Head to the Cold Outbreak News link above for developing winter cold fronts.
4-6-09, Thursday 8:30am: I recorded 192.5mm for the month of May from my home office gauge. That is a lot more rain than the average for my town. Katoomba's official rainfall of 246.6mm was more than double their long term average of 102.7mm. Average maximum and minimum temps for May in Katoomba (a better long term guide than Mt Boyce AWS) were about half a degree warmer than the long term average, coming in at 13.4C and 6.4C respectively.
23-5-09, Saturday 9am: A heck of a lot of rain has fallen in Blackheath over recent days. My gauge at the home office has recorded 142.5mm so far this week, with quite a bit more to come today, I'd say. Mt Boyce has recorced even more rainfall as it tends to pick up a bit more rain in these events. It seems to be more exposed to the uplift out of the Grose Valley when the wind is due east. This system will gradually weaken today and into tomorrow and by Monday/Tuesday we should be back to cool, partly cloudy days with the chance of a shower.
4-5-09, Monday 10am (updated 6pm): Blackheath rainfall totals for April from my gauge were 179.4mm. That is more than three times the short term average rainfall (Mt Boyce) for April and around 60mm higher than the long term average in Katoomba. A good amount of that came early in the month with some handy top up falls later in the month. Thanks to the cold end to the month, daily average maximums (16.1C) came in at about 0.5 below the Katoomba long term average and the daily minimum average of 8.6C was the same as the Katoomba long term average.
The Katoomba records have a much longer history than Mt Boyce so they are a bit more reflective of true conditions although the Katoomba observation site has moved around a bit over the years so it doesn't have a very high rating. Moving a Stevenson Screen from one part of the town to another can give quite different readings over the decades. It might be a while before we get good rain this month - see paragraph below - although I'd prefer any rain to really burst forth later in the month anyway, as it gives us a better chance of snow as winter approaches.
2-5-09, Saturday 9am: Most folk would have noticed the quite strong surface high pressure now settling in the Bight area. This tends to bring us fine days intermixed with onshore winds and cloudy or drizzly days. The surface high pressure could be in that position for a week or two, blocking any notable fronts from the southern ocean. This isn't uncommon for this time of year although such surface high pressure has generally been stronger and slower moving in recent years. There was a marked change to a more traditional winter last year with numerous fronts moving our way so lets hope this high pressure at the surface will soon break down. At this stage, mid to late May should bring some stronger fronts again.
30-4-09, Thursday 9am: Don White in the Daily Telegraph yesterday stated that it was the heaviest snow for the ski fields in more than fifty years. This is quite impressive. April snow isn't unusual of course down that way but the amount of snow recently certainly is. We are now in a bit of a blocking pattern (strong high pressure at the surface) which may prevent more frontal activity from hitting the south east of Australia for more than a week. This isn't unusual for this time of year but how this pattern breaks down as we move into winter is important, as it can hold back those snowy fronts we all love. There's no cause for concern yet though, the outlook for winter 2009 in my opinion is quite good.
27-4-09, Monday 5pm: No snow on the Oberon Plateau this morning but temps did hover close to zero out there, earlier today. Its been a cold day in Blackheath with wind chill temps below zero since yesterday. Last night with winds close to 100kph, we had a wind chill of close to -9C. It still needs to be confirmed but it seems that Thredbo top station and also Charlottes Pass and Thredbo Village have all broken their records for the coldest maximum temperature for April today. Please note, this may not be official yet.
26-4-09, Sunday 7:05am, update: There appears to be a reasonably good movement of the cold air field north this morning but its very dry in the frontal band ahead of it with just a few spots of rain here in Blackheath. This is what I thought might happen but its a bit worse than expected. The cold air field is the only hope now for snow over the Oberon Plateau and its a fair way behind the frontal band, as you can see on the sat loop. The Wagga sounding is quite good for April but any cold air cells that pass over the OP will be isolated and not well supported as the upper level temps are not co-operating. So, maybe a bit of snow out west but not much. Blackheath is unlikely to see snow now from this system now but as always, there is a very faint chance.
22-4-09, Wednesday 9am:The 12z forecasting models this morning have weakened this Sunday cold front a little but that's nothing to really worry about just yet. These ebb and flows in the models are all very typical really. 00z charts usually give a better rendition of outcomes anyway. I imagine this system will look a little stronger on the 00z runs this afternoon/evening. I still think it will fall short of last years system though, in terms of upper level cold but there's plenty of time for this system to develop nicely in real-time. Looking at approaching systems on paper is fun but in reality they are never 'real' until you see them moving into the Great Australian Bight. Fingers crossed this system develops well. Friday night will be the best guide via the charts but we should still get an idea by later today and tomorow.
