The Parting of the Storms

Legs Akimbo

Grumblebum
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Mar 3, 1999
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I live at Port Stephens, a decent sized body of water a couple of hundred ks north of Sydney. For a while I have been watching storms track towards me As they get near the Port they fizzle out and I get only a few drops of rain. 2 have done it today, and it is a fairly regular event. Obviously some hit but the rate of fizzling is significant.

Am I dreaming with some sort of confirmation bias, or is there some mechanism that diverts storms around water bodies or defuses them? If it is real, what's going on? I'd be surprised if it's some temperature differential effect as the ocean is only about 5 km away, but anything is possible. The terrain is flat for a few 10s of kilometres in all directions.
 

Belly

Part of the Furniture
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Oct 22, 2003
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As a more than occasional visitor over many years I'd say there is some sort of topographic steering influence or diffusion type effect happening from the west. I observe similar on the south coast where in some parts the topography runs closer to ocean (more storms) versus where there are extended flat sections (less storms).
In summary I reckon Port Stephens does ok for rainfall out of bog standard southerly changes and easterly coastal drizzle but only occasionally do W-NW storms hit.
 
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Steve777

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My two cents’ worth, an accurate valuation?

The sea breeze often kills storms, interposing a layer of cooler, stable air between the ground and any convection. Also, from what I can see, storms tend to favour higher ground.

I’m not familiar with the Port Stephens area, but in Sydney it’s common to see storms develop on the Tablelands, move Eastwards and fall apart in Sydney’s outer West (which is near sea level). Sometimes they get closer to the coast to get done in by the sea breeze. Sometimes you see storms jump over Sydney, redeveloping out to sea.

Storms seem to do better on the Illawarra and Central Coast, maybe because there is high ground (300 metres+) close to the coast.

It’s all determined by the complex 3-dimensional dynamics of the atmosphere and its interaction with land and sea - all beyond me.
 

piolet

Better make it three
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May 27, 2004
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My two cents’ worth, an accurate valuation?

The sea breeze often kills storms, interposing a layer of cooler, stable air between the ground and any convection. Also, from what I can see, storms tend to favour higher ground.

I’m not familiar with the Port Stephens area, but in Sydney it’s common to see storms develop on the Tablelands, move Eastwards and fall apart in Sydney’s outer West (which is near sea level). Sometimes they get closer to the coast to get done in by the sea breeze. Sometimes you see storms jump over Sydney, redeveloping out to sea.

Storms seem to do better on the Illawarra and Central Coast, maybe because there is high ground (300 metres+) close to the coast.

It’s all determined by the complex 3-dimensional dynamics of the atmosphere and its interaction with land and sea - all beyond me.
Certainly did that tonight.
 

Eddy

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Jul 4, 2019
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Port Stephens
I know how you feel Legs Akimbo, happens frequently enough, but in saying that we do get our fair share of beauties.
The last few years storms have been ordinary around here, but imo this year is one of the better ones for storm activity even if they have split south or north of us or even died on our footsteps there still have been some great structure and lightning displays.
I captured these images from the 17th
From memory they came from more of a WNW direction.
Early development.
IMG_2580 by Eddy Groot, on Flickr
Getting organised
IMG_2614 by Eddy Groot, on Flickr

IMG_2640 by Eddy Groot, on Flickr

IMG_2654 by Eddy Groot, on Flickr

Certainly nothing severe about this storm, although I wouldn't be surprised of falls of 30-50mm west of town, I received about 20mm, also from memory there were storms the following day but they mainly affected north of the Port, Bulahdelah, Myall lakes into Forster area.

Plenty of nice images coming out from this morning's storm around 4am, no images from me unfortunately, too many beers from the previous night, wasn't going to risk my license.
 
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Joshua Randazzo

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Jan 1, 2021
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My two cents’ worth, an accurate valuation?

The sea breeze often kills storms, interposing a layer of cooler, stable air between the ground and any convection. Also, from what I can see, storms tend to favour higher ground.

I’m not familiar with the Port Stephens area, but in Sydney it’s common to see storms develop on the Tablelands, move Eastwards and fall apart in Sydney’s outer West (which is near sea level). Sometimes they get closer to the coast to get done in by the sea breeze. Sometimes you see storms jump over Sydney, redeveloping out to sea.

Storms seem to do better on the Illawarra and Central Coast, maybe because there is high ground (300 metres+) close to the coast.

It’s all determined by the complex 3-dimensional dynamics of the atmosphere and its interaction with land and sea - all beyond me.


since you said sea breeze kills storms... just have to mention this: the great Sydney hailstorm of 1947 was fuelled by the north east sea breeze. yes the sea breeze can kill storms but on some days like on new year's day 1947 it can intensify storms and increases rotation.

The story of the 1947 sydney supercell: on new year's day 1947 a storm cell formed in the morning over blue mountains hitting the city and eastern suburbs at around 2:30pm. this storm was a freak of nature due to the size of the hail that fell on sydney's eastern beaches.
people sunbathing at bondi beach were subjected to hail larger than 8cm and a ww2 veteran described the event like he was in the firing line over seas.

The High humidity of the day and sydney weather patterns increased the strength of the storm with the bom noting how the storm had a very peculiar formotion over liverpool
The Storm type was a classic supercell.
1947_Sydney_hailstorm_boat.jpg

Giant hail mashing down in the water at rose bay in sydney's eastern suburbs.

tis supercell was most intense over the eastern suburbs of sydney which is rare.
 
