Weather forecast for Wednesday 20th August - Day 5 of racing at 2008 Meridien Marinas Airlie Beach Race Week 2008.

Nil Warnings current.

Synoptic Discussion:
The trades certainly lived up to their reputation yesterday. What a day to be on the water, little wonder this area is known as Yachtie's paradise! Be extra careful again today, particularly on the smaller boats and even those bigger boats heading into the Whitsunday and Molle Channels.

The high currently over South Australia will continue to move east and reach New Zealand on Thursday. The high will maintain fresh to strong SE winds about the Qld coast into Friday when the winds will temporarily ease.

The next cold front will move into the state early on Thursday and then move off the coast Friday afternoon

Observations:

At 0600hr surface winds over the Airlie Beach area were out of the SSE averaging around 12-14 kn (synoptic wind plus land breeze) and the temperature was around 10deg. At Hamilton Island the wind was ESE'ly at 20kn gusting 24kn, (temp 17C, pressure 1023hPa) indicative of the synoptic flow aided by topographic forcing.

Forecast Winds for middle of Pioneer Bay (Read Discussion below)

1000:MD140 DR(160-120) MS17 SR13-22kn could be 2-4kn stronger?
1200:MD130 DR(150-110) MS19 SR14-25kn could be 2-4kn stronger?
1400:MD130 DR(150-110) MS18 SR13-25kn could be 2-4kn stronger?
1600:MD140 DR(160-120) MS16 SR12-23kn could be 2-4kn stronger?
1800:MD150 DR(170-130) MS14 SR10-20kn could be 2-3kn stronger?

Note 1: First column is mean wind direction in deg Mag (MD). It is the 10min average (mean) value at a height of 10m above the water leading up to the hour quoted. The second cloumn is the directional range (DR) of the wind direction in deg Mag. This takes into account the natural oscillation of the wind and is a function of the atmospheric stability, etc. The third column is the mean speed (MS) in knots (kn) and is the average 10min value leading up to the hour quoted at a height of 10m above the water. The last column is the wind speed range (SR) in knots and is the lowest wind speed to highest wind speed in the 10min leading up to forecast hour.

Discussion
The wind today will again be very much gradient (weather map) driven due to the firm ridge of high pressure along the coast. There maybe a slight sea breeze influence (direction reaching about 10-20deg more left than forecast above) in very close to the mainland?
Wind lighter in lee of any landmass and briefly stronger and gusty (read Bullets) due to convergence around some headlands.

Natural oscillations today around 15 to 25 deg away from effects of topography, tending around 20 to 50 deg closer to the effects of any land mass. Showers can produce short period gusty and erratic winds (temporary shifts up to 90deg).

Wind in Whitsunday & Molle Channels should be 3-5 stronger than forecast above and about 10-20deg more right?
Weather

Chance of a shower or two (see Discussion above). Take plenty of sunscreen and warm clothes.

Maximum land temperature at Airlie Beach: 21 degrees. Sea Temperature: about 21 degrees.

Wind Waves: 1.0 to 2.5metres Less in lee of land, more when wind wave opposes tidal current.
(Wave heights quoted are Significant wave heights).

Current: Big flood and ebb today. Be very careful particularly in the Channels.
Remember: Tide floods to the south and ebbs to the north in the Whitsundays.

Tide: Low of 0.65m at 0632hr, High of 2.78m at 1247hr and low of 0.87 at 1827hr.

Outlook
Thursday: Chance of shower. SW winds 5-10 knots at first becoming SE/ENE winds 8/14knots.

by Kenn Batt

Newsfeed supplied by