The severe south-westerly gales Wellington experienced yesterday were just a foretaste of a series of, tropical origin, extreme weather events forecast for NZ over the coming 16 days.
Here is a wider angle view showing the atmospheric river set up of NZ's climate as the ICTZ (monsoon belt) is moving south for summer.
1. Warm wet air comes in from the north heading south east. 2. Cold air comes in from the south heading north west.
The storm currently affecting NZ contains a combination of warm and cold streams merging south east of NZ and curling back around to target NZ from the South West. This set up is similar to the severe easterly Canterbury Gales back in May.
The next two animations are precipitable water simulations. Atmospheric water, because it has mass, is at the core of the global physics simulations that power modern weather forecasting.
Here we have the Australian ACG simulation for the coming 10 days.
In the first few frames we see what is shown in the satellite imagery earlier in the thread. With a combined stream of wet and cold air hitting NZ from the south west.
Meanwhile over Indonesia/Oz we see the source of the next tropical atmospheric rivers which are forecast.
In the ACG (Access G) simulation the next atmospheric river is due to arrive on Saturday around midnight and sweep up the west coast through Monday evening. This rain event is similar to the West Coast flooding event which caused massive damage to Westport in August.
The third atmospheric river is the largest and hasn't quite arrived at the time this 10 day forecast ends on midday October 23.
From what we saw during 2021 we know large atmospheric rivers are damaging. Fortunately for NZ there is usually plenty of warning in the forecasts.
This second long range forecast is from the global U.S @NOAA GFS model. It's different in details, but similar in impact & timing.
[Correction: Here's the missing picture from the ACG model of the the third anticipated tropical atmospheric river - which is forecast to arrive shortly after October 23rd.]
@NOAA Here's the next storm about to arrive on Saturday afternoon, October 16th, and then leaving late on Monday October 18th after sweeping up the entire NZ West Coast.
@NOAA And as the GFS model is longer range [16 days] we can also see a forecast prediction for the third and probably largest atmospheric river, and consequently extreme rainfall event. which is forecast to begin around Oct. 23 - and persists in this forecast till at least Oct. 29
@NOAA And as you can see there it is possible that there is a fourth extreme rainfall event following fairly swiftly behind that one.
Regarding the reliability of these forecasts:
While forecasts of local weather events over four or five days out (especially rain) are not reliable. Large scale events like these [provided they are not affected by cyclones] are now remarkably accurate.
We have two additional global simulation models we can reference for these long range predictions. Canada's CMC and the EU's ECMWF models.
Forecasts for the beginning and end of the Oct 16th event: 1. ECMWF (start) 2. (finish) 3. CMC (start) 4. (finish)
Forecasts for the beginning and end of the Oct 23rd event: 1. CMC. October 22nd (setup)
3.ECMWF. Ocober 23rd (setup)
While the models differ on the precise nature of this event, all of them look fairly dangerous from a flooding potential.
The MetService's Severe Weather outlook (metservice.com/warnings/sever…) is warning about this coming weekend's severe weather. But 23rd-29th Oct. event is not yet on the radar, and possibly should be. Then people can prepare & for example not plan holidays.
But the bigger question posed by this, in the run up to COP26, is the extent to which NZ is prepared for and budgeting for Climate Change adaptation measures.
While 2021 has certainly been special in some respects, particularly wrt the scale and consistency of extreme/unusual weather events across the northern hemisphere, that consistency points to climate change rather than random chance, & the trajectory for warming remains upwards.
There are signs that ENSO is moving into a drier La Nina pattern, and it is possible that these forecast storms are a reminder and not indicative of what we should expect this NZ summer, but that is also no reason for complacency.
1000s of people have been killed this year from extreme rain events all over the globe. And 100s of billions of damage has been done to housing/infrastructure - especially in East Asia.
NZ needs to start taking the threat posed by a wetter southern hemisphere seriously.
It would be nice if climate change for NZ was just a matter of accounting for emissions and negotiating with stakeholders about the transition, but it clearly is not that simple. Climate Change is here now and as @antonioguterres says we all need to wake up.
THREAD: Some thoughts on October 7th and the importance of their being global transparency over what we know about what really happened on that terrible day.
1/ This (see screenshots in the first few posts in this thread) is one of the most important pieces of conflict related journalism published in recent years.
It relates to the orders given to soldiers on October 7th to fire on any vehicle seeking to return to the Gaza Strip to prevent the taking of hostages and was published on July 7th, 10 months later in Haaretz.
