By Lenn Thompson, Executive Editor

A month ago, Hurricane Earl threatened East End vineyards with its high winds and rain — only to pass off to the east and have little impact on developing grapes.

Now, an un-named line of storms is threatening to drop several inches of rain on local vineyards and bring wind gusts of up to 60 mph.

Most of the white wine and sparkling wine grapes have been picked. As have most of the grapes intended for rose production, so those wines won't be affected by this storm system, but 2010 red wines could be. That portion of harvest was really just getting under way, and will now pause as wineries keep one eye on their vines and the other on weather reports.

There's no doubt that they will also be thinking a bit 2005 when 20 inches of rain flooded some vineyards over the course of a week. 2005 was a great summer for growing and ripening grapes. 2010 has been even better, but storms like this serve as reminders that a vintage can't be deemed great until all of the fruit is in the winery.

So far, the East End hasn't received much rain according to the growers I've heard from this morning. Rich Pisacano of Wolffer Estate and Roanoke Vineyards reported "Less than 1/4 inch" earlier this morning and I just received an email from The Old Field Vineyards' Roz Baiz reporting only "trace amounts" of rain.

That's obviously good news — as is the fact that more than a quarter of the string of storms has come and gone. Local wineries aren't out of the woods yet though. "If this trend continues we just may dodge another bullet," said David Page from Shinn Estate Vineyards, adding "That is not a prediction. Call it a prayer. Farming is faith based."

Just how much rain a vineyard can absorb before it becomes a problem varies from site to site as well, with Page telling me via email that "volume will become important after the first 2-3 inches." Baiz thinks her vineyard can handle more "The soils are veyr dry. we can probably handle another 4-6" without having flooding issues. The water table is down 26-30" due to the summer's drought."  

Rain is only one of the threats this storm poses. High winds can cause the netting placed over vines to keep birds and other wildlife from eating the ripe berries to scrape or even cut the clusters. Combine that damage with wet, warm conditions and disease pressure builds.

Noting the impact that temperature can have during these types of storms, Paumanok Vineyards' Charles Massoud explains "The bigger problem is temperature. Rain seeps into the subsoil quickly especially after the prolonged dought. However the warmer it is, the more active the photosynthesis, the more the vine perspires, the more water is pulled from the soil and could potentially endanger the fruit."

Luckily, cooler temperatures slow all that down. Today's cloud cover and tomorrow's predicted high of 69 degrees should show photosynthesis enough to mitigate berry damage.

With her bayside vineyards site, Baiz has one other concern — salt. Big enough winds coming from the right direction can bring saltwater spray from the bay, which would scald the canopy and ruin the grapes.  

Saturday morning will be a busy — and important — one. That's when vineyard managers and winemakers will really be able to assess any damage. Positive thinking abounds — becuase it has to — with Rich Olsen-Harbich, winemaker at Bedell Cellars saying "The canopy and the fruit are in perfect shape so they will weather this small event just fine."

Let's hope that he's right.

Note: As updates and further reports come in, I'll add them to the comments.