Waiuku heavy rain episode last monday

[Manukau heads obs]

18th july, between 7am and 10am
see the rain graph here:


59mm total for the whole episode,but things were already wet before that rain (10mm overnight, and more the day before), and it was the last hour was very heavy (44mm between 8am and 9am )
(see the steepness of the graph)
the rain total was reset at 9am

there was lots of flash flooding in Waiuku, with one business having the water up to the roof tops of the parked cars!

[NZstorm]

Wow, fair drop of rain.

Looks like there was a weak front crossing the region that morning. However, I would say it was more of a convergence zone between a surface NE and a westerly change. The observed lifted index on the NZWP sounding was -1.8, which is quite unstable for July. Surface dewpoints were around 13C, which again, were on the high side for mid winter.

[spwill]

there was lots of flash flooding in Waiuku,

TV ONE showed clips of the flooding on the Mon Evening.
Could see the cloud tops from here, photo below was of that very Cb line later in the morning as it moved over Ak but it weakened as it moved E/ NE.

[Manukau heads obs]

i was away, so i just got to see and analyze the rain data records today