21-4-09, Tuesday 8:30am: Well, the computer models still have a quite strong cold front forecast for around Sunday the 26th of April. At the moment, this system could well be strong enough for some light snow on the Oberon Plateau by Sunday and maybe a flake or two across the upper mountains. Preceeding this, there will be a weaker front earlier in the weekend (around Friday) that will bring wind, cloud and maybe patchy rain. Watch this space as I will update the situation as it develops. Quite fascinating to see another April snowy front on the way (potentially) after last years event at around the same time. Still, its only Tuesday and a lot can happen over the next few days, so lets wait and see.
19-4-09, 5pm: The fresh south easterlies are certainly established now. This pattern should generally continue until at least Tuesday and possibly into Wednesday and Thursday, depending on how long the surface low lingers off the east coast. Following that, some fairly strong frontal weather (for April) looks to be heading our way by next weekend. More on that later. In the meantime, check out this article from The Australian that indicates that Antarctic ice, over most areas, is growing, not shrinking. Its a reasoned and sensible representation of what is happening down south, from what I can see. View the article here.
16-4-09, 11am: Looks like we could be heading into a burst of cool and damp autumn weather by about late Friday and into the weekend and beyond. A significant low developing off the east coast of Australia could bring fresh south easterly winds and streaming showers. This is the most likely outcome at this stage but keep an eye on the official forecasts. Following that, we could have our first genuine cold front by around the 28th of April but its very early days for that event, so lets just keep an eye on things as they develop.
4-4-09, 9am: The cold front progged to arrive over the weekend has weakened now and will only effect the ski fields and more so further south, even in those places it wont be as cold as it was looking a week ago. On another note, the respected NOAA organisation has recently issued an interesting study on climate change. It appears that all of the warming in recent decades may not be man-made after all. Not that this is surprising to many but here is the link.
There is still much to learn about climate change but its important to remember that mainstream media articles on climate change can be a little abbreviated and not as thoroughly researched as they might need to be. This is inevitable really as you can't always expect a detailed scientific explanation of climate trends from a newspaper, radio or television program. Some are better than others, of course.
2-4-09, 8am: Another 21mm overnight. So, 87.7mm has now been recorded for this event, from my gauge. There is the chance of moderate falls today but this system will now gradually weaken although cloud and shower activity could linger for the next day or two at least.
1-4-09, 7pm: Another 22.5mm since this mornings post. So, 66.7mm for this event from my gauge.
1-4-09, 6:30am: The Mount Boyce AWS is still down. Another 20mm since my last post. So from 9am yesterday to 6:30am today we've had 34.6mm. Add the 9.6mm from the 24 hours previous to that and we have had 44.2mm so far from this system.
31-3-09, 7pm: The Mount Boyce AWS is down at present. From my gauge we've had 9.6mm to 9am this morning and another 14.6mm since that time, to 7pm tonight. Heavy showers at times today but mostly light to moderate in intensity. It should get consistently heavier overnight with possibly another 20mm to 30mm by 9am tomorrow.
31-3-09: Tuesday, 8am: Well, it certainly seems like we are going from a reasonably dry period into quite a wet one across the Blue Mountains. Sea surface temps are relatively warm along the east coast and this combined with the typical placement of surface high pressure at this time of year is bringing significant rainfall. Not to mention an upper trough to enhance rainfall. This wet weather could even last for a week or two (with some occasional respite) but we will have to see how things develop over coming days to confirm this. Its not unusual in autumn to get stuck in a pattern for some weeks.
27-3-09: Friday, 6:30pm The paragraph below this one speaks of a potential cold front for the ski fields next weekend but there is also an interesting trough setup brewing for the new week across eastern NSW. There's nothing snowy in it of course but it could bring good rains to the Blue Mountains. Forecasting models will sharpen in their clarity by late in the weekend.
27-3-09: Friday, 10am: A few storms and light showers this week but only enough to bring us 3.7mm in the gauge. So far this March we have had just over 43mm in Blackheath, from my gauge. There is the prospect of some light shower activity this week but at this stage it wont be a lot. Next weekend could bring our first genuine cold front for Autumn with possible snow for the ski fields but lets see how the charts pan out over coming days. We should have a clearer idea by about Thursday.
