Thursday, September 17, 2015

El Niño Forecast for Utah


This winter is very likely going to be a El Niño winter, possibly one of the strongest on record. See the below map for precipitation anomalies during a typical 
El Niño winter. Go to https://www.climate.gov/news-features/blogs/enso/united-states-el-ni%C3%B1o-impacts-0 to see the general North America El Niño winter impact. In general weak/moderate El Niño's have no statistical impact on the Wasatch Front and northern Utah weather, slight increase towards a wet winter in Southern Utah. A strong El Niño like the one forecasted this winter do slightly increase the chance of above normal precipitation for the Wasatch Front and Northern Utah, greatly increases the chances for a wet winter in southern Utah. The last 5 strong El Niño events were 1957-1958, 1965-1966, 1972-1973, 1982-1983, and 1997-1998. In these years the Alta UDOT November through April snowfall averaged 554" which is above the long term average of 490". Not a big increase for Alta but it should be noted that many of the storms during a El Niño years come from the south which is typically not good for the Cottonwoods, much better for Sundance/Park City areas and other areas that do well in a southerly flow.



For this winter plan on 80-90% of normal for the northern Wasatch, 90-100% for the central Wasatch, 100-110% of normal for the southern Wasatch, 110-120% for central Utah, 120%+ for southern and southeastern Utah. 

October Outlook

Plan on above normal temperatures for all of Utah with above normal precipitation for the southeast areas.