Sam Northeast was the main man for Hampshire as Surrey continue to chase wickets to keep the first innings lead to a minimum at Arundel.
Stand-in captain Northeast looked serene for his second Bob Willis Trophy fifty as he reached 81, following a 121-run stand with third-wicket partner Tom Alsop, who ended the day unbeaten on 52.
Surrey had earlier been bowled out for 172 and ended day three in arrears of 26, as Hampshire reached 198 for three.
Following two days where a combined 40 overs were able to be bowled due to rain, both sides were further frustrated by a wet outfield, particularly the run-up areas, which prevented any play in the morning session.
Blue skies, punctuated by the odd non-threatening cloud, created a postcard-ready vista at the ever-pleasant Arundel Castle Ground – where Hampshire are playing their home red ball matches this season due to England’s use of the Ageas Bowl – when the action finally arrived.
Hampshire needed two Surrey wickets, but were forced to wait as Morne Morkel wielded his bat for some vital tailender runs.
The South African, who flew in from Australia last week to join up with Surrey, battered seven boundaries in his thumping 33 from 25 balls.
Leg spinner Mason Crane put an end to the fun though when he pinned him lbw, before rounding off the innings by having Amar Virdi stumped by a lightning-quick Lewis McManus.
Hampshire opener Felix Organ was lucky to survive a fiery opening over from former South Africa international Morkel.
Morkel found bounce to take the 22-year-old’s outside edge, but Ryan Patel shelled the chance to his right at second slip.
Organ smoked two boundaries on the drive off Matt Dunn, but fell when he was bowled leaving a Gus Atkinson in-ducker.
In form Weatherley, who scored 98 and 64 not out in the victory over Middlesex last week, started slowly but took a particular shine to Patel – who he eased to three boundaries.
He looked on course to repeat his heroics at Radlett but fell lbw to Virdi on the cusp of tea.
When Northeast was left out of England’s 55-man training squad earlier this summer he bemoaned a lack of opportunity to prove the selectors wrong.
Northeast’s classy array of backfoot drives, legside flicks and dabs down to third man were all on show and proved a man in form.
He needed 82 balls to reach a chanceless half-century, on a ground he scored a century on his only previous appearance – in a Second XI fixture for Kent against Sussex in 2012.
While Northeast played shot-maker, Alsop sat like a sentinel at the other end.
The left-hander had only scored eight in the 50-run stand with Weatherley, and provided a similar backbone for Northeast.
Alsop has been given the opportunity to make the No.3 spot his own for the long-term this season, having seen McManus become first-choice wicketkeeper over the last 12 months.
The trust in his batting has returned starts of 21 and 27 so far in the Bob Willis Trophy, but he kicked on to reach a gritty 128 ball 50.
He lost Northeast was lbw to one which kept low from Virdi, who had switched from the Park to the Castle End.