By Lenn Thompson, Executive Editor

Before-after There is some rain in the forecast later this week, but we're in the midst of a week-long string of sunny, dry days — conditions that were and are direly needed to keep disease pressure at bay in local vineyards and help grapes mature and ripen.

Before the sun came out late last week, many local vineyards — including Clovis Point — were working to thin red wine crops, hoping that the reduced crop load will ripen more fully.

According to Hal Ginsburg, managing partner at Clovis Point, the vineyard crew there dropped more than half of their merlot clusters to the ground (top picture is before thinning, the bottom picture after).

"Tonnage per acre before was around 4.5 tons per acre. Now, we are at less than 2 tons," he told me in an email.

In addition to being behind on ripening, disease pressure is high this year. Mostly rainy, cool weather over the last month has helped botrytis and sour rot establish themselves in local vineyards.

Merlot is sensitive to sour rot, something Ginsburg calls "especially worrisome," adding "So far, however, the merlot at Clovis is clean and ripening well, but slowly."

This brief Indian Summer could make all the difference with 2011 red wines.

I'm hoping to get some detailed updates from local growers later this week.