yes a friend told me the same thing a few years ago . and does seem to happen , not that i have done an exhaustive study or anything


but tonight the change came in around 1700 hrs and high water is about now . So coincided with the full flood 3hrs before the high water ......

MorningBird said..

madmission said..
May be of some interest to southern victorians

Some time ago an Bass strait fisherman outlined to me his observation on the relationship between the passage of cold front / depressions and the tides through the central strait and otway region.

He suggested that the passage of any front will be slowed until such time as the tide changes and begins its way in.
Has anyone else heard of this relationship ?

Being resident in high risk fire zone on days such as these , total fire ban with fire weather warning , it is useful to look to such phenomena to assist in planning

It seems that today the theory may hold some truth tide is to chain at warrnambool around midday and already it seems the change is moving through as it happens.

As a further aside being a PPB sailer , wind changes often accompany tide changes on the bay , as learnt from my father and his experience.

A theory instructor tried to put a similar view about tides and high pressure systems in Sydney Harbour. It was rubbish.

I suspect this Bass Strait view is also rubbish. A front maybe 1000nm long and with massive pressure differentials is affected by a 1.5 metre tidal difference over an area of 10s of nm!!! But the people to ask are the meteorologists who cover Bass Strait. Give em a call.

3.000 mt range here

I too was skeptical and cannot say that i have identified a relationship through any observation.

As i have limited sailing experience in bass strait and being a rural resident on the edge of the otway national park my interest is more driven by the implications associated with catastrophic fire weather and the approaching and passing of cold fronts through out the danger period , although a bit off topic on a sailing forum nonetheless useful observations do cross over pursuits

I thought i might watch today as we are experiencing a meandering low along the coast and through western to central bass strait which may be weak enough to be influenced by some phenomena .
With a midday tide change it suited my desire to see early relief from any potential fire hazard….wishful thinking

Over may years and catastrophic fire events in the state i have noted that generally the passage of the fronts do seem to occur far earlier (regardless of tide) in the southwest often not reaching north of melbourne anywhere unto 7 hours later and probably over a distance less than 100 NM's

I plan to do more sailing out of Apollo Bay and will take note of the observations regarding this discussion in planning such trips just in case.

While on the subject of weather phenomena in southern Victoria , i found this article in 2010 on Weather on the Bay and was so glad its still accessible so as i dont have to reproduce it and cause any copyright issues
www.mysailing.com.au/news/weather-on-the-bay

following on from Madmissions info on weather around the rip, this may be of interest to those sailing on Port Phillip and Corio bays, and explains some of the reasons for the varying conditions.
Taken from the Royal Geelong website for Festival of Sail regatta on this weekend: (sorry for the formatting)

SUMMER ON THE BAY by Kenn Batt, Bureau of Meteorology
Port Phillip (The Bay) is a place that one can love one day and really hate the next (just like Bass Strait). The Bay is a large area (approximately 187,800 hectares) enclosed on all sides by land except for its southern parts where the Rip (Port Phillip Heads) opens into Bass Strait. The distance from the northern tip of the Bay to its southern tip is about 60km and its width (west to east) is about 65km. Being situated where it is, Port Phillip comes under the influence of the seasonal changes in weather that one would expect in the middle latitudes of the Southern Hemisphere. But even in the summer months a lot of people, including locals, will say that Victoria can generally experience those four seasons in one day. Having said this let’s now have a look at a fairly typical summer over Port Phillip. Type 1: Highs to the west When a high pressure system remains over the Great Australian Bight or over northern Victoria, a west to south-westerly, sometimes southerly, airstream is maintained over the Bay. If a cold front moves over the state in this broad westerly stream then the surface winds will back from the west to the south-west with the passage of the system.
A sea breeze may reinforce any southerly flow in the above situation over the Bay. This is more noticeable over northern Port Phillip, where a light southerly is reinforced by a fresh sea breeze in the afternoon and evening to produce choppy to rough conditions on the Bay.
Type 2: Highs to the south of Victoria After the passage of a cold front, a high pressure system may quickly move eastwards and strengthen (not always) to the south of Tasmania. Under this regime a fresh east to south-easterly stream can be established over Bass Strait. Port Phillip winds can be complex during this situation, depending on the strength of the east to southeast stream. During the morning light to moderate winds are common over the northern end of the Bay while fresh to strong easterlies prevail in the south due to funnelling through the Latrobe Valley. As the day progresses the winds over the northern end freshen as a result of the sea breeze component reinforcing the south-easterly wind. These winds tend to die out overnight though. If the high is strong, the east to southeast winds can be fresh throughout the Bay all day and strong into the evening.
Type 3: Highs to the east of Victoria When a high pressure system is located between Tasmania and New Zealand (very common during the summer months), it can become a dominant influence over the state. Winds are generally light to moderate north to north-easterly, with the chance of afternoon sea breezes on the Bay. The north to northeasters tend to be strongest during the mid to late morning and lightest during the afternoon.
If the position of the high is north of Bass Strait, then sea breezes would be dominant.

