Predicting Morning Offshores on the North Coast / SE QLD

Morning offshores are created by the differential in land and sea temperature.

Hot air rises, and during the early mornings along the East Coast the land temperature usually cools to a lower temperature than the adjacent sea water.

Therefore the air over the sea rises, and is replaced with cooler air in the form of a land breeze.

This becomes more common heading into the cooler months with the differential between the land and ocean water being larger, and also you need a weak synoptic flow along the coast.

Also due to the local topography around the Gold Coast, cool air also sinks down the mountains and towards the sea, helping to create an early offshore wind, generally from the SW.

Each location around the country has their own unique local affects which if known, can be used to your advantage in scoring little windows of clean waves during certain weather patterns.

Couldn't have said it better myself Craig. Just supplementing Craig's info above, particularly for SE Qld, you generally need overnight land temps to be at least 4 degrees lower than the adjacent sea surface temps and synoptic winds typically forecast to be less than 15-20knts, although as Craig has pointed out, this criteria can sometimes be over-ridden around the Cooly area due to adjacent landforms assisting with the land breeze effect.

The area north of Cape Moreton sometimes known as the Sunshine Coast also receives less and briefer periods of land breeze due to being positioned closer to the stronger area of the QLD ridge, particularly in the transition period of autumn to winter.

In Sydney, if the region is under the influence of a moderate synoptic southerly flow, there'll often be a marked difference north and south of Sydney Harbour. The Northern Beaches frequently see early W/SW winds (locally induced) whilst the gradient flow will prevail at Bondi, Maroubra and Cronulla. Not sure if it's the harbour that plays a direct role in this, but its a regular occurrence in my neck of the woods.

try working it out when the land inshore is actually a harbour. So many variables down here

Thelostclimber, Hobart is similar to the Torquay and even Victor Harbor region to a slightly lesser extent, in that when front after front pass over the state in the cooler months, winds are nearly always offshore from the W/NW during the early mornings.

The only real time you get a true onshore wind is if the cold front pushes across the state during the night before or early morning, and there's no follow up front to swing winds back to the west.

Forecasting for the region, I reckon there would only be a handfull of times when winds don't at least have some form of northerly component in them over the space of a year.

like this morning. Its onshore now, but was NW most of the morning. Nice groundswell to go with it, prediction was on the money today.
Funny though, I checked a few spots, and actually live on the harbour side of South Arm. One place can have howling winds whilst another has almost nothing.
Ask any local yachtsman, the winds around the Derwent do funny things. Mostly because of all the hills and valleys funnelling winds and changing their direction.

Can someone please explain to me how the wind is blowing WSW this morning when the BOM and all other websites predict the prevailing wind to be SE? - blah blah blah - the solution is a surf check but sometimes I can't be bothered....

By: "hambone"

Fuck. Me. Dead.

I don't know whether to laugh or cry.

Mate if you're a typical young bloke and the future of this country we truly are up shit creek in a howling onshore. If you're an old bastard just stay in bed you'll only get in the way.