The National Oceanic and Atmospheric Administration (NOAA) today released their updated three month outlook, forecasting general temperature and precipitation trends over the next three months into the summer of 2019. The summertime outlook is generally a warm and wet one, with the west and east coasts likely to see above normal temperature readings while much of the entire country will see at or above normal precipitation. In the update, Alaska is expected to see the best odds for above normal temperatures this summer while also seeing above normal precipitation. The same is true in Hawaii; NOAA says higher than usual ocean temperatures around the Aloha State should translate to above normal temperatures and precipitation across much of the islands.
The June – July – August 2019 temperature outlook indicates that above normal seasonal mean temperatures are most likely for the eastern and western thirds of the US, including Alaska. Below normal seasonal mean temperatures are more likely for parts of the Central Plains. The precipitation outlook indicates that above normal seasonal total precipitation is most likely for much of the US, including the interior West across much of the Great Plains into the Central Mississippi and Ohio Valleys, stretching to the Mid-Atlantic coast. The greatest probabilities for above normal seasonal total precipitation are for areas of the Central Rockies. Below normal precipitation is more likely for a small area of the Pacific Northwest near the coast as well as southern Arizona. Above normal precipitation is more likely for most of Alaska. Incorporated into NOAA’s analysis are the combined impacts of soil moisture, trends , and the phenomena known as El Nino / Southern Oscillation, or ENSO for short.
In their graphical outlook, NOAA also has “EC” areas. “EC” stands for Equal Chances where the likelihoods for temperatures and precipitation to be near normal exist. As an example, areas that are typically wet or dry or cold or warm during the summer should expect to see more of those same conditions.
According to NOAA, the temperature and precipitation outlooks were based primarily on dynamical model guidance from the North American Multi-Model Ensemble forecast system (NMME), along with statistical model guidance, including a statistical forecast of the linear impacts of ENSO combined with decadal climate trends based on the National Weather Service’s Climate Prediction Center’s El Nino forecasts. The potential impact from a possible continuation of El Nino conditions were considered for the seasonal outlook period through next winter 2019-2020. Soil moisture conditions were strongly considered along with near-coastal sea surface temperature anomalies. Several statistical and dynamical models , as well as hybrid statistical-dynamical models, along with an objective consolidation of several forecast tools, were also examined in preparation of the seasonal outlooks.