a settling, if that colder air had reached us.
In contrast, the Sydney weather balloon sounding this morning gave -25.5C at 500hPa, -12C at 700hPa and about 0C at 850hPa. So, over the Blue Mountains area we had not very cold air in the uppers, cold air in the mid levels with passable moisture but not much cold lower down to keep the snow 'alive' as it reached us. We really need 850hPa temps of about -2C so by the time the snow reaches us at about 900hPa, it hasn't melted to sleet or rain. Upper temps need to be at least -27C but are better at -28C and colder. I may add more to this report as time permits.
July 2nd, 2010:
Light snowfalls occured across the Oberon Plateau on the evening of the 2nd of July. Sunny Corner also had a settling on Friday night and some brief snow showers the next morning. Accumulations were generally confined to above 1200 metres ASL as the temperatures in the lower levels of the atmosphere were not quite cold enough for snow. The Sydney sounding link above shows this well, cold in the uppers but lower down it was not quite cold enough. Moisture was certainly ample and if it was a degree colder, Blackheath could have seen 2cm on the ground but not to be this time. Thanks to 'snowmi' from Weatherzone forums for the excellent photos and thanks also for the email reports from Oberon Plateau residents and areas nearby - its great to hear from you.
June 9th, 2010:
Light snowfalls occured on the Oberon plateau on Wednesday. The Wagga Wagga sounding from Wednesday morning showed an air mass that was fairly cold although not overly so. 500hPa temps were around -28C, 700hPa temps were about -9C and 850hPa temps were about -2C. For those that are new to weather watching, weather balloons are sent into the atmosphere by the BoM from various areas of Australia each day and give a great profile of cold air masses in this context; including temperatures in the different layers, relative humidity and wind speed and direction. Forecasters use these readings to formulate opinions on what the weather may do for a given period. For the extra keen among us, you will notice that there is a lack of any southerly jetstream in the Wagga sounding at around 300hPa. This makes it hard for cold fronts to survive long at our lattitude. This is a feature that has tended to be missing more often over the last decade or so.
If that Wagga Wagga air mass had made it this far north, we could have been in business for some nice snow in the Blue Mountains but alas, no luck this time. You can see by the Sydney sounding last night that the air mass was notably milder up this way. No snow this morning in Blackheath apart from a few tiny snow grains on the recycle bins.
Just an update on this, as of 10/6/10 at 8am. I did see quite a few snow grains in shady areas near the tennis courts, when taking the dog for a walk and my rain gauge has 1.2mm in it, when there was only a trace in there last night. Sleet and snow grains appear to have fallen in Blackheath overnight. There is a windchill of -10C this morning (10/6, 7am) and the air temp is just over 1C. More information in this report and further photos will be added as I have time.
NB: It was nice to catch up with a couple of other snow desperados yesterday at Shooters Hill. Nick Moir and Rhys were out there, also looking for the first flakes of the season. Nick's a talented photographer from the SMH (Google him and you will see what I mean) and is a keen weather watcher. Ellie Harvey from the SMH did a nice story and pretty much reported exactly what I said. Thanks guys.