In late July, I wrote the blog post Refreshingly... brisk? An assessment of the unusual weather of summer 2010 in which I looked at the accumulated weather data for the vintage up to that point, and found that it fell most similar to the 1999 and 2005 vintages, both cool years but neither exceptionally so. It was, at that point, quite a bit warmer than 1998, our coolest year on record. My evaluation was that the vintage was a couple of weeks behind, and my (perhaps optimistic) post on veraison a week or so later adjusted that to maybe as little as a week behind normal.
So, why haven't we started harvest yet? And why have we still not completed veraison in mid-September? The answer can be found in comparing the weather since late July with that of past cool years. In 1998, 1999, and 2005, the weather in August and September heated up considerably. Take a look at the degree day chart from July 25th, followed by today's:
You'll note that at Tablas Creek, the average year accumulated about 1000 degree days between July 24th and September 15th. The cooler years were similar, with 1998 accumulating 1148 degree days, 1999 accumulating 840 degree days, and 2005 accumulating 990 degree days. As for 2010, we've added 839 degree days in that period, the least of any year on the chart.
What has kept the temperatures low? Persistent onshore flow, which draws the cool air over the Pacific Ocean inland and moderates the warmth of the sun and the inland valleys. We're in a weather pattern now that feels more like late October than it does like mid-September. It's beautiful during the day (mid-80's, typically) and downright cold at night. Night before last bottomed out at 39 degrees, and last night was only a few degrees warmer.
Are we worried? A bit. The last year that saw a similarly cool August (1999) was a drought year, with very low crop levels. We were never worried about getting our fruit ripe before the rain. The last two wet years (2005 and 2006) saw very warm August/September periods. So, we're in somewhat uncharted territory. But the vineyard looks vibrantly healthy, and the numbers are continuing to move. There is no el nino forecast for this winter, so we're hopeful we won't see unusually early rain. And all the work that we've done in getting the vineyard in good shape this year means that the vines are going to continue to photosynthesize and ripen their grapes later in the season than otherwise. But we're also taking steps to protect ourselves. We've spent the last week or so going through the vineyard thinning out any clusters in Grenache, Counoise and Mourvedre that weren't through veraison. This will lighten the load on the vines and should accelerate the ripening of the remaining clusters.
We have one additional element in our favor. Our location is relatively shielded from ocean influence, despite our position at the far west of the Paso Robles AVA, because of the unbroken height of the Santa Lucia range to our west. The photo below, taken last week looking west from the middle of the vineyard, shows the Santa Lucia Mountains holding back the coastal fog. They keep us sunny even as other parts of coastal California sit in the gloom.
Our best guess at this point is that we'll start to see a little trickling of some whites (Viognier, Vermentino, and Chardonnay) at the end of this week and next week. We're not expecting much in the way of reds before October, and are thinking that we're likely to see only Syrah in the first half of October. The second half of October will be challenging, to say the least. Still, after another week or so of weather more or less what we are seeing now, it's forecast to warm up. Hopefully, the heat will stick around for a while. Fingers crossed, please.