Farm Weather South Australia

Special Update SA cold front and low with rain, showers and isolated thunderstorms June 21st-22nd 2023 G’Day everyone, thought I’d whip out a special update as promised for this next system as it is still looking significant with a two pronged event which should give very handy totals to most districts and that is before the stronger front due a few days after (I’ll issue another update for that as it is quite dynamic atm and hard to pin down the synoptic shape) Meteorological Discussion: Cutting to the chase here and currently we have a strong upper-level trough standing up over the Bight which is squeezing the jetstream to the north of it. This jetstream has been actively feeding down mid-level moisture for a number of days now and is responsible for the cloudband that we are seeing over the inland of the country. At the surface a cold front is also providing a focal point for lift and that will be a focus for most of the precipitation on Thursday 22nd. Figure1: GFS 300hPa (30,000ft)...

June 2023 update SA *Forecast prepared between June 15th-17th 2023 Review: G’Day everyone, hope you are keeping well as we pass the mid-June mark and I have to say it’s had almost the kitchen sink apart from snow in there first 2 weeks. Record warm, strong fronts, severe thunderstorms, record large hail for June, tornadoes, large swells, squally SW winds, coastal erosion, and localised flooding. All can be attributed to an active Longwave Trough sitting right in our window enhanced by a negative Southern Annular Mode (SAM). Firstly, the very warm start to the month was right up there in terms of climatological records, with numerous sites breaking all time June records. I also cannot recall the last time when we had 20C temperatures here in Adelaide at Midnight and noticed this on two occasions with warm NE to N winds advecting warmth from well inland. This warmth was mostly driven by a very strong ridge extending north up the eastern seaboard into the Coral Sea and it did not move. Th...

Special Update SA Strong trough & cold front with severe thunderstorms June 6-7th 2023 G’Day one and all, hope you are keeping well on this beautiful sunny and mild Tuesday, a marked difference from what will be occurring this time tomorrow in some areas. Thought I’d whip this one out today to refine some thoughts on the system that is due. Whilst the broad gist of it has not changed, the position, timing and rainfall has, and I will explain all in the next section Meteorological Discussion: In short, a large powerful upper trough is advancing eastwards spun off from an active node of the Longwave Trough south of WA. Aloft this will cause the polar and subtropical jetstreams to meet over SA generating what is termed a ‘jet streak’ or ‘speed max’ over the interior where the strongest core winds of the jetstream is located. The squeeze of the upper trough pushing NE hard whilst over Cape York Peninsula we have a large equatorial upper-level ridge pushing back the other way. (Please s...

June 2023 outlook SA *Forecast prepared between May 31st-June 3rd 2023 Review: G’Day everyone, I hope you are all keeping well - time for the June outlook as we approach the halfway mark of 2023 already which feels like it has come on as quick as ever, I have to say. Now May was quite the month, a bit of yin and yang about it with a moist start, large dry middle and fairly wet finish, especially in those areas that were under streams and on windward slopes where orographic lift was the primary driver of increased precipitation. The two main points to review from May were the expected dry period with dominant high pressure and then the frontal barrage to finish. The dry spell caused by the repeat high pressure saw the highest value of the SAM recorded since measurements began and although this was a brief spike, the overall pattern saw a positive trend held for many weeks with multiple 1030-1039hPa centres recorded and an overall above average pressure anomaly for the month. Taking Rose...