As I sit here drinking my coffee and looking out at the fog, I am pondering the fact that everything looks wet and gloomy out there but really we might be headed for a drought if weather patterns don’t change soon. Well. maybe I will get lucky and the sun will come out up here in the Eola-Amity Hills!
However, the fog versus sun doesn’t change the fact that right now we are headed toward drought across much of the Pacific Northwest, California and the Southwest if we don’t move out of this powerful, persistent ridge of upper-level high pressure has prevailed off the U.S. West Coast for more than a year now. This pattern—the strongest and longest-lasting of its type in decades, according to meteorologist/blogger Daniel Swain.
California declared the state in a drought emergency on January 17th. California has broken rainfall records going back to 1849 in the San Francisco area. Oregon has yet to declare a drought although this could happen soon if we don’t receive more rain in the rest of the water year.
For clarity, it is important to understand the difference between discussions on the water year versus the calendar year. The water year runs from October to October. We are in effect about half way through the water year even though we are only about 1 month into 2014. While we had a record 6 inches of rain or so in September during the winegrape harvest, this was part of last year’s water year.
At the Aurora Agrimet agricultural weather network, it shows only 6.49 inches or rain in the water year to date while the average is 25.23 through January. The next couple weeks look like we will stay in this high pressure ridge as described in the Fox 12 Weather Blog. The question is will we move out of this high pressure ridge quick enough or are we likely to end up in drought conditions.
In comparing water year data to date from the Aurora Agrimet going back 10 years, the closest year in dryness was 2004-05 where there were 13.38 inches of rain. This is still double where were are now. In 2004-05, by June the valley had received around 30 inches of rain. We will need to have a wet spring to make to fill the soil profile with moisture prior to budbreak. In my memory, it does seem that we often have a wet late spring following a dry winter but we are in a serious deficit right now so we will have to keep a close eye on precipitation the next few months.
What does this mean for the next couple weeks; great weather to get your winter pruning done in the vineyards while it is not raining but there is plenty of humidity from the fog to tie the fruiting canes down without breaking them.