Type 4: Highs over Bass Strait This situation would produce generally light winds over Victorian waters except where sea breezes reinforce the prevailing wind to produce a moderate to fresh wind about the east coast.
Type 5: Passage of a single cold front The approach of a single cold front between highs is usually associated with a low to the south of Tasmania. Gale force winds may be associated with the passage of the front but these are generally only short-lived.

SEA BREEZE
The sea breeze is a very important feature of the summer winds affecting The Bay. There are two main features that influence the development of the sea breeze on Port Phillip. The first is the fact that The Bay is an extensive, almost land-locked, body of water. This means that local heating of the land initially creates sea breezes all around its edges, blowing from the water to the land. Therefore the ‘Bay Breeze’ blows in different directions, depending on where you are around the Bay The second feature is Bass Strait. This produces a stronger, longer-lasting sea breeze from the south which takes more time to develop than the more localised Bay breezes. The Bass Strait sea breeze (ocean sea breeze) interacts with, and finally dominates (but not always), the Bay breezes in the early afternoon through to early evening. The direction of the ocean sea breeze usually turns more into the southeast over the afternoon/early evening, especially over eastern parts. LOCAL CONDITIONS
It is fairly well known amongst local yachties that often the northern half of the Bay experiences different conditions to the southern half. Most of these differences can be explained by the local topography and in the case of the southern half, the close proximity of Bass Strait. Some examples of the effects of local topography on wind flows have been mentioned above. Others include the following: In southern parts: Winds tend to be funnelled between Mt Martha and Arthur’s Seat (near Dromana) in the southeast and near Point Henry on Corio Bay (Geelong) in the southwest. The sea breeze on Corio Bay and on Port Phillip generally, can be relied upon to strengthen to a maximum at around 1500 hours in the afternoon. The sea breeze will turn to be a southeaster during the late afternoon in eastern parts of the Bay, particularly between Mornington and Portsea. In northern parts: Wind tends to bend around the northern shores and it very often pays to “hit” the shore to sail into a “knock” and be lifted on the opposite tack. In a typical sea breeze situation, depending on your race area, it normally pays to sail your starboard tack first and be “lifted” on port heading west. In a northerly, there can be more wind north of Ricketts Point (Beaumaris) and less in the south. In the middle of the Bay: Often in a developing wind situation, there is a “No Persons Land” south of the Fawkner Beacon as the wind tends to build from the respective shores first. The Werribee shore is an area where there tends to be more “pressure” more often than not. Keep those eyes open. Another influence to bear in mind is that of tidal current. In particular those in the south near the Heads (the maximum tidal current here is about 8 knots) and in the north, adjacent to the Yarra River. The state of the tidal flow can have an influence on both the wind speed and direction and of course your leeway. Shipping movements can have a very marked effect on racing fleets on the Bay. So always keep a lookout and give yourself sufficient time to manoeuvre away from any shipping.

WEATHER PROBLEMS
Some nasty weather problems at this time of the year may be: Weather situations with strong surface pressure gradients (close isobars) may bring winds of 40 knots or more to The Bay. Wind squalls can occur on intense cold fronts. Gale force easterly winds can occur overnight on the Mornington Peninsula, extending north to Melbourne’s southern suburbs, when a high pressure system passes to the south over Tasmania. In this situation there may be gales in Bass Strait, but the strength of the wind on the Peninsula may be due to a broad-scale gully wind effect. Thunderstorms can pose problems. An east coast low, although rare at this time of the year, may create havoc over the Bay.

SUMMARY In summary we can say the following: Whilst there are some local knowledge advantages, the weather on Port Phillip is fairly predictable. Cloud movements, particularly from the west, can indicate the approach of a cold
front Use shoreline indicators, such as chimney smoke plumes, ships at anchor, etc. to give you a picture of the wind direction field and how it could be changing. It pays to consider the proximity of shorelines and also the fact that the weather (wind) conditions can be very different from north to south. The sea breeze on Port Phillip can be very complex. Corio and Port Phillip Bays can be very challenging places to sail. DO YOUR HOMEWORK. Many thanks to Rowan Simpson and Lou Abrahams for allowing me to use some of their abundant local knowledge.

western port gets a really good SE seabreeze in the summer arvos . usually a warm day with light nth wind or no wind . As i understand it , as the land heat up in the nth ,the air rises fast and sucks the air in from the sea . this comes in the after noon around 2 ish on a hot day .