Forecast 2011 Meridien Marinas Airlie Beach Race Week Day 3

10:46 PM Sat 13 Aug 2011 GMT

'MMABRW Forecast Day 3' Bureau of Meteorology

Forecast 2011 Meridien Marinas Airlie Beach Race Week Day 3

Here is the latest.

Nil Warnings current.

Synoptic Discussion:
A high south of Tasmania extends a ridge along the Queensland coast. The high is expected to drift slowly east over the next few days.

Latest surface analysis

Observations:

At 0630hr Hamilton Island was reporting the following conditions: Wind 130deg at 9kn gusting to 10kn, Temp 18C, Pressure 1020hPa).

Light SW land breezes were observed at coastal mainland places. Some weak shower cells were observed well offshore.

Forecast Winds for Middle of Pioneer Bay (Read Discussion below).

1000:MD140 DR(160-120) MS10 SR05-14kn, 2kn stronger further offshore?

1200:MD130 DR(150-110) MS12 SR08-16kn, 2kn stronger further offshore?

1400:MD120 DR(140-100) MS13 SR09-17kn, 2kn stronger further offshore?

1600:MD110 DR(130-090) MS14 SR10-18kn, 2kn stronger further offshore?

1800:MD120 DR(140-100) MS14 SR09-18kn, 2kn stronger further offshore?

Whitsunday Passage and Molle Channel: Wind speeds 2 to 3 kn stronger at times than those above, but more gusty at times, particularly around some headlands and in more constrained locations. Wind direction could be 10-20deg more left than above at times.

Team Vodafone heads for home - Meridien Marinas Airlie Beach 22nd Annual Race Week 2011 - Teri Dodds - copyright

Key to wind forecast: First column is forecast mean wind direction in deg Magnetic (MD). It is the 10min average (mean) value at a height of 10m above the water leading up to the hour quoted. The second column 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 ridge of high pressure over the Qld coast is still strengthening. The shower activity further offshore is a sign of this.
So again the big questions today are (hopefully answered in forecast above??):
1. How far left will the surface direction get?
2. How quickly will the direction turn left?
3. How strong will the winds be?

In this situation we normally experience slightly stronger winds further offshore and at times in the Whitsunday Passage and Molle Channel.
The sea state should also be higher further offshore than closer to the coast.
Note: Wind will be lighter in the lee of any landmass and stronger and more gusty between islands (in channels and passages) and around some headlands.

Natural wind oscillations today around 15 to 20 deg away from effects of topography, tending 30 to 50 deg closer to the effects of any land mass.

Other possibilities
60% chance that the wind speeds build to be about 2-3kn stronger than forecast strength during your race period. In this case max left direction will be 120deg?

35% chance that wind drops out this morning and a 8-12kn E-NE sea breeze develops late morning/early afternoon??
Weather
Remaining fine. Some cloud and shower activity further seawards.
Maximum land temperature at Airlie Beach: about 23 degrees.

Wind Waves:
0.5 to 1.5metres, less in lee of land, more when wind wave opposes tidal current and further offshore depending on fetch.
(Wave heights quoted are significant wave heights).

Tide at Shute Harbour: High of 2.73m at 10585hr and Low of 0.52m at 1640hr.

Tidal Stream: A good ebb this afternoon. Be very careful particularly in the passages, channels, close to islands, etc.
Remember: Tide floods to the south and ebbs to the north in the Whitsundays.

Sea Temperature: 20-21 degrees.

Outlook
Tuesday: Similar.

by Meridien Marinas Airlie Beach Race Week media