2/ As @IsraeliPM Benjamin Netanyahu prepares to address congress it is vital that the public in the US, Israel and globally is fully aware of what exactly happened on October 7th in Gaza.
3/ The account in this story published by Haaretz is at this time still behind a paywall and it has therefore not been read by the very large number of people who ought to have done so. I have not seen very many reports containing the detail of this report elsewhere though I presume there are many.
OK so clearly #HurricaneBeryl is not the same as #HurricaneHarvey. But there are some striking similarities in terms of what has made it so much more persistent than either forecast or as modeled.
This thread is going to look at this issue a bit more deeply.
- The overall cloud mass of the #HurricaneBeryl thunderstorm complex proved much more resilient than expected once it came over land. Why?
- Also Like #Harvey Beryl did slow down after making landfall and continued to spin over land. Why?
- I think the answer to both questions relates to the very warm waters of the Gulf of Mexico. Like Harvey back in 2017, Beryl has been fueled by a constant stream of warm wet atmospheric flows of energy off of the Gulf of Mexico.
- This is obvious in part simply from observing the astonishing expansion of the cloud field after #Beryl made landfall early this morning.
A clue to understanding this can be found in looking at the the astonishing growth progression of #HurricaneBeryl's cloud field over landafter Beryl strengthened and formed itself into a Hurricane in the period after making landfall south of Houston.
Over the course of the rest of the morning you can see in these images how much the wind field expanded.
Like Harvey #Beryl also grew and strengthened itself by feeding off of the gulf of mexico, specifically the area between the Texas coastline and what looks like the outer boundary of the convection field which expanded extremely strongly to the north.
The only source for all this additional atmospheric moisture can be the oceanic convection which took place in what is a fairly clearly bounded 136,000 km2 area of ocean which as you can see in this animation is very closely bound to the rest of the circulation.
This is a much much larger area than the area of active rainfall which settled over the city and metropolis of Houston for the morning and which is finally starting to move off to the north now.
This version of the graphic shows the comparative sizes of the area of water which is responsible for the astonitising growth of post landfall #HurricaneBeryl - and the area of the storm that remained over the ocean and which is almost certainly responsible for both why this storm was so persistent and why it (like Harvey) slowed down after coming ashore.
#HurricaneBerylis not expected to give up lightly as it moves onshore and turns north eastward over Texas and then heads north east across the great planes towards the great lakes.
Typically we expect hurricanes to weaken rapidly over land - especially wind wise. But #Berylis not forecast to behave as normal - probably because like Harvey, its tail over the Gulf is keeping it fueled. - the currently forecast pattern from Fox News's exclusive model shown in these images was present in some of the simulations of Beryl after it crossed the Yucutan a couple of days ago.
To my mind questions ought to be asked about the accuracy of the forecasting for this storm, as - like the last super destructive Texas Hurricane, Harvey in 2017 [] Beryl is proving to be a LOT more destructive in its impacts than initially forecast.en.wikipedia.org/wiki/Hurricane…
The final image in this sequence of screenshots of Fox Weather Graphics is worth drawing attention to as it shows how much broader the impacts of this hurricane are expected to be as it moves across the great planes roughly speaking heading up the Mississippi river, and continuing to dump potential flooding rain as it goes.
This image shows the forecast expected severe weather threat from the remnants of #HurricaneBeryl in Arkansas and Missouri up as far as Saint Louis.
ALERT: High Target News Environment in play - numerous consequential news events with global implications.
1. British elections - (Thursday July 4th-Friday July 5th): Delivering an unprecedented landslide win to the left's @UKLabour Party + strong showings for the Liberals and Greens . The UK Chancellor @RachelReevesMP will shortly set out her economic policy in a speech.
2. French elections (Sunday July 7th) deliver a remarkable 2nd big win for the left in politics in France - dashing the hopes of Marine le Pen's hard right wing "Rassemblement National" of first parliamentary victory
3. Overnight (7th-8th July): an unprecedented huge Hurricane , #Hurricane Beryl - makes landfall in Houston as a Category 1 Hurricane, its main threat to the epicenter of the global fossil fuel industry will be flooding. It is still night in Houston at present.
Hmmmmmm…. Why is the audio of the @youtube version of the UNSG office daily briefing for 1st July missing sound from 5:24 to 6:07?
Afghanistan, Lebanon, Myanmar & other topics - Daily Press Briefing (1 J... via @YouTube
The content of this portion is available as it is simply a quote from written remarks of UNSG @antonioguterres made to a meeting in Austria. But the missing YouTube audio is unprecedented in my experience and hard to explain.