Past IEM Features tagged: elnino
NOAA recently released their winter season forecast. For Iowa, the forecast called for about average temperatures and slightly above normal precipitation. One of the many tools used to make this forecast is the current and forecasted El Nino index. The La Nina conditions have taken a bit longer than expected to develop and the index currently still has a ways to go before getting to La Nina state. Anyway, the featured plot combines the El Nino index along with three month averaged temperatures and precipitation. The two right hand side plots provide the direct comparison and a simple linear fit. Of course, there is no magic bullet here with strong correlations to predict the upcoming winter season. The weather forecast though is more definite over the near term with chances of snow arriving for the weekend!
Much is currently being made about the very strong El Nino, which some have labelled as a "Godzilla El Nino". The concern is the impact of this on our upcoming winter season. The relationship between Iowa's weather and the El Nino is not simple as it takes time for its effects to be felt, if at all. The featured chart displays a monthly time series of El Nino 3.4 index and average Iowa monthly temperature departures. The current El Nino is the strongest since 1997.
The strengthening El Niño over the Pacific Ocean is currently generating many headlines as the current forecasts have the strength reaching levels not seen before since records began in 1950. In fact, one forecaster referred to this situation as a "Godzilla El Niño." The featured chart looks at the combination of August Southern Oscillation Index (SOI) and September plus October average temperature and total precipitation for Iowa. The color of the dots represent the SOI index. The relationship shown is not clear cut. You can generate this chart online and compare the SOI value from some number of trailing months to a summary number of months of your choice.
The featured chart displays the combination of recent monthly precipitation departures for Ames along with the monthly El Nino 3.4 index value. Many scientists believe that the El Nino index, which determines if we are in La Nina or El Nino condition, is correlated with longer timescale temperature and precipitation in the United States and elsewhere. The chart nicely shows the drought periods of the past two years and the wet periods of 2008 and 2010. This October looks to turn wet for the rest of the week with showers arriving late this evening.