Tasman Low and Ex-TC Donna - May 11-12

Manukau heads obs · Wed 10/05/2017 18:36

GFS bringing the remaining low further west, to be more direct onto the NI now, yes?
now that the LLCC is easier to see, it a bit further west than might have been factored in, and is moving SSE...straight towards the NI
if it deepens as much as some of the models suggest, which it could do , with the strong jet stream and baroclinic zone, then could cause problems!

NZstorm · Unread post by **NZstorm** » Wed 10/05/2017 18:37

European now has the low over Northland 00Z Friday 990hpa.

jamie · Unread post by **jamie** » Wed 10/05/2017 20:37

MetService now showing 130mm for Hamilton!

Manukau heads obs · Thu 11/05/2017 07:44

wow, the heavy rain band currently over the Auckland rain radar suddenly blocks out the signal, making the rain to the west look alot lighter...check out the latest animation

NZstorm · Unread post by **NZstorm** » Thu 11/05/2017 18:15

Looking like severe weather will track across Northland early tomorrow morning and down onto Coromandel and then toward eastern BOP. Torrential rain/possible severe wind gusts/possible thunder.

While Auckland will miss the heaviest precip, a downpour still possible.

spwill · Unread post by **spwill** » Thu 11/05/2017 20:37

I notice the Ak temperature has been slowly rising, currently 18.5C and rather humid. GFS has the dps staying up overnight so a warm night on the way, 17 or 18C min for Auckland.

Numbers in the GFS point to thunder for eastern Northland tomorrow morning. I see there are thunderstorms showing up north of Northland this evening.

jamie · Unread post by **jamie** » Fri 12/05/2017 01:46

Rain at times is near torrential however rain radar shows nothing more than moderate.

Manukau heads obs · Fri 12/05/2017 05:57

sometimes if its very heavy near the rain radar site, it means it cant penetrate (the beam)
51mm here overnight, was very heavy around 11pm

David · Unread post by **David** » Fri 12/05/2017 06:07

Only 42mm here so far - thought we'd get more. Was pretty heavy earlier, had 17mm in an hour.

NZstorm · Unread post by **NZstorm** » Fri 12/05/2017 06:13

Current temp is 19C so it was a warm night.

Manukau heads obs · Fri 12/05/2017 06:18

only 15c here with a southerly wind
more rain moving in

Manukau heads obs · Fri 12/05/2017 06:26

barometer is 1000 hpa here
which makes this low , a bit lower pressure than modelled by this time
and the barometer is dropping steadily
could be some good SE gales develop across central NI/Taranaki

jamie · Unread post by **jamie** » Fri 12/05/2017 06:26

Manukau heads obs wrote:only 15c here with a southerly wind
more rain moving in

Yea the temp plummeted when it went southerly in the night. Dropped a good 5 degrees suddenly.

Nev · Unread post by **Nev** » Fri 12/05/2017 07:13

Just 24mm here in the last 24 hrs so far…

Manukau heads obs · Fri 12/05/2017 07:24

that's a nice active CB east of northland
I wonder if it will impact the BOP/east cape

Manukau heads obs · Fri 12/05/2017 08:08

the BOM (access) model was spot on
thats a real clash of air masses over northland
SSE wind on the west side, with like 14C and NNW wind on the east side, with like 18 or 19C
a good CB line is now moving down the east side of northland
I wonder if that might rotate a bit into auckland as the low center consilidates from its elongated state into more circular

jamie · Unread post by **jamie** » Fri 12/05/2017 08:13

Yea the bom model stuck onto this first and held it. Not often that model gets it so correct and better than the others.

Manukau heads obs · Fri 12/05/2017 08:23

65mm here in total now, heavy rain here currently, looks to stick around here
I see its like 21C at whangarei

David · Unread post by **David** » Fri 12/05/2017 08:26

Some interesting pressure "bumps" here. My station was showing 998.2 hPa at 8:20am, then 5 minutes later 999.6 hPa

Tornado Tim · Unread post by **Tornado Tim** » Fri 12/05/2017 08:35

jamie wrote:
Manukau heads obs wrote:only 15c here with a southerly wind
more rain moving in
Yea the temp plummeted when it went southerly in the night. Dropped a good 5 degrees suddenly.

Certainly did eh, hit just after midnight... Sharp plummit in temperature with wind dropping down to 0 then ramped to 25 k southerly.

Manukau heads obs · Fri 12/05/2017 08:39

Ricky only got that colder air just after 7am
it arrived here like at 11pm last night

Manukau heads obs · Fri 12/05/2017 08:40

Ricky's temp drop ,now that is sudden

NZstorm · Unread post by **NZstorm** » Fri 12/05/2017 08:51

62mm for the event in Grey Lynn.

Manukau heads obs · Fri 12/05/2017 09:43

very heavy bursts of rain here at times

jamie · Unread post by **jamie** » Fri 12/05/2017 09:52

Rain coming down at 10mm/hr at the moment. Amazing that we have only had 32mm from the event yet the puddles look like double that. The ground simply cant take the water.

NZ Weather Forum