My two cents worth.
..During this time of year, El Nino, or Winter, forecasts are still in what’s considered the Unpredictability period. Late Fall, is when the Forecasts really begin to hone in on what the upcoming Winter will likely bring. This year there are several abnormalities to be considered in the long range outlook. A couple of examples are pictured below.
.. First off, the SST’s are 1.8c warmer than normal for the ENSO 3.4 Region. This is where the El Nino Forecasts are derived from for the West Coast of California. This year we are in what’s considered to be an El Nino State of the Ocean. Sea Surface Temperatures (SST’s) in the Equatorial Region 3.4, are running well above normal, for this time of year. Thus a strong, to very strong El Nino forecast for our area is the current outlook. However, there are other factors that come into play that are making this El Nino outlook more difficult than normal. SST’s are warmer than normal in many other areas other than the ENSO 3.4 Region. So this will all have a part in the final outcome for this year’s Winter events. The medium range outlook as of today calls for a wet period through the end of November. Then as we head into January, through March, the current outlook is trending towards wetter than normal for Central and SoCal.
..One of the many features we will be looking for is a resident area of Low pressure sitting off of the coast of Alaska. This will help to direct the Jet stream towards Central and Southern California, later this Winter. The Southern part of the Polar Jet will also be directed more to the Southern part of the State helping to bring warm and moist storms to our area. This can also be a recipe for heavy Spring snows for our local area. Typically during an El Nino year, the freezing levels run higher than normal through the Winter months. But as we transition to Spring, cold air from the North can make it’s way South and mix with the wet moist Tropical air mass, and we get heavy wet snow locally during March.
..So as we head into the month of november, things should become a little more clear as far as what to expect. Long Range Forecasting is like dropping a plastic ball in a pool, and trying to figure out where it will be tomorrow. RC