Mission Plan:
Primary Mission : N/a Alternate Mission: N/A Future Mission(s): Aircraft down through 0100 UTC 4 Dec (noon 4 Dec).Aircraft Operations
Take-off Time: Flight #21. N/A Pre-flight Weather Briefing Time: Flight #21: N/A Updates: 1100 LTD meeting 4 December Airborne Mission Scientist: Flight #20, Wang Mission Scientist: Flight #20, HuebertShip Operations
Discoverer: Discoverer located at approx 46 49'S 146 32'E at 0900 LDT 3 Dec (2200 UTC 2 Dec). They are now headed SW bound and will continue general westerly track to return to position for next experiment. Soundings have resumed the 6 hourly launch sequence. See catalog reference below for detailed instrument status. Discoverer Lead Scientist: Tim Bates Southern Surveyor: Southern Surveyor position at 1800 UTC 2 Dec is 46 49'S 150 35'E. They continue downwind along the Lagrangian track until 0200 UTC 3 Dec. and continue sampling. An attempt will be made to have an aircraft flyover of the Southern Surveyor during the third aircraft mission. Soundings are scheduled every 6 hours, if possible, through 0000 UTC 3 Dec. See catalog reference below for detailed instrument status. Southern Surveyor Lead Scientist: Bronte Tilbrook
48 hour MSL P Prognosis is here
72 hour MSL P Prognosis is here
Latest Visible Sat Picture is here
Surface Wind 24-h forecast is here
GASP trajectory analysis is here
Synoptic Situaton at 00Z Sunday 3/12/95:
Cold front near 40S 136E/50S 154E moving E at 30 knots north of 45S and southeastwards at 40 knots around 50S. Front forecast to be over eastern Tas/50S 160E at 12z tonight, however a small low may form on the front near 50S 150E.
Low about 980 hPa near 51S 138E moving E at 30 knots forecast to be 52S 145E at 12z tonight and E of the Ace area tomorrow.
Another front expected to form near 47S/130E/50S 145/E into low mentioned above, at 12z tonight. Front also likely to move E of ACE area tomorrow morning.
A 998 hPa low over the northern Bight forecast to move E'wards with another low forming in the front to be near 40S 150E at 00Z tomorrow.
Prognoses:
0-24 hours: The progs seem to be having difficulty with the complexity of the current situation, with an easterly dip over the continent around 130E likely to form a low over the southern part of Mainland Australia. Meanwhile, a significant cold outbreak occurring around the low to the far south is also expected to generate further lows and cold fronts, and the interaction between the easterly dip and the cold outbreak is likely to result in a major low forming close to or northeast of Tasmania during Monday and into Tuesday.
24-72 hours: In the wake of the cold outbreak, substantial ridging is forecast to take pace to the west of Tasmania. A 1022 hPa low is forecast to move into the area south of the Bight and extend a ridge SE'wards towards 50S 145E on Monday night, The high wll move only slowly eastwards and the ridge is expected to move across Tas on Tuesday. A weak cold front will push the ridge line northwards on Wednesday, but the front still only traverse the ACE area south of about 45S.
FORECASTS FOR THE REST OF SUNDAY AND MONDAY:
Cape Grim: Weather: Rain and showers with the chance of a thunderstorm this afternoon and evening, easing to occasional showers tomorrow. Wind: Turning south to southwesterly at 20/30 knots this afternoon, easing overnight then tending more southery tomorrow atnd restrengthening to 20/30 knots.
Macquarie Island: Weather: Showers and drizzle increasing for a period this afternoon and again tomorrow morning. Becoming colder tomorrow with the chance of some sleet or hail later in the day. Wind: North to northwesterly 20/30 knots easing briefly this evening before restrengthening ahead of a cold west to southwest change of similar strength around the middle of the day.
R/V Discoverer Weather: Showers increasing for a period this evening with the chance of some hail or even sleet overnight and tomorrow morning. Showers easing tomorrow afternoon. Wind: West to northwest winds 25/35 knots turning southwest to southerly overnight and gradually moderating to 15/20 knots during tomorrow. Stronger gusts and squaals possible tonight with the next front. Winds returning to the west late tomorrow and possibly increasing to 20/25 knots during the evening. 3 to 4 metre seas decreasing during tomorrow. Chiefly southwet swell 4 to 5 metres.
R/V Southern Surveyor Weather: Rain periods easing to showers this evening with showers then increasing for a period overnight. Showers easing tomorrow afternoon. Wind: West to northwest winds 25/35 knots turning southwest to southerly overnight and gradually moderating to 15/20 knots tomorrow morning. Stronger gusts and squaals possible tonight with the next front. 3 to 4 metre seas decreasing during tomorrow. Chiefly southwet swell 3 to 4 metres increasing to 4 to 5 metres overnight and tomorrow.
REVIEW OF PREVIOUS DAY's FORECASTS: Last night's front was a very weak feature with northwesterly winds only easing on both the Southern Surveyor and Discoverer, but not backing westerly as expected. Northwesterlies appear to be restrengthening now ahead of the next cold front, likely to be crossing the Discoverer's area now and the Southern Surveyor later this afternoon. Elsewhere, forecasts have held together well, with showers on the increase at both Cape Grim and Macquarie, although todays front is perhaps moving a little quicker than was anticipated.
Reporter: Barry Huebert
The Lagrangian experiment discussed in 1 December's Daily Summary has been completed. See 1 December's Scientific Issues and Discussionfor details.
Next Scientific Issues and Dissusion on 4 December.
