Californian wine harvests: on the lookout for Modoki flavouring of the emerging El Nino
Spring showers bring little relief
Spring showers provided temporary relief to the drought in California and enabled the Department of Water Resources to increase the allocation of State Water Project water for agricultural users from zero to 5% of amounts requested on April 18th (compared to 57.5% average over the last 4 years). But it does little to change the overall situation:
- 2013 was a record dry year in 9 of the 11 counties (records date back to 1895)
- state snowpack sits at 18% of average as at May 1st
- and there is discussion of reverse aqueduct flow (done previously in 1983 during extreme wet)
Hope in the emerging El Nino
With this backdrop it’s no surprise that all eyes are on the forecasts of an emerging El Nino (see Figure 1), since El Nino has been linked to a damp Californian winter: there are headlines based on this currently.
Flavours of El Nino: Modoki or normal?
As is often the case with the weather, the devil is in the detail. The latest focus is on where in the equatorial Pacific the sea surface warming occurs:
- anomalous warm water in the eastern equatorial Pacific is a normal flavour El Nino
- anomalous warm water in the central equatorial Pacific, with anomalous cool water in the eastern Pacific, is a Modoki El Nino
Looking at the evolution of sea surface temperatures over the last year shown in Figure 2, we can see that the largest anomaly is in the Nino 4 region in the central equatorial Pacific. [Nino 3.4 values are used as standard, eg in Figure 1 above.]
The subsurface water temperatures indicate that this may change as we move into summer: the question is will it be enough to shift the likely outcome from a Modoki El Nino to a normal El Nino? The latest El-Nino Modoki index (EMI) forecast reflects this uncertainty, as shown in Figure 3.
Insights or red herrings?
There are many ways to look for clues in history. MEI (Mulitvariate ENSO Index) analogs to this year, as of the May 7th 2014 update, are 1961 (a La Nina year) and the El Nino years of 1986, 2002 and 2006 – all of which were Modoki flavoured. Whether this is an insight or a red herring, time will tell! While we wait, expect more on the discussion of whether this El Nino will be Modoki flavoured: implications are not limited just to Californians and wine drinkers but extend to US crop harvests, tropical cyclones (Atlantic and Pacific) & more.