Mission Plan:
Primary Mission : No flight operation are planned for 6 Dec. Alternate Mission: N/A Future Mission(s): Potential Lagrangian conditions late Thursday and Friday (7-8 Dec)Aircraft Operations
Take-off Time: N/A Pre-flight Weather Briefing Time: N/A Updates: N/A Airborne Mission Scientist: N/A Mission Scientist: N/AShip Operations
Discoverer: Discoverer located at approx 41 18'S 139 57'E at 1200 LDT5 Dec (0100 UTC 5Dec). They are now conducting a survey of conditions in the vicinity of 42S. There is an ocean temperature front in this area that shows higher DMS concentrations on the warm (north) side. The ship will be working an intercomparison in the afternoon with C130. 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 0000 UTC 4 Dec is 46 43'S 150E. They are continuing a 30 hour process station at this location. Soundings will continue every 12 hours. 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 Tuesday 5/12/95:
High 1022 hPa near 38S 127E extends a ridge southeast towards 45S 140E/50S 160E moving E at 15 knots. High forecast to be near 35S 135E at 00z tomorrow with the ridge extending across Tas to another high near South Island NZ, with little movement eastwards for the remainder of tomorrow.
Cold front near 45S 115E/ 50S 122E/55S 138E moving E at 35/45knots, forecast to be near 43S 130E/50S 144E/54S 150E at 00z tomorrow and near 47S 150E/55S 157E/60S 156E at 12z tomorrow night. Front to cross Macquarie an hour or two later.
Prognoses:
0-24 hours: The high over the Bight and the ridge near Tas are forecast to track only very slowly eastwards, pushing the next front southwards as it moves into the ACE area tomorrow. Cirrus from the front is expected to (and is already) moving over the stratocumulus field, restricting opportunities for a SC experiment near TAS tomorrow. In the meantime, a low is forecast to develop to the northeast of Tas off the New South Wales coast and deepen as it moves southeastwards across the Tasman. This is likely to generate a lot of cloud east of Tasmania.
24-72 hours: The high over the eastern Bight will weaken as the front moves past tomorrow night, then redevelop a ridge across Tas on Thursday. Another front is forecast to move through the southern ACE area on Thursday night with a weak ridge following. This may prove to be an opportunity for the start of a Lagrangian experiment, although time will tell as to whether there will be sufficient clear air in its wake for a release. On Friday, a significant ridge forms east of Tasmania, and if the balloons can be released into the ridge, they will move only slowly through the Tasman Sea.
FORECASTS FOR TONIGHT AND WEDNESDAY:
Cape Grim: Weather: The chnce of a shower or two tomorrow night otherwise fine. Wind: South to southeast winds 15/20 knots easing to 10/15 knots overnight but restrengthening to 15/20 knots tomorrow afternoon. Winds tending south to southwesterly during the afternoon and evening.
Macquarie Island: Weather: Some light showers or drizzle redeveloping shortly and increasing to rain tomorrow morning as the front approaches. Wind: Northwest winds 20/30 knots possibly reaching 30/40 knots for a period this evening and again later tomorrow.
R/V Discoverer Weather: Fine until some drizzle or light rain develops tomorrow afternoon. (Earlier if you move southeastwards from you current position.) Wind: Chiefly south to southwest winds 5/15 knots gradually tending west to northwesterly overnight. Winds freshening to 15/25 knots tomorrow ahead of a late 15/20 knot west to southwest change. Seas to 1 metre rising to 2 to 3 metres tomorrow ahead of the change. West to southwest swell mostly around 2 metres.
R/V Southern Surveyor Weather: Remaining fine while you stay close to the ridge axis. Wind: Light winds, chiefly south to southwesterly, below 15 knots, turning west to northwesterly overnight and increasing to 15/20 knots tomorrow, possibly 25 knots if you are still south of 45S. A late 15/20 knot west to southwest change. Seas to 1 metre rising to 2 to 3 metres tomorrow ahead of the change if you are S of 45S. West to southwest swell 2 to 3 metres.
REVIEW OF PREVIOUS DAY's FORECASTS:
The situation has unfolded much as was forecast. Macquarie Island got a burst of snow overnight in the wake of the front, but winds and showers moderated quickly and the winds have already turned northwesterly again ahead of the next front. The cloud free area forecast for around the Discoverer has eventuated today, but not before part of this morning's mission was affected by some gravity wave activity. The waves traversed the ACE area very rapidly and tended to destabilise the SC field, particularly where they were coincident with the thermal trough just to the west of Tasmania. The C-130 reported a very rapid increase in the boundary layer as one of the waves passed, but managed to finish the stack and move a mere 50 Nm westwards to another clear area, where they were able to complete another stack successfully. The waves appeared to emminate from the approaching front to the southwest, but also from the trough activity over eastern Australia. Winds have been close to those forecast for all the platforms, with perhaps the exception of the Southern Surveyor where they have been a little lighter than forecast in the centre of the ridge.
Reporter: Barry Huebert
N/A
