Winter 2018-2019 Outlook for the Local Area

National Outlook:

For the upcoming 2018-2019 winter, NOAA's Climate Prediction Center (CPC) temperature forecasts for the most part reflect typical weak El Niño temperature anomalies in the United States.  This includes:

• Warmer-than-normal conditions being favored across the western half of the United States, from the Upper Mississippi River Valley east into New England, and in Alaska.
   
• Equal Chances of Warmer-, Near-, and Colder-than-Normal from the Ohio and Tennessee river valleys south to the Gulf Coast.

Local Outlook:

Locally, the odds are tilted slightly to warmer-than-normal for northeast Iowa, southeast Minnesota, and western Wisconsin. 

• Since 1980, there has been a shift in weak El Niños toward warmer.  All 6 of these winters were either near- or warmer-than-normal.  The strongest signal for warmer-than-normal has been in December.  Meanwhile, February has had a tendency of being colder-than-normal.
   
• In addition, most of the climate models favor warmer-than-normal conditions for the area.
   
• However, over the past 15 years, there has not been a trend for either warmer-than-normal or colder-than-normal winter temperatures in our area.  In addition, other climate signals can overwhelm weak El Niños, so this decreases the confidence.  

While temperature impacts associated with El Niño are favored, El Niño is not the only player this winter, so the temperatures could be highly variable throughout the winter.  This is often the case with weak El Niños.  Since the winter of 1949-50, there have been 12 weak El Niño winters.  In those winters:

• La Crosse WI:  The winter average temperature varied from 11.5°F (1977-78) to 24.5°F (1953-54).  The winter normal is 20.5°F. 
   
• Rochester MN:   The winter average temperature has varied from  8.7°F (1977-78) to 21.7°F (1953-54).  The winter normal is 18.5°F.

National Outlook:

For the upcoming 2018-2019 winter, NOAA's Climate Prediction Center (CPC) precipitation forecasts for the most part reflect typical El Niño precipitation anomalies in the United States.  This includes: 

• Wetter-than-normal conditions being favored across much of the southern and eastern United States, and parts of Alaska.  
   
• Drier-than-normal conditions being favored in the Great Lakes and from Idaho east into the western Dakotas.  

Local Outlook:

Locally the forecast for southeast Minnesota, northeast Iowa, and western Wisconsin is for equal chances of wetter-, near, and drier-than-normal. This forecast was based upon the following:

• While there has been a tendency toward dry during weak El Niños (8 out of 12 were drier-than-normal at both La Crosse, WI & Rochester, MN), there has been a wet trend (more similar to a La Niña) over the past 15 winters (11 out of 15 have been wetter-than-normal at both La Crosse, WI & Rochester, MN) in the Upper Mississippi River Valley.

During the 12 weak El Niño winters since 1949-50...

• La Crosse, WI:  The winter precipitation total has varied from 1.45" (2002-03) to 4.66" (2006-07).  The winter normal is 3.53".
   
• Rochester, MN:  The winter precipitation total has varied from 1.52" (2002-03) to 4.22" (2006-07).  The winter normal is 2.92".

Snow storms will likely occur at times this winter.  However, the frequency, number, and intensity of these events cannot be predicted on a seasonal timescale.  

Locally, there has been a tendency for below-normal winter (December through February) snowfall during weak El Niños.  However, the seasonal snowfall totals are a totally different story.  During these 12 weak El Niños, there have been 6 snow seasons with below-normal snowfall and 6 snow seasons with above-normal snowfall.  

During the 12 weak El Niño winters since 1949-50...

• La Crosse, WI:  The seasonal snowfall total has varied from 18.8" (1953-54) to 78.3" (1958-59).  The snow season normal is 43.3".
   
• Rochester, MN:  The seasonal snowfall total has varied from 24.8" (1953-54) to 73.6" (1951-52).  The snow season normal is 51.9".