Eddie Byrom's unbeaten half-century led Somerset's response after a strong start from Essex on a rain-affected opening day of the Bob Willis Trophy final at Lord's.
Somerset reached 119 for four as just 44 overs were possible at the home of cricket due to rain.
Byrom's 51 not out prevented an outright collapse from the Taunton side, but reigning county champions Essex made some handy inroads in between the showers.
Sam Cook took two for 38 across 18 polished overs, while Jamie Porter and Aaron Beard claimed one apiece.
Essex skipper Tom Westley won the toss and opted to let his bowlers loose, a decision which paid almost immediate dividends.
Cook landed the first blow of the match before a run had been scored to dismiss Tom Lammonby.
Tom Abell then departed for 19 when wicketkeeper Adam Wheater took a brilliant diving catch down the leg-side off the bowling of Beard.
Porter vacated the Pavilion End to allow Cook's return and he duly ended Ben Green's innings for 24 after 66 balls of resistance.
Byrom accelerated just before lunch with four boundaries in the space of eight deliveries - including three off Beard as his line strayed - in the process overtaking his previous best of the season, a modest 30.
The teams took lunch at 90 for three, but neither were able to progress considerably as their attempts to complete the day's play were frustrated by further rain and two mini-sessions.
The first of those saw Essex reassert control, Porter and Cook stitching together six successive maidens - successfully getting to the end of George Bartlett's patience as he drove at Porter and nicked to Alastair Cook at slip.
Byrom's concentration continued, allowing him to reach his fifty just before the day was abandoned, with Steve Davies in support on 13 not out.