Thunder and lightning began cracking over heard, before the rain and hail started.
"The gutters started overflowing," she said, "and the stormwater was coming up in fountains.
"There was surface flooding across Porangahau rd...and Ruataniwha Rd."
The weather meant cars on State Highway 2 had "slowed to a crawl".
After about 40 minutes, she said the storm stopped completely and the sun came out.
Although they were not able to get a gauge on how much rain had fallen so far, Ms Moes said the rainfall rates associated with these kinds of storms were quite high.
Ms Moes said it was expected that the risk would die away in the next few hours, easing before 10pm this evening.
"We're expecting high cloud and scattered areas of rain for the rest of the region, but nothing on this scale," she said.
There were currently no weather warnings, or watches issued for Hawke's Bay.
A MetService report issued this morning forecast isolated showers south of Hastings, possibly heavy and thundery, clearing this evening, with northerlies, dying out tonight.
In CHB, temperatures reached a high of 18C today, and a low of 6C.