14-3-09: Saturday, midday: Its still a good way out from winter of course but at the moment things are shaping up well, when it comes to prospective cold fronts. One of the components that has been missing for a few years now has been a consistenly strong NW cloudband. These setups bring with them good moisture inflows to approaching cold fronts. With the warm Sea Surface Temps this autumn in the eastern Indian Ocean, we could well see more classic cold fronts this winter. Time will tell though, as we need the current patterns to stablise into late autumn. As we move into late autumn, I will sit down and provide a more detailed explanation of Sea Surface Temperatures, as they have a very significant impact on our winter cold fronts.
2-3-09 177.1mm was the rainfall accumulation from my gauge in Blackheath for February. Average maximum (23.3C) and minimum (14.1C) temperatures for the month were around 1C above the long term average, going off the Katoomba longer term observations. Katoomba recorded its hottest February overnight temp in 73 years of records on the 7th of Feb (24C) and its hottest ever maximum temp (37.6C) on the 8th.
22-2-09: Sunday, midday: Crikey, I was lucky with that storm yesterday at around 1:30pm. I had unplugged the computer but forgot to unplug the router before we left for Katoomba, earlier in the day. There was no sign of hail at my place or any plant damage at all so it must have swung in from the SE, moved through Jameson Valley, taken the ridge line then swung NE. Laurier Williams from Australian Weather News reported hail in the pea to marble size range for about five minutes but he is situated in a different part of Blackheath. I wish I had the camera at Katoomba at around 12:45pm yesterday as the lowering was somewhat impressive under the storm shown below. These radar images below are stored in a temporary directory and may not be there permanently.
BoM radar image of the storm as it moved NE, situated SW of Katoomba at the time. This was when I saw the lowering and some great cloud to ground lightning strikes. Near Katoomba - Storm image 1
Second BoM radar image of the storm as it moved over Blacheath. More cloud to ground lightning occured at this time with hail pea to marble size. Near Blackheath - Storm image 2
15-2-09: Sunday, 8pm: Katoomba recorded indentical very cold days on Friday and Saturday with a temp of 11.7C, only 0.7C off the coldest ever February maximum in 1966. Mt Boyce set a new record for its coldest February maximum on Friday with a temp of 11C and narrowly missed breaking it again on Saturday with a temp of 11.1C. Both of those temps were colder than the previous record of 11.3C, going on the twelve years of records at this station. Today reached 13C in Mt Boyce. More showers to come this week, possibly heavy at times.
14-2-09: Saturday, 9am: Well, last Saturday Katoomba recorded its hottest overnight temp (24C) in 73 years of records and the following day recorded its hottest daytime temp (37.6C) in 73 years. Over the last few days since then, we have had a much cooler trend and Katoomba has now recorded one of its coldest February daytime maximums (11.7C) in over forty years. It looks as if Mt Boyce AWS will record for Friday, its coldest February daytime maximum (11C, old record = 11.3C) in twelve years. Mt Boyce records have a much shorter history compared to Katoomba of course but its still significant. Its also an outside possibility that Katoomba could break a forty three year record for coldest ever February daytime maximum (11C) today.
11-2-09: Wednesday, 8pm: The new record for our hottest summer maximum at Mt Boyce now appears to be 36.2C, up from 35.7C. Katoomba's new summer record is now 37.6C, up from 36.6C. Quite a contrast over the last couple of days, especially today where it didn't get above 13C. Breezy, cool temps will persist this week with the chance of some handy rainfall.
8-2-09: Sunday, 4pm: Its still unofficial but it appears we have broken our high maximum temp records for Mt Boyce and Katoomba with 36C (35.7 old) and 37C (36.6 old) respectively. This will probably be confirmed by later tomorrow. These records are the hottest days on record, for all summer months, not just February records.
8-2-09: Sunday, 2pm: No more high minimum records broken overnight in the upper mountains, the air was drier than the previous night so this allowed a bit more cooling. Mid level moisture at around 700hPa was shown to be increasing today, according to the MLAPS and LAPS models. This has happened to some extent with some cloudiness now present. This could see a very slight reduction in the extreme heat this afternoon and may prevent our all-time summer records from being broken. Its touch and go and the next obs check at around 2:15pm should tell us what might happen with those records. The cool change should make it to the mountains by roughly midnight or a bit before at this stage.