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Schnaxxy Schnaxxlburger

but a dream within a dream
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some years ago I lived at Gladesville
Sydney persons would know that the three bridges there cross over the Parramatta River, Tarban Creek and Lane Cove River
driving home over the big bridge in the afternoon, there were often clear differences between the weather on the Drummoyne side and where I was headed on the Gladesville side, as well as leading up to the Lane Cove area
most commonly it was rain on one side, no rain on the other
I attributed this to the influence of the rivers and the creek - not having the slightest idea why it would happen
 

Joshua Randazzo

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Jan 1, 2021
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near sydney CBD.
My two cents’ worth, an accurate valuation?

The sea breeze often kills storms, interposing a layer of cooler, stable air between the ground and any convection. Also, from what I can see, storms tend to favour higher ground.

I’m not familiar with the Port Stephens area, but in Sydney it’s common to see storms develop on the Tablelands, move Eastwards and fall apart in Sydney’s outer West (which is near sea level). Sometimes they get closer to the coast to get done in by the sea breeze. Sometimes you see storms jump over Sydney, redeveloping out to sea.

Storms seem to do better on the Illawarra and Central Coast, maybe because there is high ground (300 metres+) close to the coast.

It’s all determined by the complex 3-dimensional dynamics of the atmosphere and its interaction with land and sea - all beyond me.
if sea breezes kill storms then what happened on new years day 1947? GREAT SYDNEY HAILSTORM EASTERN SYDNEY HARDEST HIT HUNDREDS INJURED BONDI BEACH. there was a moderate north east sea breeze on that day and i don't agree with when you said the storm just slid right over the top. if it slid right over the top if would of stayed the same strength not intensify.

here's what karl
Lijnders had to say:

If the seabreeze is running into a very strong outflow boundary off the ranges and you have a trough overhead and deep instability, then the seabreeze can enhance storm activity.

the breaking of the cap also help as well.

no ill intent in this message
 
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Schnaxxy Schnaxxlburger

but a dream within a dream
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when I lived at Gladesville, driving over the big bridge - actually two bridges - it was very clear when viewed from the top that weather systems were different on either side of the Parramatta River, as well as some variation between the bits on either side of the Lane Cove River
so I reckon that water has an effect
 

Ian D

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It is to do with the Hunter Valley I believe. The storms track around the mountains, we often get storms to the north and to the south on either side of the Valley but not down near the coastal side of things. Storms will happily track across the Valley floor but the entire Lake Macquarie to Port Stephens area often misses the worst ones (not always but usually).

It is not at all uncommon to see a southerly running up from the SW and split at the southern end of Lake Mac just past Gosford/Hawksbury and track west of the city through Maitland area and re-emerge on the coast near Karuah or Buladelah with the other half heading off to sea and East of Newcastle/Port Stephens.
 

Steve777

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if sea breezes kill storms then what happened on new years day 1947? GREAT SYDNEY HAILSTORM EASTERN SYDNEY HARDEST HIT HUNDREDS INJURED BONDI BEACH. there was a moderate north east sea breeze on that day and i don't agree with when you said the storm just slid right over the top. if it slid right over the top if would of stayed the same strength not intensify.

here's what karl
Lijnders had to say:

If the seabreeze is running into a very strong outflow boundary off the ranges and you have a trough overhead and deep instability, then the seabreeze can enhance storm activity.

the breaking of the cap also help as well.

no ill intent in this message
No ill intent assumed, just discussing the weather

The dynamics of storms are complex and many here understand them far better than me. Sea breezes do seem to mostly put a dampener on storms but it’s no hard and fast rule. Then you get NE’ers which aren’t sea breezes like we had last week - deep tropical maritime air. The dynamics are completely different. Often storms form inside the Sydney Basin and they can be very powerful. I think that April 1999 was an example. And sometimes a powerful storm can ride right over the top of a sea breeze or Southerly.
 
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Richard

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Mar 14, 1995
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I live at Port Stephens, a decent sized body of water a couple of hundred ks north of Sydney. For a while I have been watching storms track towards me As they get near the Port they fizzle out and I get only a few drops of rain. 2 have done it today, and it is a fairly regular event. Obviously some hit but the rate of fizzling is significant.

Am I dreaming with some sort of confirmation bias, or is there some mechanism that diverts storms around water bodies or defuses them? If it is real, what's going on? I'd be surprised if it's some temperature differential effect as the ocean is only about 5 km away, but anything is possible. The terrain is flat for a few 10s of kilometres in all directions.
Late to party

However. When I was young I lived up on the ridge east behind Charlestown for a couple of years during high school - but my high school was in Hamilton (approx 8km north of Charlestown and in the dead flats behind bar beach) and so we got driven to school.

The outrageous number of times light rain would be falling steadily in Charlestown and be bone dry in the flats of Hamilton when we got to school, never to get wet - was clearly a pattern and no mistaken observation. The light rains from the south east would always push round the western side of the ridge (following Charlestown Rd via John Hunter).

These patterns were observable and repeated.

I’ve no doubt that what you are observing are indeed repeating super-local climate patterns.

At a guess, temp and air pressure differences over the body of Port Stephen’s waters creates a protective dome diffusing already weaking storms from the south.

(+ what Ian said)

Either that or it’s the new 5G towers secretly controlling the weather.
 
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