NZ Weather Forum

Rain really starting to pick up in the Chch CBD now.

Starting to increase in intensity here on campus at Lincoln.

I see MS have extended the warning to Rangitata River northwards and now a watch for Canterbury south of the Rangitata.

Its eased again in the CBD. Radar definitely has some shadowing affect happening. The rain has been steady but nothing more than moderate.

Having just said this, tonight looks unbelievable now! 130mm now showing on Metservice projection before midnight with the 3 day maps update!

Interesting looking at the ecan gauges, northern suburbs of ChCh up round 30mm, southern suburbs running from CBD into the Port hills around 10mm or less
https://www.ecan.govt.nz/data/rainfall-data/

Amberley over 70mm (same Wunderground PWS as earlier). Haven't looked outside for a while to check surface conditions.

Chris W wrote: ↑Wed 15/12/2021 11:32 Amberley over 70mm (same Wunderground PWS as earlier). Haven't looked outside for a while to check surface conditions.

Odd, I'm on half of that at 35mm today. Plus a couple from yesterday.

TonyT wrote: ↑Wed 15/12/2021 11:45

Chris W wrote: ↑Wed 15/12/2021 11:32 Amberley over 70mm (same Wunderground PWS as earlier). Haven't looked outside for a while to check surface conditions.

Odd, I'm on half of that at 35mm today. Plus a couple from yesterday.

Certainly would seem an outlier on the Ecan gauges too

TonyT wrote: ↑Wed 15/12/2021 11:45

Chris W wrote: ↑Wed 15/12/2021 11:32 Amberley over 70mm (same Wunderground PWS as earlier). Haven't looked outside for a while to check surface conditions.

Odd, I'm on half of that at 35mm today. Plus a couple from yesterday.

Hmm ok, I did wonder with the PWS but that station is normally reasonably reliable for other metrics. Don't want to exaggerate however!

Edit - the other station has 33mm:

https://www.wunderground.com/dashboard/pws/ICANTERB94

Can see the low starting to form just off the coast from Westport on the radar, just as modelled.

Back home in Ashburton from Hanmer Springs. Lots of surface water here and probably the heaviest rain we encountered for the whole trip. My neighbour said it’s been raining since early this morning and gradually getting heavier.

darcyplumb wrote: ↑Wed 15/12/2021 13:17 Back home in Ashburton from Hanmer Springs. Lots of surface water here and probably the heaviest rain we encountered for the whole trip. My neighbour said it’s been raining since early this morning and gradually getting heavier.

Metservice is projecting 70mm today for you guys and another 40-50 from midnight to noon tomorrow

Definitely some rain shadow going on for southern and western areas of chch. The heavy stuff seems to be hitting land and thinning out as it heads south. I've been out in Rolly all day and it has been light/moderate rain all day. Yet, at home in northwood I have 45mm and counting.

snowchaser01 wrote: ↑Wed 15/12/2021 13:35 Definitely some rain shadow going on for southern and western areas of chch. The heavy stuff seems to be hitting land and thinning out as it heads south. I've been out in Rolly all day and it has been light/moderate rain all day. Yet, at home in northwood I have 45mm and counting.

Just down the road in Lincoln its reasonable heavy at present, has come and gone a bit. I think things aren't due to really intensify til late afternoon

Razor wrote: ↑Wed 15/12/2021 13:19

darcyplumb wrote: ↑Wed 15/12/2021 13:17 Back home in Ashburton from Hanmer Springs. Lots of surface water here and probably the heaviest rain we encountered for the whole trip. My neighbour said it’s been raining since early this morning and gradually getting heavier.

Metservice is projecting 70mm today for you guys and another 40-50 from midnight to noon tomorrow

We’re in trouble if that eventuates.

Razor wrote: ↑Wed 15/12/2021 13:37

snowchaser01 wrote: ↑Wed 15/12/2021 13:35 Definitely some rain shadow going on for southern and western areas of chch. The heavy stuff seems to be hitting land and thinning out as it heads south. I've been out in Rolly all day and it has been light/moderate rain all day. Yet, at home in northwood I have 45mm and counting.

Just down the road in Lincoln its reasonable heavy at present, has come and gone a bit. I think things aren't due to really intensify til late afternoon

Yea, I tend to agree. If the numbers eventuate that MS are hinting at, the city will have some problems by midnight. I believe, they currently have approx 85mm projected between 6pm and midnight!

Does anyone know what the 24 hour rainfall record is for Christchurch City?

JP. wrote: ↑Wed 15/12/2021 13:56 Does anyone know what the 24 hour rainfall record is for Christchurch City?

161.2mm in July 2017 I beleive.. if the stars align tonight we may get close to that.. maybe. But I doubt it

Rain easing a little now in Amberley, skies lighter and drops smaller. Still plenty of them though! 45mm so far.

What was the total in March 2014? Estimations went over 150mm as below, I recall hearing something around 175mm but that may have been Lyttelton:

https://twitter.com/metservice/status/4 ... 8417579008

I don't recall the July 2017 event in any detail.

Chris W wrote: ↑Wed 15/12/2021 14:05 What was the total in March 2014? Estimations went over 150mm as below, I recall hearing something around 175mm but that may have been Lyttelton:

https://twitter.com/metservice/status/4 ... 8417579008

I don't recall the July 2017 event in any detail.

Looks like that 161 was in Oamaru in July 2017... maybe the 2014 event was the chch record?

snowchaser01 wrote: ↑Wed 15/12/2021 14:00

JP. wrote: ↑Wed 15/12/2021 13:56 Does anyone know what the 24 hour rainfall record is for Christchurch City?

161.2mm in July 2017 I beleive.. if the stars align tonight we may get close to that.. maybe. But I doubt it

Think that was 48 hours, or Friday to Sunday. Found this online for that 2017 event

"Christchurch airport weather station recorded 88.6 mm in 24 hours to 22 July. Christchurch normally sees a total of 64.7 mm for the whole of July."

I believe the march 2014 event totals for 24 hours were more or close to the above. Jeffs at Hoon hay had 102mm over 48 hours for the 5th/6th March 2014 event

Chris W wrote: ↑Wed 15/12/2021 14:05 What was the total in March 2014? Estimations went over 150mm as below, I recall hearing something around 175mm but that may have been Lyttelton:

https://twitter.com/metservice/status/4 ... 8417579008

I don't recall the July 2017 event in any detail.

Thread from here for the 2014 event viewtopic.php?t=5160&start=125

And the 2017 one viewtopic.php?t=5692&start=225

You can probably guess its a slow work day here

I remember the March 2014 event well, my parents live just off riverlaw terrace and it was under waist deep water at the end. There is a chance this may produce more for this event tonight. Very worrying