7-2-09: Saturday, midday: Its still unofficial but it looks like we have broken a seventy three year, February record (22.6C replaced by 24C) for the hottest minimum temperature in Katoomba. This site is a composite site which means it has been moved to different locations over the years, so whilst it is significant, its not as valid as other obs sites that have remained in the same place for many years. It also appears to be a hottest ever minimum temp for all of summer at this site.
Perhaps more significant is the Feb minimum temp record broken in Cowra, with a minimum temp of 28C for the twenty four hours to 9am today. That is very warm! White Cliffs in western NSW also set a new 24 hour minimum Feb record with the thermometer not going below 32C from 9am yesterday to 9am today. Mt Boyce AWS broke its Feb minimum record by almost a degree (21.2C to 22C) but it is only a short term site of twelve years duration for temperature. These temperature records are not yet official.
Today also shows a slight possibility for all time, summer maximum temp records to fall (36.6C = Katoomba, 35.7C = Mt Boyce) but this would be more likely tomorrow. With the lack of storms today to bring some cooling, we could also see our hottest Feb minimum records broken again tonight.
6-2-09: Friday 4pm: We have just had a 2C spike in the temp here in Blackheath (34.6C and rising) as the winds have moved from the NE to NW. Its even possible we could break our Feb record of 35.7C for Mt Boyce. Its only a twelve year site though so the records are short-term. Some storms are now forming to my west, so we may not break 35.7 but it will be close.
The Katoomba site has 73 years of records for maxima and its Feb record stands at 36.6C. Its possible that record could go today but its under stronger threat tomorrow/Sunday. Katoomba's highest minimum record is 22.6 and Mt Boyce is 21.2 so keep an eye on things to see if these records are broken by 9am tomorrow. Night temps are going to be uncomfortable indeed for the the next two or three nights.
4-2-09, Wednesday 9am: Heat. Very serious heat looks to be on the way for the weekend. Blackheath could see it reach 35C over the weekend and western Sydney could see it move into the mid forties. It will gradually get hotter from this Thursday onwards as a tongue of very hot air slides this way.
1-2-09, Sunday 8am: Well, if you think it has been hotter this January than for a long time, you would be right! Just going on the shorter term obs from the Mt Boyce station, it was the hottest January in 12 years at 2.7C above the short term average for max temps. More details on other stations as information comes to hand. The prolonged heat that the upper mountains is experiencing should briefly back off just a touch this week but it will still be very warm and we could be in for some super heat by around Thursday/Friday that may break all-time records. There is a moderate chance of storms throughout the BM this week but nothing major at this stage.
22-1-09, Thursday 11am: 15.8mm overnight in Blackheath which is our 24 hour reading to 9am. Most of that fell from about 8pm to 9pm last night. Mt Boyce AWS missed out on most of the shower activity. The Strike One archive website shows that the cell formed quite suddenly on the southern flank of town and a nice, moist stream kept it going for some time. Its an important thing to remember when reading radars, storms can develop quickly and not really show up on radar until the last minute. This is where a deeper understanding of storms is important and not just relying on radar images. Decent potential is there for more storms later today, that could possibly be severe.
14-1-09, Wednesday 2pm: Spare a thought for our friends in Sydney (and various other spots in NSW) as the real heat hits today and tomorrow. Thursday especially could see the mercury hit 40C or higher in western Sydney whilst Blue Mountains folk should see it reach the low thirties. Fire danger is certainly a consideration across the Blue Mountains over the next two days so keep an eye on the RFS home page.
10-1-09, Saturday 9:15am: You may have heard Graham Creed on ABC TV (best TV weatherman, IMO) talking about the potential for severe storms over the weekend. Well, he is right. The trough should slide across central NSW today, bringing with it a moderate chance of severe storms in that area. By tomorrow, this trough should be edging its way towards the central ranges of NSW and has the potential to bring severe storms with it. The Blue Mountains certainly has a moderate chance of storms that could possibly be severe as we move into tomorrow.
Severe storms are those storms that produce hail stones of 2cm or larger, have winds around 90kph or above and can also produce flash flooding. Of course, all storms are potentially dangerous with the ever present risk of lightning strikes so be careful tomorrow. As is usually the case, these storms will be isolated or scattered so not every area will experience them and the same can be said for the risk of severe storms. Still, the potential is certainly there for some wild stuff as the day goes on. Bushwalkers and anyone planning outdoor activities tomorrow should keep an eye on the latest warnings.