Audi Hamilton Island Race Week day 1 weather

by Kenn Batt on 18 Aug 2012 Audi Hamilton Island Race Week day 1 weather from Kenn Batt.

Warnings: Nil Warnings current at time of issue.

Synoptic Discussion:

Latest surface analysis

A trough of low pressure will move through the area today.A high pressure system will move east from the Bight into SE Australia behind the trough, extending a ridge of high pressure over the region.

Observations:

At 0630hr the surface wind at Hamilton Island was 310 deg at 04kn, gusting 05kn (temp 17C, pressure 1017hPa) indicative of the synoptic wind. At Hardy Reef (further offshore at 19.7S 149.2E) the wind was 040deg at 4kn.

Forecast Winds for Surprise Rock (ReadDiscussion below)

0800:Mean dir 310d Dir range330-290dMeanSp: 07knGust:13kn
1100:Mean dir190d Dir range220-160dMeanSp: 10knGust15kn
1400:Mean dir080d Dir range120-060dMeanSp: 09knGust:13kn
1700:Mean dir070d Dir range110-050dMeanSp: 10kn Gust:14kn

Key:MeanDir: Mean wind directionDegrees True, DirRange: Wind directionrangeDegT ,MeanSp: mean wind speed in Knots, Gust: Maximum wind speedpossible in the 10secs leadinguptothehour in Knots.

Pretty good model agreement for today with a weak trough pushing through the area between 0900hr and 1100hr this morning. The resulting winds should be SW’ly going through the S to a SE to ENE’er.

There is a chance that the wind speeds could be 3-5kn stronger than above on the passage of the trough before easing.

An weak early to late afternoon sea breeze is possible via a glass-out?

A complicated day wind-wise by the look of it.

Wind may be channelled and hence a little stronger at times between islands and out of some bays. Winds may be lighter and more flicky in the lee of Islands and land masses generally?

Natural oscillations: around 20-40degand up to 80deg in the lee of land masses.

Weather:
Dry and mostly sunny.
Maximum land temperature at Hamilton Island: 22 degrees.

Wind Waves:
0.3 to 0.8metres, less in lee of land,more when wind wave opposes tidal current.
(Wave heights quoted are Significant wave heights).

Current: A weakening flood this morning then slack followed by a strong ebb this afternoon/evening. Be extremely careful in channels, etc.
Remember: Tide floods to the south and ebbs to the north in the Whitsundays (there are many localized variations so be alert).

Tide at Shute Harbour: Low of 0.60m at 0500hr, High of 2.84m at 1058hr and Low of 0.42m at 1645hr

Sea Temperature: about 19 degrees.

Outlook:
Sunday 19th: Cloudy with some light rain or showers. Max temp 21deg.
S-SE 14-17kn (ave) increasing to 15-22kn (ave) during the day.