La Nina May Be Back

The Climate Prediction Center has issued it's latest ENSO diagnostic discussion.  A month ago, it was unclear if we would see a return of La Nina or ENSO neutral conditions during the coming winter.  It now appears that La Nina conditions are returning and are expected to strengthen for the winter.

See the ENSO diagnostic discussion at the link above for a full discussion.  It is interesting that many of the models used to predict ENSO are calling for ENSO-neutral conditions, but the Climate Prediction Center is going for a return of La Nina because that is what is predicted by the NCEP Climate Forecast System, which they feel is a stronger predictive tool, and because of a historical tendency for strong La Nina events to be followed by weaker La Nina events.  The strength of the La Nina, however, remains unclear.

As we have discussed previously, the development of a La Nina doesn't really tell us much about what to expect in the Wasatch Mountains during the coming winter.  Snowfall and temperature in northern Utah simply don't correlate well with La Nina.  This is reflected in the 3-month precipitation outlook for DJF, which shows equal chances for above, near-average, or below average precipitation over the northern Utah.